AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

[PATCH] uml: Move signal handlers to arch code

Browse Source 
Have most signals go through an arch-provided handler which recovers the
sigcontext and then calls a generic handler.  This replaces the
ARCH_GET_SIGCONTEXT macro, which was somewhat fragile.  On x86_64, recovering
%rdx (which holds the sigcontext pointer) must be the first thing that
happens.  sig_handler duly invokes that first, but there is no guarantee that
I can see that instructions won't be reordered such that %rdx is used before
that.  Having the arch provide the handler seems much more robust.

Some signals in some parts of UML require their own handlers - these places
don't call set_handler any more.  They call sigaction or signal themselves.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jeff Dike 2006-09-25 23:33:04 -07:00 committed by Linus Torvalds
parent 19bdf0409f
commit 4b84c69b5f
12 changed files with 102 additions and 89 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
arch/um/include/sysdep-i386/signal.h
View File

@ -1,27 +0,0 @@
/*
* Copyright (C) 2004 PathScale, Inc
* Licensed under the GPL
*/
#ifndef __I386_SIGNAL_H_
#define __I386_SIGNAL_H_
#include <signal.h>
#define ARCH_SIGHDLR_PARAM int sig
#define ARCH_GET_SIGCONTEXT(sc, sig) \
do sc = (struct sigcontext *) (&sig + 1); while(0)
#endif
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/

29
arch/um/include/sysdep-x86_64/signal.h
View File

@ -1,29 +0,0 @@
/*
* Copyright (C) 2004 PathScale, Inc
* Licensed under the GPL
*/
#ifndef __X86_64_SIGNAL_H_
#define __X86_64_SIGNAL_H_
#define ARCH_SIGHDLR_PARAM int sig
#define ARCH_GET_SIGCONTEXT(sc, sig_addr) \
do { \
struct ucontext *__uc; \
asm("movq %%rdx, %0" : "=r" (__uc)); \
sc = (struct sigcontext *) &__uc->uc_mcontext; \
} while(0)
#endif
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/

2
arch/um/os-Linux/irq.c
View File

@ -132,7 +132,7 @@ void os_set_pollfd(int i, int fd)
void os_set_ioignore(void)
{
set_handler(SIGIO, SIG_IGN, 0, -1);
signal(SIGIO, SIG_IGN);
}
void init_irq_signals(int on_sigstack)

34
arch/um/os-Linux/main.c
View File

@ -67,13 +67,32 @@ static __init void do_uml_initcalls(void)
static void last_ditch_exit(int sig)
{
signal(SIGINT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
signal(SIGHUP, SIG_DFL);
uml_cleanup();
exit(1);
}
static void install_fatal_handler(int sig)
{
struct sigaction action;
/* All signals are enabled in this handler ... */
sigemptyset(&action.sa_mask);
/* ... including the signal being handled, plus we want the
* handler reset to the default behavior, so that if an exit
* handler is hanging for some reason, the UML will just die
* after this signal is sent a second time.
*/
action.sa_flags = SA_RESETHAND | SA_NODEFER;
action.sa_restorer = NULL;
action.sa_handler = last_ditch_exit;
if(sigaction(sig, &action, NULL) < 0){
printf("failed to install handler for signal %d - errno = %d\n",
errno);
exit(1);
}
}
#define UML_LIB_PATH ":/usr/lib/uml"
static void setup_env_path(void)
@ -158,9 +177,12 @@ int main(int argc, char **argv, char **envp)
}
new_argv[argc] = NULL;
set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
/* Allow these signals to bring down a UML if all other
* methods of control fail.
*/
install_fatal_handler(SIGINT);
install_fatal_handler(SIGTERM);
install_fatal_handler(SIGHUP);
scan_elf_aux( envp);

12
arch/um/os-Linux/process.c
View File

@ -246,7 +246,17 @@ void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
set_sigstack(sig_stack, pages * page_size());
flags = SA_ONSTACK;
}
if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1);
if(usr1_handler){
struct sigaction sa;
sa.sa_handler = usr1_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = flags;
sa.sa_restorer = NULL;
if(sigaction(SIGUSR1, &sa, NULL) < 0)
panic("init_new_thread_stack - sigaction failed - "
"errno = %d\n", errno);
}
}
void init_new_thread_signals(void)

31
arch/um/os-Linux/signal.c
View File

@ -15,7 +15,6 @@
#include "user.h"
#include "signal_kern.h"
#include "sysdep/sigcontext.h"
#include "sysdep/signal.h"
#include "sigcontext.h"
#include "mode.h"
#include "os.h"
@ -38,18 +37,10 @@
static int signals_enabled = 1;
static int pending = 0;
void sig_handler(ARCH_SIGHDLR_PARAM)
void sig_handler(int sig, struct sigcontext *sc)
{
struct sigcontext *sc;
int enabled;
/* Must be the first thing that this handler does - x86_64 stores
* the sigcontext in %rdx, and we need to save it before it has a
* chance to get trashed.
*/
ARCH_GET_SIGCONTEXT(sc, sig);
enabled = signals_enabled;
if(!enabled && (sig == SIGIO)){
pending |= SIGIO_MASK;
@ -84,13 +75,10 @@ static void real_alarm_handler(int sig, struct sigcontext *sc)
}
void alarm_handler(ARCH_SIGHDLR_PARAM)
void alarm_handler(int sig, struct sigcontext *sc)
{
struct sigcontext *sc;
int enabled;
ARCH_GET_SIGCONTEXT(sc, sig);
enabled = signals_enabled;
if(!signals_enabled){
if(sig == SIGVTALRM)
@ -126,6 +114,10 @@ void remove_sigstack(void)
panic("disabling signal stack failed, errno = %d\n", errno);
}
void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
extern void hard_handler(int sig);
void set_handler(int sig, void (*handler)(int), int flags, ...)
{
struct sigaction action;
@ -133,13 +125,16 @@ void set_handler(int sig, void (*handler)(int), int flags, ...)
sigset_t sig_mask;
int mask;
va_start(ap, flags);
action.sa_handler = handler;
handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
action.sa_handler = hard_handler;
sigemptyset(&action.sa_mask);
while((mask = va_arg(ap, int)) != -1){
va_start(ap, flags);
while((mask = va_arg(ap, int)) != -1)
sigaddset(&action.sa_mask, mask);
}
va_end(ap);
action.sa_flags = flags;
action.sa_restorer = NULL;
if(sigaction(sig, &action, NULL) < 0)

17
arch/um/os-Linux/skas/process.c
View File

@ -189,14 +189,25 @@ static int userspace_tramp(void *stack)
}
}
if(!ptrace_faultinfo && (stack != NULL)){
struct sigaction sa;
unsigned long v = UML_CONFIG_STUB_CODE +
(unsigned long) stub_segv_handler -
(unsigned long) &__syscall_stub_start;
set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
SIGUSR1, -1);
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGIO);
sigaddset(&sa.sa_mask, SIGWINCH);
sigaddset(&sa.sa_mask, SIGALRM);
sigaddset(&sa.sa_mask, SIGVTALRM);
sigaddset(&sa.sa_mask, SIGUSR1);
sa.sa_flags = SA_ONSTACK;
sa.sa_handler = (void *) v;
sa.sa_restorer = NULL;
if(sigaction(SIGSEGV, &sa, NULL) < 0)
panic("userspace_tramp - setting SIGSEGV handler "
"failed - errno = %d\n", errno);
}
os_stop_process(os_getpid());

2
arch/um/os-Linux/sys-i386/Makefile
View File

@ -3,7 +3,7 @@
# Licensed under the GPL
#
obj-$(CONFIG_MODE_SKAS) = registers.o tls.o
obj-$(CONFIG_MODE_SKAS) = registers.o signal.o tls.o
USER_OBJS := $(obj-y)

15
arch/um/os-Linux/sys-i386/signal.c Normal file
View File

@ -0,0 +1,15 @@
/*
* Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include <signal.h>
extern void (*handlers[])(int sig, struct sigcontext *sc);
void hard_handler(int sig)
{
struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
(*handlers[sig])(sig, sc);
}

2
arch/um/os-Linux/sys-x86_64/Makefile
View File

@ -3,7 +3,7 @@
# Licensed under the GPL
#
obj-$(CONFIG_MODE_SKAS) = registers.o
obj-$(CONFIG_MODE_SKAS) = registers.o signal.o
USER_OBJS := $(obj-y)

16
arch/um/os-Linux/sys-x86_64/signal.c Normal file
View File

@ -0,0 +1,16 @@
/*
* Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include <signal.h>
extern void (*handlers[])(int sig, struct sigcontext *sc);
void hard_handler(int sig)
{
struct ucontext *uc;
asm("movq %%rdx, %0" : "=r" (uc));
(*handlers[sig])(sig, (struct sigcontext *) &uc->uc_mcontext);
}

4
arch/um/os-Linux/time.c
View File

@ -40,8 +40,8 @@ void disable_timer(void)
printk("disnable_timer - setitimer failed, errno = %d\n",
errno);
/* If there are signals already queued, after unblocking ignore them */
set_handler(SIGALRM, SIG_IGN, 0, -1);
set_handler(SIGVTALRM, SIG_IGN, 0, -1);
signal(SIGALRM, SIG_IGN);
signal(SIGVTALRM, SIG_IGN);
}
void switch_timers(int to_real)