Commit-ID: 0b4521e8cf1f582da3045ea460427ac2f741578f Gitweb: http://git.kernel.org/tip/0b4521e8cf1f582da3045ea460427ac2f741578f Author: Stas Sergeev <s...@list.ru> AuthorDate: Thu, 14 Apr 2016 23:20:02 +0300 Committer: Ingo Molnar <mi...@kernel.org> 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 <s...@list.ru> Cc: Al Viro <v...@zeniv.linux.org.uk> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@amacapital.net> Cc: Borislav Petkov <b...@alien8.de> Cc: Borislav Petkov <b...@suse.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Oleg Nesterov <o...@redhat.com> Cc: Pavel Emelyanov <xe...@parallels.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Richard Weinberger <rich...@nod.at> Cc: Shuah Khan <shua...@osg.samsung.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux-...@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1460665206-13646-2-git-send-email-s...@list.ru Signed-off-by: Ingo Molnar <mi...@kernel.org> --- 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) {
