patch-2.2.14 linux/arch/s390/kernel/signal.c

• Lines: 520
• Date: Tue Jan 4 10:12:12 2000
• Orig file: v2.2.13/linux/arch/s390/kernel/signal.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.2.13/linux/arch/s390/kernel/signal.c linux/arch/s390/kernel/signal.c
@@ -0,0 +1,519 @@
+/*
+ *  arch/s390/kernel/signal.c
+ *
+ *  S390 version
+ *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
+ *
+ *  based on PPC & i386 signal handling by  Linus Torvalds &  Gary Thomas 
+ *
+ *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
+ */
+
+#include <linux/config.h>
+#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/ucontext.h>
+#include <asm/uaccess.h>
+#if CONFIG_BINFMT_TOC
+#include <linux/toc.h>
+#endif
+/*
+ * These are the flags in the MSR that the user is allowed to change
+ * by modifying the saved value of the MSR on the stack.  SE and BE
+ * should not be in this list since gdb may want to change these.  I.e,
+ * you should be able to step out of a signal handler to see what
+ * instruction executes next after the signal handler completes.
+ * Alternately, if you stepped into a signal handler, you should be
+ * able to continue 'til the next breakpoint from within the signal
+ * handler, even if the handler returns.
+ */
+
+
+#define __390_TO_DO__    0
+#define __390_NEEDED__   0 
+#define DEBUG_SIG 0
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+#ifndef MIN
+#define MIN(a,b) (((a) < (b)) ? (a) : (b))
+#endif
+
+int do_signal(struct pt_regs *reg,sigset_t *oldset);
+extern int sys_wait4(pid_t pid, unsigned long *stat_addr,
+		     int options, unsigned long *ru);
+
+
+
+
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int sys_sigsuspend(struct pt_regs * regs,int history0, int history1, old_sigset_t mask)
+{
+	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->gprs[2] = -EINTR;
+
+	while (1) 
+	  {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(regs, &saveset))
+			return -EINTR;
+	  }
+}
+
+
+//
+// N.B. This hasn't been tested it just compiles easily
+//
+asmlinkage int sys_rt_sigsuspend(struct pt_regs * regs,sigset_t *unewset, size_t sigsetsize)
+{
+	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->gprs[2]	= -EINTR;
+	while (1) 
+	  {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(regs, &saveset))
+			return -EINTR;
+	  }
+}
+
+asmlinkage int sys_rt_sigreturn(unsigned long __unused)
+{
+	printk("sys_rt_sigreturn(): %s/%d not yet implemented.\n",
+	       current->comm,current->pid);
+	do_exit(SIGSEGV);
+}
+
+asmlinkage int
+sys_sigaltstack(const stack_t *uss, stack_t *uoss)
+{
+	struct pt_regs *regs = (struct pt_regs *) &uss;
+	return do_sigaltstack(uss, uoss, regs->gprs[15]);
+}
+
+
+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 (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((u32)old_ka.sa.sa_handler,&oact->sa_handler) ||
+		    __put_user((u32)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;
+}
+
+/*
+ * When we have signals to deliver, we set up on the
+ * user stack, going down from the original stack pointer:
+ *	a sigregs struct
+ *	one or more sigcontext structs
+ *	a gap of __SIGNAL_FRAMESIZE bytes
+ *
+ * Each of these things must be a multiple of 16 bytes in size.
+ *
+ * XXX ultimately we will have to stack up a siginfo and ucontext
+ * for each rt signal.
+ */
+
+struct sigregs {
+	user_regs_struct user_regs;
+
+        unsigned short   tramp[1];
+        /* Programs using the rs6000/xcoff abi can save up to 19 gp regs
+           and 18 fp regs below sp before decrementing it. */
+};   
+
+
+int sys_sigreturn(struct pt_regs *regs)
+{
+	struct sigcontext_struct *sc, sigctx;
+	struct sigregs *sr;
+	int ret;
+        user_regs_struct saved_regs;  
+	sigset_t set;
+	unsigned long prevsp;
+	routine_descriptor tempdes;
+
+	sc = (struct sigcontext_struct *)(regs->gprs[15] + __SIGNAL_FRAMESIZE);
+	if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
+		goto badframe;
+	memcpy(&set.sig[0],&sigctx.oldmask[0],SIGMASK_COPY_SIZE);
+	sigdelsetmask(&set, ~_BLOCKABLE);
+	spin_lock_irq(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
+	sc++;			/* Look at next sigcontext */
+	if (sc == (struct sigcontext_struct *)(sigctx.regs)) {
+		/* Last stacked signal - restore registers */
+		sr = (struct sigregs *) sigctx.regs;
+		if (copy_from_user(&saved_regs, &sr->user_regs,
+				   sizeof(sr->user_regs)))
+			goto badframe;
+		saved_regs.psw.mask=(regs->psw.mask&~PSW_MASK_DEBUGCHANGE)
+			|(saved_regs.psw.mask&PSW_MASK_DEBUGCHANGE);
+		saved_regs.psw.addr=(regs->psw.addr&~PSW_ADDR_DEBUGCHANGE)
+			|(saved_regs.psw.addr&PSW_ADDR_DEBUGCHANGE);
+		memcpy(regs,&saved_regs,sizeof(s390_regs));
+		restore_fp_regs(&saved_regs.fp_regs);
+		ret = regs->gprs[2];
+
+	} else {
+		/* More signals to go */
+		regs->gprs[15] = (unsigned long)sc - __SIGNAL_FRAMESIZE;
+		if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
+			goto badframe;
+		sr = (struct sigregs *) sigctx.regs;
+		regs->gprs[2] = ret = sigctx.signal;
+#if DEBUG_SIG
+		regs->gprs[3] = (unsigned long) sr; // My best guess says this is used for debugging only DJB
+#endif
+		regs->gprs[14] = (unsigned long) sr->tramp; // return address
+		
+		if(uses_routine_descriptors())
+		{
+		   if(copy_from_user(&tempdes,(char *)sigctx.handler,sizeof(tempdes)))
+		      goto badframe;
+		   fix_routine_descriptor_regs(&tempdes,regs);
+		}
+		else
+		   regs->psw.addr = FIX_PSW(sigctx.handler);
+
+		if (get_user(prevsp, &sr->user_regs.gprs[15])
+		    || put_user(prevsp, (unsigned long *) regs->gprs[15]))
+			goto badframe;
+	}
+	return ret;
+
+badframe:
+	lock_kernel();
+	do_exit(SIGSEGV);
+}	
+
+
+/*
+ * Set up a signal frame.
+ */
+void setup_frame(struct pt_regs *regs, struct sigregs *frame,unsigned long newsp)
+{
+	struct sigcontext_struct *sc = (struct sigcontext_struct *) newsp;
+	s390_fp_regs fpregs;
+
+	routine_descriptor tempdes,*tempdesptr;
+
+	if (verify_area(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto badframe;
+	save_fp_regs(&fpregs);
+	if (__copy_to_user(&frame->user_regs, regs, sizeof(s390_regs))
+	    || __copy_to_user(&frame->user_regs.fp_regs,&fpregs,sizeof(fpregs))
+	    || __put_user(0x0A77, &frame->tramp[0]))    /* SVC 0x77 */
+		goto badframe;
+	newsp -= __SIGNAL_FRAMESIZE;
+	if (put_user(regs->gprs[15], (unsigned long *)newsp) || get_user(regs->gprs[2], &sc->signal))
+		goto badframe;
+
+	if(uses_routine_descriptors())
+	{
+	    if(get_user(tempdesptr, (routine_descriptor **)& sc->handler)
+	       || copy_from_user(&tempdes,tempdesptr,sizeof(tempdes)))
+	       goto badframe;
+	    fix_routine_descriptor_regs(&tempdes,regs);
+	}
+	else
+	{
+	   if(get_user(regs->psw.addr, (void **) & sc->handler))
+		goto badframe;
+	   regs->psw.addr=FIX_PSW(regs->psw.addr);
+	}
+	regs->gprs[15] = newsp;
+#if DEBUG_SIG
+	regs->gprs[3] = (unsigned long) frame;
+#endif
+	regs->gprs[14] = (unsigned long) frame->tramp;
+
+	return;
+
+badframe:
+#if DEBUG_SIG
+	printk("badframe in setup_frame, regs=%p frame=%p newsp=%lx\n",
+	       regs, frame, newsp);
+#endif
+	lock_kernel();
+	do_exit(SIGSEGV);
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+void
+handle_signal(unsigned long sig, struct k_sigaction *ka,
+	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
+	      unsigned long *newspp, unsigned long frame)
+{
+	struct sigcontext_struct *sc;
+
+	if (regs->trap == 0x20) /* System Call! */
+	{
+		switch(regs->gprs[2])
+		{
+		case -ERESTARTNOHAND:
+				regs->gprs[2] = -EINTR;
+				break;
+		case -ERESTARTSYS:
+			if (!(ka->sa.sa_flags & SA_RESTART)) 
+			{
+				regs->gprs[2] = -EINTR;
+				break;
+			}
+			/* fallthrough */
+		case -ERESTARTNOINTR:
+			regs->gprs[2] = regs->orig_gpr2;
+			regs->psw.addr -= 2;	      
+                        /* Back up & retry system call */
+		}
+	}
+	/* Put another sigcontext on the stack */
+	*newspp -= sizeof(*sc);
+	sc = (struct sigcontext_struct *) *newspp;
+	if (verify_area(VERIFY_WRITE, sc, sizeof(*sc)))
+		goto badframe;
+
+	if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler)
+	    || copy_to_user(&sc->oldmask[0],&oldset->sig[0],SIGMASK_COPY_SIZE)
+	    || __put_user((u32)((struct pt_regs *)frame), &sc->regs)
+	    || __put_user(sig, &sc->signal))
+		goto badframe;
+
+	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;
+
+badframe:
+#if DEBUG_SIG
+	printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n",
+	       regs, frame, *newspp);
+	printk("sc=%p sig=%d ka=%p info=%p oldset=%p\n", sc, sig, ka, info, oldset);
+#endif
+	lock_kernel();
+	do_exit(SIGSEGV);
+}
+
+
+/*
+ * 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(struct pt_regs *regs,sigset_t *oldset)
+{
+	siginfo_t info;
+	struct k_sigaction *ka;
+	unsigned long frame, newsp;
+
+	if (!oldset)
+		oldset = &current->blocked;
+
+	newsp = frame = regs->gprs[15] - sizeof(struct sigregs);
+
+	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;
+			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:
+				lock_kernel();
+				if (current->binfmt
+				    && current->binfmt->core_dump
+				    && current->binfmt->core_dump(signr, regs))
+					exit_code |= 0x80;
+				unlock_kernel();
+				/* FALLTHRU */
+
+			default:
+				lock_kernel();
+				sigaddset(&current->signal, signr);
+				recalc_sigpending(current);
+				current->flags |= PF_SIGNALED;
+				do_exit(exit_code);
+				/* NOTREACHED */
+			}
+		}
+
+		/* Whee!  Actually deliver the signal.  */
+		handle_signal(signr, ka, &info, oldset, regs, &newsp, frame);
+	}
+
+	if (
+	    regs->trap == 0x20 /* System Call! */ &&
+	    ((int)regs->gprs[2] == -ERESTARTNOHAND ||
+	     (int)regs->gprs[2] == -ERESTARTSYS ||
+	     (int)regs->gprs[2] == -ERESTARTNOINTR)) {
+		regs->gprs[2] = regs->orig_gpr2;
+		regs->psw.addr -= 2;	      /* Back up & retry system call */
+	}
+
+	if (newsp == frame)
+		return 0;		/* no signals delivered */
+
+	setup_frame(regs, (struct sigregs *) frame, newsp);
+	return 1;
+}
+
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