diff options
Diffstat (limited to 'src/runtime/sys_windows_386.s')
| -rw-r--r-- | src/runtime/sys_windows_386.s | 83 |
1 files changed, 27 insertions, 56 deletions
diff --git a/src/runtime/sys_windows_386.s b/src/runtime/sys_windows_386.s index 8713f7d0d9..0983cc7b1f 100644 --- a/src/runtime/sys_windows_386.s +++ b/src/runtime/sys_windows_386.s @@ -72,13 +72,20 @@ TEXT runtime·getlasterror(SB),NOSPLIT,$0 MOVL AX, ret+0(FP) RET +TEXT runtime·sigFetchGSafe<ABIInternal>(SB),NOSPLIT|NOFRAME,$0 + get_tls(AX) + CMPL AX, $0 + JE 2(PC) + MOVL g(AX), AX + MOVL AX, ret+0(FP) + RET + // Called by Windows as a Vectored Exception Handler (VEH). -// First argument is pointer to struct containing +// AX is pointer to struct containing // exception record and context pointers. -// Handler function is stored in AX. -// Return 0 for 'not handled', -1 for handled. +// CX is the kind of sigtramp function. +// Return value of sigtrampgo is stored in AX. TEXT sigtramp<>(SB),NOSPLIT,$0-0 - MOVL ptrs+0(FP), CX SUBL $40, SP // save callee-saved registers @@ -87,58 +94,11 @@ TEXT sigtramp<>(SB),NOSPLIT,$0-0 MOVL SI, 20(SP) MOVL DI, 24(SP) - MOVL AX, SI // save handler address - - // find g - get_tls(DX) - CMPL DX, $0 - JNE 3(PC) - MOVL $0, AX // continue - JMP done - MOVL g(DX), DX - CMPL DX, $0 - JNE 2(PC) - CALL runtime·badsignal2(SB) - - // save g in case of stack switch - MOVL DX, 32(SP) // g - MOVL SP, 36(SP) - - // do we need to switch to the g0 stack? - MOVL g_m(DX), BX - MOVL m_g0(BX), BX - CMPL DX, BX - JEQ g0 - - // switch to the g0 stack - get_tls(BP) - MOVL BX, g(BP) - MOVL (g_sched+gobuf_sp)(BX), DI - // make room for sighandler arguments - // and re-save old SP for restoring later. - // (note that the 36(DI) here must match the 36(SP) above.) - SUBL $40, DI - MOVL SP, 36(DI) - MOVL DI, SP - -g0: - MOVL 0(CX), BX // ExceptionRecord* - MOVL 4(CX), CX // Context* - MOVL BX, 0(SP) + MOVL AX, 0(SP) MOVL CX, 4(SP) - MOVL DX, 8(SP) - CALL SI // call handler - // AX is set to report result back to Windows - MOVL 12(SP), AX + CALL runtime·sigtrampgo(SB) + MOVL 8(SP), AX - // switch back to original stack and g - // no-op if we never left. - MOVL 36(SP), SP - MOVL 32(SP), DX // note: different SP - get_tls(BP) - MOVL DX, g(BP) - -done: // restore callee-saved registers MOVL 24(SP), DI MOVL 20(SP), SI @@ -150,8 +110,18 @@ done: BYTE $0xC2; WORD $4 RET // unreached; make assembler happy +// Trampoline to resume execution from exception handler. +// This is part of the control flow guard workaround. +// It switches stacks and jumps to the continuation address. +// DX and CX are set above at the end of sigtrampgo +// in the context that starts executing at sigresume. +TEXT runtime·sigresume(SB),NOSPLIT|NOFRAME,$0 + MOVL DX, SP + JMP CX + TEXT runtime·exceptiontramp(SB),NOSPLIT,$0 - MOVL $runtime·exceptionhandler(SB), AX + MOVL argframe+0(FP), AX + MOVL $const_callbackVEH, CX JMP sigtramp<>(SB) TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0 @@ -159,7 +129,8 @@ TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0 INT $3 TEXT runtime·lastcontinuetramp(SB),NOSPLIT,$0-0 - MOVL $runtime·lastcontinuehandler(SB), AX + MOVL argframe+0(FP), AX + MOVL $const_callbackLastVCH, CX JMP sigtramp<>(SB) GLOBL runtime·cbctxts(SB), NOPTR, $4 |