Commit-ID: 0b4521e8cf1f582da3045ea460427ac2f741578f
Gitweb: http://git.kernel.org/tip/0b4521e8cf1f582da3045ea460427ac2f741578f
Author: Stas Sergeev <stsp@xxxxxxx>
AuthorDate: Thu, 14 Apr 2016 23:20:02 +0300
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 3 May 2016 08:37:58 +0200
signals/sigaltstack, x86/signals: Unify the x86 sigaltstack check with other architectures
Currently x86's get_sigframe() checks for "current->sas_ss_size"
to determine whether there is a need to switch to sigaltstack.
The common practice used by all other arches is to check for
sas_ss_flags(sp) == 0
This patch makes the code consistent with other architectures.
The slight complexity of the patch is added by the optimization on
!sigstack check that was requested by Andy Lutomirski: sas_ss_flags(sp)==0
already implies that we are not on a sigstack, so the code is shuffled
to avoid the duplicate checking.
This patch should have no user-visible impact.
Signed-off-by: Stas Sergeev <stsp@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-api@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1460665206-13646-2-git-send-email-stsp@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/signal.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 548ddf7..3e84ef1 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -248,18 +248,17 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
if (config_enabled(CONFIG_X86_64))
sp -= 128;
- if (!onsigstack) {
- /* This is the X/Open sanctioned signal stack switching. */
- if (ka->sa.sa_flags & SA_ONSTACK) {
- if (current->sas_ss_size)
- sp = current->sas_ss_sp + current->sas_ss_size;
- } else if (config_enabled(CONFIG_X86_32) &&
- (regs->ss & 0xffff) != __USER_DS &&
- !(ka->sa.sa_flags & SA_RESTORER) &&
- ka->sa.sa_restorer) {
- /* This is the legacy signal stack switching. */
- sp = (unsigned long) ka->sa.sa_restorer;
- }
+ /* This is the X/Open sanctioned signal stack switching. */
+ if (ka->sa.sa_flags & SA_ONSTACK) {
+ if (sas_ss_flags(sp) == 0)
+ sp = current->sas_ss_sp + current->sas_ss_size;
+ } else if (config_enabled(CONFIG_X86_32) &&
+ !onsigstack &&
+ (regs->ss & 0xffff) != __USER_DS &&
+ !(ka->sa.sa_flags & SA_RESTORER) &&
+ ka->sa.sa_restorer) {
+ /* This is the legacy signal stack switching. */
+ sp = (unsigned long) ka->sa.sa_restorer;
}
if (fpu->fpstate_active) {
--
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