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Use helper to walk past the syscall frames on FreeBSD/x86, similar to FreeBSD/x86_64.

The syscall trampolines in FreeBSD libc do not have unwind annotations.
This commit is contained in:
Konstantin Belousov 2014-06-28 23:28:08 +03:00 committed by Arun Sharma
parent f1684379df
commit 85946d9766

View file

@ -91,6 +91,11 @@ XXX
w3 == 0x14688e03 && w4 == 0x0001a1b8 && w5 == 0x80cd5000)
ret = X86_SCF_FREEBSD_SIGFRAME;
}
/* Check for syscall */
if (ret == X86_SCF_NONE && (*a->access_mem) (as, ip - 2, &w0, 0, arg) >= 0 &&
(w0 & 0xffff) == 0x80cd)
ret = X86_SCF_FREEBSD_SYSCALL;
Debug (16, "returning %d\n", ret);
c->sigcontext_format = ret;
return (ret);
@ -131,6 +136,10 @@ unw_handle_signal_frame (unw_cursor_t *cursor)
c->dwarf.loc[EFLAGS] = DWARF_LOC (uc_addr + FREEBSD_UC_MCONTEXT_EFLAGS_OFF, 0);
c->dwarf.loc[TRAPNO] = DWARF_LOC (uc_addr + FREEBSD_UC_MCONTEXT_TRAPNO_OFF, 0);
c->dwarf.loc[ST0] = DWARF_NULL_LOC;
} else if (c->sigcontext_format == X86_SCF_FREEBSD_SYSCALL) {
c->dwarf.loc[EIP] = DWARF_LOC (c->dwarf.cfa, 0);
c->dwarf.loc[EAX] = DWARF_NULL_LOC;
c->dwarf.cfa += 4;
} else {
Debug (8, "Gstep: not handling frame format %d\n", c->sigcontext_format);
abort();