#include <errno.h>
#include <signal.h>
#include <strings.h>
+#include "as-layout.h"
+#include "kern_util.h"
#include "os.h"
#include "sysdep/barrier.h"
#include "sysdep/sigcontext.h"
#include "user.h"
+/* Copied from linux/compiler-gcc.h since we can't include it directly */
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+void (*sig_info[NSIG])(int, 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 sigcontext *sc)
+{
+ 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. */
+ copy_sc(&r, sc);
+ GET_FAULTINFO_FROM_SC(r.faultinfo, sc);
+ }
+
+ /* enable signals if sig isn't IRQ signal */
+ if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGVTALRM))
+ unblock_signals();
+
+ (*sig_info[sig])(sig, &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
#define SIGVTALRM_BIT 1
#define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
-/*
- * 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;
+static int signals_enabled;
+static unsigned int signals_pending;
void sig_handler(int sig, struct sigcontext *sc)
{
enabled = signals_enabled;
if (!enabled && (sig == SIGIO)) {
- pending |= SIGIO_MASK;
+ signals_pending |= SIGIO_MASK;
return;
}
block_signals();
- sig_handler_common_skas(sig, sc);
+ sig_handler_common(sig, sc);
set_signals(enabled);
}
enabled = signals_enabled;
if (!signals_enabled) {
- pending |= SIGVTALRM_MASK;
+ signals_pending |= SIGVTALRM_MASK;
return;
}
panic("enabling signal stack failed, errno = %d\n", errno);
}
-void remove_sigstack(void)
-{
- stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE,
- .ss_sp = NULL,
- .ss_size = 0 });
-
- if (sigaltstack(&stack, NULL) != 0)
- panic("disabling signal stack failed, errno = %d\n", errno);
-}
-
void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
void handle_signal(int sig, struct sigcontext *sc)
sigaddset(&action.sa_mask, mask);
va_end(ap);
+ if (sig == SIGSEGV)
+ flags |= SA_NODEFER;
+
action.sa_flags = flags;
action.sa_restorer = NULL;
if (sigaction(sig, &action, NULL) < 0)
int change_sig(int signal, int on)
{
- sigset_t sigset, old;
+ sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, signal);
- if (sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old) < 0)
+ if (sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, NULL) < 0)
return -errno;
- return !sigismember(&old, signal);
+
+ return 0;
}
void block_signals(void)
* 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)
/*
* 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) {
+ while (1) {
/*
* Save and reset save_pending after enabling signals. This
- * way, pending won't be changed while we're reading it.
+ * 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
* back here.
*/
if (save_pending & SIGIO_MASK)
- sig_handler_common_skas(SIGIO, NULL);
+ sig_handler_common(SIGIO, NULL);
if (save_pending & SIGVTALRM_MASK)
real_alarm_handler(NULL);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff