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687d9d5d78
go/src/runtime/asm_arm64.s
Austin Clements 687d9d5d78 runtime: print a message on bad morestack 
If morestack runs on the g0 or gsignal stack, it currently performs
some abort operation that typically produces a signal (e.g., it does
an INT $3 on x86). This is useful if you're running in a debugger, but
if you're not, the runtime tries to trap this signal, which is likely
to send the program into a deeper spiral of collapse and lead to very
confusing diagnostic output.

Help out people trying to debug without a debugger by making morestack
print an informative message before blowing up.

Change-Id: I2814c64509b137bfe20a00091d8551d18c2c4749
Reviewed-on: https://go-review.googlesource.com/31133
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-17 18:56:09 +00:00

1001 lines
24 KiB
ArmAsm
Raw Blame History

// Copyright 2015 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 "go_asm.h"
#include "go_tls.h"
#include "tls_arm64.h"
#include "funcdata.h"
#include "textflag.h"
TEXT runtime·rt0_go(SB),NOSPLIT,$0
// SP = stack; R0 = argc; R1 = argv
SUB $32, RSP
MOVW R0, 8(RSP) // argc
MOVD R1, 16(RSP) // argv
// create istack out of the given (operating system) stack.
// _cgo_init may update stackguard.
MOVD $runtime·g0(SB), g
MOVD RSP, R7
MOVD $(-64*1024)(R7), R0
MOVD R0, g_stackguard0(g)
MOVD R0, g_stackguard1(g)
MOVD R0, (g_stack+stack_lo)(g)
MOVD R7, (g_stack+stack_hi)(g)
// if there is a _cgo_init, call it using the gcc ABI.
MOVD _cgo_init(SB), R12
CMP $0, R12
BEQ nocgo
MRS_TPIDR_R0 // load TLS base pointer
MOVD R0, R3 // arg 3: TLS base pointer
#ifdef TLSG_IS_VARIABLE
MOVD $runtime·tls_g(SB), R2 // arg 2: &tls_g
#else
MOVD $0, R2 // arg 2: not used when using platform's TLS
#endif
MOVD $setg_gcc<>(SB), R1 // arg 1: setg
MOVD g, R0 // arg 0: G
BL (R12)
MOVD _cgo_init(SB), R12
CMP $0, R12
BEQ nocgo
nocgo:
// update stackguard after _cgo_init
MOVD (g_stack+stack_lo)(g), R0
ADD $const__StackGuard, R0
MOVD R0, g_stackguard0(g)
MOVD R0, g_stackguard1(g)
// set the per-goroutine and per-mach "registers"
MOVD $runtime·m0(SB), R0
// save m->g0 = g0
MOVD g, m_g0(R0)
// save m0 to g0->m
MOVD R0, g_m(g)
BL runtime·check(SB)
MOVW 8(RSP), R0 // copy argc
MOVW R0, -8(RSP)
MOVD 16(RSP), R0 // copy argv
MOVD R0, 0(RSP)
BL runtime·args(SB)
BL runtime·osinit(SB)
BL runtime·schedinit(SB)
// create a new goroutine to start program
MOVD $runtime·mainPC(SB), R0 // entry
MOVD RSP, R7
MOVD.W $0, -8(R7)
MOVD.W R0, -8(R7)
MOVD.W $0, -8(R7)
MOVD.W $0, -8(R7)
MOVD R7, RSP
BL runtime·newproc(SB)
ADD $32, RSP
// start this M
BL runtime·mstart(SB)
MOVD $0, R0
MOVD R0, (R0) // boom
UNDEF
DATA runtime·mainPC+0(SB)/8,$runtime·main(SB)
GLOBL runtime·mainPC(SB),RODATA,$8
TEXT runtime·breakpoint(SB),NOSPLIT,$-8-0
BRK
RET
TEXT runtime·asminit(SB),NOSPLIT,$-8-0
RET
/*
* go-routine
*/
// void gosave(Gobuf*)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB), NOSPLIT, $-8-8
MOVD buf+0(FP), R3
MOVD RSP, R0
MOVD R0, gobuf_sp(R3)
MOVD LR, gobuf_pc(R3)
MOVD g, gobuf_g(R3)
MOVD ZR, gobuf_lr(R3)
MOVD ZR, gobuf_ret(R3)
MOVD ZR, gobuf_ctxt(R3)
RET
// void gogo(Gobuf*)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), NOSPLIT, $-8-8
MOVD buf+0(FP), R5
MOVD gobuf_g(R5), g
BL runtime·save_g(SB)
MOVD 0(g), R4 // make sure g is not nil
MOVD gobuf_sp(R5), R0
MOVD R0, RSP
MOVD gobuf_lr(R5), LR
MOVD gobuf_ret(R5), R0
MOVD gobuf_ctxt(R5), R26
MOVD $0, gobuf_sp(R5)
MOVD $0, gobuf_ret(R5)
MOVD $0, gobuf_lr(R5)
MOVD $0, gobuf_ctxt(R5)
CMP ZR, ZR // set condition codes for == test, needed by stack split
MOVD gobuf_pc(R5), R6
B (R6)
// void mcall(fn func(*g))
// Switch to m->g0's stack, call fn(g).
// Fn must never return. It should gogo(&g->sched)
// to keep running g.
TEXT runtime·mcall(SB), NOSPLIT, $-8-8
// Save caller state in g->sched
MOVD RSP, R0
MOVD R0, (g_sched+gobuf_sp)(g)
MOVD LR, (g_sched+gobuf_pc)(g)
MOVD $0, (g_sched+gobuf_lr)(g)
MOVD g, (g_sched+gobuf_g)(g)
// Switch to m->g0 & its stack, call fn.
MOVD g, R3
MOVD g_m(g), R8
MOVD m_g0(R8), g
BL runtime·save_g(SB)
CMP g, R3
BNE 2(PC)
B runtime·badmcall(SB)
MOVD fn+0(FP), R26 // context
MOVD 0(R26), R4 // code pointer
MOVD (g_sched+gobuf_sp)(g), R0
MOVD R0, RSP // sp = m->g0->sched.sp
MOVD R3, -8(RSP)
MOVD $0, -16(RSP)
SUB $16, RSP
BL (R4)
B runtime·badmcall2(SB)
// systemstack_switch is a dummy routine that systemstack 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 system stack because the one at the top of
// the system stack terminates the stack walk (see topofstack()).
TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
UNDEF
BL (LR) // make sure this function is not leaf
RET
// func systemstack(fn func())
TEXT runtime·systemstack(SB), NOSPLIT, $0-8
MOVD fn+0(FP), R3 // R3 = fn
MOVD R3, R26 // context
MOVD g_m(g), R4 // R4 = m
MOVD m_gsignal(R4), R5 // R5 = gsignal
CMP g, R5
BEQ noswitch
MOVD m_g0(R4), R5 // R5 = g0
CMP g, R5
BEQ noswitch
MOVD m_curg(R4), R6
CMP g, R6
BEQ switch
// Bad: g is not gsignal, not g0, not curg. What is it?
// Hide call from linker nosplit analysis.
MOVD $runtime·badsystemstack(SB), R3
BL (R3)
switch:
// save our state in g->sched. Pretend to
// be systemstack_switch if the G stack is scanned.
MOVD $runtime·systemstack_switch(SB), R6
ADD $8, R6 // get past prologue
MOVD R6, (g_sched+gobuf_pc)(g)
MOVD RSP, R0
MOVD R0, (g_sched+gobuf_sp)(g)
MOVD $0, (g_sched+gobuf_lr)(g)
MOVD g, (g_sched+gobuf_g)(g)
// switch to g0
MOVD R5, g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R3
// make it look like mstart called systemstack on g0, to stop traceback
SUB $16, R3
AND $~15, R3
MOVD $runtime·mstart(SB), R4
MOVD R4, 0(R3)
MOVD R3, RSP
// call target function
MOVD 0(R26), R3 // code pointer
BL (R3)
// switch back to g
MOVD g_m(g), R3
MOVD m_curg(R3), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R0
MOVD R0, RSP
MOVD $0, (g_sched+gobuf_sp)(g)
RET
noswitch:
// already on m stack, just call directly
MOVD 0(R26), R3 // code pointer
BL (R3)
RET
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
// Caller has already loaded:
// R3 prolog's LR (R30)
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must
// record an argument size. For that purpose, it has no arguments.
TEXT runtime·morestack(SB),NOSPLIT,$-8-0
// Cannot grow scheduler stack (m->g0).
MOVD g_m(g), R8
MOVD m_g0(R8), R4
CMP g, R4
BNE 3(PC)
BL runtime·badmorestackg0(SB)
B runtime·abort(SB)
// Cannot grow signal stack (m->gsignal).
MOVD m_gsignal(R8), R4
CMP g, R4
BNE 3(PC)
BL runtime·badmorestackgsignal(SB)
B runtime·abort(SB)
// Called from f.
// Set g->sched to context in f
MOVD R26, (g_sched+gobuf_ctxt)(g)
MOVD RSP, R0
MOVD R0, (g_sched+gobuf_sp)(g)
MOVD LR, (g_sched+gobuf_pc)(g)
MOVD R3, (g_sched+gobuf_lr)(g)
// Called from f.
// Set m->morebuf to f's callers.
MOVD R3, (m_morebuf+gobuf_pc)(R8) // f's caller's PC
MOVD RSP, R0
MOVD R0, (m_morebuf+gobuf_sp)(R8) // f's caller's RSP
MOVD g, (m_morebuf+gobuf_g)(R8)
// Call newstack on m->g0's stack.
MOVD m_g0(R8), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R0
MOVD R0, RSP
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.
UNDEF
TEXT runtime·morestack_noctxt(SB),NOSPLIT,$-4-0
MOVW $0, R26
B runtime·morestack(SB)
TEXT runtime·stackBarrier(SB),NOSPLIT,$0
// We came here via a RET to an overwritten LR.
// R0 may be live (see return0). Other registers are available.
// Get the original return PC, g.stkbar[g.stkbarPos].savedLRVal.
MOVD (g_stkbar+slice_array)(g), R4
MOVD g_stkbarPos(g), R5
MOVD $stkbar__size, R6
MUL R5, R6
ADD R4, R6
MOVD stkbar_savedLRVal(R6), R6
// Record that this stack barrier was hit.
ADD $1, R5
MOVD R5, g_stkbarPos(g)
// Jump to the original return PC.
B (R6)
// reflectcall: call a function with the given argument list
// func call(argtype *_type, 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) \
MOVD $MAXSIZE, R27; \
CMP R27, R16; \
BGT 3(PC); \
MOVD $NAME(SB), R27; \
B (R27)
// Note: can't just "B NAME(SB)" - bad inlining results.
TEXT reflect·call(SB), NOSPLIT, $0-0
B ·reflectcall(SB)
TEXT ·reflectcall(SB), NOSPLIT, $-8-32
MOVWU argsize+24(FP), R16
// NOTE(rsc): No call16, because CALLFN needs four words
// of argument space to invoke callwritebarrier.
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)
MOVD $runtime·badreflectcall(SB), R0
B (R0)
#define CALLFN(NAME,MAXSIZE) \
TEXT NAME(SB), WRAPPER, $MAXSIZE-24; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
MOVD arg+16(FP), R3; \
MOVWU argsize+24(FP), R4; \
MOVD RSP, R5; \
ADD $(8-1), R5; \
SUB $1, R3; \
ADD R5, R4; \
CMP R5, R4; \
BEQ 4(PC); \
MOVBU.W 1(R3), R6; \
MOVBU.W R6, 1(R5); \
B -4(PC); \
/* call function */ \
MOVD f+8(FP), R26; \
MOVD (R26), R0; \
PCDATA $PCDATA_StackMapIndex, $0; \
BL (R0); \
/* copy return values back */ \
MOVD arg+16(FP), R3; \
MOVWU n+24(FP), R4; \
MOVWU retoffset+28(FP), R6; \
MOVD RSP, R5; \
ADD R6, R5; \
ADD R6, R3; \
SUB R6, R4; \
ADD $(8-1), R5; \
SUB $1, R3; \
ADD R5, R4; \
loop: \
CMP R5, R4; \
BEQ end; \
MOVBU.W 1(R5), R6; \
MOVBU.W R6, 1(R3); \
B loop; \
end: \
/* execute write barrier updates */ \
MOVD argtype+0(FP), R7; \
MOVD arg+16(FP), R3; \
MOVWU n+24(FP), R4; \
MOVWU retoffset+28(FP), R6; \
MOVD R7, 8(RSP); \
MOVD R3, 16(RSP); \
MOVD R4, 24(RSP); \
MOVD R6, 32(RSP); \
BL runtime·callwritebarrier(SB); \
RET
// These have 8 added to make the overall frame size a multiple of 16,
// as required by the ABI. (There is another +8 for the saved LR.)
CALLFN(·call32, 40 )
CALLFN(·call64, 72 )
CALLFN(·call128, 136 )
CALLFN(·call256, 264 )
CALLFN(·call512, 520 )
CALLFN(·call1024, 1032 )
CALLFN(·call2048, 2056 )
CALLFN(·call4096, 4104 )
CALLFN(·call8192, 8200 )
CALLFN(·call16384, 16392 )
CALLFN(·call32768, 32776 )
CALLFN(·call65536, 65544 )
CALLFN(·call131072, 131080 )
CALLFN(·call262144, 262152 )
CALLFN(·call524288, 524296 )
CALLFN(·call1048576, 1048584 )
CALLFN(·call2097152, 2097160 )
CALLFN(·call4194304, 4194312 )
CALLFN(·call8388608, 8388616 )
CALLFN(·call16777216, 16777224 )
CALLFN(·call33554432, 33554440 )
CALLFN(·call67108864, 67108872 )
CALLFN(·call134217728, 134217736 )
CALLFN(·call268435456, 268435464 )
CALLFN(·call536870912, 536870920 )
CALLFN(·call1073741824, 1073741832 )
// AES hashing not implemented for ARM64, issue #10109.
TEXT runtime·aeshash(SB),NOSPLIT,$-8-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshash32(SB),NOSPLIT,$-8-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshash64(SB),NOSPLIT,$-8-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·aeshashstr(SB),NOSPLIT,$-8-0
MOVW $0, R0
MOVW (R0), R1
TEXT runtime·procyield(SB),NOSPLIT,$0-0
MOVWU cycles+0(FP), R0
again:
YIELD
SUBW $1, R0
CBNZ R0, again
RET
// void jmpdefer(fv, sp);
// called from deferreturn.
// 1. grab stored LR for caller
// 2. sub 4 bytes to get back to BL deferreturn
// 3. BR to fn
TEXT runtime·jmpdefer(SB), NOSPLIT, $-8-16
MOVD 0(RSP), R0
SUB $4, R0
MOVD R0, LR
MOVD fv+0(FP), R26
MOVD argp+8(FP), R0
MOVD R0, RSP
SUB $8, RSP
MOVD 0(R26), R3
B (R3)
// Save state of caller into g->sched. Smashes R0.
TEXT gosave<>(SB),NOSPLIT,$-8
MOVD LR, (g_sched+gobuf_pc)(g)
MOVD RSP, R0
MOVD R0, (g_sched+gobuf_sp)(g)
MOVD $0, (g_sched+gobuf_lr)(g)
MOVD $0, (g_sched+gobuf_ret)(g)
MOVD $0, (g_sched+gobuf_ctxt)(g)
RET
// func asmcgocall(fn, arg unsafe.Pointer) int32
// Call fn(arg) on the scheduler stack,
// aligned appropriately for the gcc ABI.
// See cgocall.go for more details.
TEXT ·asmcgocall(SB),NOSPLIT,$0-20
MOVD fn+0(FP), R1
MOVD arg+8(FP), R0
MOVD RSP, R2 // save original stack pointer
MOVD 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.
MOVD g_m(g), R8
MOVD m_g0(R8), R3
CMP R3, g
BEQ g0
MOVD R0, R9 // gosave<> and save_g might clobber R0
BL gosave<>(SB)
MOVD R3, g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R0
MOVD R0, RSP
MOVD R9, R0
// Now on a scheduling stack (a pthread-created stack).
g0:
// Save room for two of our pointers /*, plus 32 bytes of callee
// save area that lives on the caller stack. */
MOVD RSP, R13
SUB $16, R13
MOVD R13, RSP
MOVD R4, 0(RSP) // save old g on stack
MOVD (g_stack+stack_hi)(R4), R4
SUB R2, R4
MOVD R4, 8(RSP) // save depth in old g stack (can't just save SP, as stack might be copied during a callback)
BL (R1)
MOVD R0, R9
// Restore g, stack pointer. R0 is errno, so don't touch it
MOVD 0(RSP), g
BL runtime·save_g(SB)
MOVD (g_stack+stack_hi)(g), R5
MOVD 8(RSP), R6
SUB R6, R5
MOVD R9, R0
MOVD R5, RSP
MOVW R0, ret+16(FP)
RET
// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt)
// Turn the fn into a Go func (by taking its address) and call
// cgocallback_gofunc.
TEXT runtime·cgocallback(SB),NOSPLIT,$40-32
MOVD $fn+0(FP), R0
MOVD R0, 8(RSP)
MOVD frame+8(FP), R0
MOVD R0, 16(RSP)
MOVD framesize+16(FP), R0
MOVD R0, 24(RSP)
MOVD ctxt+24(FP), R0
MOVD R0, 32(RSP)
MOVD $runtime·cgocallback_gofunc(SB), R0
BL (R0)
RET
// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize, uintptr ctxt)
// See cgocall.go for more details.
TEXT ·cgocallback_gofunc(SB),NOSPLIT,$24-32
NO_LOCAL_POINTERS
// Load g from thread-local storage.
MOVB runtime·iscgo(SB), R3
CMP $0, R3
BEQ nocgo
BL runtime·load_g(SB)
nocgo:
// 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.
CMP $0, g
BEQ needm
MOVD g_m(g), R8
MOVD R8, savedm-8(SP)
B havem
needm:
MOVD g, savedm-8(SP) // g is zero, so is m.
MOVD $runtime·needm(SB), R0
BL (R0)
// Set m->sched.sp = SP, so that if a panic happens
// during the function we are about to execute, it will
// have a valid SP to run on the g0 stack.
// The next few lines (after the havem label)
// will save this SP onto the stack and then write
// the same SP back to m->sched.sp. That seems redundant,
// but if an unrecovered panic happens, unwindm will
// restore the g->sched.sp from the stack location
// and then systemstack will try to use it. If we don't set it here,
// that restored SP will be uninitialized (typically 0) and
// will not be usable.
MOVD g_m(g), R8
MOVD m_g0(R8), R3
MOVD RSP, R0
MOVD R0, (g_sched+gobuf_sp)(R3)
havem:
// 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 16(RSP) aka savedsp-16(SP).
// Beware that the frame size is actually 32.
MOVD m_g0(R8), R3
MOVD (g_sched+gobuf_sp)(R3), R4
MOVD R4, savedsp-16(SP)
MOVD RSP, R0
MOVD R0, (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) is unused (where SP refers to
// m->curg's SP while we're setting it up, before we've adjusted it).
MOVD m_curg(R8), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R4 // prepare stack as R4
MOVD (g_sched+gobuf_pc)(g), R5
MOVD R5, -(24+8)(R4)
MOVD ctxt+24(FP), R0
MOVD R0, -(16+8)(R4)
MOVD $-(24+8)(R4), R0 // maintain 16-byte SP alignment
MOVD R0, RSP
BL runtime·cgocallbackg(SB)
// Restore g->sched (== m->curg->sched) from saved values.
MOVD 0(RSP), R5
MOVD R5, (g_sched+gobuf_pc)(g)
MOVD RSP, R4
ADD $(24+8), R4, R4
MOVD 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.)
MOVD g_m(g), R8
MOVD m_g0(R8), g
BL runtime·save_g(SB)
MOVD (g_sched+gobuf_sp)(g), R0
MOVD R0, RSP
MOVD savedsp-16(SP), R4
MOVD R4, (g_sched+gobuf_sp)(g)
// 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.
MOVD savedm-8(SP), R6
CMP $0, R6
BNE droppedm
MOVD $runtime·dropm(SB), R0
BL (R0)
droppedm:
// Done!
RET
// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
TEXT _cgo_topofstack(SB),NOSPLIT,$24
// g (R28) and REGTMP (R27) might be clobbered by load_g. They
// are callee-save in the gcc calling convention, so save them.
MOVD R27, savedR27-8(SP)
MOVD g, saveG-16(SP)
BL runtime·load_g(SB)
MOVD g_m(g), R0
MOVD m_curg(R0), R0
MOVD (g_stack+stack_hi)(R0), R0
MOVD saveG-16(SP), g
MOVD savedR28-8(SP), R27
RET
// void setg(G*); set g. for use by needm.
TEXT runtime·setg(SB), NOSPLIT, $0-8
MOVD gg+0(FP), g
// This only happens if iscgo, so jump straight to save_g
BL runtime·save_g(SB)
RET
// void setg_gcc(G*); set g called from gcc
TEXT setg_gcc<>(SB),NOSPLIT,$8
MOVD R0, g
MOVD R27, savedR27-8(SP)
BL runtime·save_g(SB)
MOVD savedR27-8(SP), R27
RET
TEXT runtime·getcallerpc(SB),NOSPLIT,$8-16
MOVD 16(RSP), R0 // LR saved by caller
MOVD runtime·stackBarrierPC(SB), R1
CMP R0, R1
BNE nobar
// Get original return PC.
BL runtime·nextBarrierPC(SB)
MOVD 8(RSP), R0
nobar:
MOVD R0, ret+8(FP)
RET
TEXT runtime·setcallerpc(SB),NOSPLIT,$8-16
MOVD pc+8(FP), R0
MOVD 16(RSP), R1
MOVD runtime·stackBarrierPC(SB), R2
CMP R1, R2
BEQ setbar
MOVD R0, 16(RSP) // set LR in caller
RET
setbar:
// Set the stack barrier return PC.
MOVD R0, 8(RSP)
BL runtime·setNextBarrierPC(SB)
RET
TEXT runtime·abort(SB),NOSPLIT,$-8-0
B (ZR)
UNDEF
// memhash_varlen(p unsafe.Pointer, h seed) uintptr
// redirects to memhash(p, h, size) using the size
// stored in the closure.
TEXT runtime·memhash_varlen(SB),NOSPLIT,$40-24
GO_ARGS
NO_LOCAL_POINTERS
MOVD p+0(FP), R3
MOVD h+8(FP), R4
MOVD 8(R26), R5
MOVD R3, 8(RSP)
MOVD R4, 16(RSP)
MOVD R5, 24(RSP)
BL runtime·memhash(SB)
MOVD 32(RSP), R3
MOVD R3, ret+16(FP)
RET
// memequal(p, q unsafe.Pointer, size uintptr) bool
TEXT runtime·memequal(SB),NOSPLIT,$-8-25
MOVD a+0(FP), R1
MOVD b+8(FP), R2
MOVD size+16(FP), R3
ADD R1, R3, R6
MOVD $1, R0
MOVB R0, ret+24(FP)
CMP R1, R2
BEQ done
loop:
CMP R1, R6
BEQ done
MOVBU.P 1(R1), R4
MOVBU.P 1(R2), R5
CMP R4, R5
BEQ loop
MOVB $0, ret+24(FP)
done:
RET
// memequal_varlen(a, b unsafe.Pointer) bool
TEXT runtime·memequal_varlen(SB),NOSPLIT,$40-17
MOVD a+0(FP), R3
MOVD b+8(FP), R4
CMP R3, R4
BEQ eq
MOVD 8(R26), R5 // compiler stores size at offset 8 in the closure
MOVD R3, 8(RSP)
MOVD R4, 16(RSP)
MOVD R5, 24(RSP)
BL runtime·memequal(SB)
MOVBU 32(RSP), R3
MOVB R3, ret+16(FP)
RET
eq:
MOVD $1, R3
MOVB R3, ret+16(FP)
RET
TEXT runtime·cmpstring(SB),NOSPLIT,$-4-40
MOVD s1_base+0(FP), R2
MOVD s1_len+8(FP), R0
MOVD s2_base+16(FP), R3
MOVD s2_len+24(FP), R1
ADD $40, RSP, R7
B runtime·cmpbody<>(SB)
TEXT bytes·Compare(SB),NOSPLIT,$-4-56
MOVD s1+0(FP), R2
MOVD s1+8(FP), R0
MOVD s2+24(FP), R3
MOVD s2+32(FP), R1
ADD $56, RSP, R7
B runtime·cmpbody<>(SB)
// On entry:
// R0 is the length of s1
// R1 is the length of s2
// R2 points to the start of s1
// R3 points to the start of s2
// R7 points to return value (-1/0/1 will be written here)
//
// On exit:
// R4, R5, and R6 are clobbered
TEXT runtime·cmpbody<>(SB),NOSPLIT,$-4-0
CMP R2, R3
BEQ samebytes // same starting pointers; compare lengths
CMP R0, R1
CSEL LT, R1, R0, R6 // R6 is min(R0, R1)
ADD R2, R6 // R2 is current byte in s1, R6 is last byte in s1 to compare
loop:
CMP R2, R6
BEQ samebytes // all compared bytes were the same; compare lengths
MOVBU.P 1(R2), R4
MOVBU.P 1(R3), R5
CMP R4, R5
BEQ loop
// bytes differed
MOVD $1, R4
CSNEG LT, R4, R4, R4
MOVD R4, (R7)
RET
samebytes:
MOVD $1, R4
CMP R0, R1
CSNEG LT, R4, R4, R4
CSEL EQ, ZR, R4, R4
MOVD R4, (R7)
RET
// eqstring tests whether two strings are equal.
// The compiler guarantees that strings passed
// to eqstring have equal length.
// See runtime_test.go:eqstring_generic for
// equivalent Go code.
TEXT runtime·eqstring(SB),NOSPLIT,$0-33
MOVD s1_base+0(FP), R0
MOVD s1_len+8(FP), R1
MOVD s2_base+16(FP), R2
ADD R0, R1 // end
loop:
CMP R0, R1
BEQ equal // reaches the end
MOVBU.P 1(R0), R4
MOVBU.P 1(R2), R5
CMP R4, R5
BEQ loop
notequal:
MOVB ZR, ret+32(FP)
RET
equal:
MOVD $1, R0
MOVB R0, ret+32(FP)
RET
//
// functions for other packages
//
TEXT bytes·IndexByte(SB),NOSPLIT,$0-40
MOVD b+0(FP), R0
MOVD b_len+8(FP), R1
MOVBU c+24(FP), R2 // byte to find
MOVD R0, R4 // store base for later
ADD R0, R1 // end
loop:
CMP R0, R1
BEQ notfound
MOVBU.P 1(R0), R3
CMP R2, R3
BNE loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVD R0, ret+32(FP)
RET
notfound:
MOVD $-1, R0
MOVD R0, ret+32(FP)
RET
TEXT strings·IndexByte(SB),NOSPLIT,$0-32
MOVD s+0(FP), R0
MOVD s_len+8(FP), R1
MOVBU c+16(FP), R2 // byte to find
MOVD R0, R4 // store base for later
ADD R0, R1 // end
loop:
CMP R0, R1
BEQ notfound
MOVBU.P 1(R0), R3
CMP R2, R3
BNE loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVD R0, ret+24(FP)
RET
notfound:
MOVD $-1, R0
MOVD R0, ret+24(FP)
RET
// TODO: share code with memequal?
TEXT bytes·Equal(SB),NOSPLIT,$0-49
MOVD a_len+8(FP), R1
MOVD b_len+32(FP), R3
CMP R1, R3 // unequal lengths are not equal
BNE notequal
MOVD a+0(FP), R0
MOVD b+24(FP), R2
ADD R0, R1 // end
loop:
CMP R0, R1
BEQ equal // reaches the end
MOVBU.P 1(R0), R4
MOVBU.P 1(R2), R5
CMP R4, R5
BEQ loop
notequal:
MOVB ZR, ret+48(FP)
RET
equal:
MOVD $1, R0
MOVB R0, ret+48(FP)
RET
TEXT runtime·fastrand(SB),NOSPLIT,$-8-4
MOVD g_m(g), R1
MOVWU m_fastrand(R1), R0
ADD R0, R0
CMPW $0, R0
BGE notneg
EOR $0x88888eef, R0
notneg:
MOVW R0, m_fastrand(R1)
MOVW R0, ret+0(FP)
RET
TEXT runtime·return0(SB), NOSPLIT, $0
MOVW $0, R0
RET
// The top-most function running on a goroutine
// returns to goexit+PCQuantum.
TEXT runtime·goexit(SB),NOSPLIT,$-8-0
MOVD R0, R0 // NOP
BL runtime·goexit1(SB) // does not return
// TODO(aram): use PRFM here.
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-8
RET
TEXT runtime·prefetcht1(SB),NOSPLIT,$0-8
RET
TEXT runtime·prefetcht2(SB),NOSPLIT,$0-8
RET
TEXT runtime·prefetchnta(SB),NOSPLIT,$0-8
RET
TEXT runtime·sigreturn(SB),NOSPLIT,$0-0
RET
// This is called from .init_array and follows the platform, not Go, ABI.
TEXT runtime·addmoduledata(SB),NOSPLIT,$0-0
SUB $0x10, RSP
MOVD R27, 8(RSP) // The access to global variables below implicitly uses R27, which is callee-save
MOVD runtime·lastmoduledatap(SB), R1
MOVD R0, moduledata_next(R1)
MOVD R0, runtime·lastmoduledatap(SB)
MOVD 8(RSP), R27
ADD $0x10, RSP
RET
TEXT ·checkASM(SB),NOSPLIT,$0-1
MOVW $1, R3
MOVB R3, ret+0(FP)
RET
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