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runtime: preserve callee-saved C registers in sigtramp
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This fixes Linux and the *BSD platforms on 386/amd64.

A few OS/arch combinations were already saving registers and/or doing
something that doesn't clearly resemble the SysV C ABI; those have
been left alone.

Fixes #18328.

Change-Id: I6398f6c71020de108fc8b26ca5946f0ba0258667
Reviewed-on: https://go-review.googlesource.com/34501
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
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@ianlancetaylor
Bryan C. Mills authored and ianlancetaylor committed Dec 15, 2016
1 parent c1d449c commit 29cb721
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Showing 9 changed files with 156 additions and 27 deletions.
11 changes: 9 additions & 2 deletions misc/cgo/testsanitizers/tsan9.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,8 @@ package main

// This program failed when run under the C/C++ ThreadSanitizer. The
// TSAN library was not keeping track of whether signals should be
// delivered on the alternate signal stack.
// delivered on the alternate signal stack, and the Go signal handler
// was not preserving callee-saved registers from C callers.

/*
#cgo CFLAGS: -g -fsanitize=thread
Expand All @@ -19,10 +20,14 @@ void spin() {
size_t n;
struct timeval tvstart, tvnow;
int diff;
void *prev = NULL, *cur;
gettimeofday(&tvstart, NULL);
for (n = 0; n < 1<<20; n++) {
free(malloc(n));
cur = malloc(n);
free(prev);
prev = cur;
gettimeofday(&tvnow, NULL);
diff = (tvnow.tv_sec - tvstart.tv_sec) * 1000 * 1000 + (tvnow.tv_usec - tvstart.tv_usec);
Expand All @@ -32,6 +37,8 @@ void spin() {
break;
}
}
free(prev);
}
*/
import "C"
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25 changes: 21 additions & 4 deletions src/runtime/sys_dragonfly_amd64.s
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Expand Up @@ -200,11 +200,28 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
POPQ BP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$24
MOVQ DI, 0(SP)
MOVQ SI, 8(SP)
MOVQ DX, 16(SP)
TEXT runtime·sigtramp(SB),NOSPLIT,$72
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVQ BX, bx-8(SP)
MOVQ BP, bp-16(SP) // save in case GOEXPERIMENT=noframepointer is set
MOVQ R12, r12-24(SP)
MOVQ R13, r13-32(SP)
MOVQ R14, r14-40(SP)
MOVQ R15, r15-48(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVQ DX, ctx-56(SP)
MOVQ SI, info-64(SP)
MOVQ DI, signum-72(SP)
CALL runtime·sigtrampgo(SB)

MOVQ r15-48(SP), R15
MOVQ r14-40(SP), R14
MOVQ r13-32(SP), R13
MOVQ r12-24(SP), R12
MOVQ bp-16(SP), BP
MOVQ bx-8(SP), BX
RET

TEXT runtime·mmap(SB),NOSPLIT,$0
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25 changes: 21 additions & 4 deletions src/runtime/sys_freebsd_amd64.s
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Expand Up @@ -196,11 +196,28 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
POPQ BP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$24
MOVQ DI, 0(SP)
MOVQ SI, 8(SP)
MOVQ DX, 16(SP)
TEXT runtime·sigtramp(SB),NOSPLIT,$72
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVQ BX, bx-8(SP)
MOVQ BP, bp-16(SP) // save in case GOEXPERIMENT=noframepointer is set
MOVQ R12, r12-24(SP)
MOVQ R13, r13-32(SP)
MOVQ R14, r14-40(SP)
MOVQ R15, r15-48(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVQ DX, ctx-56(SP)
MOVQ SI, info-64(SP)
MOVQ DI, signum-72(SP)
CALL runtime·sigtrampgo(SB)

MOVQ r15-48(SP), R15
MOVQ r14-40(SP), R14
MOVQ r13-32(SP), R13
MOVQ r12-24(SP), R12
MOVQ bp-16(SP), BP
MOVQ bx-8(SP), BX
RET

TEXT runtime·mmap(SB),NOSPLIT,$0
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15 changes: 14 additions & 1 deletion src/runtime/sys_linux_386.s
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Expand Up @@ -228,14 +228,27 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$12-16
MOVL AX, SP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$12
TEXT runtime·sigtramp(SB),NOSPLIT,$28
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVL BX, bx-4(SP)
MOVL BP, bp-8(SP)
MOVL SI, si-12(SP)
MOVL DI, di-16(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVL sig+0(FP), BX
MOVL BX, 0(SP)
MOVL info+4(FP), BX
MOVL BX, 4(SP)
MOVL ctx+8(FP), BX
MOVL BX, 8(SP)
CALL runtime·sigtrampgo(SB)

MOVL di-16(SP), DI
MOVL si-12(SP), SI
MOVL bp-8(SP), BP
MOVL bx-4(SP), BX
RET

TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0
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25 changes: 21 additions & 4 deletions src/runtime/sys_linux_amd64.s
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Expand Up @@ -244,12 +244,29 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
POPQ BP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$24
MOVQ DI, 0(SP) // signum
MOVQ SI, 8(SP) // info
MOVQ DX, 16(SP) // ctx
TEXT runtime·sigtramp(SB),NOSPLIT,$72
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVQ BX, bx-8(SP)
MOVQ BP, bp-16(SP) // save in case GOEXPERIMENT=noframepointer is set
MOVQ R12, r12-24(SP)
MOVQ R13, r13-32(SP)
MOVQ R14, r14-40(SP)
MOVQ R15, r15-48(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVQ DX, ctx-56(SP)
MOVQ SI, info-64(SP)
MOVQ DI, signum-72(SP)
MOVQ $runtime·sigtrampgo(SB), AX
CALL AX

MOVQ r15-48(SP), R15
MOVQ r14-40(SP), R14
MOVQ r13-32(SP), R13
MOVQ r12-24(SP), R12
MOVQ bp-16(SP), BP
MOVQ bx-8(SP), BX
RET

// Used instead of sigtramp in programs that use cgo.
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15 changes: 14 additions & 1 deletion src/runtime/sys_netbsd_386.s
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Original file line number Diff line number Diff line change
Expand Up @@ -232,14 +232,27 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$12-16
MOVL AX, SP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$12
TEXT runtime·sigtramp(SB),NOSPLIT,$28
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVL BX, bx-4(SP)
MOVL BP, bp-8(SP)
MOVL SI, si-12(SP)
MOVL DI, di-16(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

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)
CALL runtime·sigtrampgo(SB)

MOVL di-16(SP), DI
MOVL si-12(SP), SI
MOVL bp-8(SP), BP
MOVL bx-4(SP), BX
RET

// int32 lwp_create(void *context, uintptr flags, void *lwpid);
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27 changes: 21 additions & 6 deletions src/runtime/sys_netbsd_amd64.s
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Original file line number Diff line number Diff line change
Expand Up @@ -250,13 +250,28 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
POPQ BP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$32
MOVQ DI, 0(SP) // signum
MOVQ SI, 8(SP) // info
MOVQ DX, 16(SP) // ctx
MOVQ R15, 24(SP) // for sigreturn
TEXT runtime·sigtramp(SB),NOSPLIT,$72
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVQ BX, bx-8(SP)
MOVQ BP, bp-16(SP) // save in case GOEXPERIMENT=noframepointer is set
MOVQ R12, r12-24(SP)
MOVQ R13, r13-32(SP)
MOVQ R14, r14-40(SP)
MOVQ R15, r15-48(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVQ DX, ctx-56(SP)
MOVQ SI, info-64(SP)
MOVQ DI, signum-72(SP)
CALL runtime·sigtrampgo(SB)
MOVQ 24(SP), R15

MOVQ r15-48(SP), R15
MOVQ r14-40(SP), R14
MOVQ r13-32(SP), R13
MOVQ r12-24(SP), R12
MOVQ bp-16(SP), BP
MOVQ bx-8(SP), BX
RET

TEXT runtime·mmap(SB),NOSPLIT,$0
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15 changes: 14 additions & 1 deletion src/runtime/sys_openbsd_386.s
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Original file line number Diff line number Diff line change
Expand Up @@ -213,14 +213,27 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$12-16
MOVL AX, SP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$12
TEXT runtime·sigtramp(SB),NOSPLIT,$28
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVL BX, bx-4(SP)
MOVL BP, bp-8(SP)
MOVL SI, si-12(SP)
MOVL DI, di-16(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

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)
CALL runtime·sigtrampgo(SB)

MOVL di-16(SP), DI
MOVL si-12(SP), SI
MOVL bp-8(SP), BP
MOVL bx-4(SP), BX
RET

// int32 tfork(void *param, uintptr psize, M *mp, G *gp, void (*fn)(void));
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25 changes: 21 additions & 4 deletions src/runtime/sys_openbsd_amd64.s
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Original file line number Diff line number Diff line change
Expand Up @@ -242,11 +242,28 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
POPQ BP
RET

TEXT runtime·sigtramp(SB),NOSPLIT,$24
MOVQ DI, 0(SP)
MOVQ SI, 8(SP)
MOVQ DX, 16(SP)
TEXT runtime·sigtramp(SB),NOSPLIT,$72
// Save callee-saved C registers, since the caller may be a C signal handler.
MOVQ BX, bx-8(SP)
MOVQ BP, bp-16(SP) // save in case GOEXPERIMENT=noframepointer is set
MOVQ R12, r12-24(SP)
MOVQ R13, r13-32(SP)
MOVQ R14, r14-40(SP)
MOVQ R15, r15-48(SP)
// We don't save mxcsr or the x87 control word because sigtrampgo doesn't
// modify them.

MOVQ DX, ctx-56(SP)
MOVQ SI, info-64(SP)
MOVQ DI, signum-72(SP)
CALL runtime·sigtrampgo(SB)

MOVQ r15-48(SP), R15
MOVQ r14-40(SP), R14
MOVQ r13-32(SP), R13
MOVQ r12-24(SP), R12
MOVQ bp-16(SP), BP
MOVQ bx-8(SP), BX
RET

TEXT runtime·mmap(SB),NOSPLIT,$0
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