From 3982294b0342474ff91472b34c6afb701785f524 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 10 Jul 2011 21:27:27 +0200 Subject: x86, signals: Convert the X86_32 code to use set_current_blocked() sys_sigsuspend() and sys_sigreturn() change ->blocked directly. This is not correct, see the changelog in e6fa16ab "signal: sigprocmask() should do retarget_shared_pending()" Change them to use set_current_blocked(). Signed-off-by: Oleg Nesterov Link: http://lkml.kernel.org/r/20110710192727.GA31759@redhat.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/signal.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 40a24932a8a1..bf9345da380b 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -485,17 +485,18 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask) { - mask &= _BLOCKABLE; - spin_lock_irq(¤t->sighand->siglock); + sigset_t blocked; + current->saved_sigmask = current->blocked; - siginitset(¤t->blocked, mask); - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); + + mask &= _BLOCKABLE; + siginitset(&blocked, mask); + set_current_blocked(&blocked); current->state = TASK_INTERRUPTIBLE; schedule(); - set_restore_sigmask(); + set_restore_sigmask(); return -ERESTARTNOHAND; } @@ -572,10 +573,7 @@ unsigned long sys_sigreturn(struct pt_regs *regs) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); - spin_lock_irq(¤t->sighand->siglock); - current->blocked = set; - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); + set_current_blocked(&set); if (restore_sigcontext(regs, &frame->sc, &ax)) goto badframe; -- cgit v1.2.3 From 9b429620740945363b746414e8b9a84b8119914c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 10 Jul 2011 20:22:03 +0200 Subject: x86, do_signal: Simplify the TS_RESTORE_SIGMASK logic 1. do_signal() looks at TS_RESTORE_SIGMASK and calculates the mask which should be stored in the signal frame, then it passes "oldset" to the callees, down to setup_rt_frame(). This is ugly, setup_rt_frame() can do this itself and nobody else needs this sigset_t. Move this code into setup_rt_frame. 2. do_signal() also clears TS_RESTORE_SIGMASK if handle_signal() succeeds. We can move this to setup_rt_frame() as well, this avoids the unnecessary checks and makes the logic more clear. 3. use set_current_blocked() instead of sigprocmask(SIG_SETMASK), sigprocmask() should be avoided. Signed-off-by: Oleg Nesterov Link: http://lkml.kernel.org/r/20110710182203.GA27979@redhat.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/signal.c | 29 ++++++++++------------------- 1 file changed, 10 insertions(+), 19 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index bf9345da380b..8c55f97728cd 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -651,11 +651,15 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka, static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, - sigset_t *set, struct pt_regs *regs) + struct pt_regs *regs) { int usig = signr_convert(sig); + sigset_t *set = ¤t->blocked; int ret; + if (current_thread_info()->status & TS_RESTORE_SIGMASK) + set = ¤t->saved_sigmask; + /* Set up the stack frame */ if (is_ia32) { if (ka->sa.sa_flags & SA_SIGINFO) @@ -670,12 +674,13 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, return -EFAULT; } + current_thread_info()->status &= ~TS_RESTORE_SIGMASK; return ret; } static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, - sigset_t *oldset, struct pt_regs *regs) + struct pt_regs *regs) { sigset_t blocked; int ret; @@ -710,7 +715,7 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, likely(test_and_clear_thread_flag(TIF_FORCED_TF))) regs->flags &= ~X86_EFLAGS_TF; - ret = setup_rt_frame(sig, ka, info, oldset, regs); + ret = setup_rt_frame(sig, ka, info, regs); if (ret) return ret; @@ -765,7 +770,6 @@ static void do_signal(struct pt_regs *regs) struct k_sigaction ka; siginfo_t info; int signr; - sigset_t *oldset; /* * We want the common case to go fast, which is why we may in certain @@ -777,23 +781,10 @@ static void do_signal(struct pt_regs *regs) if (!user_mode(regs)) return; - if (current_thread_info()->status & TS_RESTORE_SIGMASK) - oldset = ¤t->saved_sigmask; - else - oldset = ¤t->blocked; - signr = get_signal_to_deliver(&info, &ka, regs, NULL); if (signr > 0) { /* Whee! Actually deliver the signal. */ - if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { - /* - * A signal was successfully delivered; the saved - * sigmask will have been stored in the signal frame, - * and will be restored by sigreturn, so we can simply - * clear the TS_RESTORE_SIGMASK flag. - */ - current_thread_info()->status &= ~TS_RESTORE_SIGMASK; - } + handle_signal(signr, &info, &ka, regs); return; } @@ -821,7 +812,7 @@ static void do_signal(struct pt_regs *regs) */ if (current_thread_info()->status & TS_RESTORE_SIGMASK) { current_thread_info()->status &= ~TS_RESTORE_SIGMASK; - sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + set_current_blocked(¤t->saved_sigmask); } } -- cgit v1.2.3 From 73d382deccac186d103496bf10388bc2432a8384 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 10 Jul 2011 18:44:24 +0200 Subject: x86: Kill handle_signal()->set_fs() handle_signal()->set_fs() has a nice comment which explains what set_fs() is, but it doesn't explain why it is needed and why it depends on CONFIG_X86_64. Afaics, the history of this confusion is: 1. I guess today nobody can explain why it was needed in arch/i386/kernel/signal.c, perhaps it was always wrong. This predates 2.4.0 kernel. 2. then it was copy-and-past'ed to the new x86_64 arch. 3. then it was removed from i386 (but not from x86_64) by b93b6ca3 "i386: remove unnecessary code". 4. then it was reintroduced under CONFIG_X86_64 when x86 unified i386 and x86_64, because the patch above didn't touch x86_64. Remove it. ->addr_limit should be correct. Even if it was possible that it is wrong, it is too late to fix it after setup_rt_frame(). Linus commented in: http://lkml.kernel.org/r/alpine.LFD.0.999.0707170902570.19166@woody.linux-foundation.org ... about the equivalent bit from i386: Heh. I think it's entirely historical. Please realize that the whole reason that function is called "set_fs()" is that it literally used to set the %fs segment register, not "->addr_limit". So I think the "set_fs(USER_DS)" is there _only_ to match the other regs->xds = __USER_DS; regs->xes = __USER_DS; regs->xss = __USER_DS; regs->xcs = __USER_CS; things, and never mattered. And now it matters even less, and has been copied to all other architectures where it is just totally insane. Signed-off-by: Oleg Nesterov Link: http://lkml.kernel.org/r/20110710164424.GA20261@redhat.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/signal.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 8c55f97728cd..54ddaeb221c1 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -720,15 +720,6 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, if (ret) return ret; -#ifdef CONFIG_X86_64 - /* - * This has nothing to do with segment registers, - * despite the name. This magic affects uaccess.h - * macros' behavior. Reset it to the normal setting. - */ - set_fs(USER_DS); -#endif - /* * Clear the direction flag as per the ABI for function entry. */ -- cgit v1.2.3