| /* |
| * Signal handling |
| * |
| * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> |
| * Copyright (C) 2008-2009 PetaLogix |
| * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au> |
| * Copyright (C) 2001 NEC Corporation |
| * Copyright (C) 2001 Miles Bader <miles@gnu.org> |
| * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima |
| * Copyright (C) 1991,1992 Linus Torvalds |
| * |
| * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson |
| * |
| * This file was was derived from the sh version, arch/sh/kernel/signal.c |
| * |
| * This file is subject to the terms and conditions of the GNU General |
| * Public License. See the file COPYING in the main directory of this |
| * archive for more details. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/smp_lock.h> |
| #include <linux/kernel.h> |
| #include <linux/signal.h> |
| #include <linux/errno.h> |
| #include <linux/wait.h> |
| #include <linux/ptrace.h> |
| #include <linux/unistd.h> |
| #include <linux/stddef.h> |
| #include <linux/personality.h> |
| #include <linux/percpu.h> |
| #include <linux/linkage.h> |
| #include <asm/entry.h> |
| #include <asm/ucontext.h> |
| #include <linux/uaccess.h> |
| #include <asm/pgtable.h> |
| #include <asm/pgalloc.h> |
| #include <linux/syscalls.h> |
| #include <asm/cacheflush.h> |
| #include <asm/syscalls.h> |
| |
| #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) |
| |
| asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_sycall); |
| |
| /* |
| * Atomically swap in the new signal mask, and wait for a signal. |
| */ |
| asmlinkage int |
| sys_sigsuspend(old_sigset_t mask, struct pt_regs *regs) |
| { |
| sigset_t saveset; |
| |
| mask &= _BLOCKABLE; |
| spin_lock_irq(¤t->sighand->siglock); |
| saveset = current->blocked; |
| siginitset(¤t->blocked, mask); |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| |
| regs->r3 = -EINTR; |
| while (1) { |
| current->state = TASK_INTERRUPTIBLE; |
| schedule(); |
| if (do_signal(regs, &saveset, 1)) |
| return -EINTR; |
| } |
| } |
| |
| asmlinkage int |
| sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, |
| 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->r3 = -EINTR; |
| while (1) { |
| current->state = TASK_INTERRUPTIBLE; |
| schedule(); |
| if (do_signal(regs, &saveset, 1)) |
| return -EINTR; |
| } |
| } |
| |
| asmlinkage int |
| sys_sigaction(int sig, const struct old_sigaction *act, |
| struct old_sigaction *oact) |
| { |
| struct k_sigaction new_ka, old_ka; |
| int ret; |
| |
| if (act) { |
| old_sigset_t mask; |
| if (!access_ok(VERIFY_READ, act, sizeof(*act)) || |
| __get_user(new_ka.sa.sa_handler, &act->sa_handler) || |
| __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) |
| return -EFAULT; |
| __get_user(new_ka.sa.sa_flags, &act->sa_flags); |
| __get_user(mask, &act->sa_mask); |
| siginitset(&new_ka.sa.sa_mask, mask); |
| } |
| |
| ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
| |
| if (!ret && oact) { |
| if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || |
| __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || |
| __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) |
| return -EFAULT; |
| __put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
| __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); |
| } |
| |
| return ret; |
| } |
| |
| asmlinkage int |
| sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, |
| struct pt_regs *regs) |
| { |
| return do_sigaltstack(uss, uoss, regs->r1); |
| } |
| |
| /* |
| * Do a signal return; undo the signal stack. |
| */ |
| |
| struct sigframe { |
| struct sigcontext sc; |
| unsigned long extramask[_NSIG_WORDS-1]; |
| unsigned long tramp[2]; /* signal trampoline */ |
| }; |
| |
| struct rt_sigframe { |
| struct siginfo info; |
| struct ucontext uc; |
| unsigned long tramp[2]; /* signal trampoline */ |
| }; |
| |
| static int |
| restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p) |
| { |
| unsigned int err = 0; |
| |
| #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); } |
| COPY(r0); |
| COPY(r1); |
| COPY(r2); COPY(r3); COPY(r4); COPY(r5); |
| COPY(r6); COPY(r7); COPY(r8); COPY(r9); |
| COPY(r10); COPY(r11); COPY(r12); COPY(r13); |
| COPY(r14); COPY(r15); COPY(r16); COPY(r17); |
| COPY(r18); COPY(r19); COPY(r20); COPY(r21); |
| COPY(r22); COPY(r23); COPY(r24); COPY(r25); |
| COPY(r26); COPY(r27); COPY(r28); COPY(r29); |
| COPY(r30); COPY(r31); |
| COPY(pc); COPY(ear); COPY(esr); COPY(fsr); |
| #undef COPY |
| |
| *rval_p = regs->r3; |
| |
| return err; |
| } |
| |
| asmlinkage int sys_sigreturn(struct pt_regs *regs) |
| { |
| struct sigframe *frame = (struct sigframe *)regs->r1; |
| sigset_t set; |
| int rval; |
| |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| |
| if (__get_user(set.sig[0], &frame->sc.oldmask) |
| || (_NSIG_WORDS > 1 |
| && __copy_from_user(&set.sig[1], &frame->extramask, |
| sizeof(frame->extramask)))) |
| goto badframe; |
| |
| sigdelsetmask(&set, ~_BLOCKABLE); |
| |
| spin_lock_irq(¤t->sighand->siglock); |
| current->blocked = set; |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| |
| if (restore_sigcontext(regs, &frame->sc, &rval)) |
| goto badframe; |
| return rval; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) |
| { |
| struct rt_sigframe *frame = (struct rt_sigframe *)regs->r1; |
| sigset_t set; |
| stack_t st; |
| int rval; |
| |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| |
| if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) |
| goto badframe; |
| |
| sigdelsetmask(&set, ~_BLOCKABLE); |
| spin_lock_irq(¤t->sighand->siglock); |
| current->blocked = set; |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| |
| if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval)) |
| goto badframe; |
| |
| if (__copy_from_user((void *)&st, &frame->uc.uc_stack, sizeof(st))) |
| goto badframe; |
| /* It is more difficult to avoid calling this function than to |
| call it and ignore errors. */ |
| do_sigaltstack(&st, NULL, regs->r1); |
| |
| return rval; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| /* |
| * Set up a signal frame. |
| */ |
| |
| static int |
| setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, |
| unsigned long mask) |
| { |
| int err = 0; |
| |
| #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); } |
| COPY(r0); |
| COPY(r1); |
| COPY(r2); COPY(r3); COPY(r4); COPY(r5); |
| COPY(r6); COPY(r7); COPY(r8); COPY(r9); |
| COPY(r10); COPY(r11); COPY(r12); COPY(r13); |
| COPY(r14); COPY(r15); COPY(r16); COPY(r17); |
| COPY(r18); COPY(r19); COPY(r20); COPY(r21); |
| COPY(r22); COPY(r23); COPY(r24); COPY(r25); |
| COPY(r26); COPY(r27); COPY(r28); COPY(r29); |
| COPY(r30); COPY(r31); |
| COPY(pc); COPY(ear); COPY(esr); COPY(fsr); |
| #undef COPY |
| |
| err |= __put_user(mask, &sc->oldmask); |
| |
| return err; |
| } |
| |
| /* |
| * Determine which stack to use.. |
| */ |
| static inline void * |
| get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) |
| { |
| /* Default to using normal stack */ |
| unsigned long sp = regs->r1; |
| |
| if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp)) |
| sp = current->sas_ss_sp + current->sas_ss_size; |
| |
| return (void *)((sp - frame_size) & -8UL); |
| } |
| |
| static void setup_frame(int sig, struct k_sigaction *ka, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| struct sigframe *frame; |
| int err = 0; |
| int signal; |
| |
| frame = get_sigframe(ka, regs, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| goto give_sigsegv; |
| |
| signal = current_thread_info()->exec_domain |
| && current_thread_info()->exec_domain->signal_invmap |
| && sig < 32 |
| ? current_thread_info()->exec_domain->signal_invmap[sig] |
| : sig; |
| |
| err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); |
| |
| if (_NSIG_WORDS > 1) { |
| err |= __copy_to_user(frame->extramask, &set->sig[1], |
| sizeof(frame->extramask)); |
| } |
| |
| /* Set up to return from userspace. If provided, use a stub |
| already in userspace. */ |
| /* minus 8 is offset to cater for "rtsd r15,8" offset */ |
| if (ka->sa.sa_flags & SA_RESTORER) { |
| regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8; |
| } else { |
| /* Note, these encodings are _big endian_! */ |
| |
| /* addi r12, r0, __NR_sigreturn */ |
| err |= __put_user(0x31800000 | __NR_sigreturn , |
| frame->tramp + 0); |
| /* brki r14, 0x8 */ |
| err |= __put_user(0xb9cc0008, frame->tramp + 1); |
| |
| /* Return from sighandler will jump to the tramp. |
| Negative 8 offset because return is rtsd r15, 8 */ |
| regs->r15 = ((unsigned long)frame->tramp)-8; |
| |
| __invalidate_cache_sigtramp((unsigned long)frame->tramp); |
| } |
| |
| if (err) |
| goto give_sigsegv; |
| |
| /* Set up registers for signal handler */ |
| regs->r1 = (unsigned long) frame; |
| /* Signal handler args: */ |
| regs->r5 = signal; /* Arg 0: signum */ |
| regs->r6 = (unsigned long) &frame->sc; /* arg 1: sigcontext */ |
| |
| /* Offset of 4 to handle microblaze rtid r14, 0 */ |
| regs->pc = (unsigned long)ka->sa.sa_handler; |
| |
| set_fs(USER_DS); |
| |
| #ifdef DEBUG_SIG |
| printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n", |
| current->comm, current->pid, frame, regs->pc); |
| #endif |
| |
| return; |
| |
| give_sigsegv: |
| if (sig == SIGSEGV) |
| ka->sa.sa_handler = SIG_DFL; |
| force_sig(SIGSEGV, current); |
| } |
| |
| static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| struct rt_sigframe *frame; |
| int err = 0; |
| int signal; |
| |
| frame = get_sigframe(ka, regs, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| goto give_sigsegv; |
| |
| signal = current_thread_info()->exec_domain |
| && current_thread_info()->exec_domain->signal_invmap |
| && sig < 32 |
| ? current_thread_info()->exec_domain->signal_invmap[sig] |
| : sig; |
| |
| err |= copy_siginfo_to_user(&frame->info, info); |
| |
| /* Create the ucontext. */ |
| err |= __put_user(0, &frame->uc.uc_flags); |
| err |= __put_user(0, &frame->uc.uc_link); |
| err |= __put_user((void *)current->sas_ss_sp, |
| &frame->uc.uc_stack.ss_sp); |
| err |= __put_user(sas_ss_flags(regs->r1), |
| &frame->uc.uc_stack.ss_flags); |
| err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, |
| regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| |
| /* Set up to return from userspace. If provided, use a stub |
| already in userspace. */ |
| /* minus 8 is offset to cater for "rtsd r15,8" */ |
| if (ka->sa.sa_flags & SA_RESTORER) { |
| regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8; |
| } else { |
| /* addi r12, r0, __NR_sigreturn */ |
| err |= __put_user(0x31800000 | __NR_rt_sigreturn , |
| frame->tramp + 0); |
| /* brki r14, 0x8 */ |
| err |= __put_user(0xb9cc0008, frame->tramp + 1); |
| |
| /* Return from sighandler will jump to the tramp. |
| Negative 8 offset because return is rtsd r15, 8 */ |
| regs->r15 = ((unsigned long)frame->tramp)-8; |
| |
| __invalidate_cache_sigtramp((unsigned long)frame->tramp); |
| } |
| |
| if (err) |
| goto give_sigsegv; |
| |
| /* Set up registers for signal handler */ |
| regs->r1 = (unsigned long) frame; |
| /* Signal handler args: */ |
| regs->r5 = signal; /* arg 0: signum */ |
| regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ |
| regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ |
| /* Offset to handle microblaze rtid r14, 0 */ |
| regs->pc = (unsigned long)ka->sa.sa_handler; |
| |
| set_fs(USER_DS); |
| |
| #ifdef DEBUG_SIG |
| printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n", |
| current->comm, current->pid, frame, regs->pc); |
| #endif |
| |
| return; |
| |
| give_sigsegv: |
| if (sig == SIGSEGV) |
| ka->sa.sa_handler = SIG_DFL; |
| force_sig(SIGSEGV, current); |
| } |
| |
| /* Handle restarting system calls */ |
| static inline void |
| handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) |
| { |
| switch (regs->r3) { |
| case -ERESTART_RESTARTBLOCK: |
| case -ERESTARTNOHAND: |
| if (!has_handler) |
| goto do_restart; |
| regs->r3 = -EINTR; |
| break; |
| case -ERESTARTSYS: |
| if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { |
| regs->r3 = -EINTR; |
| break; |
| } |
| /* fallthrough */ |
| case -ERESTARTNOINTR: |
| do_restart: |
| /* offset of 4 bytes to re-execute trap (brki) instruction */ |
| regs->pc -= 4; |
| break; |
| } |
| } |
| |
| /* |
| * OK, we're invoking a handler |
| */ |
| |
| static void |
| handle_signal(unsigned long sig, struct k_sigaction *ka, |
| siginfo_t *info, sigset_t *oldset, struct pt_regs *regs) |
| { |
| /* Set up the stack frame */ |
| if (ka->sa.sa_flags & SA_SIGINFO) |
| 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; |
| |
| if (!(ka->sa.sa_flags & SA_NODEFER)) { |
| spin_lock_irq(¤t->sighand->siglock); |
| sigorsets(¤t->blocked, |
| ¤t->blocked, &ka->sa.sa_mask); |
| sigaddset(¤t->blocked, sig); |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| } |
| } |
| |
| /* |
| * Note that 'init' is a special process: it doesn't get signals it doesn't |
| * want to handle. Thus you cannot kill init even with a SIGKILL even by |
| * mistake. |
| * |
| * Note that we go through the signals twice: once to check the signals that |
| * the kernel can handle, and then we build all the user-level signal handling |
| * stack-frames in one go after that. |
| */ |
| int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall) |
| { |
| siginfo_t info; |
| int signr; |
| struct k_sigaction ka; |
| #ifdef DEBUG_SIG |
| printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall); |
| printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1, |
| regs->r12, current_thread_info()->flags); |
| #endif |
| /* |
| * We want the common case to go fast, which |
| * is why we may in certain cases get here from |
| * kernel mode. Just return without doing anything |
| * if so. |
| */ |
| if (kernel_mode(regs)) |
| return 1; |
| |
| if (!oldset) |
| oldset = ¤t->blocked; |
| |
| signr = get_signal_to_deliver(&info, &ka, regs, NULL); |
| if (signr > 0) { |
| /* Whee! Actually deliver the signal. */ |
| if (in_syscall) |
| handle_restart(regs, &ka, 1); |
| handle_signal(signr, &ka, &info, oldset, regs); |
| return 1; |
| } |
| |
| if (in_syscall) |
| handle_restart(regs, NULL, 0); |
| |
| /* Did we come from a system call? */ |
| return 0; |
| } |