Don't push on original stack during alternate signal stack setup
* exceptions.cc (_cygtls::call_signal_handler): Drop pushing a register on the original stack, it confuses GCC. Rearrange the assembler code so that $rax/$eax is not used by GCC to prepare an argument value. Use $rax/$eax without saving. Drop clearing $rbp/$epb. Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen
parent
2b615b47d4
commit
f4abb28ea8
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@ -1,3 +1,10 @@
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2015-06-22 Corinna Vinschen <corinna@vinschen.de>
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* exceptions.cc (_cygtls::call_signal_handler): Drop pushing a register
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on the original stack, it confuses GCC. Rearrange the assembler code
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so that $rax/$eax is not used by GCC to prepare an argument value.
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Use $rax/$eax without saving. Drop clearing $rbp/$epb.
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2015-06-21 Corinna Vinschen <corinna@vinschen.de>
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* exceptions.cc (_cygtls::call_signal_handler): Drop subtracting 16
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@ -1604,76 +1604,69 @@ _cygtls::call_signal_handler ()
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/* In assembler: Save regs on new stack, move to alternate stack,
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call thisfunc, revert stack regs. */
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#ifdef __x86_64__
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/* Clobbered regs: rax, rcx, rdx, r8, r9, r10, r11, rbp, rsp */
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/* Clobbered regs: rcx, rdx, r8, r9, r10, r11, rbp, rsp */
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__asm__ ("\n\
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pushq %%r9 # Push r9 on orig stack \n\
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movq %[NEW_SP], %%r9 # Load alt stack into r9 \n\
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subq $0x40, %%r9 # Make room on alt stack to \n\
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# save clobbered regs \n\
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movq %%rax, (%%r9) # Save other clobbered regs \n\
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movq %%rcx, 0x8(%%r9) \n\
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movq %%rdx, 0x10(%%r9) \n\
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movq %%r8, 0x18(%%r9) \n\
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movq %%r10, 0x20(%%r9) \n\
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movq %%r11, 0x28(%%r9) \n\
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movq %%rbp, 0x30(%%r9) \n\
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movq %%rsp, 0x38(%%r9) \n\
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movq %[NEW_SP], %%rax # Load alt stack into rax \n\
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subq $0x60, %%rax # Make room on alt stack \n\
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# for clobbered regs and \n\
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# required shadow space \n\
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movq %%rcx, 0x20(%%rax)# Save clobbered regs \n\
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movq %%rdx, 0x28(%%rax) \n\
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movq %%r8, 0x30(%%rax) \n\
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movq %%r9, 0x38(%%rax) \n\
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movq %%r10, 0x40(%%rax) \n\
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movq %%r11, 0x48(%%rax) \n\
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movq %%rbp, 0x50(%%rax) \n\
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movq %%rsp, 0x58(%%rax) \n\
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movl %[SIG], %%ecx # thissig to 1st arg reg \n\
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movq %[SI], %%rdx # &thissi to 2nd arg reg \n\
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leaq %[SI], %%rdx # &thissi to 2nd arg reg \n\
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movq %[CTX], %%r8 # thiscontext to 3rd arg reg \n\
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movq %[FUNC], %%rax # thisfunc to rax \n\
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movq %%r9, %%rsp # Move alt stack into rsp \n\
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xorq %%rbp, %%rbp # Set rbp to 0 \n\
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subq $0x20, %%rsp # Setup shadow space \n\
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call *%%rax # Call thisfunc \n\
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addq $0x20, %%rsp # Revert shadow space \n\
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movq %%rsp, %%r9 # Restore clobbered regs \n\
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movq 0x38(%%r9), %%rsp \n\
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movq 0x30(%%r9), %%rbp \n\
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movq 0x28(%%r9), %%r11 \n\
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movq 0x20(%%r9), %%r10 \n\
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movq 0x18(%%r9), %%r8 \n\
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movq 0x10(%%r9), %%rdx \n\
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movq 0x8(%%r9), %%rcx \n\
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movq (%%r9), %%rax \n\
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popq %%r9 \n"
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movq %[FUNC], %%r9 # thisfunc to r9 \n\
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movq %%rax, %%rsp # Move alt stack into rsp \n\
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call *%%r9 # Call thisfunc \n\
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movq %%rsp, %%rax # Restore clobbered regs \n\
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movq 0x58(%%rax), %%rsp \n\
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movq 0x50(%%rax), %%rbp \n\
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movq 0x48(%%rax), %%r11 \n\
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movq 0x40(%%rax), %%r10 \n\
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movq 0x38(%%rax), %%r9 \n\
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movq 0x30(%%rax), %%r8 \n\
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movq 0x28(%%rax), %%rdx \n\
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movq 0x20(%%rax), %%rcx \n"
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: : [NEW_SP] "o" (new_sp),
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[SIG] "o" (thissig),
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[SI] "p" (&thissi),
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[SI] "o" (thissi),
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[CTX] "o" (thiscontext),
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[FUNC] "o" (thisfunc)
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: "memory");
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#else
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/* Clobbered regs: eax, ecx, edx, ebp, esp */
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/* Clobbered regs: ecx, edx, ebp, esp */
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__asm__ ("\n\
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push %%ecx # Push ecx on orig stack \n\
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movl %[NEW_SP], %%ecx # Load alt stack into ecx \n\
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subl $28, %%ecx # Make room on alt stack for \n\
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movl %[NEW_SP], %%eax # Load alt stack into eax \n\
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subl $28, %%eax # Make room on alt stack for \n\
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# clobbered regs and args to \n\
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# signal handler \n\
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movl %%eax, 12(%%ecx) # Save other clobbered regs \n\
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movl %%edx, 16(%%ecx) \n\
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movl %%ebp, 20(%%ecx) \n\
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movl %%esp, 24(%%ecx) \n\
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movl %[SIG], %%edx # thissig to 1st arg slot \n\
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movl %%edx, (%%ecx) \n\
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movl %[SI], %%edx # &thissi to 2nd arg slot \n\
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movl %%edx, 4(%%ecx) \n\
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movl %[CTX], %%edx # thiscontext to 3rd arg slot\n\
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movl %%edx, 8(%%ecx) \n\
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movl %[FUNC], %%eax # thisfunc to eax \n\
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movl %%ecx, %%esp # Move alt stack into esp \n\
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xorl %%ebp, %%ebp # Set ebp to 0 \n\
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call *%%eax # Call thisfunc \n\
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movl %%esp, %%ecx # Restore clobbered regs \n\
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movl 24(%%ecx), %%esp \n\
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movl 20(%%ecx), %%ebp \n\
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movl 16(%%ecx), %%edx \n\
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movl 12(%%ecx), %%eax \n\
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popl %%ecx \n"
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movl %%ecx, 12(%%eax) # Save other clobbered regs \n\
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movl %%edx, 16(%%eax) \n\
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movl %%ebp, 20(%%eax) \n\
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movl %%esp, 24(%%eax) \n\
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movl %[SIG], %%ecx # thissig to 1st arg slot \n\
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movl %%ecx, (%%eax) \n\
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leal %[SI], %%ecx # &thissi to 2nd arg slot \n\
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movl %%ecx, 4(%%eax) \n\
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movl %[CTX], %%ecx # thiscontext to 3rd arg slot\n\
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movl %%ecx, 8(%%eax) \n\
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movl %[FUNC], %%ecx # thisfunc to ecx \n\
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movl %%eax, %%esp # Move alt stack into esp \n\
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call *%%ecx # Call thisfunc \n\
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movl %%esp, %%eax # Restore clobbered regs \n\
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movl 24(%%eax), %%esp \n\
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movl 20(%%eax), %%ebp \n\
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movl 16(%%eax), %%edx \n\
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movl 12(%%eax), %%eax \n"
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: : [NEW_SP] "o" (new_sp),
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[SIG] "o" (thissig),
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[SI] "p" (&thissi),
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[SI] "o" (thissi),
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[CTX] "o" (thiscontext),
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[FUNC] "o" (thisfunc)
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: "memory");
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