patch-2.4.2 linux/arch/cris/kernel/signal.c

• Lines: 668
• Date: Thu Feb 8 16:32:44 2001
• Orig file: v2.4.1/linux/arch/cris/kernel/signal.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.1/linux/arch/cris/kernel/signal.c linux/arch/cris/kernel/signal.c
@@ -0,0 +1,667 @@
+/*
+ *  linux/arch/cris/kernel/signal.c
+ *
+ *  Based on arch/i386/kernel/signal.c by
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *     1997-11-28  Modified for POSIX.1b signals by Richard Henderson *
+ *
+ *  Ideas also taken from arch/arm.
+ *
+ *  Copyright (C) 2000 Axis Communications AB
+ *
+ *  Authors:  Bjorn Wesen (bjornw@axis.com)
+ *
+ */
+
+#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 <asm/processor.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+
+#define DEBUG_SIG 0
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
+/* manipulate regs so that upon return, it will be re-executed */
+
+#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2;
+
+int sys_wait4(pid_t pid, unsigned long *stat_addr,
+			 int options, unsigned long *ru);
+
+int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs);
+
+int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
+{
+	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
+		return -EFAULT;
+	if (from->si_code < 0)
+		return __copy_to_user(to, from, sizeof(siginfo_t));
+	else {
+		int err;
+
+		/* If you change siginfo_t structure, please be sure
+		   this code is fixed accordingly.
+		   It should never copy any pad contained in the structure
+		   to avoid security leaks, but must copy the generic
+		   3 ints plus the relevant union member.  */
+		err = __put_user(from->si_signo, &to->si_signo);
+		err |= __put_user(from->si_errno, &to->si_errno);
+		err |= __put_user((short)from->si_code, &to->si_code);
+		/* First 32bits of unions are always present.  */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		switch (from->si_code >> 16) {
+		case __SI_FAULT >> 16:
+			break;
+		case __SI_CHLD >> 16:
+			err |= __put_user(from->si_utime, &to->si_utime);
+			err |= __put_user(from->si_stime, &to->si_stime);
+			err |= __put_user(from->si_status, &to->si_status);
+		default:
+			err |= __put_user(from->si_uid, &to->si_uid);
+			break;
+		/* case __SI_RT: This is not generated by the kernel as of now.  */
+		}
+		return err;
+	}
+}
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+int
+sys_sigsuspend(old_sigset_t mask)
+{
+	struct pt_regs * regs = (struct pt_regs *)current_regs();
+	sigset_t saveset;
+
+	mask &= _BLOCKABLE;
+	spin_lock_irq(&current->sigmask_lock);
+	saveset = current->blocked;
+	siginitset(&current->blocked, mask);
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
+	regs->r10 = -EINTR;
+	while (1) {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(0, &saveset, regs))
+			return -EINTR;
+	}
+}
+
+int
+sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize)
+{
+	struct pt_regs * regs = (struct pt_regs *)current_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(&current->sigmask_lock);
+	saveset = current->blocked;
+	current->blocked = newset;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
+	regs->r10 = -EINTR;
+	while (1) {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(0, &saveset, regs))
+			return -EINTR;
+	}
+}
+
+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 (verify_area(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 (verify_area(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;
+}
+
+int
+sys_sigaltstack(const stack_t *uss, stack_t *uoss)
+{
+	return do_sigaltstack(uss, uoss, rdusp());
+}
+
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+struct sigframe {
+	struct sigcontext sc;
+	unsigned long extramask[_NSIG_WORDS-1];
+	unsigned char retcode[8];  /* trampoline code */
+};
+
+struct rt_sigframe {
+	struct siginfo *pinfo;
+	void *puc;
+	struct siginfo info;
+	struct ucontext uc;
+	unsigned char retcode[8];  /* trampoline code */
+};
+
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
+{
+	unsigned int err = 0;
+	unsigned long old_usp;
+
+	/* restore the regs from &sc->regs (same as sc, since regs is first)
+	 * (sc is already checked for VERIFY_READ since the sigframe was
+	 *  checked in sys_sigreturn previously)
+	 */
+
+	if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
+                goto badframe;
+
+	/* make sure the U-flag is set so user-mode cannot fool us */
+
+	regs->dccr |= 1 << 8;
+
+	/* restore the old USP as it was before we stacked the sc etc.
+	 * (we cannot just pop the sigcontext since we aligned the sp and
+	 *  stuff after pushing it)
+	 */
+
+	err |= __get_user(old_usp, &sc->usp);
+
+	wrusp(old_usp);
+
+	/* 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 ? 
+	 */
+
+	return err;
+
+badframe:
+	return 1;
+}
+
+asmlinkage int sys_sigreturn(void)
+{
+	struct pt_regs *regs = (struct pt_regs *)current_regs();
+	struct sigframe *frame = (struct sigframe *)rdusp();
+	sigset_t set;
+
+        /*
+         * Since we stacked the signal on a dword boundary,
+         * then frame should be dword aligned here.  If it's
+         * not, then the user is trying to mess with us.
+         */
+        if (((long)frame) & 3)
+                goto badframe;
+
+	if (verify_area(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(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+	
+	if (restore_sigcontext(regs, &frame->sc))
+		goto badframe;
+
+	/* TODO: SIGTRAP when single-stepping as in arm ? */
+
+	return regs->r10;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}	
+
+asmlinkage int sys_rt_sigreturn(void)
+{
+	struct pt_regs *regs = (struct pt_regs *)current_regs();
+	struct rt_sigframe *frame = (struct rt_sigframe *)rdusp();
+	sigset_t set;
+	stack_t st;
+
+        /*
+         * Since we stacked the signal on a dword boundary,
+         * then frame should be dword aligned here.  If it's
+         * not, then the user is trying to mess with us.
+         */
+        if (((long)frame) & 3)
+                goto badframe;
+
+	if (verify_area(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(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+	
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	if (__copy_from_user(&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, rdusp());
+
+	return regs->r10;
+
+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;
+	unsigned long usp = rdusp();
+
+	/* copy the regs. they are first in sc so we can use sc directly */
+
+	err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
+
+	/* then some other stuff */
+
+	err |= __put_user(mask, &sc->oldmask);
+
+	err |= __put_user(usp, &sc->usp);
+
+	return err;
+}
+
+/* figure out where we want to put the new signal frame - usually on the stack */
+
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
+{
+	unsigned long sp = rdusp();
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	if (ka->sa.sa_flags & SA_ONSTACK) {
+		if (! on_sig_stack(sp))
+			sp = current->sas_ss_sp + current->sas_ss_size;
+	}
+
+	/* make sure the frame is dword-aligned */
+
+	sp &= ~3;
+
+	return (void *)(sp - 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)
+{
+	struct sigframe *frame;
+	unsigned long return_ip;
+	int err = 0;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
+	if (err)
+		goto give_sigsegv;
+
+	if (_NSIG_WORDS > 1) {
+		err |= __copy_to_user(frame->extramask, &set->sig[1],
+				      sizeof(frame->extramask));
+	}
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up to return from userspace.  If provided, use a stub
+	   already in userspace.  */
+	if (ka->sa.sa_flags & SA_RESTORER) {
+		return_ip = (unsigned long)ka->sa.sa_restorer;
+	} else {
+		/* trampoline - the desired return ip is the retcode itself */
+		return_ip = (unsigned long)&frame->retcode;
+		/* This is movu.w __NR_sigreturn, r1; break 13; */
+		/* TODO: check byteorder */
+		err |= __put_user(0x1c5f,         (short *)(frame->retcode+0));
+		err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));
+		err |= __put_user(0xe93d,         (short *)(frame->retcode+4));
+	}
+
+	if (err)
+		goto give_sigsegv;
+
+	/* 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 */
+
+	/* actually move the usp to reflect the stacked frame */
+
+	wrusp((unsigned long)frame);
+
+	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;
+	unsigned long return_ip;
+	int err = 0;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, info);
+	if (err)
+		goto give_sigsegv;
+
+	/* Clear all the bits of the ucontext we don't use.  */
+        err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
+
+	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
+
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up to return from userspace.  If provided, use a stub
+	   already in userspace.  */
+	if (ka->sa.sa_flags & SA_RESTORER) {
+		return_ip = (unsigned long)ka->sa.sa_restorer;
+	} else {
+		/* trampoline - the desired return ip is the retcode itself */
+		return_ip = (unsigned long)&frame->retcode;
+		/* This is movu.w __NR_sigreturn, r1; break 13; */
+		/* TODO: check byteorder */
+		err |= __put_user(0x1c5f,         (short *)(frame->retcode+0));
+		err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));
+		err |= __put_user(0xe93d,         (short *)(frame->retcode+4));
+	}
+
+	if (err)
+		goto give_sigsegv;
+
+	/* TODO what is the current->exec_domain stuff and invmap ? */
+
+	/* 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 */
+
+	/* actually move the usp to reflect the stacked frame */
+
+	wrusp((unsigned long)frame);
+
+	return;
+
+give_sigsegv:
+	if (sig == SIGSEGV)
+		ka->sa.sa_handler = SIG_DFL;
+	force_sig(SIGSEGV, current);
+}
+
+/*
+ * OK, we're invoking a handler
+ */	
+
+static inline void
+handle_signal(int canrestart, unsigned long sig, struct k_sigaction *ka,
+	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
+{
+	/* Are we from a system call? */
+	if (canrestart) {
+		/* If so, check system call restarting.. */
+		switch (regs->r10) {
+			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 dont 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);
+		}
+	}
+
+	/* 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(&current->sigmask_lock);
+		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+		sigaddset(&current->blocked,sig);
+		recalc_sigpending(current);
+		spin_unlock_irq(&current->sigmask_lock);
+	}
+}
+
+/*
+ * 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.
+ */
+int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
+{
+	siginfo_t info;
+	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 = &current->blocked;
+
+	for (;;) {
+		unsigned long signr;
+
+		spin_lock_irq(&current->sigmask_lock);
+		signr = dequeue_signal(&current->blocked, &info);
+		spin_unlock_irq(&current->sigmask_lock);
+
+		if (!signr)
+			break;
+
+		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
+			/* Let the debugger run.  */
+			current->exit_code = signr;
+			current->state = TASK_STOPPED;
+			notify_parent(current, SIGCHLD);
+			schedule();
+
+			/* We're back.  Did the debugger cancel the sig?  */
+			if (!(signr = current->exit_code))
+				continue;
+			current->exit_code = 0;
+
+			/* The debugger continued.  Ignore SIGSTOP.  */
+			if (signr == SIGSTOP)
+				continue;
+
+			/* Update the siginfo structure.  Is this good?  */
+			if (signr != info.si_signo) {
+				info.si_signo = signr;
+				info.si_errno = 0;
+				info.si_code = SI_USER;
+				info.si_pid = current->p_pptr->pid;
+				info.si_uid = current->p_pptr->uid;
+			}
+
+			/* If the (new) signal is now blocked, requeue it.  */
+			if (sigismember(&current->blocked, signr)) {
+				send_sig_info(signr, &info, current);
+				continue;
+			}
+		}
+
+		ka = &current->sig->action[signr-1];
+		if (ka->sa.sa_handler == SIG_IGN) {
+			if (signr != SIGCHLD)
+				continue;
+			/* Check for SIGCHLD: it's special.  */
+			while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
+				/* nothing */;
+			continue;
+		}
+
+		if (ka->sa.sa_handler == SIG_DFL) {
+			int exit_code = signr;
+
+			/* Init gets no signals it doesn't want.  */
+			if (current->pid == 1)
+				continue;
+
+			switch (signr) {
+			case SIGCONT: case SIGCHLD: case SIGWINCH:
+				continue;
+
+			case SIGTSTP: case SIGTTIN: case SIGTTOU:
+				if (is_orphaned_pgrp(current->pgrp))
+					continue;
+				/* FALLTHRU */
+
+			case SIGSTOP:
+				current->state = TASK_STOPPED;
+				current->exit_code = signr;
+				if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
+					notify_parent(current, SIGCHLD);
+				schedule();
+				continue;
+
+			case SIGQUIT: case SIGILL: case SIGTRAP:
+			case SIGABRT: case SIGFPE: case SIGSEGV:
+			case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
+				if (do_coredump(signr, regs))
+					exit_code |= 0x80;
+				/* FALLTHRU */
+
+			default:
+				lock_kernel();
+				sigaddset(&current->pending.signal, signr);
+				recalc_sigpending(current);
+				current->flags |= PF_SIGNALED;
+				do_exit(exit_code);
+				/* NOTREACHED */
+			}
+		}
+
+		/* Whee!  Actually deliver the signal.  */
+		handle_signal(canrestart, signr, ka, &info, 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);
+		}
+	}
+	return 0;
+}