1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
580 lines
16 KiB
C
580 lines
16 KiB
C
/*
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* linux/arch/cris/kernel/signal.c
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*
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* Based on arch/i386/kernel/signal.c by
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* Copyright (C) 1991, 1992 Linus Torvalds
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson *
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*
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* Ideas also taken from arch/arm.
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*
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* Copyright (C) 2000, 2001 Axis Communications AB
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*
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* Authors: Bjorn Wesen (bjornw@axis.com)
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*
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <asm/processor.h>
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#include <asm/ucontext.h>
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#include <asm/uaccess.h>
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#define DEBUG_SIG 0
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
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/* manipulate regs so that upon return, it will be re-executed */
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/* We rely on that pc points to the instruction after "break 13", so the
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* library must never do strange things like putting it in a delay slot.
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*/
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#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2;
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int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs);
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/*
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* Atomically swap in the new signal mask, and wait for a signal. Define
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* dummy arguments to be able to reach the regs argument. (Note that this
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* arrangement relies on old_sigset_t occupying one register.)
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*/
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int
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sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof,
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long srp, struct pt_regs *regs)
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{
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sigset_t saveset;
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mask &= _BLOCKABLE;
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spin_lock_irq(¤t->sighand->siglock);
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saveset = current->blocked;
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siginitset(¤t->blocked, mask);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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regs->r10 = -EINTR;
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while (1) {
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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if (do_signal(0, &saveset, regs))
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/* We will get here twice: once to call the signal
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handler, then again to return from the
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sigsuspend system call. When calling the
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signal handler, R10 holds the signal number as
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set through do_signal. The sigsuspend call
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will return with the restored value set above;
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always -EINTR. */
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return regs->r10;
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}
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}
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/* Define dummy arguments to be able to reach the regs argument. (Note that
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* this arrangement relies on size_t occupying one register.)
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*/
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int
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sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r12, long r13,
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long mof, long srp, struct pt_regs *regs)
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{
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sigset_t saveset, newset;
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/* XXX: Don't preclude handling different sized sigset_t's. */
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if (sigsetsize != sizeof(sigset_t))
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return -EINVAL;
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if (copy_from_user(&newset, unewset, sizeof(newset)))
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return -EFAULT;
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sigdelsetmask(&newset, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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saveset = current->blocked;
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current->blocked = newset;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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regs->r10 = -EINTR;
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while (1) {
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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if (do_signal(0, &saveset, regs))
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/* We will get here twice: once to call the signal
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handler, then again to return from the
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sigsuspend system call. When calling the
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signal handler, R10 holds the signal number as
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set through do_signal. The sigsuspend call
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will return with the restored value set above;
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always -EINTR. */
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return regs->r10;
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}
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}
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int
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sys_sigaction(int sig, const struct old_sigaction __user *act,
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struct old_sigaction *oact)
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{
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struct k_sigaction new_ka, old_ka;
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int ret;
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if (act) {
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old_sigset_t mask;
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if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
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__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
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__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
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return -EFAULT;
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__get_user(new_ka.sa.sa_flags, &act->sa_flags);
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__get_user(mask, &act->sa_mask);
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siginitset(&new_ka.sa.sa_mask, mask);
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}
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ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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if (!ret && oact) {
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if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
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__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
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__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
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return -EFAULT;
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__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
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__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
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}
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return ret;
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}
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int
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sys_sigaltstack(const stack_t *uss, stack_t __user *uoss)
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{
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return do_sigaltstack(uss, uoss, rdusp());
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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struct sigframe {
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struct sigcontext sc;
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unsigned long extramask[_NSIG_WORDS-1];
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unsigned char retcode[8]; /* trampoline code */
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};
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struct rt_sigframe {
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struct siginfo *pinfo;
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void *puc;
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struct siginfo info;
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struct ucontext uc;
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unsigned char retcode[8]; /* trampoline code */
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};
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static int
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restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
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{
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unsigned int err = 0;
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unsigned long old_usp;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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/* restore the regs from &sc->regs (same as sc, since regs is first)
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* (sc is already checked for VERIFY_READ since the sigframe was
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* checked in sys_sigreturn previously)
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*/
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if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
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goto badframe;
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/* make sure the U-flag is set so user-mode cannot fool us */
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regs->dccr |= 1 << 8;
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/* restore the old USP as it was before we stacked the sc etc.
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* (we cannot just pop the sigcontext since we aligned the sp and
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* stuff after pushing it)
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*/
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err |= __get_user(old_usp, &sc->usp);
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wrusp(old_usp);
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/* TODO: the other ports use regs->orig_XX to disable syscall checks
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* after this completes, but we don't use that mechanism. maybe we can
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* use it now ?
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*/
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return err;
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badframe:
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return 1;
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}
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/* Define dummy arguments to be able to reach the regs argument. */
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asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof,
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long srp, struct pt_regs *regs)
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{
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struct sigframe __user *frame = (struct sigframe *)rdusp();
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sigset_t set;
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/*
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* Since we stacked the signal on a dword boundary,
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* then frame should be dword aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (((long)frame) & 3)
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goto badframe;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__get_user(set.sig[0], &frame->sc.oldmask)
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|| (_NSIG_WORDS > 1
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&& __copy_from_user(&set.sig[1], frame->extramask,
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sizeof(frame->extramask))))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(regs, &frame->sc))
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goto badframe;
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/* TODO: SIGTRAP when single-stepping as in arm ? */
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return regs->r10;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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/* Define dummy arguments to be able to reach the regs argument. */
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asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13,
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long mof, long srp, struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp();
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sigset_t set;
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/*
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* Since we stacked the signal on a dword boundary,
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* then frame should be dword aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (((long)frame) & 3)
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goto badframe;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
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goto badframe;
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if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT)
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goto badframe;
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return regs->r10;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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/*
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* Set up a signal frame.
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*/
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static int
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask)
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{
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int err = 0;
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unsigned long usp = rdusp();
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/* copy the regs. they are first in sc so we can use sc directly */
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err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
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/* Set the frametype to CRIS_FRAME_NORMAL for the execution of
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the signal handler. The frametype will be restored to its previous
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value in restore_sigcontext. */
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regs->frametype = CRIS_FRAME_NORMAL;
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/* then some other stuff */
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err |= __put_user(mask, &sc->oldmask);
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err |= __put_user(usp, &sc->usp);
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return err;
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}
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/* figure out where we want to put the new signal frame - usually on the stack */
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static inline void __user *
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get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
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{
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unsigned long sp = rdusp();
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/* This is the X/Open sanctioned signal stack switching. */
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if (ka->sa.sa_flags & SA_ONSTACK) {
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if (! on_sig_stack(sp))
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sp = current->sas_ss_sp + current->sas_ss_size;
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}
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/* make sure the frame is dword-aligned */
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sp &= ~3;
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return (void __user*)(sp - frame_size);
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}
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/* grab and setup a signal frame.
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*
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* basically we stack a lot of state info, and arrange for the
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* user-mode program to return to the kernel using either a
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* trampoline which performs the syscall sigreturn, or a provided
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* user-mode trampoline.
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*/
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static void setup_frame(int sig, struct k_sigaction *ka,
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sigset_t *set, struct pt_regs * regs)
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{
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struct sigframe __user *frame;
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unsigned long return_ip;
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int err = 0;
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frame = get_sigframe(ka, regs, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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goto give_sigsegv;
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err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
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if (err)
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goto give_sigsegv;
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if (_NSIG_WORDS > 1) {
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err |= __copy_to_user(frame->extramask, &set->sig[1],
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sizeof(frame->extramask));
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}
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if (err)
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goto give_sigsegv;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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if (ka->sa.sa_flags & SA_RESTORER) {
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return_ip = (unsigned long)ka->sa.sa_restorer;
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} else {
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/* trampoline - the desired return ip is the retcode itself */
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return_ip = (unsigned long)&frame->retcode;
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/* This is movu.w __NR_sigreturn, r9; break 13; */
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err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
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err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
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err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
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}
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if (err)
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goto give_sigsegv;
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/* Set up registers for signal handler */
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regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */
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regs->srp = return_ip; /* what we enter LATER */
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regs->r10 = sig; /* first argument is signo */
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/* actually move the usp to reflect the stacked frame */
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wrusp((unsigned long)frame);
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return;
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give_sigsegv:
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force_sigsegv(sig, current);
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}
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static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs * regs)
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{
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struct rt_sigframe __user *frame;
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unsigned long return_ip;
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int err = 0;
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frame = get_sigframe(ka, regs, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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goto give_sigsegv;
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err |= __put_user(&frame->info, &frame->pinfo);
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err |= __put_user(&frame->uc, &frame->puc);
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err |= copy_siginfo_to_user(&frame->info, info);
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if (err)
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goto give_sigsegv;
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/* Clear all the bits of the ucontext we don't use. */
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err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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goto give_sigsegv;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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if (ka->sa.sa_flags & SA_RESTORER) {
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return_ip = (unsigned long)ka->sa.sa_restorer;
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} else {
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/* trampoline - the desired return ip is the retcode itself */
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return_ip = (unsigned long)&frame->retcode;
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/* This is movu.w __NR_rt_sigreturn, r9; break 13; */
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err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
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err |= __put_user(__NR_rt_sigreturn, (short __user*)(frame->retcode+2));
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err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
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}
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if (err)
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goto give_sigsegv;
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/* TODO what is the current->exec_domain stuff and invmap ? */
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/* Set up registers for signal handler */
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regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */
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regs->srp = return_ip; /* what we enter LATER */
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regs->r10 = sig; /* first argument is signo */
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regs->r11 = (unsigned long) &frame->info; /* second argument is (siginfo_t *) */
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regs->r12 = 0; /* third argument is unused */
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/* actually move the usp to reflect the stacked frame */
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wrusp((unsigned long)frame);
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return;
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give_sigsegv:
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force_sigsegv(sig, current);
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}
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/*
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* OK, we're invoking a handler
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*/
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extern inline void
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handle_signal(int canrestart, unsigned long sig,
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siginfo_t *info, struct k_sigaction *ka,
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sigset_t *oldset, struct pt_regs * regs)
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{
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/* Are we from a system call? */
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if (canrestart) {
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/* If so, check system call restarting.. */
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switch (regs->r10) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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/* ERESTARTNOHAND means that the syscall should only be
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restarted if there was no handler for the signal, and since
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we only get here if there is a handler, we don't restart */
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regs->r10 = -EINTR;
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break;
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case -ERESTARTSYS:
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/* ERESTARTSYS means to restart the syscall if there is no
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handler or the handler was registered with SA_RESTART */
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if (!(ka->sa.sa_flags & SA_RESTART)) {
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regs->r10 = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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/* ERESTARTNOINTR means that the syscall should be called again
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after the signal handler returns. */
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RESTART_CRIS_SYS(regs);
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}
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}
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/* Set up the stack frame */
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if (ka->sa.sa_flags & SA_SIGINFO)
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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.
|
|
*
|
|
* Also note that the regs structure given here as an argument, is the latest
|
|
* pushed pt_regs. It may or may not be the same as the first pushed registers
|
|
* when the initial usermode->kernelmode transition took place. Therefore
|
|
* we can use user_mode(regs) to see if we came directly from kernel or user
|
|
* mode below.
|
|
*/
|
|
|
|
int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
|
|
{
|
|
siginfo_t info;
|
|
int signr;
|
|
struct k_sigaction ka;
|
|
|
|
/*
|
|
* 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 (!user_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. */
|
|
handle_signal(canrestart, signr, &info, &ka, oldset, regs);
|
|
return 1;
|
|
}
|
|
|
|
/* Did we come from a system call? */
|
|
if (canrestart) {
|
|
/* Restart the system call - no handlers present */
|
|
if (regs->r10 == -ERESTARTNOHAND ||
|
|
regs->r10 == -ERESTARTSYS ||
|
|
regs->r10 == -ERESTARTNOINTR) {
|
|
RESTART_CRIS_SYS(regs);
|
|
}
|
|
if (regs->r10 == -ERESTART_RESTARTBLOCK){
|
|
regs->r10 = __NR_restart_syscall;
|
|
regs->irp -= 2;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|