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Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/sigaction.c')
-rw-r--r--sysdeps/unix/sysv/linux/i386/sigaction.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/sigaction.c b/sysdeps/unix/sysv/linux/i386/sigaction.c
index 2571f1d922..5e431218e9 100644
--- a/sysdeps/unix/sysv/linux/i386/sigaction.c
+++ b/sysdeps/unix/sysv/linux/i386/sigaction.c
@@ -148,12 +148,20 @@ __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
weak_alias (__sigaction, sigaction)
+/* NOTE: Please think twice before making any changes to the bits of
+ code below. GDB needs some intimate knowledge about it to
+ recognize them as signal trampolines, and make backtraces through
+ signal handlers work right. Important are both the names
+ (__restore and __restore_rt) and the exact instruction sequence.
+ If you ever feel the need to make any changes, please notify the
+ appropriate GDB maintainer. */
+
#define RESTORE(name, syscall) RESTORE2 (name, syscall)
#define RESTORE2(name, syscall) \
asm \
( \
".align 16\n" \
- "__" #name ":\n" \
+ "__" #name ":\n" \
" movl $" #syscall ", %eax\n" \
" int $0x80" \
);
@@ -168,8 +176,8 @@ RESTORE (restore_rt, __NR_rt_sigreturn)
# define RESTORE2(name, syscall) \
asm \
( \
- ".align 8\n" \
- "__" #name ":\n" \
+ ".align 8\n" \
+ "__" #name ":\n" \
" popl %eax\n" \
" movl $" #syscall ", %eax\n" \
" int $0x80" \