diff options
| -rw-r--r-- | arch/um/include/longjmp.h | 19 | ||||
| -rw-r--r-- | arch/um/os-Linux/main.c | 12 | ||||
| -rw-r--r-- | arch/um/os-Linux/process.c | 30 | ||||
| -rw-r--r-- | arch/um/os-Linux/signal.c | 203 | ||||
| -rw-r--r-- | arch/um/os-Linux/skas/process.c | 29 | ||||
| -rw-r--r-- | arch/um/os-Linux/trap.c | 3 | ||||
| -rw-r--r-- | arch/um/os-Linux/uaccess.c | 4 | ||||
| -rw-r--r-- | arch/um/os-Linux/util.c | 1 |
8 files changed, 183 insertions, 118 deletions
diff --git a/arch/um/include/longjmp.h b/arch/um/include/longjmp.h new file mode 100644 index 0000000..50f5df1 --- /dev/null +++ b/arch/um/include/longjmp.h @@ -0,0 +1,19 @@ +#ifndef __UML_LONGJMP_H +#define __UML_LONGJMP_H + +#include <setjmp.h> +#include "os.h" + +#define UML_SIGLONGJMP(buf, val) do { \ + siglongjmp(*buf, val); \ +} while(0) + +#define UML_SIGSETJMP(buf, enable) ({ \ + int n; \ + enable = get_signals(); \ + n = sigsetjmp(*buf, 1); \ + if(n != 0) \ + set_signals(enable); \ + n; }) + +#endif diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c index 98becd1..2878e89 100644 --- a/arch/um/os-Linux/main.c +++ b/arch/um/os-Linux/main.c @@ -81,20 +81,8 @@ extern void scan_elf_aux( char **envp); int main(int argc, char **argv, char **envp) { char **new_argv; - sigset_t mask; int ret, i, err; - /* Enable all signals except SIGIO - in some environments, we can - * enter with some signals blocked - */ - - sigemptyset(&mask); - sigaddset(&mask, SIGIO); - if(sigprocmask(SIG_SETMASK, &mask, NULL) < 0){ - perror("sigprocmask"); - exit(1); - } - #ifdef UML_CONFIG_CMDLINE_ON_HOST /* Allocate memory for thread command lines */ if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){ diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index 39815c6..7f5e2da 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -18,6 +18,7 @@ #include "process.h" #include "irq_user.h" #include "kern_util.h" +#include "longjmp.h" #define ARBITRARY_ADDR -1 #define FAILURE_PID -1 @@ -205,24 +206,13 @@ void init_new_thread_signals(int altstack) int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr) { - sigjmp_buf buf; - int n; - - *jmp_ptr = &buf; - n = sigsetjmp(buf, 1); - if(n != 0) - return(n); - (*fn)(arg); - return(0); + sigjmp_buf buf; + int n, enable; + + *jmp_ptr = &buf; + n = UML_SIGSETJMP(&buf, enable); + if(n != 0) + return(n); + (*fn)(arg); + return(0); } - -/* - * 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/signal.c b/arch/um/os-Linux/signal.c index 56ca959..f11b312 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -20,23 +20,58 @@ #include "mode.h" #include "os.h" +/* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled + * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to + * be able to profile all of UML, not just the non-critical sections. If + * profiling is not thread-safe, then that is not my problem. We can disable + * profiling when SMP is enabled in that case. + */ +#define SIGIO_BIT 0 +#define SIGIO_MASK (1 << SIGIO_BIT) + +#define SIGVTALRM_BIT 1 +#define SIGVTALRM_MASK (1 << SIGVTALRM_BIT) + +#define SIGALRM_BIT 2 +#define SIGALRM_MASK (1 << SIGALRM_BIT) + +static int signals_enabled = 1; +static int pending = 0; + void sig_handler(ARCH_SIGHDLR_PARAM) { 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; + return; + } + + block_signals(); + CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas, sig, sc); + + set_signals(enabled); } extern int timer_irq_inited; -void alarm_handler(ARCH_SIGHDLR_PARAM) +static void real_alarm_handler(int sig, struct sigcontext *sc) { - struct sigcontext *sc; - - ARCH_GET_SIGCONTEXT(sc, sig); - if(!timer_irq_inited) return; + if(!timer_irq_inited){ + signals_enabled = 1; + return; + } if(sig == SIGALRM) switch_timers(0); @@ -46,6 +81,29 @@ void alarm_handler(ARCH_SIGHDLR_PARAM) if(sig == SIGALRM) switch_timers(1); + +} + +void alarm_handler(ARCH_SIGHDLR_PARAM) +{ + struct sigcontext *sc; + int enabled; + + ARCH_GET_SIGCONTEXT(sc, sig); + + enabled = signals_enabled; + if(!signals_enabled){ + if(sig == SIGVTALRM) + pending |= SIGVTALRM_MASK; + else pending |= SIGALRM_MASK; + + return; + } + + block_signals(); + + real_alarm_handler(sig, sc); + set_signals(enabled); } extern void do_boot_timer_handler(struct sigcontext * sc); @@ -53,10 +111,22 @@ extern void do_boot_timer_handler(struct sigcontext * sc); void boot_timer_handler(ARCH_SIGHDLR_PARAM) { struct sigcontext *sc; + int enabled; ARCH_GET_SIGCONTEXT(sc, sig); + enabled = signals_enabled; + if(!enabled){ + if(sig == SIGVTALRM) + pending |= SIGVTALRM_MASK; + else pending |= SIGALRM_MASK; + return; + } + + block_signals(); + do_boot_timer_handler(sc); + set_signals(enabled); } void set_sigstack(void *sig_stack, int size) @@ -83,6 +153,7 @@ void set_handler(int sig, void (*handler)(int), int flags, ...) { struct sigaction action; va_list ap; + sigset_t sig_mask; int mask; va_start(ap, flags); @@ -95,7 +166,12 @@ void set_handler(int sig, void (*handler)(int), int flags, ...) action.sa_flags = flags; action.sa_restorer = NULL; if(sigaction(sig, &action, NULL) < 0) - panic("sigaction failed"); + panic("sigaction failed - errno = %d\n", errno); + + sigemptyset(&sig_mask); + sigaddset(&sig_mask, sig); + if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0) + panic("sigprocmask failed - errno = %d\n", errno); } int change_sig(int signal, int on) @@ -108,91 +184,74 @@ int change_sig(int signal, int on) return(!sigismember(&old, signal)); } -/* Both here and in set/get_signal we don't touch SIGPROF, because we must not - * disable profiling; it's safe because the profiling code does not interact - * with the kernel code at all.*/ - -static void change_signals(int type) -{ - sigset_t mask; - - sigemptyset(&mask); - sigaddset(&mask, SIGVTALRM); - sigaddset(&mask, SIGALRM); - sigaddset(&mask, SIGIO); - if(sigprocmask(type, &mask, NULL) < 0) - panic("Failed to change signal mask - errno = %d", errno); -} - void block_signals(void) { - change_signals(SIG_BLOCK); + signals_enabled = 0; } void unblock_signals(void) { - change_signals(SIG_UNBLOCK); -} + int save_pending; -/* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled - * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to - * be able to profile all of UML, not just the non-critical sections. If - * profiling is not thread-safe, then that is not my problem. We can disable - * profiling when SMP is enabled in that case. - */ -#define SIGIO_BIT 0 -#define SIGVTALRM_BIT 1 - -static int enable_mask(sigset_t *mask) -{ - int sigs; + if(signals_enabled == 1) + return; - sigs = sigismember(mask, SIGIO) ? 0 : 1 << SIGIO_BIT; - sigs |= sigismember(mask, SIGVTALRM) ? 0 : 1 << SIGVTALRM_BIT; - sigs |= sigismember(mask, SIGALRM) ? 0 : 1 << SIGVTALRM_BIT; - return(sigs); + /* We loop because the IRQ handler returns with interrupts off. So, + * interrupts may have arrived and we need to re-enable them and + * recheck pending. + */ + while(1){ + /* Save and reset save_pending after enabling signals. This + * way, pending won't be changed while we're reading it. + */ + signals_enabled = 1; + + save_pending = pending; + if(save_pending == 0) + return; + + pending = 0; + + /* We have pending interrupts, so disable signals, as the + * handlers expect them off when they are called. They will + * be enabled again above. + */ + + signals_enabled = 0; + + /* Deal with SIGIO first because the alarm handler might + * schedule, leaving the pending SIGIO stranded until we come + * back here. + */ + if(save_pending & SIGIO_MASK) + CHOOSE_MODE_PROC(sig_handler_common_tt, + sig_handler_common_skas, SIGIO, NULL); + + if(save_pending & SIGALRM_MASK) + real_alarm_handler(SIGALRM, NULL); + + if(save_pending & SIGVTALRM_MASK) + real_alarm_handler(SIGVTALRM, NULL); + } } int get_signals(void) { - sigset_t mask; - - if(sigprocmask(SIG_SETMASK, NULL, &mask) < 0) - panic("Failed to get signal mask"); - return(enable_mask(&mask)); + return signals_enabled; } int set_signals(int enable) { - sigset_t mask; int ret; + if(signals_enabled == enable) + return enable; - sigemptyset(&mask); - if(enable & (1 << SIGIO_BIT)) - sigaddset(&mask, SIGIO); - if(enable & (1 << SIGVTALRM_BIT)){ - sigaddset(&mask, SIGVTALRM); - sigaddset(&mask, SIGALRM); - } - - /* This is safe - sigprocmask is guaranteed to copy locally the - * value of new_set, do his work and then, at the end, write to - * old_set. - */ - if(sigprocmask(SIG_UNBLOCK, &mask, &mask) < 0) - panic("Failed to enable signals"); - ret = enable_mask(&mask); - sigemptyset(&mask); - if((enable & (1 << SIGIO_BIT)) == 0) - sigaddset(&mask, SIGIO); - if((enable & (1 << SIGVTALRM_BIT)) == 0){ - sigaddset(&mask, SIGVTALRM); - sigaddset(&mask, SIGALRM); - } - if(sigprocmask(SIG_BLOCK, &mask, NULL) < 0) - panic("Failed to block signals"); + ret = signals_enabled; + if(enable) + unblock_signals(); + else block_signals(); - return(ret); + return ret; } void os_usr1_signal(int on) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index b959b26..120a21c 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -34,6 +34,7 @@ #include "mem.h" #include "uml-config.h" #include "process.h" +#include "longjmp.h" int is_skas_winch(int pid, int fd, void *data) { @@ -433,6 +434,7 @@ void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, { unsigned long flags; sigjmp_buf switch_buf, fork_buf; + int enable; *switch_buf_ptr = &switch_buf; *fork_buf_ptr = &fork_buf; @@ -447,7 +449,7 @@ void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, */ flags = get_signals(); block_signals(); - if(sigsetjmp(fork_buf, 1) == 0) + if(UML_SIGSETJMP(&fork_buf, enable) == 0) new_thread_proc(stack, handler); remove_sigstack(); @@ -458,20 +460,22 @@ void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, void thread_wait(void *sw, void *fb) { sigjmp_buf buf, **switch_buf = sw, *fork_buf; + int enable; *switch_buf = &buf; fork_buf = fb; - if(sigsetjmp(buf, 1) == 0) + if(UML_SIGSETJMP(&buf, enable) == 0) siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); } void switch_threads(void *me, void *next) { sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; + int enable; *me_ptr = &my_buf; - if(sigsetjmp(my_buf, 1) == 0) - siglongjmp(*next_buf, 1); + if(UML_SIGSETJMP(&my_buf, enable) == 0) + UML_SIGLONGJMP(next_buf, 1); } static sigjmp_buf initial_jmpbuf; @@ -484,14 +488,14 @@ static sigjmp_buf *cb_back; int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) { sigjmp_buf **switch_buf = switch_buf_ptr; - int n; + int n, enable; set_handler(SIGWINCH, (__sighandler_t) sig_handler, SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, SIGVTALRM, -1); *fork_buf_ptr = &initial_jmpbuf; - n = sigsetjmp(initial_jmpbuf, 1); + n = UML_SIGSETJMP(&initial_jmpbuf, enable); switch(n){ case INIT_JMP_NEW_THREAD: new_thread_proc((void *) stack, new_thread_handler); @@ -501,7 +505,7 @@ int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) break; case INIT_JMP_CALLBACK: (*cb_proc)(cb_arg); - siglongjmp(*cb_back, 1); + UML_SIGLONGJMP(cb_back, 1); break; case INIT_JMP_HALT: kmalloc_ok = 0; @@ -512,20 +516,21 @@ 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); } - siglongjmp(**switch_buf, 1); + UML_SIGLONGJMP(*switch_buf, 1); } void initial_thread_cb_skas(void (*proc)(void *), void *arg) { sigjmp_buf here; + int enable; cb_proc = proc; cb_arg = arg; cb_back = &here; block_signals(); - if(sigsetjmp(here, 1) == 0) - siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK); + if(UML_SIGSETJMP(&here, enable) == 0) + UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK); unblock_signals(); cb_proc = NULL; @@ -536,13 +541,13 @@ void initial_thread_cb_skas(void (*proc)(void *), void *arg) void halt_skas(void) { block_signals(); - siglongjmp(initial_jmpbuf, INIT_JMP_HALT); + UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_HALT); } void reboot_skas(void) { block_signals(); - siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT); + UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT); } void switch_mm_skas(struct mm_id *mm_idp) diff --git a/arch/um/os-Linux/trap.c b/arch/um/os-Linux/trap.c index 321e1c8..a9f6b26 100644 --- a/arch/um/os-Linux/trap.c +++ b/arch/um/os-Linux/trap.c @@ -10,6 +10,7 @@ #include "user_util.h" #include "os.h" #include "mode.h" +#include "longjmp.h" void usr2_handler(int sig, union uml_pt_regs *regs) { @@ -36,5 +37,5 @@ void do_longjmp(void *b, int val) { sigjmp_buf *buf = b; - siglongjmp(*buf, val); + UML_SIGLONGJMP(buf, val); } diff --git a/arch/um/os-Linux/uaccess.c b/arch/um/os-Linux/uaccess.c index 38d7101..166fb66 100644 --- a/arch/um/os-Linux/uaccess.c +++ b/arch/um/os-Linux/uaccess.c @@ -6,6 +6,7 @@ #include <setjmp.h> #include <string.h> +#include "longjmp.h" unsigned long __do_user_copy(void *to, const void *from, int n, void **fault_addr, void **fault_catcher, @@ -13,10 +14,11 @@ unsigned long __do_user_copy(void *to, const void *from, int n, int n), int *faulted_out) { unsigned long *faddrp = (unsigned long *) fault_addr, ret; + int enable; sigjmp_buf jbuf; *fault_catcher = &jbuf; - if(sigsetjmp(jbuf, 1) == 0){ + if(UML_SIGSETJMP(&jbuf, enable) == 0){ (*op)(to, from, n); ret = 0; *faulted_out = 0; diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index d224434..e32065e 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -30,6 +30,7 @@ #include "ptrace_user.h" #include "uml-config.h" #include "os.h" +#include "longjmp.h" void stack_protections(unsigned long address) { |
