From: Jesper Nilsson Date: Mon, 14 Jan 2008 08:55:22 +0000 (-0800) Subject: CRIS v10: correct do_signal to fix oops and clean up signal handling in general X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a4858d4dab4580ec8b1fb7576f91522b6962502c;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git CRIS v10: correct do_signal to fix oops and clean up signal handling in general This fixes a kernel panic on boot due to do_signal not being compatible with it's callers. - do_signal now returns void, and does not have the previous signal set as a parameter. - Remove sys_rt_sigsuspend, we can use the common one instead. - Change sys_sigsuspend to be more like x86, don't call do_signal here. - handle_signal, setup_frame and setup_rt_frame now return -EFAULT if we've delivered a segfault, which is used by callers to perform necessary cleanup. - Break long lines, correct whitespace and formatting errors. Signed-off-by: Jesper Nilsson Cc: Mikael Starvik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/cris/arch-v10/kernel/signal.c b/arch/cris/arch-v10/kernel/signal.c index 41d4a5f93284..b6be705c2a3e 100644 --- a/arch/cris/arch-v10/kernel/signal.c +++ b/arch/cris/arch-v10/kernel/signal.c @@ -7,7 +7,7 @@ * * Ideas also taken from arch/arm. * - * Copyright (C) 2000, 2001 Axis Communications AB + * Copyright (C) 2000-2007 Axis Communications AB * * Authors: Bjorn Wesen (bjornw@axis.com) * @@ -40,84 +40,30 @@ */ #define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2; -int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs); +void do_signal(int canrestart, struct pt_regs *regs); /* - * Atomically swap in the new signal mask, and wait for a signal. Define + * Atomically swap in the new signal mask, and wait for a signal. Define * dummy arguments to be able to reach the regs argument. (Note that this * arrangement relies on old_sigset_t occupying one register.) */ -int -sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof, - long srp, struct pt_regs *regs) +int sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof, + long srp, struct pt_regs *regs) { - 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->r10 = -EINTR; - while (1) { - current->state = TASK_INTERRUPTIBLE; - schedule(); - if (do_signal(0, &saveset, regs)) - /* We will get here twice: once to call the signal - handler, then again to return from the - sigsuspend system call. When calling the - signal handler, R10 holds the signal number as - set through do_signal. The sigsuspend call - will return with the restored value set above; - always -EINTR. */ - return regs->r10; - } + current->state = TASK_INTERRUPTIBLE; + schedule(); + set_thread_flag(TIF_RESTORE_SIGMASK); + return -ERESTARTNOHAND; } -/* Define dummy arguments to be able to reach the regs argument. (Note that - * this arrangement relies on size_t occupying one register.) - */ -int -sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r12, long r13, - long mof, long srp, struct pt_regs *regs) -{ - sigset_t saveset, newset; - - /* XXX: Don't preclude handling different sized sigset_t's. */ - if (sigsetsize != sizeof(sigset_t)) - return -EINVAL; - - if (copy_from_user(&newset, unewset, 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->r10 = -EINTR; - while (1) { - current->state = TASK_INTERRUPTIBLE; - schedule(); - if (do_signal(0, &saveset, regs)) - /* We will get here twice: once to call the signal - handler, then again to return from the - sigsuspend system call. When calling the - signal handler, R10 holds the signal number as - set through do_signal. The sigsuspend call - will return with the restored value set above; - always -EINTR. */ - return regs->r10; - } -} - -int -sys_sigaction(int sig, const struct old_sigaction __user *act, - struct old_sigaction *oact) +int sys_sigaction(int sig, const struct old_sigaction __user *act, + struct old_sigaction *oact) { struct k_sigaction new_ka, old_ka; int ret; @@ -147,8 +93,7 @@ sys_sigaction(int sig, const struct old_sigaction __user *act, return ret; } -int -sys_sigaltstack(const stack_t *uss, stack_t __user *uoss) +int sys_sigaltstack(const stack_t *uss, stack_t __user *uoss) { return do_sigaltstack(uss, uoss, rdusp()); } @@ -205,7 +150,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) /* TODO: the other ports use regs->orig_XX to disable syscall checks * after this completes, but we don't use that mechanism. maybe we can - * use it now ? + * use it now ? */ return err; @@ -216,7 +161,7 @@ badframe: /* Define dummy arguments to be able to reach the regs argument. */ -asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof, +asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp, struct pt_regs *regs) { struct sigframe __user *frame = (struct sigframe *)rdusp(); @@ -243,7 +188,7 @@ asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof, current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - + if (restore_sigcontext(regs, &frame->sc)) goto badframe; @@ -254,11 +199,11 @@ asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof, badframe: force_sig(SIGSEGV, current); return 0; -} +} /* Define dummy arguments to be able to reach the regs argument. */ -asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13, +asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp, struct pt_regs *regs) { struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp(); @@ -282,7 +227,7 @@ asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13, current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; @@ -294,14 +239,14 @@ asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13, badframe: force_sig(SIGSEGV, current); return 0; -} +} /* * Set up a signal frame. */ -static int -setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask) +static int setup_sigcontext(struct sigcontext __user *sc, + struct pt_regs *regs, unsigned long mask) { int err = 0; unsigned long usp = rdusp(); @@ -324,10 +269,11 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned lo return err; } -/* figure out where we want to put the new signal frame - usually on the stack */ +/* Figure out where we want to put the new signal frame + * - usually on the stack. */ static inline void __user * -get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) +get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) { unsigned long sp = rdusp(); @@ -345,15 +291,15 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) } /* grab and setup a signal frame. - * + * * basically we stack a lot of state info, and arrange for the * user-mode program to return to the kernel using either a * trampoline which performs the syscall sigreturn, or a provided * user-mode trampoline. */ -static void setup_frame(int sig, struct k_sigaction *ka, - sigset_t *set, struct pt_regs * regs) +static int setup_frame(int sig, struct k_sigaction *ka, + sigset_t *set, struct pt_regs *regs) { struct sigframe __user *frame; unsigned long return_ip; @@ -401,14 +347,15 @@ static void setup_frame(int sig, struct k_sigaction *ka, wrusp((unsigned long)frame); - return; + return 0; give_sigsegv: force_sigsegv(sig, current); + return -EFAULT; } -static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, - sigset_t *set, struct pt_regs * regs) +static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *frame; unsigned long return_ip; @@ -443,9 +390,10 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, /* trampoline - the desired return ip is the retcode itself */ return_ip = (unsigned long)&frame->retcode; /* This is movu.w __NR_rt_sigreturn, r9; break 13; */ - err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0)); - err |= __put_user(__NR_rt_sigreturn, (short __user*)(frame->retcode+2)); - err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); + err |= __put_user(0x9c5f, (short __user *)(frame->retcode+0)); + err |= __put_user(__NR_rt_sigreturn, + (short __user *)(frame->retcode+2)); + err |= __put_user(0xe93d, (short __user *)(frame->retcode+4)); } if (err) @@ -455,73 +403,81 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, /* Set up registers for signal handler */ - regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */ - regs->srp = return_ip; /* what we enter LATER */ - regs->r10 = sig; /* first argument is signo */ - regs->r11 = (unsigned long) &frame->info; /* second argument is (siginfo_t *) */ - regs->r12 = 0; /* third argument is unused */ - - /* actually move the usp to reflect the stacked frame */ - + /* What we enter NOW */ + regs->irp = (unsigned long) ka->sa.sa_handler; + /* What we enter LATER */ + regs->srp = return_ip; + /* First argument is signo */ + regs->r10 = sig; + /* Second argument is (siginfo_t *) */ + regs->r11 = (unsigned long)&frame->info; + /* Third argument is unused */ + regs->r12 = 0; + + /* Actually move the usp to reflect the stacked frame */ wrusp((unsigned long)frame); - return; + return 0; give_sigsegv: force_sigsegv(sig, current); + return -EFAULT; } /* * OK, we're invoking a handler - */ + */ -static inline void -handle_signal(int canrestart, unsigned long sig, - siginfo_t *info, struct k_sigaction *ka, - sigset_t *oldset, struct pt_regs * regs) +static inline int handle_signal(int canrestart, unsigned long sig, + siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs *regs) { + int ret; + /* Are we from a system call? */ if (canrestart) { /* If so, check system call restarting.. */ switch (regs->r10) { - case -ERESTART_RESTARTBLOCK: - case -ERESTARTNOHAND: - /* ERESTARTNOHAND means that the syscall should only be - restarted if there was no handler for the signal, and since - we only get here if there is a handler, we don't restart */ + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + /* ERESTARTNOHAND means that the syscall should + * only be restarted if there was no handler for + * the signal, and since we only get here if there + * is a handler, we don't restart */ + regs->r10 = -EINTR; + break; + case -ERESTARTSYS: + /* ERESTARTSYS means to restart the syscall if + * there is no handler or the handler was + * registered with SA_RESTART */ + if (!(ka->sa.sa_flags & SA_RESTART)) { regs->r10 = -EINTR; break; - - case -ERESTARTSYS: - /* ERESTARTSYS means to restart the syscall if there is no - handler or the handler was registered with SA_RESTART */ - if (!(ka->sa.sa_flags & SA_RESTART)) { - regs->r10 = -EINTR; - break; - } - /* fallthrough */ - case -ERESTARTNOINTR: - /* ERESTARTNOINTR means that the syscall should be called again - after the signal handler returns. */ - RESTART_CRIS_SYS(regs); + } + /* fallthrough */ + case -ERESTARTNOINTR: + /* ERESTARTNOINTR means that the syscall should + * be called again after the signal handler returns. */ + RESTART_CRIS_SYS(regs); } } /* Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) - setup_rt_frame(sig, ka, info, oldset, regs); + ret = setup_rt_frame(sig, ka, info, oldset, regs); else - setup_frame(sig, ka, oldset, regs); - - if (ka->sa.sa_flags & SA_ONESHOT) - ka->sa.sa_handler = SIG_DFL; - - spin_lock_irq(¤t->sighand->siglock); - sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); - if (!(ka->sa.sa_flags & SA_NODEFER)) - sigaddset(¤t->blocked,sig); - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); + ret = setup_frame(sig, ka, oldset, regs); + + 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)) + sigaddset(¤t->blocked, sig); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } + return ret; } /* @@ -536,11 +492,12 @@ handle_signal(int canrestart, unsigned long sig, * mode below. */ -int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs) +void do_signal(int canrestart, 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 @@ -549,16 +506,26 @@ int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs) * if so. */ if (!user_mode(regs)) - return 1; + return; - 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); if (signr > 0) { /* Whee! Actually deliver the signal. */ - handle_signal(canrestart, signr, &info, &ka, oldset, regs); - return 1; + if (handle_signal(canrestart, signr, &info, &ka, + oldset, regs)) { + /* 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; } /* Did we come from a system call? */ @@ -569,10 +536,16 @@ int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs) regs->r10 == -ERESTARTNOINTR) { RESTART_CRIS_SYS(regs); } - if (regs->r10 == -ERESTART_RESTARTBLOCK){ + if (regs->r10 == -ERESTART_RESTARTBLOCK) { regs->r10 = __NR_restart_syscall; regs->irp -= 2; } } - 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); + } }