From 13c06be399902c9ebda08e092edb1614bb4a3761 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 25 Sep 2006 23:32:59 -0700 Subject: [PATCH] uml: Use klibc setjmp/longjmp This patch adds an implementation of setjmp and longjmp to UML, allowing access to the inside of a jmpbuf without needing the access macros formerly provided by libc. The implementation is stolen from klibc. I copy the relevant files into arch/um. I have another patch which avoids the copying, but requires klibc be in the tree. setjmp and longjmp users required some tweaking. Includes of were removed and includes of the UML longjmp.h were added where necessary. There are also replacements of siglongjmp with UML_LONGJMP which I somehow missed earlier. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/process.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/um/os-Linux/process.c') diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index b98d3ca2cd1b..3afde92ad2c0 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -7,7 +7,6 @@ #include #include #include -#include #include #include #include -- cgit From 4b84c69b5f6c08a540e3683f1360a6cdef2806c7 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 25 Sep 2006 23:33:04 -0700 Subject: [PATCH] uml: Move signal handlers to arch code 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/sysdep-i386/signal.h | 27 --------------------------- arch/um/include/sysdep-x86_64/signal.h | 29 ----------------------------- arch/um/os-Linux/irq.c | 2 +- arch/um/os-Linux/main.c | 34 ++++++++++++++++++++++++++++------ arch/um/os-Linux/process.c | 12 +++++++++++- arch/um/os-Linux/signal.c | 31 +++++++++++++------------------ arch/um/os-Linux/skas/process.c | 17 ++++++++++++++--- arch/um/os-Linux/sys-i386/Makefile | 2 +- arch/um/os-Linux/sys-i386/signal.c | 15 +++++++++++++++ arch/um/os-Linux/sys-x86_64/Makefile | 2 +- arch/um/os-Linux/sys-x86_64/signal.c | 16 ++++++++++++++++ arch/um/os-Linux/time.c | 4 ++-- 12 files changed, 102 insertions(+), 89 deletions(-) delete mode 100644 arch/um/include/sysdep-i386/signal.h delete mode 100644 arch/um/include/sysdep-x86_64/signal.h create mode 100644 arch/um/os-Linux/sys-i386/signal.c create mode 100644 arch/um/os-Linux/sys-x86_64/signal.c (limited to 'arch/um/os-Linux/process.c') diff --git a/arch/um/include/sysdep-i386/signal.h b/arch/um/include/sysdep-i386/signal.h deleted file mode 100644 index 07518b162136..000000000000 --- a/arch/um/include/sysdep-i386/signal.h +++ /dev/null @@ -1,27 +0,0 @@ -/* - * Copyright (C) 2004 PathScale, Inc - * Licensed under the GPL - */ - -#ifndef __I386_SIGNAL_H_ -#define __I386_SIGNAL_H_ - -#include - -#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: - */ diff --git a/arch/um/include/sysdep-x86_64/signal.h b/arch/um/include/sysdep-x86_64/signal.h deleted file mode 100644 index 6142897af3d1..000000000000 --- a/arch/um/include/sysdep-x86_64/signal.h +++ /dev/null @@ -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: - */ diff --git a/arch/um/os-Linux/irq.c b/arch/um/os-Linux/irq.c index 7555bf9c33d9..a97206df5b52 100644 --- a/arch/um/os-Linux/irq.c +++ b/arch/um/os-Linux/irq.c @@ -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) diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c index 90912aaca7aa..d1c5670787dc 100644 --- a/arch/um/os-Linux/main.c +++ b/arch/um/os-Linux/main.c @@ -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); diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index 3afde92ad2c0..ff203625a4bd 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -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) diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index 60e4faedf254..55b62e2b8f41 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -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) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 50418a5e7134..88ff0de95cd3 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -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()); diff --git a/arch/um/os-Linux/sys-i386/Makefile b/arch/um/os-Linux/sys-i386/Makefile index b3213613c41c..37806621b25d 100644 --- a/arch/um/os-Linux/sys-i386/Makefile +++ b/arch/um/os-Linux/sys-i386/Makefile @@ -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 := $(obj-y) diff --git a/arch/um/os-Linux/sys-i386/signal.c b/arch/um/os-Linux/sys-i386/signal.c new file mode 100644 index 000000000000..0d3eae518352 --- /dev/null +++ b/arch/um/os-Linux/sys-i386/signal.c @@ -0,0 +1,15 @@ +/* + * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com) + * Licensed under the GPL + */ + +#include + +extern void (*handlers[])(int sig, struct sigcontext *sc); + +void hard_handler(int sig) +{ + struct sigcontext *sc = (struct sigcontext *) (&sig + 1); + + (*handlers[sig])(sig, sc); +} diff --git a/arch/um/os-Linux/sys-x86_64/Makefile b/arch/um/os-Linux/sys-x86_64/Makefile index 340ef26f5944..f67842a7735b 100644 --- a/arch/um/os-Linux/sys-x86_64/Makefile +++ b/arch/um/os-Linux/sys-x86_64/Makefile @@ -3,7 +3,7 @@ # Licensed under the GPL # -obj-$(CONFIG_MODE_SKAS) = registers.o +obj-$(CONFIG_MODE_SKAS) = registers.o signal.o USER_OBJS := $(obj-y) diff --git a/arch/um/os-Linux/sys-x86_64/signal.c b/arch/um/os-Linux/sys-x86_64/signal.c new file mode 100644 index 000000000000..3f369e5f976b --- /dev/null +++ b/arch/um/os-Linux/sys-x86_64/signal.c @@ -0,0 +1,16 @@ +/* + * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com) + * Licensed under the GPL + */ + +#include + +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); +} diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c index 4ae73c0e5485..7f5ebbadca63 100644 --- a/arch/um/os-Linux/time.c +++ b/arch/um/os-Linux/time.c @@ -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) -- cgit