From 283828f3c19ceb3a64a8544d42cc189003e8b0fe Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 18 Jan 2006 17:44:00 -0800 Subject: [PATCH] Handle TIF_RESTORE_SIGMASK for i386 Handle TIF_RESTORE_SIGMASK as added by David Woodhouse's patch entitled: [PATCH] 2/3 Add TIF_RESTORE_SIGMASK support for arch/powerpc [PATCH] 3/3 Generic sys_rt_sigsuspend It does the following: (1) Declares TIF_RESTORE_SIGMASK for i386. (2) Invokes it over to do_signal() when TIF_RESTORE_SIGMASK is set. (3) Makes do_signal() support TIF_RESTORE_SIGMASK, using the signal mask saved in current->saved_sigmask. (4) Discards sys_rt_sigsuspend() from the arch, using the generic one instead. (5) Makes sys_sigsuspend() save the signal mask and set TIF_RESTORE_SIGMASK rather than attempting to fudge the return registers. (6) Makes sys_sigsuspend() return -ERESTARTNOHAND rather than looping intrinsically. (7) Makes setup_frame(), setup_rt_frame() and handle_signal() return 0 or -EFAULT rather than true/false to be consistent with the rest of the kernel. Due to the fact do_signal() is then only called from one place: (8) Makes do_signal() no longer have a return value is it was just being ignored; force_sig() takes care of this. (9) Discards the old sigmask argument to do_signal() as it's no longer necessary. (10) Makes do_signal() static. (11) Marks the second argument to do_notify_resume() as unused. The unused argument should remain in the middle as the arguments are passed in as registers, and the ordering is specific in entry.S Given the way do_signal() is now no longer called from sys_{,rt_}sigsuspend(), they no longer need access to the exception frame, and so can just take arguments normally. This patch depends on sys_rt_sigsuspend patch. Signed-off-by: David Howells Signed-off-by: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/signal.c | 109 ++++++++++++++++++----------------------- include/asm-i386/signal.h | 1 - include/asm-i386/thread_info.h | 2 + include/asm-i386/unistd.h | 1 + 4 files changed, 51 insertions(+), 62 deletions(-) diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c index adcd069db91e8..963616d364ec4 100644 --- a/arch/i386/kernel/signal.c +++ b/arch/i386/kernel/signal.c @@ -37,51 +37,17 @@ asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask) { - struct pt_regs * regs = (struct pt_regs *) &history0; - sigset_t saveset; - mask &= _BLOCKABLE; spin_lock_irq(¤t->sighand->siglock); - saveset = current->blocked; + current->saved_sigmask = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - regs->eax = -EINTR; - while (1) { - current->state = TASK_INTERRUPTIBLE; - schedule(); - if (do_signal(regs, &saveset)) - return -EINTR; - } -} - -asmlinkage int -sys_rt_sigsuspend(struct pt_regs regs) -{ - sigset_t saveset, newset; - - /* XXX: Don't preclude handling different sized sigset_t's. */ - if (regs.ecx != sizeof(sigset_t)) - return -EINVAL; - - if (copy_from_user(&newset, (sigset_t __user *)regs.ebx, sizeof(newset))) - return -EFAULT; - sigdelsetmask(&newset, ~_BLOCKABLE); - - spin_lock_irq(¤t->sighand->siglock); - saveset = current->blocked; - current->blocked = newset; - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); - - regs.eax = -EINTR; - while (1) { - current->state = TASK_INTERRUPTIBLE; - schedule(); - if (do_signal(®s, &saveset)) - return -EINTR; - } + current->state = TASK_INTERRUPTIBLE; + schedule(); + set_thread_flag(TIF_RESTORE_SIGMASK); + return -ERESTARTNOHAND; } asmlinkage int @@ -433,11 +399,11 @@ static int setup_frame(int sig, struct k_sigaction *ka, current->comm, current->pid, frame, regs->eip, frame->pretcode); #endif - return 1; + return 0; give_sigsegv: force_sigsegv(sig, current); - return 0; + return -EFAULT; } static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, @@ -527,11 +493,11 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, current->comm, current->pid, frame, regs->eip, frame->pretcode); #endif - return 1; + return 0; give_sigsegv: force_sigsegv(sig, current); - return 0; + return -EFAULT; } /* @@ -581,7 +547,7 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, else ret = setup_frame(sig, ka, oldset, regs); - if (ret) { + if (ret == 0) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); if (!(ka->sa.sa_flags & SA_NODEFER)) @@ -598,11 +564,12 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ -int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset) +static void fastcall do_signal(struct pt_regs *regs) { siginfo_t info; int signr; struct k_sigaction ka; + sigset_t *oldset; /* * We want the common case to go fast, which @@ -613,12 +580,14 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset) * CS suffices. */ if (!user_mode(regs)) - return 1; + return; if (try_to_freeze()) goto no_signal; - if (!oldset) + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, &ka, regs, NULL); @@ -628,38 +597,55 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset) * have been cleared if the watchpoint triggered * inside the kernel. */ - if (unlikely(current->thread.debugreg[7])) { + if (unlikely(current->thread.debugreg[7])) set_debugreg(current->thread.debugreg[7], 7); - } /* Whee! Actually deliver the signal. */ - return handle_signal(signr, &info, &ka, oldset, regs); + 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 TIF_RESTORE_SIGMASK flag */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + clear_thread_flag(TIF_RESTORE_SIGMASK); + } + + return; } - no_signal: +no_signal: /* Did we come from a system call? */ if (regs->orig_eax >= 0) { /* Restart the system call - no handlers present */ - if (regs->eax == -ERESTARTNOHAND || - regs->eax == -ERESTARTSYS || - regs->eax == -ERESTARTNOINTR) { + switch (regs->eax) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: regs->eax = regs->orig_eax; regs->eip -= 2; - } - if (regs->eax == -ERESTART_RESTARTBLOCK){ + break; + + case -ERESTART_RESTARTBLOCK: regs->eax = __NR_restart_syscall; regs->eip -= 2; + break; } } - return 0; + + /* if there's no signal to deliver, we just put the saved sigmask + * back */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) { + clear_thread_flag(TIF_RESTORE_SIGMASK); + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + } } /* * notification of userspace execution resumption - * - triggered by current->work.notify_resume + * - triggered by the TIF_WORK_MASK flags */ __attribute__((regparm(3))) -void do_notify_resume(struct pt_regs *regs, sigset_t *oldset, +void do_notify_resume(struct pt_regs *regs, void *_unused, __u32 thread_info_flags) { /* Pending single-step? */ @@ -667,9 +653,10 @@ void do_notify_resume(struct pt_regs *regs, sigset_t *oldset, regs->eflags |= TF_MASK; clear_thread_flag(TIF_SINGLESTEP); } + /* deal with pending signal delivery */ - if (thread_info_flags & _TIF_SIGPENDING) - do_signal(regs,oldset); + if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) + do_signal(regs); clear_thread_flag(TIF_IRET); } diff --git a/include/asm-i386/signal.h b/include/asm-i386/signal.h index 76524b4052ac0..026fd231488dc 100644 --- a/include/asm-i386/signal.h +++ b/include/asm-i386/signal.h @@ -218,7 +218,6 @@ static __inline__ int sigfindinword(unsigned long word) } struct pt_regs; -extern int FASTCALL(do_signal(struct pt_regs *regs, sigset_t *oldset)); #define ptrace_signal_deliver(regs, cookie) \ do { \ diff --git a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h index 2493e77e8c305..e20e99551d710 100644 --- a/include/asm-i386/thread_info.h +++ b/include/asm-i386/thread_info.h @@ -140,6 +140,7 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__; #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SECCOMP 8 /* secure computing */ +#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */ #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */ #define TIF_MEMDIE 17 @@ -152,6 +153,7 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__; #define _TIF_SYSCALL_EMU (1<