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go/src/pkg/runtime/sys_openbsd_386.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.
//
// System calls and other sys.stuff for 386, OpenBSD
// /usr/src/sys/kern/syscalls.master for syscall numbers.
//
#include "zasm_GOOS_GOARCH.h"
// Exit the entire program (like C exit)
TEXT runtime·exit(SB),7,$-4
MOVL $1, AX
INT $0x80
MOVL $0xf1, 0xf1 // crash
RET
TEXT runtime·exit1(SB),7,$8
MOVL $0, 0(SP)
MOVL $0, 4(SP) // arg 1 - notdead
MOVL $302, AX // sys___threxit
INT $0x80
JAE 2(PC)
MOVL $0xf1, 0xf1 // crash
RET
TEXT runtime·write(SB),7,$-4
MOVL $4, AX // sys_write
INT $0x80
RET
TEXT runtime·usleep(SB),7,$20
MOVL $0, DX
MOVL usec+0(FP), AX
MOVL $1000000, CX
DIVL CX
MOVL AX, 12(SP) // tv_sec
MOVL $1000, AX
MULL DX
MOVL AX, 16(SP) // tv_nsec
MOVL $0, 0(SP)
LEAL 12(SP), AX
MOVL AX, 4(SP) // arg 1 - rqtp
MOVL $0, 8(SP) // arg 2 - rmtp
MOVL $240, AX // sys_nanosleep
INT $0x80
RET
TEXT runtime·raisesigpipe(SB),7,$12
MOVL $299, AX // sys_getthrid
INT $0x80
MOVL $0, 0(SP)
MOVL AX, 4(SP) // arg 1 - pid
MOVL $13, 8(SP) // arg 2 - signum == SIGPIPE
MOVL $37, AX // sys_kill
INT $0x80
RET
TEXT runtime·mmap(SB),7,$36
LEAL arg0+0(FP), SI
LEAL 4(SP), DI
CLD
MOVSL // arg 1 - addr
MOVSL // arg 2 - len
MOVSL // arg 3 - prot
MOVSL // arg 4 - flags
MOVSL // arg 5 - fd
MOVL $0, AX
STOSL // arg 6 - pad
MOVSL // arg 7 - offset
MOVL $0, AX // top 32 bits of file offset
STOSL
MOVL $197, AX // sys_mmap
INT $0x80
JCC 2(PC)
NEGL AX
RET
TEXT runtime·munmap(SB),7,$-4
MOVL $73, AX // sys_munmap
INT $0x80
JAE 2(PC)
MOVL $0xf1, 0xf1 // crash
RET
TEXT runtime·setitimer(SB),7,$-4
MOVL $83, AX
INT $0x80
RET
// func now() (sec int64, nsec int32)
TEXT time·now(SB), 7, $32
MOVL $116, AX
LEAL 12(SP), BX
MOVL BX, 4(SP)
MOVL $0, 8(SP)
INT $0x80
MOVL 12(SP), AX // sec
MOVL 16(SP), BX // usec
// sec is in AX, usec in BX
MOVL AX, sec+0(FP)
MOVL $0, sec+4(FP)
IMULL $1000, BX
MOVL BX, nsec+8(FP)
RET
// int64 nanotime(void) so really
// void nanotime(int64 *nsec)
TEXT runtime·nanotime(SB),7,$32
MOVL $116, AX
LEAL 12(SP), BX
MOVL BX, 4(SP)
MOVL $0, 8(SP)
INT $0x80
MOVL 12(SP), AX // sec
MOVL 16(SP), BX // usec
// sec is in AX, usec in BX
// convert to DX:AX nsec
MOVL $1000000000, CX
MULL CX
IMULL $1000, BX
ADDL BX, AX
ADCL $0, DX
MOVL ret+0(FP), DI
MOVL AX, 0(DI)
MOVL DX, 4(DI)
RET
TEXT runtime·sigaction(SB),7,$-4
MOVL $46, AX // sys_sigaction
INT $0x80
JAE 2(PC)
MOVL $0xf1, 0xf1 // crash
RET
TEXT runtime·sigprocmask(SB),7,$-4
MOVL $48, AX // sys_sigprocmask
INT $0x80
JAE 2(PC)
MOVL $0xf1, 0xf1 // crash
MOVL AX, oset+0(FP)
RET
TEXT runtime·sigtramp(SB),7,$44
get_tls(CX)
// check that m exists
MOVL m(CX), BX
CMPL BX, $0
runtime: discard SIGPROF delivered to non-Go threads. Signal handlers are global resources but many language environments (Go, C++ at Google, etc) assume they have sole ownership of a particular handler. Signal handlers in mixed-language applications must therefore be robust against unexpected delivery of certain signals, such as SIGPROF. The default Go signal handler runtime·sigtramp assumes that it will never be called on a non-Go thread, but this assumption is violated by when linking in C++ code that spawns threads. Specifically, the handler asserts the thread has an associated "m" (Go scheduler). This CL is a very simple workaround: discard SIGPROF delivered to non-Go threads. runtime.badsignal(int32) now receives the signal number; if it returns without panicking (e.g. sig==SIGPROF) the signal is discarded. I don't think there is any really satisfactory solution to the problem of signal-based profiling in a mixed-language application. It's not only the issue of handler clobbering, but also that a C++ SIGPROF handler called in a Go thread can't unwind the Go stack (and vice versa). The best we can hope for is not crashing. Note: - I've ported this to all POSIX platforms, except ARM-linux which already ignores unexpected signals on m-less threads. - I've avoided tail-calling runtime.badsignal because AFAICT the 6a/6l don't support it. - I've avoided hoisting 'push sig' (common to both function calls) because it makes the code harder to read. - Fixed an (apparently incorrect?) docstring. R=iant, rsc, minux.ma CC=golang-dev https://golang.org/cl/6498057
2012-09-04 12:40:49 -06:00
JNE 5(PC)
MOVL signo+0(FP), BX
MOVL BX, 0(SP)
CALL runtime·badsignal(SB)
runtime: discard SIGPROF delivered to non-Go threads. Signal handlers are global resources but many language environments (Go, C++ at Google, etc) assume they have sole ownership of a particular handler. Signal handlers in mixed-language applications must therefore be robust against unexpected delivery of certain signals, such as SIGPROF. The default Go signal handler runtime·sigtramp assumes that it will never be called on a non-Go thread, but this assumption is violated by when linking in C++ code that spawns threads. Specifically, the handler asserts the thread has an associated "m" (Go scheduler). This CL is a very simple workaround: discard SIGPROF delivered to non-Go threads. runtime.badsignal(int32) now receives the signal number; if it returns without panicking (e.g. sig==SIGPROF) the signal is discarded. I don't think there is any really satisfactory solution to the problem of signal-based profiling in a mixed-language application. It's not only the issue of handler clobbering, but also that a C++ SIGPROF handler called in a Go thread can't unwind the Go stack (and vice versa). The best we can hope for is not crashing. Note: - I've ported this to all POSIX platforms, except ARM-linux which already ignores unexpected signals on m-less threads. - I've avoided tail-calling runtime.badsignal because AFAICT the 6a/6l don't support it. - I've avoided hoisting 'push sig' (common to both function calls) because it makes the code harder to read. - Fixed an (apparently incorrect?) docstring. R=iant, rsc, minux.ma CC=golang-dev https://golang.org/cl/6498057
2012-09-04 12:40:49 -06:00
RET
// save g
MOVL g(CX), DI
MOVL DI, 20(SP)
// g = m->gsignal
MOVL m_gsignal(BX), BX
MOVL BX, g(CX)
// copy arguments for call to sighandler
MOVL signo+0(FP), BX
MOVL BX, 0(SP)
MOVL info+4(FP), BX
MOVL BX, 4(SP)
MOVL context+8(FP), BX
MOVL BX, 8(SP)
MOVL DI, 12(SP)
CALL runtime·sighandler(SB)
// restore g
get_tls(CX)
MOVL 20(SP), BX
MOVL BX, g(CX)
// call sigreturn
MOVL context+8(FP), AX
MOVL $0, 0(SP) // syscall gap
MOVL AX, 4(SP) // arg 1 - sigcontext
MOVL $103, AX // sys_sigreturn
INT $0x80
MOVL $0xf1, 0xf1 // crash
RET
// int32 tfork(void *param, uintptr psize, M *m, G *g, void (*fn)(void));
TEXT runtime·tfork(SB),7,$12
// Copy m, g and fn from the parent stack onto the child stack.
MOVL params+4(FP), AX
MOVL 8(AX), CX // tf_stack
SUBL $16, CX
MOVL CX, 8(AX)
MOVL mm+12(FP), SI
MOVL SI, 0(CX)
MOVL gg+16(FP), SI
MOVL SI, 4(CX)
MOVL fn+20(FP), SI
MOVL SI, 8(CX)
MOVL $1234, 12(CX)
MOVL $0, 0(SP) // syscall gap
MOVL params+4(FP), AX
MOVL AX, 4(SP) // arg 1 - param
MOVL psize+8(FP), AX
MOVL AX, 8(SP) // arg 2 - psize
MOVL $8, AX // sys___tfork
INT $0x80
// Return if tfork syscall failed.
JCC 5(PC)
NEGL AX
MOVL ret+0(FP), DX
MOVL AX, 0(DX)
RET
// In parent, return.
CMPL AX, $0
JEQ 4(PC)
MOVL ret+0(FP), DX
MOVL AX, 0(DX)
RET
// Paranoia: check that SP is as we expect.
MOVL 12(SP), BP
CMPL BP, $1234
JEQ 2(PC)
INT $3
// Reload registers.
MOVL 0(SP), BX // m
MOVL 4(SP), DX // g
MOVL 8(SP), SI // fn
// Set FS to point at m->tls.
LEAL m_tls(BX), BP
PUSHAL // save registers
PUSHL BP
CALL runtime·settls(SB)
POPL AX
POPAL
// Now segment is established. Initialize m, g.
get_tls(AX)
MOVL DX, g(AX)
MOVL BX, m(AX)
CALL runtime·stackcheck(SB) // smashes AX, CX
MOVL 0(DX), DX // paranoia; check they are not nil
MOVL 0(BX), BX
// More paranoia; check that stack splitting code works.
PUSHAL
CALL runtime·emptyfunc(SB)
POPAL
// Call fn.
CALL SI
CALL runtime·exit1(SB)
MOVL $0x1234, 0x1005
RET
TEXT runtime·sigaltstack(SB),7,$-8
MOVL $288, AX // sys_sigaltstack
MOVL new+4(SP), BX
MOVL old+8(SP), CX
INT $0x80
CMPL AX, $0xfffff001
JLS 2(PC)
INT $3
RET
TEXT runtime·setldt(SB),7,$4
// Under OpenBSD we set the GS base instead of messing with the LDT.
MOVL tls0+4(FP), AX
MOVL AX, 0(SP)
CALL runtime·settls(SB)
RET
TEXT runtime·settls(SB),7,$8
// adjust for ELF: wants to use -8(GS) and -4(GS) for g and m
MOVL tlsbase+0(FP), CX
ADDL $8, CX
MOVL $0, 0(SP) // syscall gap
MOVL CX, 4(SP) // arg 1 - tcb
MOVL $329, AX // sys___set_tcb
INT $0x80
JCC 2(PC)
MOVL $0xf1, 0xf1 // crash
RET
TEXT runtime·osyield(SB),7,$-4
MOVL $298, AX // sys_sched_yield
INT $0x80
RET
TEXT runtime·thrsleep(SB),7,$-4
MOVL $300, AX // sys___thrsleep
INT $0x80
RET
TEXT runtime·thrwakeup(SB),7,$-4
MOVL $301, AX // sys___thrwakeup
INT $0x80
RET
TEXT runtime·sysctl(SB),7,$28
LEAL arg0+0(FP), SI
LEAL 4(SP), DI
CLD
MOVSL // arg 1 - name
MOVSL // arg 2 - namelen
MOVSL // arg 3 - oldp
MOVSL // arg 4 - oldlenp
MOVSL // arg 5 - newp
MOVSL // arg 6 - newlen
MOVL $202, AX // sys___sysctl
INT $0x80
JCC 3(PC)
NEGL AX
RET
MOVL $0, AX
RET
GLOBL runtime·tlsoffset(SB),$4