patch-1.3.45 linux/arch/ppc/kernel/signal.c

• Lines: 235
• Date: Tue Oct 24 21:30:25 1995
• Orig file: v1.3.44/linux/arch/ppc/kernel/signal.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.44/linux/arch/ppc/kernel/signal.c linux/arch/ppc/kernel/signal.c
@@ -0,0 +1,234 @@
+/*
+ *  linux/arch/ppc/kernel/signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *  Adapted for PowerPC by Gary Thomas
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.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>
+
+#define _S(nr) (1<<((nr)-1))
+
+#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
+
+asmlinkage int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options);
+
+/*
+ * atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int sys_sigsuspend(unsigned long set, int p2, int p3, int p4, int p6, int p7, struct pt_regs *regs)
+{
+	unsigned long mask;
+
+	mask = current->blocked;
+	current->blocked = set & _BLOCKABLE;
+	regs->gpr[3] = -EINTR;
+#if 0	
+printk("Task: %x[%d] - SIGSUSPEND at %x, Mask: %x\n", current, current->pid, regs->nip, set);	
+#endif
+	while (1) {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(mask,regs))
+			return -EINTR;
+	}
+}
+
+/*
+ * This sets regs->esp even though we don't actually use sigstacks yet..
+ */
+asmlinkage int sys_sigreturn(struct pt_regs *regs)
+{
+	struct sigcontext_struct *sc;
+	struct pt_regs *int_regs;
+	int signo;
+	sc = (struct sigcontext_struct *)regs->gpr[1];
+	current->blocked = sc->oldmask & _BLOCKABLE;
+	int_regs = sc->regs;
+	signo = sc->signal;
+	sc++;  /* Pop signal 'context' */
+	if (sc == (struct sigcontext_struct *)(int_regs))
+	{ /* Last stacked signal */
+		memcpy(regs, int_regs, sizeof(*regs));
+		if ((int)regs->orig_gpr3 >= 0 &&
+		    ((int)regs->result == -ERESTARTNOHAND ||
+		     (int)regs->result == -ERESTARTSYS ||
+		     (int)regs->result == -ERESTARTNOINTR))
+		{
+			regs->gpr[3] = regs->orig_gpr3;
+			regs->nip -= 4; /* Back up & retry system call */
+			regs->result = 0;
+		}
+		return (regs->result);
+	} else
+	{ /* More signals to go */
+		regs->gpr[1] = (unsigned long)sc;
+		regs->gpr[3] = sc->signal;
+		regs->gpr[4] = sc->regs;
+		regs->link = (unsigned long)((sc->regs)+1);
+		regs->nip = sc->handler;
+		return (sc->signal);
+	}
+}
+
+
+/*
+ * 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.
+ */
+asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
+{
+	unsigned long mask = ~current->blocked;
+	unsigned long handler_signal = 0;
+	unsigned long *frame = NULL;
+	unsigned long *trampoline;
+	unsigned long *regs_ptr;
+	unsigned long nip = 0;
+	unsigned long signr;
+	int bitno;
+	struct sigcontext_struct *sc;
+	struct sigaction * sa;
+	int s = _disable_interrupts();
+
+	while ((signr = current->signal & mask)) {
+#if 0
+		signr = ffz(~signr);  /* Compute bit # */
+#else
+		for (bitno = 0;  bitno < 32;  bitno++)
+		{
+			if (signr & (1<<bitno)) break;
+		}
+		signr = bitno;
+#endif		
+		current->signal &= ~(1<<signr);  /* Clear bit */
+		sa = current->sig->action + signr;
+		signr++;
+		if ((current->flags & PF_PTRACED) && signr != SIGKILL) {
+			current->exit_code = signr;
+			current->state = TASK_STOPPED;
+			notify_parent(current);
+			schedule();
+			if (!(signr = current->exit_code))
+				continue;
+			current->exit_code = 0;
+			if (signr == SIGSTOP)
+				continue;
+			if (_S(signr) & current->blocked) {
+				current->signal |= _S(signr);
+				continue;
+			}
+			sa = current->sig->action + signr - 1;
+		}
+		if (sa->sa_handler == SIG_IGN) {
+			if (signr != SIGCHLD)
+				continue;
+			/* check for SIGCHLD: it's special */
+			while (sys_waitpid(-1,NULL,WNOHANG) > 0)
+				/* nothing */;
+			continue;
+		}
+		if (sa->sa_handler == SIG_DFL) {
+			if (current->pid == 1)
+				continue;
+			switch (signr) {
+			case SIGCONT: case SIGCHLD: case SIGWINCH:
+				continue;
+
+			case SIGSTOP: case SIGTSTP: case SIGTTIN: case SIGTTOU:
+				if (current->flags & PF_PTRACED)
+					continue;
+				current->state = TASK_STOPPED;
+				current->exit_code = signr;
+				if (!(current->p_pptr->sig->action[SIGCHLD-1].sa_flags &
+						SA_NOCLDSTOP))
+					notify_parent(current);
+				schedule();
+				continue;
+
+			case SIGQUIT: case SIGILL: case SIGTRAP:
+			case SIGIOT: case SIGFPE: case SIGSEGV:
+				if (current->binfmt && current->binfmt->core_dump) {
+					if (current->binfmt->core_dump(signr, regs))
+						signr |= 0x80;
+				}
+				/* fall through */
+			default:
+				current->signal |= _S(signr & 0x7f);
+				do_exit(signr);
+			}
+		}
+		/*
+		 * OK, we're invoking a handler
+		 */
+		if ((int)regs->orig_gpr3 >= 0) {
+			if ((int)regs->result == -ERESTARTNOHAND ||
+			   ((int)regs->result == -ERESTARTSYS && !(sa->sa_flags & SA_RESTART)))
+				(int)regs->result = -EINTR;
+		}
+		handler_signal |= 1 << (signr-1);
+		mask &= ~sa->sa_mask;
+	}
+	if (!handler_signal)		/* no handler will be called - return 0 */
+	{
+		_enable_interrupts(s);
+		return 0;
+	}
+	nip = regs->nip;
+	frame = (unsigned long *) regs->gpr[1];
+	/* Build trampoline code on stack */
+	frame -= 2;
+	trampoline = frame;
+	trampoline[0] = 0x38007777;  /* li r0,0x7777 */
+	trampoline[1] = 0x44000002;  /* sc           */
+	frame -= sizeof(*regs) / sizeof(long);
+	regs_ptr = frame;
+	memcpy(regs_ptr, regs, sizeof(*regs));
+	signr = 1;
+	sa = current->sig->action;
+	for (mask = 1 ; mask ; sa++,signr++,mask += mask) {
+		if (mask > handler_signal)
+			break;
+		if (!(mask & handler_signal))
+			continue;
+		frame -= sizeof(struct sigcontext_struct) / sizeof(long);
+		sc = (struct sigcontext_struct *)frame;
+		nip = (unsigned long) sa->sa_handler;
+#if 0 /* Old compiler */		
+		nip = *(unsigned long *)nip;
+#endif		
+		if (sa->sa_flags & SA_ONESHOT)
+			sa->sa_handler = NULL;
+		sc->handler = nip;
+		sc->oldmask = current->blocked;
+		sc->regs = (unsigned long)regs_ptr;
+		sc->signal = signr;
+		current->blocked |= sa->sa_mask;
+		regs->gpr[3] = signr;
+		regs->gpr[4] = (unsigned long)regs_ptr;
+	}
+	regs->link = (unsigned long)trampoline;
+	regs->nip = nip;
+	regs->gpr[1] = (unsigned long)sc;
+	/* The DATA cache must be flushed here to insure coherency */
+	/* between the DATA & INSTRUCTION caches.  Since we just */
+	/* created an instruction stream using the DATA [cache] space */
+	/* and since the instruction cache will not look in the DATA */
+	/* cache for new data, we have to force the data to go on to */
+	/* memory and flush the instruction cache to force it to look */
+	/* there.  The following function performs this magic */
+	flush_instruction_cache();
+	_enable_interrupts(s);
+	return 1;
+}