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Diffstat (limited to 'arch/um/os-Linux/signal.c')
-rw-r--r--arch/um/os-Linux/signal.c124
1 files changed, 65 insertions, 59 deletions
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index b11ed66c8bb0..327fb3c52fc7 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -20,15 +20,17 @@
#include <um_malloc.h>
#include <sys/ucontext.h>
#include <timetravel.h>
+#include "internal.h"
-void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
+void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *, void *mc) = {
[SIGTRAP] = relay_signal,
[SIGFPE] = relay_signal,
[SIGILL] = relay_signal,
[SIGWINCH] = winch,
- [SIGBUS] = bus_handler,
+ [SIGBUS] = relay_signal,
[SIGSEGV] = segv_handler,
[SIGIO] = sigio_handler,
+ [SIGCHLD] = sigchld_handler,
};
static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
@@ -44,10 +46,10 @@ 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))
+ if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGCHLD))
unblock_signals_trace();
- (*sig_info[sig])(sig, si, &r);
+ (*sig_info[sig])(sig, si, &r, mc);
errno = save_errno;
}
@@ -64,18 +66,21 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
#define SIGALRM_BIT 1
#define SIGALRM_MASK (1 << SIGALRM_BIT)
-int signals_enabled;
-#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+#define SIGCHLD_BIT 2
+#define SIGCHLD_MASK (1 << SIGCHLD_BIT)
+
+__thread int signals_enabled;
+#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT)
static int signals_blocked, signals_blocked_pending;
#endif
-static unsigned int signals_pending;
-static unsigned int signals_active = 0;
+static __thread unsigned int signals_pending;
+static __thread unsigned int signals_active;
static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
{
int enabled = signals_enabled;
-#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT)
if ((signals_blocked ||
__atomic_load_n(&signals_blocked_pending, __ATOMIC_SEQ_CST)) &&
(sig == SIGIO)) {
@@ -102,6 +107,11 @@ static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
return;
}
+ if (!enabled && (sig == SIGCHLD)) {
+ signals_pending |= SIGCHLD_MASK;
+ return;
+ }
+
block_signals_trace();
sig_handler_common(sig, si, mc);
@@ -150,6 +160,11 @@ void timer_set_signal_handler(void)
set_handler(SIGALRM);
}
+int timer_alarm_pending(void)
+{
+ return !!(signals_pending & SIGALRM_MASK);
+}
+
void set_sigstack(void *sig_stack, int size)
{
stack_t stack = {
@@ -181,6 +196,8 @@ static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {
[SIGIO] = sig_handler,
[SIGWINCH] = sig_handler,
+ /* SIGCHLD is only actually registered in seccomp mode. */
+ [SIGCHLD] = sig_handler,
[SIGALRM] = timer_alarm_handler,
[SIGUSR1] = sigusr1_handler,
@@ -190,43 +207,8 @@ static void hard_handler(int sig, siginfo_t *si, void *p)
{
ucontext_t *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;
-
- nested = pending & 1;
- pending &= ~1;
-
- while ((sig = ffs(pending)) != 0){
- sig--;
- pending &= ~(1 << sig);
- (*handlers[sig])(sig, (struct siginfo *)si, mc);
- }
- /*
- * 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);
+ (*handlers[sig])(sig, (struct siginfo *)si, mc);
}
void set_handler(int sig)
@@ -277,9 +259,29 @@ int change_sig(int signal, int on)
return 0;
}
-void block_signals(void)
+static inline void __block_signals(void)
{
+ if (!signals_enabled)
+ return;
+
+ os_local_ipi_disable();
+ barrier();
signals_enabled = 0;
+}
+
+static inline void __unblock_signals(void)
+{
+ if (signals_enabled)
+ return;
+
+ signals_enabled = 1;
+ barrier();
+ os_local_ipi_enable();
+}
+
+void block_signals(void)
+{
+ __block_signals();
/*
* This must return with signals disabled, so this barrier
* ensures that writes are flushed out before the return.
@@ -296,8 +298,9 @@ void unblock_signals(void)
if (signals_enabled == 1)
return;
- signals_enabled = 1;
-#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+ __unblock_signals();
+
+#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT)
deliver_time_travel_irqs();
#endif
@@ -330,7 +333,7 @@ void unblock_signals(void)
* tracing that happens inside the handlers we call for the
* pending signals will mess up the tracing state.
*/
- signals_enabled = 0;
+ __block_signals();
um_trace_signals_off();
/*
@@ -344,6 +347,12 @@ void unblock_signals(void)
if (save_pending & SIGIO_MASK)
sig_handler_common(SIGIO, NULL, NULL);
+ if (save_pending & SIGCHLD_MASK) {
+ struct uml_pt_regs regs = {};
+
+ sigchld_handler(SIGCHLD, NULL, &regs, NULL);
+ }
+
/* Do not reenter the handler */
if ((save_pending & SIGALRM_MASK) && (!(signals_active & SIGALRM_MASK)))
@@ -356,10 +365,15 @@ void unblock_signals(void)
/* Re-enable signals and trace that we're doing so. */
um_trace_signals_on();
- signals_enabled = 1;
+ __unblock_signals();
}
}
+int um_get_signals(void)
+{
+ return signals_enabled;
+}
+
int um_set_signals(int enable)
{
int ret;
@@ -389,7 +403,7 @@ int um_set_signals_trace(int enable)
return ret;
}
-#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT)
void mark_sigio_pending(void)
{
/*
@@ -487,11 +501,3 @@ void unblock_signals_hard(void)
unblocking = false;
}
#endif
-
-int os_is_signal_stack(void)
-{
- stack_t ss;
- sigaltstack(NULL, &ss);
-
- return ss.ss_flags & SS_ONSTACK;
-}
generated by cgit (git 2.34.1) at 2025-12-22 12:40:05 +0000