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[PATCHv2] hurd: libgcc unwinding over signal trampolines with SIGINFO
From: |
Samuel Thibault |
Subject: |
[PATCHv2] hurd: libgcc unwinding over signal trampolines with SIGINFO |
Date: |
Mon, 21 Dec 2020 15:36:30 +0100 |
User-agent: |
NeoMutt/20170609 (1.8.3) |
When the application sets SA_SIGINFO, the signal trampoline parameters
are different to follow POSIX.
libgcc/
* config/i386/gnu-unwind.h (x86_gnu_fallback_frame_state): Add the posix
siginfo case to struct handler_args. Detect between legacy and siginfo from
the second parameter, which is a small sigcode in the legacy case, and a
pointer in the siginfo case.
diff --git a/libgcc/config/i386/gnu-unwind.h b/libgcc/config/i386/gnu-unwind.h
index db47f0ac1d4..f83411e3de4 100644
--- a/libgcc/config/i386/gnu-unwind.h
+++ b/libgcc/config/i386/gnu-unwind.h
@@ -38,10 +38,21 @@ x86_gnu_fallback_frame_state
{
struct handler_args {
int signo;
- int sigcode;
- struct sigcontext *scp;
+ union
+ {
+ struct
+ {
+ long int sigcode;
+ struct sigcontext *scp;
+ } legacy;
+ struct
+ {
+ siginfo_t *siginfop;
+ ucontext_t *uctxp;
+ } posix;
+ };
} *handler_args;
- struct sigcontext *scp;
+ long int sigcode;
unsigned long usp;
/*
@@ -75,29 +86,52 @@ x86_gnu_fallback_frame_state
return _URC_END_OF_STACK;
handler_args = context->cfa;
- scp = handler_args->scp;
- usp = scp->sc_uesp;
+ sigcode = handler_args->legacy.sigcode;
+ if (sigcode >= -16 && sigcode < 4096)
+ {
+ /* This cannot be a SIGINFO pointer, assume legacy. */
+ struct sigcontext *scp = handler_args->legacy.scp;
+ usp = scp->sc_uesp;
+
+ fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
+ fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
+ fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
+ fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
+ fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
+ fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
+ fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
+ fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+ }
+ else
+ {
+ /* This is not a valid sigcode, assume SIGINFO. */
+ ucontext_t *uctxp = handler_args->posix.uctxp;
+ gregset_t *gregset = &uctxp->uc_mcontext.gregs;
+ usp = (*gregset)[REG_UESP];
+
+ fs->regs.reg[0].loc.offset = (unsigned long)&(*gregset)[REG_EAX] - usp;
+ fs->regs.reg[1].loc.offset = (unsigned long)&(*gregset)[REG_ECX] - usp;
+ fs->regs.reg[2].loc.offset = (unsigned long)&(*gregset)[REG_EDX] - usp;
+ fs->regs.reg[3].loc.offset = (unsigned long)&(*gregset)[REG_EBX] - usp;
+ fs->regs.reg[5].loc.offset = (unsigned long)&(*gregset)[REG_EBP] - usp;
+ fs->regs.reg[6].loc.offset = (unsigned long)&(*gregset)[REG_ESI] - usp;
+ fs->regs.reg[7].loc.offset = (unsigned long)&(*gregset)[REG_EDI] - usp;
+ fs->regs.reg[8].loc.offset = (unsigned long)&(*gregset)[REG_EIP] - usp;
+ }
fs->regs.cfa_how = CFA_REG_OFFSET;
fs->regs.cfa_reg = 4;
fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
fs->regs.reg[0].how = REG_SAVED_OFFSET;
- fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
fs->regs.reg[1].how = REG_SAVED_OFFSET;
- fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
fs->regs.reg[2].how = REG_SAVED_OFFSET;
- fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
fs->regs.reg[3].how = REG_SAVED_OFFSET;
- fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
fs->regs.reg[5].how = REG_SAVED_OFFSET;
- fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
fs->regs.reg[6].how = REG_SAVED_OFFSET;
- fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
fs->regs.reg[7].how = REG_SAVED_OFFSET;
- fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
fs->regs.reg[8].how = REG_SAVED_OFFSET;
- fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
+
fs->retaddr_column = 8;
fs->signal_frame = 1;
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