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runtime: correct seh installation during callbacks

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Every time we enter callback from Windows, it is
possible that go exception handler is not at the top
of per-thread exception handlers chain. So it needs
to be installed again. At this moment this is done
by replacing top SEH frame with SEH frame as at time
of syscall for the time of callback. This is incorrect,
because, if exception strike, we won't be able to call
any exception handlers installed inside syscall,
because they are not in the chain. This changes
procedure to add new SEH frame on top of existing
chain instead.

I also removed m sehframe field, because I don't
think it is needed. We use single global exception
handler everywhere.

R=golang-dev, r
CC=golang-dev, hectorchu
https://golang.org/cl/4832060
This commit is contained in:
Alex Brainman 2011-08-10 17:17:28 +10:00
parent 8fced60a72
commit 9c774c3f26
2 changed files with 15 additions and 14 deletions
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3
src/pkg/runtime/runtime.h
View File

@ -248,12 +248,9 @@ struct M
uint32 freghi[16]; // D[i] msb and F[i+16]
uint32 fflag; // floating point compare flags
#ifdef __WINDOWS__
void* sehframe;
#ifdef _64BIT
void* gostack;
#endif
#endif
};

26
src/pkg/runtime/windows/386/sys.s
View File

@ -14,8 +14,6 @@ TEXT runtime·stdcall_raw(SB),7,$0
// Switch to m->g0 if needed.
get_tls(DI)
MOVL m(DI), DX
MOVL 0(FS), SI
MOVL SI, m_sehframe(DX)
MOVL m_g0(DX), SI
CMPL g(DI), SI
MOVL SP, BX
@ -116,7 +114,7 @@ TEXT runtime·ctrlhandler(SB),7,$0
MOVL SP, BX
// setup dummy m, g
SUBL $(m_sehframe+4), SP // at least space for m_sehframe
SUBL $(m_fflag+4), SP // at least space for m_fflag
LEAL m_tls(SP), CX
MOVL CX, 0x2c(FS)
MOVL SP, m(CX)
@ -159,33 +157,39 @@ TEXT runtime·callbackasm+0(SB),7,$0
ADDL $4, DX // extend argsize by size of return value
// save registers as required for windows callback
PUSHL 0(FS)
PUSHL DI
PUSHL SI
PUSHL BP
PUSHL BX
// set up SEH frame again
PUSHL $runtime·sigtramp(SB)
PUSHL 0(FS)
MOVL SP, 0(FS)
// callback parameters
PUSHL DX
PUSHL CX
PUSHL AX
// reinstall our SEH handler
get_tls(CX)
MOVL m(CX), CX
MOVL m_sehframe(CX), CX
MOVL CX, 0(FS)
CLD
CALL runtime·cgocallback(SB)
// restore registers as required for windows callback
POPL AX
POPL CX
POPL DX
// pop SEH frame
POPL 0(FS)
POPL BX
// restore registers as required for windows callback
POPL BX
POPL BP
POPL SI
POPL DI
POPL 0(FS)
CLD
MOVL -4(CX)(DX*1), AX