1 files changed, 172 insertions, 108 deletions

diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index b897e8592d7..7b605e4dfff 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -1,27 +1,53 @@
 /*
  * Copyright (C) 2004 PathScale, Inc
+ * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include <signal.h>
-#include <stdio.h>
-#include <unistd.h>
 #include <stdlib.h>
-#include <errno.h>
 #include <stdarg.h>
-#include <string.h>
-#include <sys/mman.h>
-#include "user_util.h"
-#include "user.h"
-#include "signal_kern.h"
-#include "sysdep/sigcontext.h"
-#include "sysdep/barrier.h"
-#include "sigcontext.h"
-#include "mode.h"
-#include "os.h"
-
-/* These are the asynchronous signals.  SIGVTALRM and SIGARLM are handled
- * together under SIGVTALRM_BIT.  SIGPROF is excluded because we want to
+#include <errno.h>
+#include <signal.h>
+#include <strings.h>
+#include <as-layout.h>
+#include <kern_util.h>
+#include <os.h>
+#include <sysdep/mcontext.h>
+#include "internal.h"
+
+void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
+	[SIGTRAP]	= relay_signal,
+	[SIGFPE]	= relay_signal,
+	[SIGILL]	= relay_signal,
+	[SIGWINCH]	= winch,
+	[SIGBUS]	= bus_handler,
+	[SIGSEGV]	= segv_handler,
+	[SIGIO]		= sigio_handler,
+	[SIGVTALRM]	= timer_handler };
+
+static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
+{
+	struct uml_pt_regs r;
+	int save_errno = errno;
+
+	r.is_user = 0;
+	if (sig == SIGSEGV) {
+		/* For segfaults, we want the data from the sigcontext. */
+		get_regs_from_mc(&r, mc);
+		GET_FAULTINFO_FROM_MC(r.faultinfo, mc);
+	}
+
+	/* enable signals if sig isn't IRQ signal */
+	if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGVTALRM))
+		unblock_signals();
+
+	(*sig_info[sig])(sig, si, &r);
+
+	errno = save_errno;
+}
+
+/*
+ * These are the asynchronous signals.  SIGPROF is excluded because we want to
  * be able to profile all of UML, not just the non-critical sections.  If
  * profiling is not thread-safe, then that is not my problem.  We can disable
  * profiling when SMP is enabled in that case.
@@ -32,196 +58,231 @@
 #define SIGVTALRM_BIT 1
 #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
 
-#define SIGALRM_BIT 2
-#define SIGALRM_MASK (1 << SIGALRM_BIT)
+static int signals_enabled;
+static unsigned int signals_pending;
 
-/* These are used by both the signal handlers and
- * block/unblock_signals.  I don't want modifications cached in a
- * register - they must go straight to memory.
- */
-static volatile int signals_enabled = 1;
-static volatile int pending = 0;
-
-void sig_handler(int sig, struct sigcontext *sc)
+void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 {
 	int enabled;
 
 	enabled = signals_enabled;
-	if(!enabled && (sig == SIGIO)){
-		pending |= SIGIO_MASK;
+	if (!enabled && (sig == SIGIO)) {
+		signals_pending |= SIGIO_MASK;
 		return;
 	}
 
 	block_signals();
 
-	CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
-			 sig, sc);
+	sig_handler_common(sig, si, mc);
 
 	set_signals(enabled);
 }
 
-static void real_alarm_handler(int sig, struct sigcontext *sc)
+static void real_alarm_handler(mcontext_t *mc)
 {
-	if(sig == SIGALRM)
-		switch_timers(0);
-
-	CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
-			 sig, sc);
-
-	if(sig == SIGALRM)
-		switch_timers(1);
+	struct uml_pt_regs regs;
 
+	if (mc != NULL)
+		get_regs_from_mc(&regs, mc);
+	regs.is_user = 0;
+	unblock_signals();
+	timer_handler(SIGVTALRM, NULL, &regs);
 }
 
-void alarm_handler(int sig, struct sigcontext *sc)
+void alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
 {
 	int enabled;
 
 	enabled = signals_enabled;
-	if(!signals_enabled){
-		if(sig == SIGVTALRM)
-			pending |= SIGVTALRM_MASK;
-		else pending |= SIGALRM_MASK;
-
+	if (!signals_enabled) {
+		signals_pending |= SIGVTALRM_MASK;
 		return;
 	}
 
 	block_signals();
 
-	real_alarm_handler(sig, sc);
+	real_alarm_handler(mc);
 	set_signals(enabled);
 }
 
+void timer_init(void)
+{
+	set_handler(SIGVTALRM);
+}
+
 void set_sigstack(void *sig_stack, int size)
 {
 	stack_t stack = ((stack_t) { .ss_flags	= 0,
 				     .ss_sp	= (__ptr_t) sig_stack,
 				     .ss_size 	= size - sizeof(void *) });
 
-	if(sigaltstack(&stack, NULL) != 0)
+	if (sigaltstack(&stack, NULL) != 0)
 		panic("enabling signal stack failed, errno = %d\n", errno);
 }
 
-void remove_sigstack(void)
+static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {
+	[SIGSEGV] = sig_handler,
+	[SIGBUS] = sig_handler,
+	[SIGILL] = sig_handler,
+	[SIGFPE] = sig_handler,
+	[SIGTRAP] = sig_handler,
+
+	[SIGIO] = sig_handler,
+	[SIGWINCH] = sig_handler,
+	[SIGVTALRM] = alarm_handler
+};
+
+
+static void hard_handler(int sig, siginfo_t *si, void *p)
 {
-	stack_t stack = ((stack_t) { .ss_flags	= SS_DISABLE,
-				     .ss_sp	= NULL,
-				     .ss_size	= 0 });
+	struct ucontext *uc = p;
+	mcontext_t *mc = &uc->uc_mcontext;
+	unsigned long pending = 1UL << sig;
+
+	do {
+		int nested, bail;
+
+		/*
+		 * pending comes back with one bit set for each
+		 * interrupt that arrived while setting up the stack,
+		 * plus a bit for this interrupt, plus the zero bit is
+		 * set if this is a nested interrupt.
+		 * If bail is true, then we interrupted another
+		 * handler setting up the stack.  In this case, we
+		 * have to return, and the upper handler will deal
+		 * with this interrupt.
+		 */
+		bail = to_irq_stack(&pending);
+		if (bail)
+			return;
 
-	if(sigaltstack(&stack, NULL) != 0)
-		panic("disabling signal stack failed, errno = %d\n", errno);
-}
+		nested = pending & 1;
+		pending &= ~1;
 
-void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
+		while ((sig = ffs(pending)) != 0){
+			sig--;
+			pending &= ~(1 << sig);
+			(*handlers[sig])(sig, (struct siginfo *)si, mc);
+		}
 
-extern void hard_handler(int sig);
+		/*
+		 * Again, pending comes back with a mask of signals
+		 * that arrived while tearing down the stack.  If this
+		 * is non-zero, we just go back, set up the stack
+		 * again, and handle the new interrupts.
+		 */
+		if (!nested)
+			pending = from_irq_stack(nested);
+	} while (pending);
+}
 
-void set_handler(int sig, void (*handler)(int), int flags, ...)
+void set_handler(int sig)
 {
 	struct sigaction action;
-	va_list ap;
+	int flags = SA_SIGINFO | SA_ONSTACK;
 	sigset_t sig_mask;
-	int mask;
 
-	handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
-	action.sa_handler = hard_handler;
+	action.sa_sigaction = hard_handler;
 
+	/* block irq ones */
 	sigemptyset(&action.sa_mask);
+	sigaddset(&action.sa_mask, SIGVTALRM);
+	sigaddset(&action.sa_mask, SIGIO);
+	sigaddset(&action.sa_mask, SIGWINCH);
 
-	va_start(ap, flags);
-	while((mask = va_arg(ap, int)) != -1)
-		sigaddset(&action.sa_mask, mask);
-	va_end(ap);
+	if (sig == SIGSEGV)
+		flags |= SA_NODEFER;
+
+	if (sigismember(&action.sa_mask, sig))
+		flags |= SA_RESTART; /* if it's an irq signal */
 
 	action.sa_flags = flags;
 	action.sa_restorer = NULL;
-	if(sigaction(sig, &action, NULL) < 0)
+	if (sigaction(sig, &action, NULL) < 0)
 		panic("sigaction failed - errno = %d\n", errno);
 
 	sigemptyset(&sig_mask);
 	sigaddset(&sig_mask, sig);
-	if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
+	if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
 		panic("sigprocmask failed - errno = %d\n", errno);
 }
 
 int change_sig(int signal, int on)
 {
-	sigset_t sigset, old;
+	sigset_t sigset;
 
 	sigemptyset(&sigset);
 	sigaddset(&sigset, signal);
-	sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
-	return(!sigismember(&old, signal));
+	if (sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, NULL) < 0)
+		return -errno;
+
+	return 0;
 }
 
 void block_signals(void)
 {
 	signals_enabled = 0;
-	/* This must return with signals disabled, so this barrier
+	/*
+	 * This must return with signals disabled, so this barrier
 	 * ensures that writes are flushed out before the return.
 	 * This might matter if gcc figures out how to inline this and
 	 * decides to shuffle this code into the caller.
 	 */
-	mb();
+	barrier();
 }
 
 void unblock_signals(void)
 {
 	int save_pending;
 
-	if(signals_enabled == 1)
+	if (signals_enabled == 1)
 		return;
 
-	/* We loop because the IRQ handler returns with interrupts off.  So,
+	/*
+	 * We loop because the IRQ handler returns with interrupts off.  So,
 	 * interrupts may have arrived and we need to re-enable them and
-	 * recheck pending.
+	 * recheck signals_pending.
 	 */
-	while(1){
-		/* Save and reset save_pending after enabling signals.  This
-		 * way, pending won't be changed while we're reading it.
+	while (1) {
+		/*
+		 * Save and reset save_pending after enabling signals.  This
+		 * way, signals_pending won't be changed while we're reading it.
 		 */
 		signals_enabled = 1;
 
-		/* Setting signals_enabled and reading pending must
+		/*
+		 * Setting signals_enabled and reading signals_pending must
 		 * happen in this order.
 		 */
-		mb();
-
-		save_pending = pending;
-		if(save_pending == 0){
-			/* This must return with signals enabled, so
-			 * this barrier ensures that writes are
-			 * flushed out before the return.  This might
-			 * matter if gcc figures out how to inline
-			 * this (unlikely, given its size) and decides
-			 * to shuffle this code into the caller.
-			 */
-			mb();
+		barrier();
+
+		save_pending = signals_pending;
+		if (save_pending == 0)
 			return;
-		}
 
-		pending = 0;
+		signals_pending = 0;
 
-		/* We have pending interrupts, so disable signals, as the
+		/*
+		 * We have pending interrupts, so disable signals, as the
 		 * handlers expect them off when they are called.  They will
 		 * be enabled again above.
 		 */
 
 		signals_enabled = 0;
 
-		/* Deal with SIGIO first because the alarm handler might
+		/*
+		 * Deal with SIGIO first because the alarm handler might
 		 * schedule, leaving the pending SIGIO stranded until we come
 		 * back here.
+		 *
+		 * SIGIO's handler doesn't use siginfo or mcontext,
+		 * so they can be NULL.
 		 */
-		if(save_pending & SIGIO_MASK)
-			CHOOSE_MODE_PROC(sig_handler_common_tt,
-					 sig_handler_common_skas, SIGIO, NULL);
+		if (save_pending & SIGIO_MASK)
+			sig_handler_common(SIGIO, NULL, NULL);
 
-		if(save_pending & SIGALRM_MASK)
-			real_alarm_handler(SIGALRM, NULL);
-
-		if(save_pending & SIGVTALRM_MASK)
-			real_alarm_handler(SIGVTALRM, NULL);
+		if (save_pending & SIGVTALRM_MASK)
+			real_alarm_handler(NULL);
 	}
 }
 
@@ -233,18 +294,21 @@ int get_signals(void)
 int set_signals(int enable)
 {
 	int ret;
-	if(signals_enabled == enable)
+	if (signals_enabled == enable)
 		return enable;
 
 	ret = signals_enabled;
-	if(enable)
+	if (enable)
 		unblock_signals();
 	else block_signals();
 
 	return ret;
 }
 
-void os_usr1_signal(int on)
+int os_is_signal_stack(void)
 {
-	change_sig(SIGUSR1, on);
+	stack_t ss;
+	sigaltstack(NULL, &ss);
+
+	return ss.ss_flags & SS_ONSTACK;
 }