patch-2.3.43 linux/arch/ia64/kernel/signal.c

• Lines: 538
• Date: Tue Feb 8 12:01:59 2000
• Orig file: v2.3.42/linux/arch/ia64/kernel/signal.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/arch/ia64/kernel/signal.c linux/arch/ia64/kernel/signal.c
@@ -0,0 +1,537 @@
+/*
+ * Architecture-specific signal handling support.
+ *
+ * Copyright (C) 1999-2000 Hewlett-Packard Co
+ * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * Derived from i386 and Alpha versions.
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/wait.h>
+
+#include <asm/ia32.h>
+#include <asm/uaccess.h>
+#include <asm/rse.h>
+#include <asm/sigcontext.h>
+
+#define DEBUG_SIG	0
+#define STACK_ALIGN	16		/* minimal alignment for stack pointer */
+#define _BLOCKABLE	(~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+#if _NSIG_WORDS > 1
+# define PUT_SIGSET(k,u)	__copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
+# define GET_SIGSET(k,u)	__copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
+#else
+# define PUT_SIGSET(k,u)	__put_user((k)->sig[0], &(u)->sig[0])
+# define GET_SIGSET(k,u)	__get_user((k)->sig[0], &(u)->sig[0])
+#endif
+
+struct sigframe {
+	struct siginfo info;
+	struct sigcontext sc;
+};
+
+extern long sys_wait4 (int, int *, int, struct rusage *);
+extern long ia64_do_signal (sigset_t *, struct pt_regs *, long);	/* forward decl */
+
+long
+ia64_rt_sigsuspend (sigset_t *uset, size_t sigsetsize, struct pt_regs *pt)
+{
+	sigset_t oldset, set;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+	if (GET_SIGSET(&set, uset))
+		return -EFAULT;
+
+	sigdelsetmask(&set, ~_BLOCKABLE);
+
+	spin_lock_irq(&current->sigmask_lock);
+	{
+		oldset = current->blocked;
+		current->blocked = set;
+		recalc_sigpending(current);
+	}
+	spin_unlock_irq(&current->sigmask_lock);
+
+	/*
+	 * The return below usually returns to the signal handler.  We need to
+	 * pre-set the correct error code here to ensure that the right values
+	 * get saved in sigcontext by ia64_do_signal.
+	 */
+	pt->r8 = EINTR;
+	pt->r10 = -1;
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+		if (ia64_do_signal(&oldset, pt, 1))
+			return -EINTR;
+	}
+}
+
+asmlinkage long
+sys_sigaltstack (const stack_t *uss, stack_t *uoss, long arg2, long arg3, long arg4,
+		 long arg5, long arg6, long arg7, long stack)
+{
+	struct pt_regs *pt = (struct pt_regs *) &stack;
+
+	return do_sigaltstack(uss, uoss, pt->r12);
+}
+
+static long
+restore_sigcontext (struct sigcontext *sc, struct pt_regs *pt)
+{
+	struct switch_stack *sw = (struct switch_stack *) pt - 1;
+	unsigned long ip, flags, nat, um;
+	long err;
+
+	/* restore scratch that always needs gets updated during signal delivery: */
+	err = __get_user(flags, &sc->sc_flags);
+
+	err |= __get_user(nat, &sc->sc_nat);
+	err |= __get_user(ip, &sc->sc_ip);			/* instruction pointer */
+	err |= __get_user(pt->ar_fpsr, &sc->sc_ar_fpsr);
+	err |= __get_user(pt->ar_pfs, &sc->sc_ar_pfs);
+	err |= __get_user(um, &sc->sc_um);			/* user mask */
+	err |= __get_user(pt->ar_rsc, &sc->sc_ar_rsc);
+	err |= __get_user(pt->ar_ccv, &sc->sc_ar_ccv);
+	err |= __get_user(pt->ar_unat, &sc->sc_ar_unat);
+	err |= __get_user(pt->pr, &sc->sc_pr);			/* predicates */
+	err |= __get_user(pt->b0, &sc->sc_br[0]);		/* b0 (rp) */
+	err |= __get_user(pt->b6, &sc->sc_br[6]);
+	err |= __copy_from_user(&pt->r1, &sc->sc_gr[1], 3*8);	/* r1-r3 */
+	err |= __copy_from_user(&pt->r8, &sc->sc_gr[8], 4*8);	/* r8-r11 */
+	err |= __copy_from_user(&pt->r12, &sc->sc_gr[12], 4*8);	/* r12-r15 */
+	err |= __copy_from_user(&pt->r16, &sc->sc_gr[16], 16*8);	/* r16-r31 */
+
+	/* establish new instruction pointer: */
+	pt->cr_iip = ip & ~0x3UL;
+	ia64_psr(pt)->ri = ip & 0x3;
+	pt->cr_ipsr = (pt->cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
+
+	ia64_put_nat_bits (pt, sw, nat);	/* restore the original scratch NaT bits */
+
+	if (flags & IA64_SC_FLAG_FPH_VALID) {
+		struct task_struct *fpu_owner = ia64_get_fpu_owner();
+
+		__copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
+		if (fpu_owner == current) {
+			__ia64_load_fpu(current->thread.fph);
+		}
+	}
+	return err;
+}
+
+/*
+ * When we get here, ((struct switch_stack *) pt - 1) is a
+ * switch_stack frame that has no defined value.  Upon return, we
+ * expect sw->caller_unat to contain the new unat value.  The reason
+ * we use a full switch_stack frame is so everything is symmetric
+ * with ia64_do_signal().
+ */
+long
+ia64_rt_sigreturn (struct pt_regs *pt)
+{
+	extern char ia64_strace_leave_kernel, ia64_leave_kernel;
+	struct sigcontext *sc;
+	struct siginfo si;
+	sigset_t set;
+	long retval;
+
+	sc = &((struct sigframe *) (pt->r12 + 16))->sc;
+
+	/*
+	 * When we return to the previously executing context, r8 and
+	 * r10 have already been setup the way we want them.  Indeed,
+	 * if the signal wasn't delivered while in a system call, we
+	 * must not touch r8 or r10 as otherwise user-level stat could
+	 * be corrupted.
+	 */
+	retval = (long) &ia64_leave_kernel | 1;
+	if ((current->flags & PF_TRACESYS)
+	    && (sc->sc_flags & IA64_SC_FLAG_IN_SYSCALL))
+		retval = (long) &ia64_strace_leave_kernel;
+
+	if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
+		goto give_sigsegv;
+
+	if (GET_SIGSET(&set, &sc->sc_mask))
+		goto give_sigsegv;
+
+	sigdelsetmask(&set, ~_BLOCKABLE);
+	spin_lock_irq(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
+	if (restore_sigcontext(sc, pt))
+		goto give_sigsegv;
+
+#if DEBUG_SIG
+	printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
+	       current->comm, current->pid, pt->r12, pt->cr_iip);
+#endif
+	/*
+	 * It is more difficult to avoid calling this function than to
+	 * call it and ignore errors.
+	 */
+	do_sigaltstack(&sc->sc_stack, 0, pt->r12);
+	return retval;
+
+  give_sigsegv:
+	si.si_signo = SIGSEGV;
+	si.si_errno = 0;
+	si.si_code = SI_KERNEL;
+	si.si_pid = current->pid;
+	si.si_uid = current->uid;
+	si.si_addr = sc;
+	force_sig_info(SIGSEGV, &si, current);
+	return retval;
+}
+
+/*
+ * This does just the minimum required setup of sigcontext.
+ * Specifically, it only installs data that is either not knowable at
+ * the user-level or that gets modified before execution in the
+ * trampoline starts.  Everything else is done at the user-level.
+ */
+static long
+setup_sigcontext (struct sigcontext *sc, sigset_t *mask, struct pt_regs *pt)
+{
+	struct switch_stack *sw = (struct switch_stack *) pt - 1;
+	struct task_struct *fpu_owner = ia64_get_fpu_owner();
+	unsigned long flags = 0, ifs, nat;
+	long err;
+
+	ifs = pt->cr_ifs;
+
+	if (on_sig_stack((unsigned long) sc))
+		flags |= IA64_SC_FLAG_ONSTACK;
+	if ((ifs & (1UL << 63)) == 0) {
+		/* if cr_ifs isn't valid, we got here through a syscall */
+		flags |= IA64_SC_FLAG_IN_SYSCALL;
+	}
+	if ((fpu_owner == current) || (current->thread.flags & IA64_THREAD_FPH_VALID)) {
+		flags |= IA64_SC_FLAG_FPH_VALID;
+		if (fpu_owner == current) {
+			__ia64_save_fpu(current->thread.fph);
+		}
+		__copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
+	}
+
+	/*
+	 * Note: sw->ar_unat is UNDEFINED unless the process is being
+	 * PTRACED.  However, this is OK because the NaT bits of the
+	 * preserved registers (r4-r7) are never being looked at by
+	 * the signal handler (register r4-r7 are used instead).
+	 */
+	nat = ia64_get_nat_bits(pt, sw);
+
+	err  = __put_user(flags, &sc->sc_flags);
+	err |= __put_user(nat, &sc->sc_nat);
+	err |= PUT_SIGSET(mask, &sc->sc_mask);
+	err |= __put_user(pt->cr_ipsr & IA64_PSR_UM, &sc->sc_um);
+	err |= __put_user(pt->ar_rsc, &sc->sc_ar_rsc);
+	err |= __put_user(pt->ar_ccv, &sc->sc_ar_ccv);
+	err |= __put_user(pt->ar_unat, &sc->sc_ar_unat);		/* ar.unat */
+	err |= __put_user(pt->ar_fpsr, &sc->sc_ar_fpsr);		/* ar.fpsr */
+	err |= __put_user(pt->ar_pfs, &sc->sc_ar_pfs);
+	err |= __put_user(pt->pr, &sc->sc_pr);				/* predicates */
+	err |= __put_user(pt->b0, &sc->sc_br[0]);			/* b0 (rp) */
+	err |= __put_user(pt->b6, &sc->sc_br[6]);			/* b6 */
+	err |= __put_user(pt->b7, &sc->sc_br[7]);			/* b7 */
+
+	err |= __copy_to_user(&sc->sc_gr[1], &pt->r1, 3*8);		/* r1-r3 */
+	err |= __copy_to_user(&sc->sc_gr[8], &pt->r8, 4*8);		/* r8-r11 */
+	err |= __copy_to_user(&sc->sc_gr[12], &pt->r12, 4*8);	/* r12-r15 */
+	err |= __copy_to_user(&sc->sc_gr[16], &pt->r16, 16*8);	/* r16-r31 */
+
+	err |= __put_user(pt->cr_iip + ia64_psr(pt)->ri, &sc->sc_ip);
+	err |= __put_user(pt->r12, &sc->sc_gr[12]);			/* r12 */
+	return err;
+}
+
+static long
+setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *pt)
+{
+	struct switch_stack *sw = (struct switch_stack *) pt - 1;
+	extern char ia64_sigtramp[], __start_gate_section[];
+	unsigned long tramp_addr, new_rbs = 0;
+	struct sigframe *frame;
+	struct siginfo si;
+	long err;
+
+	frame = (void *) pt->r12;
+	tramp_addr = GATE_ADDR + (ia64_sigtramp - __start_gate_section);
+	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack((unsigned long) frame)) {
+		new_rbs  = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
+		frame = (void *) ((current->sas_ss_sp + current->sas_ss_size)
+				  & ~(STACK_ALIGN - 1));
+	}
+	frame = (void *) frame - ((sizeof(*frame) + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	err  = __copy_to_user(&frame->info, info, sizeof(siginfo_t));
+
+	err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
+	err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
+	err |= __put_user(sas_ss_flags(pt->r12), &frame->sc.sc_stack.ss_flags);
+	err |= setup_sigcontext(&frame->sc, set, pt);
+
+	if (err)
+		goto give_sigsegv;
+
+	pt->r12 = (unsigned long) frame - 16;		/* new stack pointer */
+	pt->r2  = sig;					/* signal number */
+	pt->r3  = (unsigned long) ka->sa.sa_handler;	/* addr. of handler's proc. descriptor */
+	pt->r15 = new_rbs;
+	pt->ar_fpsr = FPSR_DEFAULT;			/* reset fpsr for signal handler */
+	pt->cr_iip = tramp_addr;
+	ia64_psr(pt)->ri = 0;				/* start executing in first slot */
+
+	/*
+	 * Note: this affects only the NaT bits of the scratch regs
+	 * (the ones saved in pt_regs, which is exactly what we want.
+	 * The NaT bits for the preserved regs (r4-r7) are in
+	 * sw->ar_unat iff this process is being PTRACED.
+	 */
+	sw->caller_unat = 0;	/* ensure NaT bits of at least r2, r3, r12, and r15 are clear */
+
+#if DEBUG_SIG
+	printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%lx\n",
+	       current->comm, current->pid, sig, pt->r12, pt->cr_iip, pt->r3);
+#endif
+	return 1;
+
+  give_sigsegv:
+	if (sig == SIGSEGV)
+		ka->sa.sa_handler = SIG_DFL;
+	si.si_signo = SIGSEGV;
+	si.si_errno = 0;
+	si.si_code = SI_KERNEL;
+	si.si_pid = current->pid;
+	si.si_uid = current->uid;
+	si.si_addr = frame;
+	force_sig_info(SIGSEGV, &si, current);
+	return 0;
+}
+
+static long
+handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
+	       struct pt_regs *pt)
+{
+#ifdef CONFIG_IA32_SUPPORT
+	if (IS_IA32_PROCESS(pt)) {
+		/* send signal to IA-32 process */
+		if (!ia32_setup_frame1(sig, ka, info, oldset, pt))
+			return 0;
+	} else
+#endif
+	/* send signal to IA-64 process */
+	if (!setup_frame(sig, ka, info, oldset, pt))
+		return 0;
+
+	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);
+	}
+	return 1;
+}
+
+/*
+ * When we get here, `pt' points to struct pt_regs and ((struct
+ * switch_stack *) pt - 1) points to a switch stack structure.
+ * HOWEVER, in the normal case, the ONLY value valid in the
+ * switch_stack is the caller_unat field.  The entire switch_stack is
+ * valid ONLY if current->flags has PF_PTRACED set.
+ *
+ * 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.
+ */
+long
+ia64_do_signal (sigset_t *oldset, struct pt_regs *pt, long in_syscall)
+{
+	struct k_sigaction *ka;
+	siginfo_t info;
+	long restart = in_syscall;
+
+	/*
+	 * In the ia64_leave_kernel code path, 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(pt))
+		return 0;
+
+	if (!oldset)
+		oldset = &current->blocked;
+
+	if (pt->r10 != -1) {
+		/*
+		 * A system calls has to be restarted only if one of
+		 * the error codes ERESTARTNOHAND, ERESTARTSYS, or
+		 * ERESTARTNOINTR is returned.  If r10 isn't -1 then
+		 * r8 doesn't hold an error code and we don't need to
+		 * restart the syscall, so we set in_syscall to zero.
+		 */
+		restart = 0;
+	}
+
+	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->flags & PF_PTRACED) && signr != SIGKILL) {
+			/* Let the debugger run.  */
+			current->exit_code = signr;
+			set_current_state(TASK_STOPPED);
+			notify_parent(current, SIGCHLD);
+			schedule();
+			signr = current->exit_code;
+
+			/* We're back.  Did the debugger cancel the sig?  */
+			if (!signr)
+				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:
+				set_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, pt))
+					exit_code |= 0x80;
+				/* FALLTHRU */
+
+			      default:
+				lock_kernel();
+				sigaddset(&current->signal, signr);
+				recalc_sigpending(current);
+				current->flags |= PF_SIGNALED;
+				do_exit(exit_code);
+				/* NOTREACHED */
+			}
+		}
+
+		if (restart) {
+			switch (pt->r8) {
+			      case ERESTARTSYS:
+				if ((ka->sa.sa_flags & SA_RESTART) == 0) {
+			      case ERESTARTNOHAND:
+					pt->r8 = EINTR;
+					/* note: pt->r10 is already -1 */
+					break;
+				}
+			      case ERESTARTNOINTR:
+				ia64_decrement_ip(pt);
+			}
+		}
+
+		/* Whee!  Actually deliver the signal.  If the
+		   delivery failed, we need to continue to iterate in
+		   this loop so we can deliver the SIGSEGV... */
+		if (handle_signal(signr, ka, &info, oldset, pt))
+			return 1;
+	}
+
+	/* Did we come from a system call? */
+	if (restart) {
+		/* Restart the system call - no handlers present */
+		if (pt->r8 == ERESTARTNOHAND ||
+		    pt->r8 == ERESTARTSYS ||
+		    pt->r8 == ERESTARTNOINTR) {
+			/*
+			 * Note: the syscall number is in r15 which is
+			 * saved in pt_regs so all we need to do here
+			 * is adjust ip so that the "break"
+			 * instruction gets re-executed.
+			 */
+			ia64_decrement_ip(pt);
+		}
+	}
+	return 0;
+}