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Diffstat (limited to 'arch/um/os-Linux/signal.c')
-rw-r--r--arch/um/os-Linux/signal.c52
1 files changed, 37 insertions, 15 deletions
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 75b10235d369..b58bc68cbe64 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -1,15 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2004 PathScale, Inc
* Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- * Licensed under the GPL
*/
#include <stdlib.h>
#include <stdarg.h>
#include <errno.h>
#include <signal.h>
+#include <string.h>
#include <strings.h>
#include <as-layout.h>
#include <kern_util.h>
@@ -26,7 +27,6 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
[SIGBUS] = bus_handler,
[SIGSEGV] = segv_handler,
[SIGIO] = sigio_handler,
- [SIGALRM] = timer_handler
};
static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
@@ -42,8 +42,8 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
}
/* enable signals if sig isn't IRQ signal */
- if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGALRM))
- unblock_signals();
+ if ((sig != SIGIO) && (sig != SIGWINCH))
+ unblock_signals_trace();
(*sig_info[sig])(sig, si, &r);
@@ -76,11 +76,11 @@ void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
return;
}
- block_signals();
+ block_signals_trace();
sig_handler_common(sig, si, mc);
- set_signals(enabled);
+ set_signals_trace(enabled);
}
static void timer_real_alarm_handler(mcontext_t *mc)
@@ -89,6 +89,8 @@ static void timer_real_alarm_handler(mcontext_t *mc)
if (mc != NULL)
get_regs_from_mc(&regs, mc);
+ else
+ memset(&regs, 0, sizeof(regs));
timer_handler(SIGALRM, NULL, &regs);
}
@@ -102,7 +104,7 @@ void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
return;
}
- block_signals();
+ block_signals_trace();
signals_active |= SIGALRM_MASK;
@@ -110,7 +112,7 @@ void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
signals_active &= ~SIGALRM_MASK;
- set_signals(enabled);
+ set_signals_trace(enabled);
}
void deliver_alarm(void) {
@@ -251,6 +253,8 @@ void unblock_signals(void)
if (signals_enabled == 1)
return;
+ signals_enabled = 1;
+
/*
* We loop because the IRQ handler returns with interrupts off. So,
* interrupts may have arrived and we need to re-enable them and
@@ -260,12 +264,9 @@ void unblock_signals(void)
/*
* 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 signals_pending must
- * happen in this order.
+ * happen in this order, so have the barrier here.
*/
barrier();
@@ -278,10 +279,13 @@ void unblock_signals(void)
/*
* We have pending interrupts, so disable signals, as the
* handlers expect them off when they are called. They will
- * be enabled again above.
+ * be enabled again above. We need to trace this, as we're
+ * expected to be enabling interrupts already, but any more
+ * tracing that happens inside the handlers we call for the
+ * pending signals will mess up the tracing state.
*/
-
signals_enabled = 0;
+ um_trace_signals_off();
/*
* Deal with SIGIO first because the alarm handler might
@@ -304,6 +308,9 @@ void unblock_signals(void)
if (!(signals_pending & SIGIO_MASK) && (signals_active & SIGALRM_MASK))
return;
+ /* Re-enable signals and trace that we're doing so. */
+ um_trace_signals_on();
+ signals_enabled = 1;
}
}
@@ -326,6 +333,21 @@ int set_signals(int enable)
return ret;
}
+int set_signals_trace(int enable)
+{
+ int ret;
+ if (signals_enabled == enable)
+ return enable;
+
+ ret = signals_enabled;
+ if (enable)
+ unblock_signals_trace();
+ else
+ block_signals_trace();
+
+ return ret;
+}
+
int os_is_signal_stack(void)
{
stack_t ss;