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go/src/runtime/asm_arm.s

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "zasm_GOOS_GOARCH.h"
#include "funcdata.h"
#include "textflag.h"
// using frame size $-4 means do not save LR on stack.
TEXT runtime·rt0_go(SB),NOSPLIT,$-4
MOVW $0xcafebabe, R12
// copy arguments forward on an even stack
// use R13 instead of SP to avoid linker rewriting the offsets
MOVW 0(R13), R0 // argc
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
MOVW 4(R13), R1 // argv
ld: detect stack overflow due to NOSPLIT Fix problems found. On amd64, various library routines had bigger stack frames than expected, because large function calls had been added. runtime.assertI2T: nosplit stack overflow 120 assumed on entry to runtime.assertI2T 8 after runtime.assertI2T uses 112 0 on entry to runtime.newTypeAssertionError -8 on entry to runtime.morestack01 runtime.assertE2E: nosplit stack overflow 120 assumed on entry to runtime.assertE2E 16 after runtime.assertE2E uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.assertE2T: nosplit stack overflow 120 assumed on entry to runtime.assertE2T 16 after runtime.assertE2T uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.newselect: nosplit stack overflow 120 assumed on entry to runtime.newselect 56 after runtime.newselect uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectdefault: nosplit stack overflow 120 assumed on entry to runtime.selectdefault 56 after runtime.selectdefault uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectgo: nosplit stack overflow 120 assumed on entry to runtime.selectgo 0 after runtime.selectgo uses 120 -8 on entry to runtime.gosched On arm, 5c was tagging functions NOSPLIT that should not have been, like the recursive function printpanics: printpanics: nosplit stack overflow 124 assumed on entry to printpanics 112 after printpanics uses 12 108 on entry to printpanics 96 after printpanics uses 12 92 on entry to printpanics 80 after printpanics uses 12 76 on entry to printpanics 64 after printpanics uses 12 60 on entry to printpanics 48 after printpanics uses 12 44 on entry to printpanics 32 after printpanics uses 12 28 on entry to printpanics 16 after printpanics uses 12 12 on entry to printpanics 0 after printpanics uses 12 -4 on entry to printpanics R=r, r2 CC=golang-dev https://golang.org/cl/4188061
2011-02-22 15:40:40 -07:00
SUB $64, R13 // plenty of scratch
AND $~7, R13
ld: detect stack overflow due to NOSPLIT Fix problems found. On amd64, various library routines had bigger stack frames than expected, because large function calls had been added. runtime.assertI2T: nosplit stack overflow 120 assumed on entry to runtime.assertI2T 8 after runtime.assertI2T uses 112 0 on entry to runtime.newTypeAssertionError -8 on entry to runtime.morestack01 runtime.assertE2E: nosplit stack overflow 120 assumed on entry to runtime.assertE2E 16 after runtime.assertE2E uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.assertE2T: nosplit stack overflow 120 assumed on entry to runtime.assertE2T 16 after runtime.assertE2T uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.newselect: nosplit stack overflow 120 assumed on entry to runtime.newselect 56 after runtime.newselect uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectdefault: nosplit stack overflow 120 assumed on entry to runtime.selectdefault 56 after runtime.selectdefault uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectgo: nosplit stack overflow 120 assumed on entry to runtime.selectgo 0 after runtime.selectgo uses 120 -8 on entry to runtime.gosched On arm, 5c was tagging functions NOSPLIT that should not have been, like the recursive function printpanics: printpanics: nosplit stack overflow 124 assumed on entry to printpanics 112 after printpanics uses 12 108 on entry to printpanics 96 after printpanics uses 12 92 on entry to printpanics 80 after printpanics uses 12 76 on entry to printpanics 64 after printpanics uses 12 60 on entry to printpanics 48 after printpanics uses 12 44 on entry to printpanics 32 after printpanics uses 12 28 on entry to printpanics 16 after printpanics uses 12 12 on entry to printpanics 0 after printpanics uses 12 -4 on entry to printpanics R=r, r2 CC=golang-dev https://golang.org/cl/4188061
2011-02-22 15:40:40 -07:00
MOVW R0, 60(R13) // save argc, argv away
MOVW R1, 64(R13)
2014-06-26 09:54:39 -06:00
// set up g register
// g is R10
MOVW $runtime·g0(SB), g
2014-06-26 09:54:39 -06:00
MOVW $runtime·m0(SB), R8
// save m->g0 = g0
2014-06-26 09:54:39 -06:00
MOVW g, m_g0(R8)
// save g->m = m0
MOVW R8, g_m(g)
// create istack out of the OS stack
MOVW $(-8192+104)(R13), R0
MOVW R0, g_stackguard0(g)
MOVW R0, g_stackguard1(g)
MOVW R0, (g_stack+stack_lo)(g)
MOVW R13, (g_stack+stack_hi)(g)
BL runtime·emptyfunc(SB) // fault if stack check is wrong
#ifndef GOOS_nacl
// if there is an _cgo_init, call it.
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
MOVW _cgo_init(SB), R4
CMP $0, R4
B.EQ nocgo
MRC 15, 0, R0, C13, C0, 3 // load TLS base pointer
MOVW R0, R3 // arg 3: TLS base pointer
MOVW $runtime·tlsg(SB), R2 // arg 2: tlsg
MOVW $setg_gcc<>(SB), R1 // arg 1: setg
MOVW g, R0 // arg 0: G
BL (R4) // will clobber R0-R3
#endif
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
nocgo:
// update stackguard after _cgo_init
MOVW (g_stack+stack_lo)(g), R0
ADD $const_StackGuard, R0
MOVW R0, g_stackguard0(g)
MOVW R0, g_stackguard1(g)
BL runtime·checkgoarm(SB)
BL runtime·check(SB)
// saved argc, argv
ld: detect stack overflow due to NOSPLIT Fix problems found. On amd64, various library routines had bigger stack frames than expected, because large function calls had been added. runtime.assertI2T: nosplit stack overflow 120 assumed on entry to runtime.assertI2T 8 after runtime.assertI2T uses 112 0 on entry to runtime.newTypeAssertionError -8 on entry to runtime.morestack01 runtime.assertE2E: nosplit stack overflow 120 assumed on entry to runtime.assertE2E 16 after runtime.assertE2E uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.assertE2T: nosplit stack overflow 120 assumed on entry to runtime.assertE2T 16 after runtime.assertE2T uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.newselect: nosplit stack overflow 120 assumed on entry to runtime.newselect 56 after runtime.newselect uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectdefault: nosplit stack overflow 120 assumed on entry to runtime.selectdefault 56 after runtime.selectdefault uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectgo: nosplit stack overflow 120 assumed on entry to runtime.selectgo 0 after runtime.selectgo uses 120 -8 on entry to runtime.gosched On arm, 5c was tagging functions NOSPLIT that should not have been, like the recursive function printpanics: printpanics: nosplit stack overflow 124 assumed on entry to printpanics 112 after printpanics uses 12 108 on entry to printpanics 96 after printpanics uses 12 92 on entry to printpanics 80 after printpanics uses 12 76 on entry to printpanics 64 after printpanics uses 12 60 on entry to printpanics 48 after printpanics uses 12 44 on entry to printpanics 32 after printpanics uses 12 28 on entry to printpanics 16 after printpanics uses 12 12 on entry to printpanics 0 after printpanics uses 12 -4 on entry to printpanics R=r, r2 CC=golang-dev https://golang.org/cl/4188061
2011-02-22 15:40:40 -07:00
MOVW 60(R13), R0
MOVW R0, 4(R13)
ld: detect stack overflow due to NOSPLIT Fix problems found. On amd64, various library routines had bigger stack frames than expected, because large function calls had been added. runtime.assertI2T: nosplit stack overflow 120 assumed on entry to runtime.assertI2T 8 after runtime.assertI2T uses 112 0 on entry to runtime.newTypeAssertionError -8 on entry to runtime.morestack01 runtime.assertE2E: nosplit stack overflow 120 assumed on entry to runtime.assertE2E 16 after runtime.assertE2E uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.assertE2T: nosplit stack overflow 120 assumed on entry to runtime.assertE2T 16 after runtime.assertE2T uses 104 8 on entry to runtime.panic 0 on entry to runtime.morestack16 -8 after runtime.morestack16 uses 8 runtime.newselect: nosplit stack overflow 120 assumed on entry to runtime.newselect 56 after runtime.newselect uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectdefault: nosplit stack overflow 120 assumed on entry to runtime.selectdefault 56 after runtime.selectdefault uses 64 48 on entry to runtime.printf 8 after runtime.printf uses 40 0 on entry to vprintf -8 on entry to runtime.morestack16 runtime.selectgo: nosplit stack overflow 120 assumed on entry to runtime.selectgo 0 after runtime.selectgo uses 120 -8 on entry to runtime.gosched On arm, 5c was tagging functions NOSPLIT that should not have been, like the recursive function printpanics: printpanics: nosplit stack overflow 124 assumed on entry to printpanics 112 after printpanics uses 12 108 on entry to printpanics 96 after printpanics uses 12 92 on entry to printpanics 80 after printpanics uses 12 76 on entry to printpanics 64 after printpanics uses 12 60 on entry to printpanics 48 after printpanics uses 12 44 on entry to printpanics 32 after printpanics uses 12 28 on entry to printpanics 16 after printpanics uses 12 12 on entry to printpanics 0 after printpanics uses 12 -4 on entry to printpanics R=r, r2 CC=golang-dev https://golang.org/cl/4188061
2011-02-22 15:40:40 -07:00
MOVW 64(R13), R1
MOVW R1, 8(R13)
BL runtime·args(SB)
BL runtime·osinit(SB)
BL runtime·schedinit(SB)
// create a new goroutine to start program
MOVW $runtime·main·f(SB), R0
MOVW.W R0, -4(R13)
MOVW $8, R0
MOVW.W R0, -4(R13)
MOVW $0, R0
MOVW.W R0, -4(R13) // push $0 as guard
BL runtime·newproc(SB)
MOVW $12(R13), R13 // pop args and LR
// start this M
BL runtime·mstart(SB)
MOVW $1234, R0
MOVW $1000, R1
MOVW R0, (R1) // fail hard
DATA runtime·main·f+0(SB)/4,$runtime·main(SB)
GLOBL runtime·main·f(SB),RODATA,$4
TEXT runtime·breakpoint(SB),NOSPLIT,$0-0
// gdb won't skip this breakpoint instruction automatically,
// so you must manually "set $pc+=4" to skip it and continue.
#ifdef GOOS_nacl
WORD $0xe125be7f // BKPT 0x5bef, NACL_INSTR_ARM_BREAKPOINT
#else
WORD $0xe7f001f0 // undefined instruction that gdb understands is a software breakpoint
#endif
RET
TEXT runtime·asminit(SB),NOSPLIT,$0-0
// disable runfast (flush-to-zero) mode of vfp if runtime.goarm > 5
MOVB runtime·goarm(SB), R11
CMP $5, R11
BLE 4(PC)
WORD $0xeef1ba10 // vmrs r11, fpscr
BIC $(1<<24), R11
WORD $0xeee1ba10 // vmsr fpscr, r11
RET
/*
* go-routine
*/
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
// void gosave(Gobuf*)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB),NOSPLIT,$-4-4
MOVW 0(FP), R0 // gobuf
MOVW SP, gobuf_sp(R0)
MOVW LR, gobuf_pc(R0)
MOVW g, gobuf_g(R0)
MOVW $0, R11
MOVW R11, gobuf_lr(R0)
MOVW R11, gobuf_ret(R0)
MOVW R11, gobuf_ctxt(R0)
RET
// void gogo(Gobuf*)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB),NOSPLIT,$-4-4
MOVW 0(FP), R1 // gobuf
MOVW gobuf_g(R1), R0
BL setg<>(SB)
// NOTE: We updated g above, and we are about to update SP.
// Until LR and PC are also updated, the g/SP/LR/PC quadruple
// are out of sync and must not be used as the basis of a traceback.
// Sigprof skips the traceback when SP is not within g's bounds,
// and when the PC is inside this function, runtime.gogo.
// Since we are about to update SP, until we complete runtime.gogo
// we must not leave this function. In particular, no calls
// after this point: it must be straight-line code until the
// final B instruction.
// See large comment in sigprof for more details.
MOVW gobuf_sp(R1), SP // restore SP
MOVW gobuf_lr(R1), LR
MOVW gobuf_ret(R1), R0
MOVW gobuf_ctxt(R1), R7
MOVW $0, R11
MOVW R11, gobuf_sp(R1) // clear to help garbage collector
MOVW R11, gobuf_ret(R1)
MOVW R11, gobuf_lr(R1)
MOVW R11, gobuf_ctxt(R1)
MOVW gobuf_pc(R1), R11
CMP R11, R11 // set condition codes for == test, needed by stack split
B (R11)
// func mcall(fn func(*g))
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
// Switch to m->g0's stack, call fn(g).
runtime: stack split + garbage collection bug The g->sched.sp saved stack pointer and the g->stackbase and g->stackguard stack bounds can change even while "the world is stopped", because a goroutine has to call functions (and therefore might split its stack) when exiting a system call to check whether the world is stopped (and if so, wait until the world continues). That means the garbage collector cannot access those values safely (without a race) for goroutines executing system calls. Instead, save a consistent triple in g->gcsp, g->gcstack, g->gcguard during entersyscall and have the garbage collector refer to those. The old code was occasionally seeing (because of the race) an sp and stk that did not correspond to each other, so that stk - sp was not the number of stack bytes following sp. In that case, if sp < stk then the call scanblock(sp, stk - sp) scanned too many bytes (anything between the two pointers, which pointed into different allocation blocks). If sp > stk then stk - sp wrapped around. On 32-bit, stk - sp is a uintptr (uint32) converted to int64 in the call to scanblock, so a large (~4G) but positive number. Scanblock would try to scan that many bytes and eventually fault accessing unmapped memory. On 64-bit, stk - sp is a uintptr (uint64) promoted to int64 in the call to scanblock, so a negative number. Scanblock would not scan anything, possibly causing in-use blocks to be freed. In short, 32-bit platforms would have seen either ineffective garbage collection or crashes during garbage collection, while 64-bit platforms would have seen either ineffective or incorrect garbage collection. You can see the invalid arguments to scanblock in the stack traces in issue 1620. Fixes #1620. Fixes #1746. R=iant, r CC=golang-dev https://golang.org/cl/4437075
2011-04-27 21:21:12 -06:00
// Fn must never return. It should gogo(&g->sched)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
// to keep running g.
TEXT runtime·mcall(SB),NOSPLIT,$-4-4
// Save caller state in g->sched.
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
MOVW SP, (g_sched+gobuf_sp)(g)
MOVW LR, (g_sched+gobuf_pc)(g)
runtime: record proper goroutine state during stack split Until now, the goroutine state has been scattered during the execution of newstack and oldstack. It's all there, and those routines know how to get back to a working goroutine, but other pieces of the system, like stack traces, do not. If something does interrupt the newstack or oldstack execution, the rest of the system can't understand the goroutine. For example, if newstack decides there is an overflow and calls throw, the stack tracer wouldn't dump the goroutine correctly. For newstack to save a useful state snapshot, it needs to be able to rewind the PC in the function that triggered the split back to the beginning of the function. (The PC is a few instructions in, just after the call to morestack.) To make that possible, we change the prologues to insert a jmp back to the beginning of the function after the call to morestack. That is, the prologue used to be roughly: TEXT myfunc check for split jmpcond nosplit call morestack nosplit: sub $xxx, sp Now an extra instruction is inserted after the call: TEXT myfunc start: check for split jmpcond nosplit call morestack jmp start nosplit: sub $xxx, sp The jmp is not executed directly. It is decoded and simulated by runtime.rewindmorestack to discover the beginning of the function, and then the call to morestack returns directly to the start label instead of to the jump instruction. So logically the jmp is still executed, just not by the cpu. The prologue thus repeats in the case of a function that needs a stack split, but against the cost of the split itself, the extra few instructions are noise. The repeated prologue has the nice effect of making a stack split double-check that the new stack is big enough: if morestack happens to return on a too-small stack, we'll now notice before corruption happens. The ability for newstack to rewind to the beginning of the function should help preemption too. If newstack decides that it was called for preemption instead of a stack split, it now has the goroutine state correctly paused if rescheduling is needed, and when the goroutine can run again, it can return to the start label on its original stack and re-execute the split check. Here is an example of a split stack overflow showing the full trace, without any special cases in the stack printer. (This one was triggered by making the split check incorrect.) runtime: newstack framesize=0x0 argsize=0x18 sp=0x6aebd0 stack=[0x6b0000, 0x6b0fa0] morebuf={pc:0x69f5b sp:0x6aebd8 lr:0x0} sched={pc:0x68880 sp:0x6aebd0 lr:0x0 ctxt:0x34e700} runtime: split stack overflow: 0x6aebd0 < 0x6b0000 fatal error: runtime: split stack overflow goroutine 1 [stack split]: runtime.mallocgc(0x290, 0x100000000, 0x1) /Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:21 fp=0x6aebd8 runtime.new() /Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:682 +0x5b fp=0x6aec08 go/build.(*Context).Import(0x5ae340, 0xc210030c71, 0xa, 0xc2100b4380, 0x1b, ...) /Users/rsc/g/go/src/pkg/go/build/build.go:424 +0x3a fp=0x6b00a0 main.loadImport(0xc210030c71, 0xa, 0xc2100b4380, 0x1b, 0xc2100b42c0, ...) /Users/rsc/g/go/src/cmd/go/pkg.go:249 +0x371 fp=0x6b01a8 main.(*Package).load(0xc21017c800, 0xc2100b42c0, 0xc2101828c0, 0x0, 0x0, ...) /Users/rsc/g/go/src/cmd/go/pkg.go:431 +0x2801 fp=0x6b0c98 main.loadPackage(0x369040, 0x7, 0xc2100b42c0, 0x0) /Users/rsc/g/go/src/cmd/go/pkg.go:709 +0x857 fp=0x6b0f80 ----- stack segment boundary ----- main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc2100e6c00, 0xc2100e5750, ...) /Users/rsc/g/go/src/cmd/go/build.go:539 +0x437 fp=0x6b14a0 main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc21015b400, 0x2, ...) /Users/rsc/g/go/src/cmd/go/build.go:528 +0x1d2 fp=0x6b1658 main.(*builder).test(0xc2100902a0, 0xc210092000, 0x0, 0x0, 0xc21008ff60, ...) /Users/rsc/g/go/src/cmd/go/test.go:622 +0x1b53 fp=0x6b1f68 ----- stack segment boundary ----- main.runTest(0x5a6b20, 0xc21000a020, 0x2, 0x2) /Users/rsc/g/go/src/cmd/go/test.go:366 +0xd09 fp=0x6a5cf0 main.main() /Users/rsc/g/go/src/cmd/go/main.go:161 +0x4f9 fp=0x6a5f78 runtime.main() /Users/rsc/g/go/src/pkg/runtime/proc.c:183 +0x92 fp=0x6a5fa0 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1266 fp=0x6a5fa8 And here is a seg fault during oldstack: SIGSEGV: segmentation violation PC=0x1b2a6 runtime.oldstack() /Users/rsc/g/go/src/pkg/runtime/stack.c:159 +0x76 runtime.lessstack() /Users/rsc/g/go/src/pkg/runtime/asm_amd64.s:270 +0x22 goroutine 1 [stack unsplit]: fmt.(*pp).printArg(0x2102e64e0, 0xe5c80, 0x2102c9220, 0x73, 0x0, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:818 +0x3d3 fp=0x221031e6f8 fmt.(*pp).doPrintf(0x2102e64e0, 0x12fb20, 0x2, 0x221031eb98, 0x1, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:1183 +0x15cb fp=0x221031eaf0 fmt.Sprintf(0x12fb20, 0x2, 0x221031eb98, 0x1, 0x1, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:234 +0x67 fp=0x221031eb40 flag.(*stringValue).String(0x2102c9210, 0x1, 0x0) /Users/rsc/g/go/src/pkg/flag/flag.go:180 +0xb3 fp=0x221031ebb0 flag.(*FlagSet).Var(0x2102f6000, 0x293d38, 0x2102c9210, 0x143490, 0xa, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:633 +0x40 fp=0x221031eca0 flag.(*FlagSet).StringVar(0x2102f6000, 0x2102c9210, 0x143490, 0xa, 0x12fa60, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:550 +0x91 fp=0x221031ece8 flag.(*FlagSet).String(0x2102f6000, 0x143490, 0xa, 0x12fa60, 0x0, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:563 +0x87 fp=0x221031ed38 flag.String(0x143490, 0xa, 0x12fa60, 0x0, 0x161950, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:570 +0x6b fp=0x221031ed80 testing.init() /Users/rsc/g/go/src/pkg/testing/testing.go:-531 +0xbb fp=0x221031edc0 strings_test.init() /Users/rsc/g/go/src/pkg/strings/strings_test.go:1115 +0x62 fp=0x221031ef70 main.init() strings/_test/_testmain.go:90 +0x3d fp=0x221031ef78 runtime.main() /Users/rsc/g/go/src/pkg/runtime/proc.c:180 +0x8a fp=0x221031efa0 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1269 fp=0x221031efa8 goroutine 2 [runnable]: runtime.MHeap_Scavenger() /Users/rsc/g/go/src/pkg/runtime/mheap.c:438 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1269 created by runtime.main /Users/rsc/g/go/src/pkg/runtime/proc.c:166 rax 0x23ccc0 rbx 0x23ccc0 rcx 0x0 rdx 0x38 rdi 0x2102c0170 rsi 0x221032cfe0 rbp 0x221032cfa0 rsp 0x7fff5fbff5b0 r8 0x2102c0120 r9 0x221032cfa0 r10 0x221032c000 r11 0x104ce8 r12 0xe5c80 r13 0x1be82baac718 r14 0x13091135f7d69200 r15 0x0 rip 0x1b2a6 rflags 0x10246 cs 0x2b fs 0x0 gs 0x0 Fixes #5723. R=r, dvyukov, go.peter.90, dave, iant CC=golang-dev https://golang.org/cl/10360048
2013-06-27 09:32:01 -06:00
MOVW $0, R11
MOVW R11, (g_sched+gobuf_lr)(g)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
MOVW g, (g_sched+gobuf_g)(g)
// Switch to m->g0 & its stack, call fn.
MOVW g, R1
2014-06-26 09:54:39 -06:00
MOVW g_m(g), R8
MOVW m_g0(R8), R0
BL setg<>(SB)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
CMP g, R1
B.NE 2(PC)
B runtime·badmcall(SB)
2014-06-26 09:54:39 -06:00
MOVB runtime·iscgo(SB), R11
CMP $0, R11
BL.NE runtime·save_g(SB)
MOVW fn+0(FP), R0
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
MOVW (g_sched+gobuf_sp)(g), SP
SUB $8, SP
MOVW R1, 4(SP)
MOVW R0, R7
MOVW 0(R0), R0
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
BL (R0)
B runtime·badmcall2(SB)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
RET
// switchtoM is a dummy routine that onM leaves at the bottom
// of the G stack. We need to distinguish the routine that
// lives at the bottom of the G stack from the one that lives
// at the top of the M stack because the one at the top of
// the M stack terminates the stack walk (see topofstack()).
TEXT runtime·switchtoM(SB),NOSPLIT,$0-0
MOVW $0, R0
BL (R0) // clobber lr to ensure push {lr} is kept
RET
// func onM_signalok(fn func())
TEXT runtime·onM_signalok(SB), NOSPLIT, $-4-4
MOVW g_m(g), R1
MOVW m_gsignal(R1), R2
CMP g, R2
B.EQ ongsignal
B runtime·onM(SB)
ongsignal:
MOVW fn+0(FP), R0
MOVW R0, R7
MOVW 0(R0), R0
BL (R0)
RET
// func onM(fn func())
TEXT runtime·onM(SB),NOSPLIT,$0-4
MOVW fn+0(FP), R0 // R0 = fn
MOVW g_m(g), R1 // R1 = m
runtime: reject onM calls from gsignal stack The implementation and use patterns of onM assume that they run on either the m->curg or m->g0 stack. Calling onM from m->gsignal has two problems: (1) When not on g0, onM switches to g0 and then "back" to curg. If we didn't start at curg, bad things happen. (2) The use of scalararg/ptrarg to pass C arguments and results assumes that there is only one onM call at a time. If a gsignal starts running, it may have interrupted the setup/teardown of the args for an onM on the curg or g0 stack. Using scalararg/ptrarg itself would smash those. We can fix (1) by remembering what g was running before the switch. We can fix (2) by requiring that uses of onM that might happen on a signal handling stack must save the old scalararg/ptrarg and restore them after the call, instead of zeroing them. The only sane way to do this is to introduce a separate onM_signalsafe that omits the signal check, and then if you see a call to onM_signalsafe you know the surrounding code must preserve the old scalararg/ptrarg values. (The implementation would be that onM_signalsafe just calls fn if on the signal stack or else jumps to onM. It's not necessary to have two whole copies of the function.) (2) is not a problem if the caller and callee are both Go and a closure is used instead of the scalararg/ptrarg slots. For now, I think we can avoid calling onM from code executing on gsignal stacks, so just reject it. In the long term, (2) goes away (as do the scalararg/ptrarg slots) once everything is in Go, and at that point fixing (1) would be trivial and maybe worth doing just for regularity. LGTM=iant R=golang-codereviews, iant CC=dvyukov, golang-codereviews, khr, r https://golang.org/cl/135400043
2014-09-03 22:10:10 -06:00
MOVW m_g0(R1), R2 // R2 = g0
CMP g, R2
B.EQ onm
runtime: reject onM calls from gsignal stack The implementation and use patterns of onM assume that they run on either the m->curg or m->g0 stack. Calling onM from m->gsignal has two problems: (1) When not on g0, onM switches to g0 and then "back" to curg. If we didn't start at curg, bad things happen. (2) The use of scalararg/ptrarg to pass C arguments and results assumes that there is only one onM call at a time. If a gsignal starts running, it may have interrupted the setup/teardown of the args for an onM on the curg or g0 stack. Using scalararg/ptrarg itself would smash those. We can fix (1) by remembering what g was running before the switch. We can fix (2) by requiring that uses of onM that might happen on a signal handling stack must save the old scalararg/ptrarg and restore them after the call, instead of zeroing them. The only sane way to do this is to introduce a separate onM_signalsafe that omits the signal check, and then if you see a call to onM_signalsafe you know the surrounding code must preserve the old scalararg/ptrarg values. (The implementation would be that onM_signalsafe just calls fn if on the signal stack or else jumps to onM. It's not necessary to have two whole copies of the function.) (2) is not a problem if the caller and callee are both Go and a closure is used instead of the scalararg/ptrarg slots. For now, I think we can avoid calling onM from code executing on gsignal stacks, so just reject it. In the long term, (2) goes away (as do the scalararg/ptrarg slots) once everything is in Go, and at that point fixing (1) would be trivial and maybe worth doing just for regularity. LGTM=iant R=golang-codereviews, iant CC=dvyukov, golang-codereviews, khr, r https://golang.org/cl/135400043
2014-09-03 22:10:10 -06:00
MOVW m_curg(R1), R3
runtime: reject onM calls from gsignal stack The implementation and use patterns of onM assume that they run on either the m->curg or m->g0 stack. Calling onM from m->gsignal has two problems: (1) When not on g0, onM switches to g0 and then "back" to curg. If we didn't start at curg, bad things happen. (2) The use of scalararg/ptrarg to pass C arguments and results assumes that there is only one onM call at a time. If a gsignal starts running, it may have interrupted the setup/teardown of the args for an onM on the curg or g0 stack. Using scalararg/ptrarg itself would smash those. We can fix (1) by remembering what g was running before the switch. We can fix (2) by requiring that uses of onM that might happen on a signal handling stack must save the old scalararg/ptrarg and restore them after the call, instead of zeroing them. The only sane way to do this is to introduce a separate onM_signalsafe that omits the signal check, and then if you see a call to onM_signalsafe you know the surrounding code must preserve the old scalararg/ptrarg values. (The implementation would be that onM_signalsafe just calls fn if on the signal stack or else jumps to onM. It's not necessary to have two whole copies of the function.) (2) is not a problem if the caller and callee are both Go and a closure is used instead of the scalararg/ptrarg slots. For now, I think we can avoid calling onM from code executing on gsignal stacks, so just reject it. In the long term, (2) goes away (as do the scalararg/ptrarg slots) once everything is in Go, and at that point fixing (1) would be trivial and maybe worth doing just for regularity. LGTM=iant R=golang-codereviews, iant CC=dvyukov, golang-codereviews, khr, r https://golang.org/cl/135400043
2014-09-03 22:10:10 -06:00
CMP g, R3
B.EQ oncurg
// Not g0, not curg. Must be gsignal, but that's not allowed.
// Hide call from linker nosplit analysis.
MOVW $runtime·badonm(SB), R0
BL (R0)
oncurg:
// save our state in g->sched. Pretend to
// be switchtoM if the G stack is scanned.
MOVW $runtime·switchtoM(SB), R3
ADD $4, R3, R3 // get past push {lr}
MOVW R3, (g_sched+gobuf_pc)(g)
MOVW SP, (g_sched+gobuf_sp)(g)
MOVW LR, (g_sched+gobuf_lr)(g)
MOVW g, (g_sched+gobuf_g)(g)
// switch to g0
MOVW R0, R5
MOVW R2, R0
BL setg<>(SB)
MOVW R5, R0
MOVW (g_sched+gobuf_sp)(R2), R3
// make it look like mstart called onM on g0, to stop traceback
SUB $4, R3, R3
MOVW $runtime·mstart(SB), R4
MOVW R4, 0(R3)
MOVW R3, SP
// call target function
MOVW R0, R7
MOVW 0(R0), R0
BL (R0)
// switch back to g
MOVW g_m(g), R1
MOVW m_curg(R1), R0
BL setg<>(SB)
MOVW (g_sched+gobuf_sp)(g), SP
MOVW $0, R3
MOVW R3, (g_sched+gobuf_sp)(g)
RET
onm:
MOVW R0, R7
MOVW 0(R0), R0
BL (R0)
RET
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
// R1 frame size
// R2 arg size
// R3 prolog's LR
// NB. we do not save R0 because we've forced 5c to pass all arguments
// on the stack.
// using frame size $-4 means do not save LR on stack.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must
// record an argument size. For that purpose, it has no arguments.
TEXT runtime·morestack(SB),NOSPLIT,$-4-0
// Cannot grow scheduler stack (m->g0).
2014-06-26 09:54:39 -06:00
MOVW g_m(g), R8
MOVW m_g0(R8), R4
CMP g, R4
BL.EQ runtime·abort(SB)
// Cannot grow signal stack (m->gsignal).
MOVW m_gsignal(R8), R4
CMP g, R4
BL.EQ runtime·abort(SB)
runtime: record proper goroutine state during stack split Until now, the goroutine state has been scattered during the execution of newstack and oldstack. It's all there, and those routines know how to get back to a working goroutine, but other pieces of the system, like stack traces, do not. If something does interrupt the newstack or oldstack execution, the rest of the system can't understand the goroutine. For example, if newstack decides there is an overflow and calls throw, the stack tracer wouldn't dump the goroutine correctly. For newstack to save a useful state snapshot, it needs to be able to rewind the PC in the function that triggered the split back to the beginning of the function. (The PC is a few instructions in, just after the call to morestack.) To make that possible, we change the prologues to insert a jmp back to the beginning of the function after the call to morestack. That is, the prologue used to be roughly: TEXT myfunc check for split jmpcond nosplit call morestack nosplit: sub $xxx, sp Now an extra instruction is inserted after the call: TEXT myfunc start: check for split jmpcond nosplit call morestack jmp start nosplit: sub $xxx, sp The jmp is not executed directly. It is decoded and simulated by runtime.rewindmorestack to discover the beginning of the function, and then the call to morestack returns directly to the start label instead of to the jump instruction. So logically the jmp is still executed, just not by the cpu. The prologue thus repeats in the case of a function that needs a stack split, but against the cost of the split itself, the extra few instructions are noise. The repeated prologue has the nice effect of making a stack split double-check that the new stack is big enough: if morestack happens to return on a too-small stack, we'll now notice before corruption happens. The ability for newstack to rewind to the beginning of the function should help preemption too. If newstack decides that it was called for preemption instead of a stack split, it now has the goroutine state correctly paused if rescheduling is needed, and when the goroutine can run again, it can return to the start label on its original stack and re-execute the split check. Here is an example of a split stack overflow showing the full trace, without any special cases in the stack printer. (This one was triggered by making the split check incorrect.) runtime: newstack framesize=0x0 argsize=0x18 sp=0x6aebd0 stack=[0x6b0000, 0x6b0fa0] morebuf={pc:0x69f5b sp:0x6aebd8 lr:0x0} sched={pc:0x68880 sp:0x6aebd0 lr:0x0 ctxt:0x34e700} runtime: split stack overflow: 0x6aebd0 < 0x6b0000 fatal error: runtime: split stack overflow goroutine 1 [stack split]: runtime.mallocgc(0x290, 0x100000000, 0x1) /Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:21 fp=0x6aebd8 runtime.new() /Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:682 +0x5b fp=0x6aec08 go/build.(*Context).Import(0x5ae340, 0xc210030c71, 0xa, 0xc2100b4380, 0x1b, ...) /Users/rsc/g/go/src/pkg/go/build/build.go:424 +0x3a fp=0x6b00a0 main.loadImport(0xc210030c71, 0xa, 0xc2100b4380, 0x1b, 0xc2100b42c0, ...) /Users/rsc/g/go/src/cmd/go/pkg.go:249 +0x371 fp=0x6b01a8 main.(*Package).load(0xc21017c800, 0xc2100b42c0, 0xc2101828c0, 0x0, 0x0, ...) /Users/rsc/g/go/src/cmd/go/pkg.go:431 +0x2801 fp=0x6b0c98 main.loadPackage(0x369040, 0x7, 0xc2100b42c0, 0x0) /Users/rsc/g/go/src/cmd/go/pkg.go:709 +0x857 fp=0x6b0f80 ----- stack segment boundary ----- main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc2100e6c00, 0xc2100e5750, ...) /Users/rsc/g/go/src/cmd/go/build.go:539 +0x437 fp=0x6b14a0 main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc21015b400, 0x2, ...) /Users/rsc/g/go/src/cmd/go/build.go:528 +0x1d2 fp=0x6b1658 main.(*builder).test(0xc2100902a0, 0xc210092000, 0x0, 0x0, 0xc21008ff60, ...) /Users/rsc/g/go/src/cmd/go/test.go:622 +0x1b53 fp=0x6b1f68 ----- stack segment boundary ----- main.runTest(0x5a6b20, 0xc21000a020, 0x2, 0x2) /Users/rsc/g/go/src/cmd/go/test.go:366 +0xd09 fp=0x6a5cf0 main.main() /Users/rsc/g/go/src/cmd/go/main.go:161 +0x4f9 fp=0x6a5f78 runtime.main() /Users/rsc/g/go/src/pkg/runtime/proc.c:183 +0x92 fp=0x6a5fa0 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1266 fp=0x6a5fa8 And here is a seg fault during oldstack: SIGSEGV: segmentation violation PC=0x1b2a6 runtime.oldstack() /Users/rsc/g/go/src/pkg/runtime/stack.c:159 +0x76 runtime.lessstack() /Users/rsc/g/go/src/pkg/runtime/asm_amd64.s:270 +0x22 goroutine 1 [stack unsplit]: fmt.(*pp).printArg(0x2102e64e0, 0xe5c80, 0x2102c9220, 0x73, 0x0, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:818 +0x3d3 fp=0x221031e6f8 fmt.(*pp).doPrintf(0x2102e64e0, 0x12fb20, 0x2, 0x221031eb98, 0x1, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:1183 +0x15cb fp=0x221031eaf0 fmt.Sprintf(0x12fb20, 0x2, 0x221031eb98, 0x1, 0x1, ...) /Users/rsc/g/go/src/pkg/fmt/print.go:234 +0x67 fp=0x221031eb40 flag.(*stringValue).String(0x2102c9210, 0x1, 0x0) /Users/rsc/g/go/src/pkg/flag/flag.go:180 +0xb3 fp=0x221031ebb0 flag.(*FlagSet).Var(0x2102f6000, 0x293d38, 0x2102c9210, 0x143490, 0xa, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:633 +0x40 fp=0x221031eca0 flag.(*FlagSet).StringVar(0x2102f6000, 0x2102c9210, 0x143490, 0xa, 0x12fa60, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:550 +0x91 fp=0x221031ece8 flag.(*FlagSet).String(0x2102f6000, 0x143490, 0xa, 0x12fa60, 0x0, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:563 +0x87 fp=0x221031ed38 flag.String(0x143490, 0xa, 0x12fa60, 0x0, 0x161950, ...) /Users/rsc/g/go/src/pkg/flag/flag.go:570 +0x6b fp=0x221031ed80 testing.init() /Users/rsc/g/go/src/pkg/testing/testing.go:-531 +0xbb fp=0x221031edc0 strings_test.init() /Users/rsc/g/go/src/pkg/strings/strings_test.go:1115 +0x62 fp=0x221031ef70 main.init() strings/_test/_testmain.go:90 +0x3d fp=0x221031ef78 runtime.main() /Users/rsc/g/go/src/pkg/runtime/proc.c:180 +0x8a fp=0x221031efa0 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1269 fp=0x221031efa8 goroutine 2 [runnable]: runtime.MHeap_Scavenger() /Users/rsc/g/go/src/pkg/runtime/mheap.c:438 runtime.goexit() /Users/rsc/g/go/src/pkg/runtime/proc.c:1269 created by runtime.main /Users/rsc/g/go/src/pkg/runtime/proc.c:166 rax 0x23ccc0 rbx 0x23ccc0 rcx 0x0 rdx 0x38 rdi 0x2102c0170 rsi 0x221032cfe0 rbp 0x221032cfa0 rsp 0x7fff5fbff5b0 r8 0x2102c0120 r9 0x221032cfa0 r10 0x221032c000 r11 0x104ce8 r12 0xe5c80 r13 0x1be82baac718 r14 0x13091135f7d69200 r15 0x0 rip 0x1b2a6 rflags 0x10246 cs 0x2b fs 0x0 gs 0x0 Fixes #5723. R=r, dvyukov, go.peter.90, dave, iant CC=golang-dev https://golang.org/cl/10360048
2013-06-27 09:32:01 -06:00
// Called from f.
// Set g->sched to context in f.
MOVW R7, (g_sched+gobuf_ctxt)(g)
MOVW SP, (g_sched+gobuf_sp)(g)
MOVW LR, (g_sched+gobuf_pc)(g)
MOVW R3, (g_sched+gobuf_lr)(g)
// Called from f.
// Set m->morebuf to f's caller.
2014-06-26 09:54:39 -06:00
MOVW R3, (m_morebuf+gobuf_pc)(R8) // f's caller's PC
MOVW SP, (m_morebuf+gobuf_sp)(R8) // f's caller's SP
MOVW $4(SP), R3 // f's argument pointer
2014-06-26 09:54:39 -06:00
MOVW g, (m_morebuf+gobuf_g)(R8)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
// Call newstack on m->g0's stack.
MOVW m_g0(R8), R0
BL setg<>(SB)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
MOVW (g_sched+gobuf_sp)(g), SP
BL runtime·newstack(SB)
// Not reached, but make sure the return PC from the call to newstack
// is still in this function, and not the beginning of the next.
RET
TEXT runtime·morestack_noctxt(SB),NOSPLIT,$-4-0
MOVW $0, R7
B runtime·morestack(SB)
// reflectcall: call a function with the given argument list
// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
#define DISPATCH(NAME,MAXSIZE) \
CMP $MAXSIZE, R0; \
B.HI 3(PC); \
MOVW $NAME(SB), R1; \
B (R1)
TEXT runtime·reflectcall(SB),NOSPLIT,$-4-16
MOVW argsize+8(FP), R0
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
DISPATCH(runtime·call128, 128)
DISPATCH(runtime·call256, 256)
DISPATCH(runtime·call512, 512)
DISPATCH(runtime·call1024, 1024)
DISPATCH(runtime·call2048, 2048)
DISPATCH(runtime·call4096, 4096)
DISPATCH(runtime·call8192, 8192)
DISPATCH(runtime·call16384, 16384)
DISPATCH(runtime·call32768, 32768)
DISPATCH(runtime·call65536, 65536)
DISPATCH(runtime·call131072, 131072)
DISPATCH(runtime·call262144, 262144)
DISPATCH(runtime·call524288, 524288)
DISPATCH(runtime·call1048576, 1048576)
DISPATCH(runtime·call2097152, 2097152)
DISPATCH(runtime·call4194304, 4194304)
DISPATCH(runtime·call8388608, 8388608)
DISPATCH(runtime·call16777216, 16777216)
DISPATCH(runtime·call33554432, 33554432)
DISPATCH(runtime·call67108864, 67108864)
DISPATCH(runtime·call134217728, 134217728)
DISPATCH(runtime·call268435456, 268435456)
DISPATCH(runtime·call536870912, 536870912)
DISPATCH(runtime·call1073741824, 1073741824)
MOVW $runtime·badreflectcall(SB), R1
B (R1)
// Argument map for the callXX frames. Each has one stack map.
DATA gcargs_reflectcall<>+0x00(SB)/4, $1 // 1 stackmap
DATA gcargs_reflectcall<>+0x04(SB)/4, $8 // 4 words
DATA gcargs_reflectcall<>+0x08(SB)/1, $(const_BitsPointer+(const_BitsPointer<<2)+(const_BitsScalar<<4)+(const_BitsScalar<<6))
GLOBL gcargs_reflectcall<>(SB),RODATA,$12
// callXX frames have no locals
DATA gclocals_reflectcall<>+0x00(SB)/4, $1 // 1 stackmap
DATA gclocals_reflectcall<>+0x04(SB)/4, $0 // 0 locals
GLOBL gclocals_reflectcall<>(SB),RODATA,$8
#define CALLFN(NAME,MAXSIZE) \
TEXT NAME(SB), WRAPPER, $MAXSIZE-16; \
FUNCDATA $FUNCDATA_ArgsPointerMaps,gcargs_reflectcall<>(SB); \
FUNCDATA $FUNCDATA_LocalsPointerMaps,gclocals_reflectcall<>(SB);\
/* copy arguments to stack */ \
MOVW argptr+4(FP), R0; \
MOVW argsize+8(FP), R2; \
ADD $4, SP, R1; \
CMP $0, R2; \
B.EQ 5(PC); \
MOVBU.P 1(R0), R5; \
MOVBU.P R5, 1(R1); \
SUB $1, R2, R2; \
B -5(PC); \
/* call function */ \
MOVW f+0(FP), R7; \
MOVW (R7), R0; \
PCDATA $PCDATA_StackMapIndex, $0; \
BL (R0); \
/* copy return values back */ \
MOVW argptr+4(FP), R0; \
MOVW argsize+8(FP), R2; \
reflect, runtime: fix crash in GC due to reflect.call + precise GC Given type Outer struct { *Inner ... } the compiler generates the implementation of (*Outer).M dispatching to the embedded Inner. The implementation is logically: func (p *Outer) M() { (p.Inner).M() } but since the only change here is the replacement of one pointer receiver with another, the actual generated code overwrites the original receiver with the p.Inner pointer and then jumps to the M method expecting the *Inner receiver. During reflect.Value.Call, we create an argument frame and the associated data structures to describe it to the garbage collector, populate the frame, call reflect.call to run a function call using that frame, and then copy the results back out of the frame. The reflect.call function does a memmove of the frame structure onto the stack (to set up the inputs), runs the call, and the memmoves the stack back to the frame structure (to preserve the outputs). Originally reflect.call did not distinguish inputs from outputs: both memmoves were for the full stack frame. However, in the case where the called function was one of these wrappers, the rewritten receiver is almost certainly a different type than the original receiver. This is not a problem on the stack, where we use the program counter to determine the type information and understand that during (*Outer).M the receiver is an *Outer while during (*Inner).M the receiver in the same memory word is now an *Inner. But in the statically typed argument frame created by reflect, the receiver is always an *Outer. Copying the modified receiver pointer off the stack into the frame will store an *Inner there, and then if a garbage collection happens to scan that argument frame before it is discarded, it will scan the *Inner memory as if it were an *Outer. If the two have different memory layouts, the collection will intepret the memory incorrectly. Fix by only copying back the results. Fixes #7725. LGTM=khr R=khr CC=dave, golang-codereviews https://golang.org/cl/85180043
2014-04-08 09:11:35 -06:00
MOVW retoffset+12(FP), R3; \
ADD $4, SP, R1; \
reflect, runtime: fix crash in GC due to reflect.call + precise GC Given type Outer struct { *Inner ... } the compiler generates the implementation of (*Outer).M dispatching to the embedded Inner. The implementation is logically: func (p *Outer) M() { (p.Inner).M() } but since the only change here is the replacement of one pointer receiver with another, the actual generated code overwrites the original receiver with the p.Inner pointer and then jumps to the M method expecting the *Inner receiver. During reflect.Value.Call, we create an argument frame and the associated data structures to describe it to the garbage collector, populate the frame, call reflect.call to run a function call using that frame, and then copy the results back out of the frame. The reflect.call function does a memmove of the frame structure onto the stack (to set up the inputs), runs the call, and the memmoves the stack back to the frame structure (to preserve the outputs). Originally reflect.call did not distinguish inputs from outputs: both memmoves were for the full stack frame. However, in the case where the called function was one of these wrappers, the rewritten receiver is almost certainly a different type than the original receiver. This is not a problem on the stack, where we use the program counter to determine the type information and understand that during (*Outer).M the receiver is an *Outer while during (*Inner).M the receiver in the same memory word is now an *Inner. But in the statically typed argument frame created by reflect, the receiver is always an *Outer. Copying the modified receiver pointer off the stack into the frame will store an *Inner there, and then if a garbage collection happens to scan that argument frame before it is discarded, it will scan the *Inner memory as if it were an *Outer. If the two have different memory layouts, the collection will intepret the memory incorrectly. Fix by only copying back the results. Fixes #7725. LGTM=khr R=khr CC=dave, golang-codereviews https://golang.org/cl/85180043
2014-04-08 09:11:35 -06:00
ADD R3, R1; \
ADD R3, R0; \
SUB R3, R2; \
CMP $0, R2; \
RET.EQ ; \
MOVBU.P 1(R1), R5; \
MOVBU.P R5, 1(R0); \
SUB $1, R2, R2; \
B -5(PC) \
CALLFN(runtime·call16, 16)
CALLFN(runtime·call32, 32)
CALLFN(runtime·call64, 64)
CALLFN(runtime·call128, 128)
CALLFN(runtime·call256, 256)
CALLFN(runtime·call512, 512)
CALLFN(runtime·call1024, 1024)
CALLFN(runtime·call2048, 2048)
CALLFN(runtime·call4096, 4096)
CALLFN(runtime·call8192, 8192)
CALLFN(runtime·call16384, 16384)
CALLFN(runtime·call32768, 32768)
CALLFN(runtime·call65536, 65536)
CALLFN(runtime·call131072, 131072)
CALLFN(runtime·call262144, 262144)
CALLFN(runtime·call524288, 524288)
CALLFN(runtime·call1048576, 1048576)
CALLFN(runtime·call2097152, 2097152)
CALLFN(runtime·call4194304, 4194304)
CALLFN(runtime·call8388608, 8388608)
CALLFN(runtime·call16777216, 16777216)
CALLFN(runtime·call33554432, 33554432)
CALLFN(runtime·call67108864, 67108864)
CALLFN(runtime·call134217728, 134217728)
CALLFN(runtime·call268435456, 268435456)
CALLFN(runtime·call536870912, 536870912)
CALLFN(runtime·call1073741824, 1073741824)
// void jmpdefer(fn, sp);
// called from deferreturn.
// 1. grab stored LR for caller
// 2. sub 4 bytes to get back to BL deferreturn
// 3. B to fn
// TODO(rsc): Push things on stack and then use pop
// to load all registers simultaneously, so that a profiling
// interrupt can never see mismatched SP/LR/PC.
// (And double-check that pop is atomic in that way.)
TEXT runtime·jmpdefer(SB),NOSPLIT,$0-8
MOVW 0(SP), LR
MOVW $-4(LR), LR // BL deferreturn
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
MOVW fv+0(FP), R7
MOVW argp+4(FP), SP
MOVW $-4(SP), SP // SP is 4 below argp, due to saved LR
MOVW 0(R7), R1
B (R1)
// Save state of caller into g->sched. Smashes R11.
TEXT gosave<>(SB),NOSPLIT,$0
MOVW LR, (g_sched+gobuf_pc)(g)
MOVW R13, (g_sched+gobuf_sp)(g)
MOVW $0, R11
MOVW R11, (g_sched+gobuf_lr)(g)
MOVW R11, (g_sched+gobuf_ret)(g)
MOVW R11, (g_sched+gobuf_ctxt)(g)
RET
// asmcgocall(void(*fn)(void*), void *arg)
// Call fn(arg) on the scheduler stack,
// aligned appropriately for the gcc ABI.
// See cgocall.c for more details.
TEXT ·asmcgocall(SB),NOSPLIT,$0-8
MOVW fn+0(FP), R1
MOVW arg+4(FP), R0
BL asmcgocall<>(SB)
RET
TEXT ·asmcgocall_errno(SB),NOSPLIT,$0-12
MOVW fn+0(FP), R1
MOVW arg+4(FP), R0
BL asmcgocall<>(SB)
MOVW R0, ret+8(FP)
RET
TEXT asmcgocall<>(SB),NOSPLIT,$0-0
// fn in R1, arg in R0.
MOVW R13, R2
MOVW g, R4
// Figure out if we need to switch to m->g0 stack.
// We get called to create new OS threads too, and those
// come in on the m->g0 stack already.
2014-06-26 09:54:39 -06:00
MOVW g_m(g), R8
MOVW m_g0(R8), R3
CMP R3, g
BEQ asmcgocall_g0
BL gosave<>(SB)
MOVW R0, R5
MOVW R3, R0
BL setg<>(SB)
MOVW R5, R0
MOVW (g_sched+gobuf_sp)(g), R13
// Now on a scheduling stack (a pthread-created stack).
asmcgocall_g0:
SUB $24, R13
BIC $0x7, R13 // alignment for gcc ABI
MOVW R4, 20(R13) // save old g
MOVW (g_stack+stack_hi)(R4), R4
SUB R2, R4
MOVW R4, 16(R13) // save depth in stack (can't just save SP, as stack might be copied during a callback)
BL (R1)
// Restore registers, g, stack pointer.
MOVW R0, R5
MOVW 20(R13), R0
BL setg<>(SB)
MOVW (g_stack+stack_hi)(g), R1
MOVW 16(R13), R2
SUB R2, R1
MOVW R5, R0
MOVW R1, R13
RET
// cgocallback(void (*fn)(void*), void *frame, uintptr framesize)
// Turn the fn into a Go func (by taking its address) and call
// cgocallback_gofunc.
TEXT runtime·cgocallback(SB),NOSPLIT,$12-12
MOVW $fn+0(FP), R0
MOVW R0, 4(R13)
MOVW frame+4(FP), R0
MOVW R0, 8(R13)
MOVW framesize+8(FP), R0
MOVW R0, 12(R13)
MOVW $runtime·cgocallback_gofunc(SB), R0
BL (R0)
RET
// cgocallback_gofunc(void (*fn)(void*), void *frame, uintptr framesize)
// See cgocall.c for more details.
TEXT ·cgocallback_gofunc(SB),NOSPLIT,$8-12
NO_LOCAL_POINTERS
// Load m and g from thread-local storage.
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
MOVB runtime·iscgo(SB), R0
CMP $0, R0
2014-06-26 09:54:39 -06:00
BL.NE runtime·load_g(SB)
2014-06-26 09:54:39 -06:00
// If g is nil, Go did not create the current thread.
// Call needm to obtain one for temporary use.
// In this case, we're running on the thread stack, so there's
// lots of space, but the linker doesn't know. Hide the call from
// the linker analysis by using an indirect call.
2014-06-26 09:54:39 -06:00
CMP $0, g
B.NE havem
2014-06-26 09:54:39 -06:00
MOVW g, savedm-4(SP) // g is zero, so is m.
MOVW $runtime·needm(SB), R0
BL (R0)
havem:
2014-06-26 09:54:39 -06:00
MOVW g_m(g), R8
MOVW R8, savedm-4(SP)
// Now there's a valid m, and we're running on its m->g0.
// Save current m->g0->sched.sp on stack and then set it to SP.
// Save current sp in m->g0->sched.sp in preparation for
// switch back to m->curg stack.
// NOTE: unwindm knows that the saved g->sched.sp is at 4(R13) aka savedsp-8(SP).
2014-06-26 09:54:39 -06:00
MOVW m_g0(R8), R3
MOVW (g_sched+gobuf_sp)(R3), R4
MOVW R4, savedsp-8(SP)
MOVW R13, (g_sched+gobuf_sp)(R3)
// Switch to m->curg stack and call runtime.cgocallbackg.
// Because we are taking over the execution of m->curg
// but *not* resuming what had been running, we need to
// save that information (m->curg->sched) so we can restore it.
// We can restore m->curg->sched.sp easily, because calling
// runtime.cgocallbackg leaves SP unchanged upon return.
// To save m->curg->sched.pc, we push it onto the stack.
// This has the added benefit that it looks to the traceback
// routine like cgocallbackg is going to return to that
// PC (because the frame we allocate below has the same
// size as cgocallback_gofunc's frame declared above)
// so that the traceback will seamlessly trace back into
// the earlier calls.
//
// In the new goroutine, -8(SP) and -4(SP) are unused.
MOVW m_curg(R8), R0
BL setg<>(SB)
MOVW (g_sched+gobuf_sp)(g), R4 // prepare stack as R4
MOVW (g_sched+gobuf_pc)(g), R5
MOVW R5, -12(R4)
MOVW $-12(R4), R13
BL runtime·cgocallbackg(SB)
// Restore g->sched (== m->curg->sched) from saved values.
MOVW 0(R13), R5
MOVW R5, (g_sched+gobuf_pc)(g)
MOVW $12(R13), R4
MOVW R4, (g_sched+gobuf_sp)(g)
// Switch back to m->g0's stack and restore m->g0->sched.sp.
// (Unlike m->curg, the g0 goroutine never uses sched.pc,
// so we do not have to restore it.)
2014-06-26 09:54:39 -06:00
MOVW g_m(g), R8
MOVW m_g0(R8), R0
BL setg<>(SB)
MOVW (g_sched+gobuf_sp)(g), R13
MOVW savedsp-8(SP), R4
MOVW R4, (g_sched+gobuf_sp)(g)
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
// If the m on entry was nil, we called needm above to borrow an m
// for the duration of the call. Since the call is over, return it with dropm.
MOVW savedm-4(SP), R6
CMP $0, R6
B.NE 3(PC)
MOVW $runtime·dropm(SB), R0
BL (R0)
// Done!
RET
runtime: scheduler, cgo reorganization * Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054
2011-03-07 08:37:42 -07:00
2014-06-26 09:54:39 -06:00
// void setg(G*); set g. for use by needm.
TEXT runtime·setg(SB),NOSPLIT,$-4-4
MOVW gg+0(FP), R0
B setg<>(SB)
TEXT setg<>(SB),NOSPLIT,$-4-0
MOVW R0, g
2014-06-26 09:54:39 -06:00
// Save g to thread-local storage.
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
MOVB runtime·iscgo(SB), R0
CMP $0, R0
B.EQ 2(PC)
B runtime·save_g(SB)
MOVW g, R0
RET
TEXT runtime·getcallerpc(SB),NOSPLIT,$-4-4
MOVW 0(SP), R0
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
MOVW R0, ret+4(FP)
RET
TEXT runtime·gogetcallerpc(SB),NOSPLIT,$-4-8
MOVW R14, ret+4(FP)
RET
TEXT runtime·setcallerpc(SB),NOSPLIT,$-4-8
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
MOVW pc+4(FP), R0
MOVW R0, 0(SP)
RET
TEXT runtime·getcallersp(SB),NOSPLIT,$-4-4
MOVW 0(FP), R0
MOVW $-4(R0), R0
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
MOVW R0, ret+4(FP)
RET
// func gogetcallersp(p unsafe.Pointer) uintptr
TEXT runtime·gogetcallersp(SB),NOSPLIT,$-4-8
MOVW 0(FP), R0
MOVW $-4(R0), R0
MOVW R0, ret+4(FP)
RET
TEXT runtime·emptyfunc(SB),0,$0-0
RET
TEXT runtime·abort(SB),NOSPLIT,$-4-0
MOVW $0, R0
MOVW (R0), R1
// bool armcas(int32 *val, int32 old, int32 new)
// Atomically:
// if(*val == old){
// *val = new;
// return 1;
// }else
// return 0;
//
// To implement runtime·cas in sys_$GOOS_arm.s
// using the native instructions, use:
//
// TEXT runtime·cas(SB),NOSPLIT,$0
// B runtime·armcas(SB)
//
TEXT runtime·armcas(SB),NOSPLIT,$0-13
MOVW valptr+0(FP), R1
MOVW old+4(FP), R2
MOVW new+8(FP), R3
casl:
LDREX (R1), R0
CMP R0, R2
BNE casfail
STREX R3, (R1), R0
CMP $0, R0
BNE casl
MOVW $1, R0
MOVB R0, ret+12(FP)
RET
casfail:
MOVW $0, R0
MOVB R0, ret+12(FP)
RET
TEXT runtime·casuintptr(SB),NOSPLIT,$0-13
B runtime·cas(SB)
TEXT runtime·atomicloaduintptr(SB),NOSPLIT,$0-8
B runtime·atomicload(SB)
TEXT runtime·atomicloaduint(SB),NOSPLIT,$0-8
B runtime·atomicload(SB)
// AES hashing not implemented for ARM
TEXT runtime·aeshash(SB),NOSPLIT,$-4-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshash32(SB),NOSPLIT,$-4-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshash64(SB),NOSPLIT,$-4-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshashstr(SB),NOSPLIT,$-4-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·memeq(SB),NOSPLIT,$-4-13
MOVW a+0(FP), R1
MOVW b+4(FP), R2
MOVW size+8(FP), R3
ADD R1, R3, R6
MOVW $1, R0
MOVB R0, ret+12(FP)
_next2:
CMP R1, R6
RET.EQ
MOVBU.P 1(R1), R4
MOVBU.P 1(R2), R5
CMP R4, R5
BEQ _next2
MOVW $0, R0
MOVB R0, ret+12(FP)
RET
// eqstring tests whether two strings are equal.
// See runtime_test.go:eqstring_generic for
// equivalent Go code.
TEXT runtime·eqstring(SB),NOSPLIT,$-4-17
MOVW s1len+4(FP), R0
MOVW s2len+12(FP), R1
MOVW $0, R7
CMP R0, R1
MOVB.NE R7, v+16(FP)
RET.NE
MOVW s1str+0(FP), R2
MOVW s2str+8(FP), R3
MOVW $1, R8
MOVB R8, v+16(FP)
CMP R2, R3
RET.EQ
ADD R2, R0, R6
_eqnext:
CMP R2, R6
RET.EQ
MOVBU.P 1(R2), R4
MOVBU.P 1(R3), R5
CMP R4, R5
BEQ _eqnext
MOVB R7, v+16(FP)
RET
// void setg_gcc(G*); set g called from gcc.
2014-06-26 09:54:39 -06:00
TEXT setg_gcc<>(SB),NOSPLIT,$0
MOVW R0, g
B runtime·save_g(SB)
runtime.cmd/ld: Add ARM external linking and implement -shared in terms of external linking This CL is an aggregate of 10271047, 10499043, 9733044. Descriptions of each follow: 10499043 runtime,cmd/ld: Merge TLS symbols and teach 5l about ARM TLS This CL prepares for external linking support to ARM. The pseudo-symbols runtime.g and runtime.m are merged into a single runtime.tlsgm symbol. When external linking, the offset of a thread local variable is stored at a memory location instead of being embedded into a offset of a ldr instruction. With a single runtime.tlsgm symbol for both g and m, only one such offset is needed. The larger part of this CL moves TLS code from gcc compiled to internally compiled. The TLS code now uses the modern MRC instruction, and 5l is taught about TLS fallbacks in case the instruction is not available or appropriate. 10271047 This CL adds support for -linkmode external to 5l. For 5l itself, use addrel to allow for D_CALL relocations to be handled by the host linker. Of the cases listed in rsc's comment in issue 4069, only case 5 and 63 needed an update. One of the TODO: addrel cases was since replaced, and the rest of the cases are either covered by indirection through addpool (cases with LTO or LFROM flags) or stubs (case 74). The addpool cases are covered because addpool emits AWORD instructions, which in turn are handled by case 11. In the runtime, change the argv argument in the rt0* functions slightly to be a pointer to the argv list, instead of relying on a particular location of argv. 9733044 The -shared flag to 6l outputs a shared library, implemented in Go and callable from non-Go programs such as C. The main part of this CL change the thread local storage model. Go uses the fastest and least general mode, local exec. TLS data in shared libraries normally requires at least the local dynamic mode, however, this CL instead opts for using the initial exec mode. Initial exec mode is faster than local dynamic mode and can be used in linux since the linker has reserved a limited amount of TLS space for performance sensitive TLS code. Initial exec mode requires an extra load from the GOT table to determine the TLS offset. This penalty will not be paid if ld is not in -shared mode, since TLS accesses will be reduced to local exec. The elf sections .init_array and .rela.init_array are added to register the Go runtime entry with cgo at library load time. The "hidden" attribute is added to Cgo functions called from Go, since Go does not generate call through the GOT table, and adding non-GOT relocations for a global function is not supported by gcc. Cgo symbols don't need to be global and avoiding the GOT table is also faster. The changes to 8l are only removes code relevant to the old -shared mode where internal linking was used. This CL only address the low level linker work. It can be submitted by itself, but to be useful, the runtime changes in CL 9738047 is also needed. Design discussion at https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/zmjXkGrEx6Q Fixes #5590. R=rsc CC=golang-dev https://golang.org/cl/12871044
2013-08-14 09:38:54 -06:00
// TODO: share code with memeq?
TEXT bytes·Equal(SB),NOSPLIT,$0
MOVW a_len+4(FP), R1
MOVW b_len+16(FP), R3
CMP R1, R3 // unequal lengths are not equal
B.NE _notequal
MOVW a+0(FP), R0
MOVW b+12(FP), R2
ADD R0, R1 // end
_byteseq_next:
CMP R0, R1
B.EQ _equal // reached the end
MOVBU.P 1(R0), R4
MOVBU.P 1(R2), R5
CMP R4, R5
B.EQ _byteseq_next
_notequal:
MOVW $0, R0
MOVBU R0, ret+24(FP)
RET
_equal:
MOVW $1, R0
MOVBU R0, ret+24(FP)
RET
TEXT bytes·IndexByte(SB),NOSPLIT,$0
MOVW s+0(FP), R0
MOVW s_len+4(FP), R1
MOVBU c+12(FP), R2 // byte to find
MOVW R0, R4 // store base for later
ADD R0, R1 // end
_loop:
CMP R0, R1
B.EQ _notfound
MOVBU.P 1(R0), R3
CMP R2, R3
B.NE _loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVW R0, ret+16(FP)
RET
_notfound:
MOVW $-1, R0
MOVW R0, ret+16(FP)
RET
TEXT strings·IndexByte(SB),NOSPLIT,$0
MOVW s+0(FP), R0
MOVW s_len+4(FP), R1
MOVBU c+8(FP), R2 // byte to find
MOVW R0, R4 // store base for later
ADD R0, R1 // end
_sib_loop:
CMP R0, R1
B.EQ _sib_notfound
MOVBU.P 1(R0), R3
CMP R2, R3
B.NE _sib_loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVW R0, ret+12(FP)
RET
_sib_notfound:
MOVW $-1, R0
MOVW R0, ret+12(FP)
RET
// A Duff's device for zeroing memory.
// The compiler jumps to computed addresses within
// this routine to zero chunks of memory. Do not
// change this code without also changing the code
// in ../../cmd/5g/ggen.c:clearfat.
// R0: zero
// R1: ptr to memory to be zeroed
// R1 is updated as a side effect.
TEXT runtime·duffzero(SB),NOSPLIT,$0-0
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
MOVW.P R0, 4(R1)
RET
// A Duff's device for copying memory.
// The compiler jumps to computed addresses within
// this routine to copy chunks of memory. Source
// and destination must not overlap. Do not
// change this code without also changing the code
// in ../../cmd/5g/cgen.c:sgen.
// R0: scratch space
// R1: ptr to source memory
// R2: ptr to destination memory
// R1 and R2 are updated as a side effect
TEXT runtime·duffcopy(SB),NOSPLIT,$0-0
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
MOVW.P 4(R1), R0
MOVW.P R0, 4(R2)
RET
TEXT runtime·fastrand1(SB),NOSPLIT,$-4-4
MOVW g_m(g), R1
MOVW m_fastrand(R1), R0
ADD.S R0, R0
EOR.MI $0x88888eef, R0
MOVW R0, m_fastrand(R1)
MOVW R0, ret+0(FP)
RET
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
TEXT runtime·gocputicks(SB),NOSPLIT,$0
cmd/cc, runtime: convert C compilers to use Go calling convention To date, the C compilers and Go compilers differed only in how values were returned from functions. This made it difficult to call Go from C or C from Go if return values were involved. It also made assembly called from Go and assembly called from C different. This CL changes the C compiler to use the Go conventions, passing results on the stack, after the arguments. [Exception: this does not apply to C ... functions, because you can't know where on the stack the arguments end.] By doing this, the CL makes it possible to rewrite C functions into Go one at a time, without worrying about which languages call that function or which languages it calls. This CL also updates all the assembly files in package runtime to use the new conventions. Argument references of the form 40(SP) have been rewritten to the form name+10(FP) instead, and there are now Go func prototypes for every assembly function called from C or Go. This means that 'go vet runtime' checks effectively every assembly function, and go vet's output was used to automate the bulk of the conversion. Some functions, like seek and nsec on Plan 9, needed to be rewritten. Many assembly routines called from C were reading arguments incorrectly, using MOVL instead of MOVQ or vice versa, especially on the less used systems like openbsd. These were found by go vet and have been corrected too. If we're lucky, this may reduce flakiness on those systems. Tested on: darwin/386 darwin/amd64 linux/arm linux/386 linux/amd64 If this breaks another system, the bug is almost certainly in the sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested by the combination of the above systems. LGTM=dvyukov, iant R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant CC=golang-codereviews, josharian, r https://golang.org/cl/135830043
2014-08-27 09:32:17 -06:00
B runtime·cputicks(SB)
TEXT runtime·return0(SB),NOSPLIT,$0
MOVW $0, R0
RET
TEXT runtime·procyield(SB),NOSPLIT,$-4
MOVW cycles+0(FP), R1
MOVW $0, R0
yieldloop:
CMP R0, R1
B.NE 2(PC)
RET
SUB $1, R1
B yieldloop
// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
TEXT cgo_topofstack(SB),NOSPLIT,$0
MOVW g_m(g), R0
MOVW m_curg(R0), R0
MOVW (g_stack+stack_hi)(R0), R0
RET