diff options
Diffstat (limited to 'arch/um/os-Linux/signal.c')
| -rw-r--r-- | arch/um/os-Linux/signal.c | 52 |
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(®s, mc); + else + memset(®s, 0, sizeof(regs)); timer_handler(SIGALRM, NULL, ®s); } @@ -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; |