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/skas/process.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/um/os-Linux/skas/process.c') diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 7baf90fda58b..50418a5e7134 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -8,7 +8,6 @@ #include #include #include -#include #include #include "ptrace_user.h" #include @@ -470,7 +469,7 @@ void thread_wait(void *sw, void *fb) *switch_buf = &buf; fork_buf = fb; if(UML_SETJMP(&buf) == 0) - siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); + UML_LONGJMP(fork_buf, INIT_JMP_REMOVE_SIGSTACK); } void switch_threads(void *me, void *next) -- 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/skas/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 From 537ae946e808d0f22d660f7a3500832fe0c07d14 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 25 Sep 2006 23:33:05 -0700 Subject: [PATCH] uml: timer cleanups set_interval returns an error instead of panicing if setitimer fails. Some of its callers now check the return. enable_timer is largely tt-mode-specific, so it is marked as such, and the only skas-mode caller is made to call set-interval instead. user_time_init was a no-value-added wrapper around set_interval, so it is gone. Since set_interval is now called from kernel code, callers no longer pass ITIMER_* to it. Instead, they pass a flag which is converted into ITIMER_REAL or ITIMER_VIRTUAL. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/os.h | 4 +++- arch/um/kernel/time.c | 7 +++++-- arch/um/os-Linux/skas/process.c | 6 +++++- arch/um/os-Linux/time.c | 18 +++++++++--------- 4 files changed, 22 insertions(+), 13 deletions(-) (limited to 'arch/um/os-Linux/skas/process.c') diff --git a/arch/um/include/os.h b/arch/um/include/os.h index c73dfa78f943..24fb6d8680e1 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -276,9 +276,11 @@ extern int setjmp_wrapper(void (*proc)(void *, void *), ...); extern void switch_timers(int to_real); extern void idle_sleep(int secs); +extern int set_interval(int is_virtual); +#ifdef CONFIG_MODE_TT extern void enable_timer(void); +#endif extern void disable_timer(void); -extern void user_time_init(void); extern void uml_idle_timer(void); extern unsigned long long os_nsecs(void); diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c index 552ca1cb9847..d1d799346e04 100644 --- a/arch/um/kernel/time.c +++ b/arch/um/kernel/time.c @@ -113,12 +113,15 @@ static void register_timer(void) err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL); if(err != 0) - printk(KERN_ERR "timer_init : request_irq failed - " + printk(KERN_ERR "register_timer : request_irq failed - " "errno = %d\n", -err); timer_irq_inited = 1; - user_time_init(); + err = set_interval(1); + if(err != 0) + printk(KERN_ERR "register_timer : set_interval failed - " + "errno = %d\n", -err); } extern void (*late_time_init)(void); diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 88ff0de95cd3..42e3d1ed802c 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -155,11 +155,15 @@ extern int __syscall_stub_start; static int userspace_tramp(void *stack) { void *addr; + int err; ptrace(PTRACE_TRACEME, 0, 0, 0); init_new_thread_signals(); - enable_timer(); + err = set_interval(1); + if(err) + panic("userspace_tramp - setting timer failed, errno = %d\n", + err); if(!proc_mm){ /* This has a pte, but it can't be mapped in with the usual diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c index 7f5ebbadca63..38be096e750f 100644 --- a/arch/um/os-Linux/time.c +++ b/arch/um/os-Linux/time.c @@ -17,20 +17,25 @@ #include "kern_constants.h" #include "os.h" -static void set_interval(int timer_type) +int set_interval(int is_virtual) { int usec = 1000000/hz(); + int timer_type = is_virtual ? ITIMER_VIRTUAL : ITIMER_REAL; struct itimerval interval = ((struct itimerval) { { 0, usec }, { 0, usec } }); if(setitimer(timer_type, &interval, NULL) == -1) - panic("setitimer failed - errno = %d\n", errno); + return -errno; + + return 0; } +#ifdef CONFIG_MODE_TT void enable_timer(void) { - set_interval(ITIMER_VIRTUAL); + set_interval(1); } +#endif void disable_timer(void) { @@ -74,7 +79,7 @@ void uml_idle_timer(void) set_handler(SIGALRM, (__sighandler_t) alarm_handler, SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1); - set_interval(ITIMER_REAL); + set_interval(0); } #endif @@ -94,8 +99,3 @@ void idle_sleep(int secs) ts.tv_nsec = 0; nanosleep(&ts, NULL); } - -void user_time_init(void) -{ - set_interval(ITIMER_VIRTUAL); -} -- cgit From 3c9173509985b957bea692ea887a8a0e5055cfe8 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Wed, 27 Sep 2006 01:50:40 -0700 Subject: [PATCH] uml: thread creation tidying fork on UML has always somewhat subtle. The underlying cause has been the need to initialize a stack for the new process. The only portable way to initialize a new stack is to set it as the alternate signal stack and take a signal. The signal handler does whatever initialization is needed and jumps back to the original stack, where the fork processing is finished. The basic context switching mechanism is a jmp_buf for each process. You switch to a new process by longjmping to its jmp_buf. Now that UML has its own implementation of setjmp and longjmp, and I can poke around inside a jmp_buf without fear that libc will change the structure, a much simpler mechanism is possible. The jmpbuf can simply be initialized by hand. This eliminates - the need to set up and remove the alternate signal stack sending and handling a signal the signal blocking needed around the stack switching, since there is no stack switching setting up the jmp_buf needed to jump back to the original stack after the new one is set up In addition, since jmp_buf is now defined by UML, and not by libc, it can be embedded in the thread struct. This makes it unnecessary to have it exist on the stack, where it used to be. It also simplifies interfaces, since the switch jmp_buf used to be a void * inside the thread struct, and functions which took it as an argument needed to define a jmp_buf variable and assign it from the void *. Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/os.h | 10 ++--- arch/um/include/skas/skas.h | 3 +- arch/um/include/sysdep-i386/archsetjmp.h | 3 ++ arch/um/include/sysdep-x86_64/archsetjmp.h | 3 ++ arch/um/kernel/skas/process_kern.c | 36 ++++++---------- arch/um/os-Linux/skas/process.c | 68 +++++++----------------------- include/asm-um/processor-generic.h | 6 +-- 7 files changed, 43 insertions(+), 86 deletions(-) (limited to 'arch/um/os-Linux/skas/process.c') diff --git a/arch/um/include/os.h b/arch/um/include/os.h index be71b3d4c961..120ca21a513a 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -14,6 +14,7 @@ #include "skas/mm_id.h" #include "irq_user.h" #include "sysdep/tls.h" +#include "sysdep/archsetjmp.h" #define OS_TYPE_FILE 1 #define OS_TYPE_DIR 2 @@ -308,12 +309,9 @@ extern int copy_context_skas0(unsigned long stack, int pid); extern void userspace(union uml_pt_regs *regs); extern void map_stub_pages(int fd, unsigned long code, unsigned long data, unsigned long stack); -extern void new_thread(void *stack, void **switch_buf_ptr, - void **fork_buf_ptr, void (*handler)(int)); -extern void thread_wait(void *sw, void *fb); -extern void switch_threads(void *me, void *next); -extern int start_idle_thread(void *stack, void *switch_buf_ptr, - void **fork_buf_ptr); +extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)); +extern void switch_threads(jmp_buf *me, jmp_buf *you); +extern int start_idle_thread(void *stack, jmp_buf *switch_buf); extern void initial_thread_cb_skas(void (*proc)(void *), void *arg); extern void halt_skas(void); diff --git a/arch/um/include/skas/skas.h b/arch/um/include/skas/skas.h index 853b26f148c5..e88926b16072 100644 --- a/arch/um/include/skas/skas.h +++ b/arch/um/include/skas/skas.h @@ -14,8 +14,7 @@ extern int proc_mm, ptrace_faultinfo, ptrace_ldt; extern int skas_needs_stub; extern int user_thread(unsigned long stack, int flags); -extern void new_thread_proc(void *stack, void (*handler)(int sig)); -extern void new_thread_handler(int sig); +extern void new_thread_handler(void); extern void handle_syscall(union uml_pt_regs *regs); extern int new_mm(unsigned long stack); extern void get_skas_faultinfo(int pid, struct faultinfo * fi); diff --git a/arch/um/include/sysdep-i386/archsetjmp.h b/arch/um/include/sysdep-i386/archsetjmp.h index ea1ba3d42aee..11bafab669e9 100644 --- a/arch/um/include/sysdep-i386/archsetjmp.h +++ b/arch/um/include/sysdep-i386/archsetjmp.h @@ -16,4 +16,7 @@ struct __jmp_buf { typedef struct __jmp_buf jmp_buf[1]; +#define JB_IP __eip +#define JB_SP __esp + #endif /* _SETJMP_H */ diff --git a/arch/um/include/sysdep-x86_64/archsetjmp.h b/arch/um/include/sysdep-x86_64/archsetjmp.h index 454fc60aff6d..9a5e1a6ec800 100644 --- a/arch/um/include/sysdep-x86_64/archsetjmp.h +++ b/arch/um/include/sysdep-x86_64/archsetjmp.h @@ -18,4 +18,7 @@ struct __jmp_buf { typedef struct __jmp_buf jmp_buf[1]; +#define JB_IP __rip +#define JB_SP __rsp + #endif /* _SETJMP_H */ diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c index 55caeec8b257..c73d47c57abe 100644 --- a/arch/um/kernel/skas/process_kern.c +++ b/arch/um/kernel/skas/process_kern.c @@ -33,7 +33,7 @@ void switch_to_skas(void *prev, void *next) switch_timers(0); switch_threads(&from->thread.mode.skas.switch_buf, - to->thread.mode.skas.switch_buf); + &to->thread.mode.skas.switch_buf); arch_switch_to_skas(current->thread.prev_sched, current); @@ -43,21 +43,21 @@ void switch_to_skas(void *prev, void *next) extern void schedule_tail(struct task_struct *prev); -void new_thread_handler(int sig) +/* This is called magically, by its address being stuffed in a jmp_buf + * and being longjmp-d to. + */ +void new_thread_handler(void) { int (*fn)(void *), n; void *arg; - fn = current->thread.request.u.thread.proc; - arg = current->thread.request.u.thread.arg; - os_usr1_signal(1); - thread_wait(¤t->thread.mode.skas.switch_buf, - current->thread.mode.skas.fork_buf); - if(current->thread.prev_sched != NULL) schedule_tail(current->thread.prev_sched); current->thread.prev_sched = NULL; + fn = current->thread.request.u.thread.proc; + arg = current->thread.request.u.thread.arg; + /* The return value is 1 if the kernel thread execs a process, * 0 if it just exits */ @@ -70,22 +70,13 @@ void new_thread_handler(int sig) else do_exit(0); } -void new_thread_proc(void *stack, void (*handler)(int sig)) -{ - init_new_thread_stack(stack, handler); - os_usr1_process(os_getpid()); -} - void release_thread_skas(struct task_struct *task) { } -void fork_handler(int sig) +/* Called magically, see new_thread_handler above */ +void fork_handler(void) { - os_usr1_signal(1); - thread_wait(¤t->thread.mode.skas.switch_buf, - current->thread.mode.skas.fork_buf); - force_flush_all(); if(current->thread.prev_sched == NULL) panic("blech"); @@ -109,7 +100,7 @@ int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp, unsigned long stack_top, struct task_struct * p, struct pt_regs *regs) { - void (*handler)(int); + void (*handler)(void); if(current->thread.forking){ memcpy(&p->thread.regs.regs.skas, ®s->regs.skas, @@ -128,7 +119,7 @@ int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp, } new_thread(task_stack_page(p), &p->thread.mode.skas.switch_buf, - &p->thread.mode.skas.fork_buf, handler); + handler); return(0); } @@ -182,8 +173,7 @@ int start_uml_skas(void) init_task.thread.request.u.thread.proc = start_kernel_proc; init_task.thread.request.u.thread.arg = NULL; return(start_idle_thread(task_stack_page(&init_task), - &init_task.thread.mode.skas.switch_buf, - &init_task.thread.mode.skas.fork_buf)); + &init_task.thread.mode.skas.switch_buf)); } int external_pid_skas(struct task_struct *task) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 42e3d1ed802c..cb9ab54146cc 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -444,56 +444,22 @@ void map_stub_pages(int fd, unsigned long code, } } -void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, - void (*handler)(int)) +void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)) { - unsigned long flags; - jmp_buf switch_buf, fork_buf; - - *switch_buf_ptr = &switch_buf; - *fork_buf_ptr = &fork_buf; - - /* Somewhat subtle - siglongjmp restores the signal mask before doing - * the longjmp. This means that when jumping from one stack to another - * when the target stack has interrupts enabled, an interrupt may occur - * on the source stack. This is bad when starting up a process because - * it's not supposed to get timer ticks until it has been scheduled. - * So, we disable interrupts around the sigsetjmp to ensure that - * they can't happen until we get back here where they are safe. - */ - flags = get_signals(); - block_signals(); - if(UML_SETJMP(&fork_buf) == 0) - new_thread_proc(stack, handler); - - remove_sigstack(); - - set_signals(flags); + (*buf)[0].JB_IP = (unsigned long) handler; + (*buf)[0].JB_SP = (unsigned long) stack + + (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - sizeof(void *); } #define INIT_JMP_NEW_THREAD 0 -#define INIT_JMP_REMOVE_SIGSTACK 1 -#define INIT_JMP_CALLBACK 2 -#define INIT_JMP_HALT 3 -#define INIT_JMP_REBOOT 4 - -void thread_wait(void *sw, void *fb) -{ - jmp_buf buf, **switch_buf = sw, *fork_buf; - - *switch_buf = &buf; - fork_buf = fb; - if(UML_SETJMP(&buf) == 0) - UML_LONGJMP(fork_buf, INIT_JMP_REMOVE_SIGSTACK); -} +#define INIT_JMP_CALLBACK 1 +#define INIT_JMP_HALT 2 +#define INIT_JMP_REBOOT 3 -void switch_threads(void *me, void *next) +void switch_threads(jmp_buf *me, jmp_buf *you) { - jmp_buf my_buf, **me_ptr = me, *next_buf = next; - - *me_ptr = &my_buf; - if(UML_SETJMP(&my_buf) == 0) - UML_LONGJMP(next_buf, 1); + if(UML_SETJMP(me) == 0) + UML_LONGJMP(you, 1); } static jmp_buf initial_jmpbuf; @@ -503,23 +469,21 @@ static void (*cb_proc)(void *arg); static void *cb_arg; static jmp_buf *cb_back; -int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) +int start_idle_thread(void *stack, jmp_buf *switch_buf) { - jmp_buf **switch_buf = switch_buf_ptr; int n; set_handler(SIGWINCH, (__sighandler_t) sig_handler, SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, SIGVTALRM, -1); - *fork_buf_ptr = &initial_jmpbuf; n = UML_SETJMP(&initial_jmpbuf); switch(n){ case INIT_JMP_NEW_THREAD: - new_thread_proc((void *) stack, new_thread_handler); - break; - case INIT_JMP_REMOVE_SIGSTACK: - remove_sigstack(); + (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler; + (*switch_buf)[0].JB_SP = (unsigned long) stack + + (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - + sizeof(void *); break; case INIT_JMP_CALLBACK: (*cb_proc)(cb_arg); @@ -534,7 +498,7 @@ int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) default: panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); } - UML_LONGJMP(*switch_buf, 1); + UML_LONGJMP(switch_buf, 1); } void initial_thread_cb_skas(void (*proc)(void *), void *arg) diff --git a/include/asm-um/processor-generic.h b/include/asm-um/processor-generic.h index afa4fe1ca9f1..d99bbddffdb9 100644 --- a/include/asm-um/processor-generic.h +++ b/include/asm-um/processor-generic.h @@ -13,6 +13,7 @@ struct task_struct; #include "asm/ptrace.h" #include "choose-mode.h" #include "registers.h" +#include "sysdep/archsetjmp.h" struct mm_struct; @@ -43,8 +44,7 @@ struct thread_struct { #endif #ifdef CONFIG_MODE_SKAS struct { - void *switch_buf; - void *fork_buf; + jmp_buf switch_buf; int mm_count; } skas; #endif @@ -138,7 +138,7 @@ extern struct cpuinfo_um cpu_data[]; #ifdef CONFIG_MODE_SKAS #define KSTK_REG(tsk, reg) \ - get_thread_reg(reg, tsk->thread.mode.skas.switch_buf) + get_thread_reg(reg, &tsk->thread.mode.skas.switch_buf) #else #define KSTK_REG(tsk, reg) (0xbadbabe) #endif -- cgit