From 473e1cb5e0edaedcbbde70b6db5b67efee755fec Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 1 Dec 2011 19:00:01 +0100 Subject: [PATCH] XXX work around SA_RESTART race with boehm-gc (ARM only) [AF: CPUState -> CPUArchState, adapt to reindentation] --- linux-user/main.c | 25 +++++++++----- linux-user/qemu.h | 3 ++ linux-user/signal.c | 22 ++++++++++++ linux-user/syscall.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 130 insertions(+), 10 deletions(-) diff --git a/linux-user/main.c b/linux-user/main.c index dd340b2..503ecfa 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -848,15 +848,22 @@ void cpu_loop(CPUARMState *env) break; } } else { - env->regs[0] = do_syscall(env, - n, - env->regs[0], - env->regs[1], - env->regs[2], - env->regs[3], - env->regs[4], - env->regs[5], - 0, 0); + TaskState *ts = ((CPUArchState*)env)->opaque; + target_ulong r; + r = do_syscall(env, n, env->regs[0], env->regs[1], + env->regs[2], env->regs[3], env->regs[4], + env->regs[5], 0, 0); + if ((r == -EINTR) && ts->signal_restart && + syscall_restartable(n)) { + if (env->thumb) { + env->regs[15] -= 2; + } else { + env->regs[15] -= 4; + } + } else { + env->regs[0] = r; + } + ts->signal_restart = 0; } } else { goto error; diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 7b299b7..dc12b23 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -137,6 +137,8 @@ typedef struct TaskState { struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */ struct sigqueue *first_free; /* first free siginfo queue entry */ int signal_pending; /* non zero if a signal may be pending */ + int signal_in_syscall; /* non zero if we are in do_syscall() */ + int signal_restart; /* non zero if we need to restart a syscall */ } __attribute__((aligned(16))) TaskState; extern char *exec_path; @@ -203,6 +205,7 @@ char *target_strerror(int err); int get_osversion(void); void fork_start(void); void fork_end(int child); +int syscall_restartable(int syscall_nr); /* Return true if the proposed guest_base is suitable for the guest. * The guest code may leave a page mapped and populate it if the diff --git a/linux-user/signal.c b/linux-user/signal.c index 0d6cb7b..c00cf75 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "qemu.h" #include "qemu-common.h" @@ -481,6 +482,11 @@ int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info) k->pending = 1; /* signal that a new signal is pending */ ts->signal_pending = 1; + /* check if we have to restart the current syscall */ + if ((sigact_table[sig - 1].sa_flags & SA_RESTART) && + ts->signal_in_syscall) { + ts->signal_restart = 1; + } return 1; /* indicates that the signal was queued */ } } @@ -621,8 +627,24 @@ int do_sigaction(int sig, const struct target_sigaction *act, if (host_sig != SIGSEGV && host_sig != SIGBUS) { sigfillset(&act1.sa_mask); act1.sa_flags = SA_SIGINFO; +#ifdef TARGET_ARM + /* Breaks boehm-gc, we have to do this manually */ + /* + * Unfortunately our hacks only work as long as we don't do parallel + * signal delivery and futexes, so let's do a dirty hack here to + * pin our guest process to a single host CPU if we're using the + * boehm-gc. + */ + if ((k->sa_flags & TARGET_SA_RESTART) && host_sig == SIGPWR) { + cpu_set_t mask; + CPU_ZERO(&mask); + CPU_SET(0, &mask); + sched_setaffinity(0, sizeof(mask), &mask); + } +#else if (k->sa_flags & TARGET_SA_RESTART) act1.sa_flags |= SA_RESTART; +#endif /* NOTE: it is important to update the host kernel signal ignore state to avoid getting unexpected interrupted syscalls */ diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 20d2a74..2a210e7 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -5031,6 +5031,87 @@ static int do_open(void *cpu_env, const char *pathname, int flags, mode_t mode) return get_errno(open(path(pathname), flags, mode)); } +int syscall_restartable(int syscall_nr) +{ + switch (syscall_nr) { +#ifdef TARGET_NR_sigsuspend + case TARGET_NR_sigsuspend: +#endif +#ifdef TARGET_NR_pause + case TARGET_NR_pause: +#endif +#ifdef TARGET_NR_setsockopt + case TARGET_NR_setsockopt: +#endif +#ifdef TARGET_NR_accept + case TARGET_NR_accept: +#endif +#ifdef TARGET_NR_recv + case TARGET_NR_recv: +#endif +#ifdef TARGET_NR_recvfrom + case TARGET_NR_recvfrom: +#endif +#ifdef TARGET_NR_recvmsg + case TARGET_NR_recvmsg: +#endif +#ifdef TARGET_NR_socketcall + case TARGET_NR_socketcall: +#endif +#ifdef TARGET_NR_connect + case TARGET_NR_connect: +#endif +#ifdef TARGET_NR_send + case TARGET_NR_send: +#endif +#ifdef TARGET_NR_sendmsg + case TARGET_NR_sendmsg: +#endif +#ifdef TARGET_NR_sendto + case TARGET_NR_sendto: +#endif +#ifdef TARGET_NR_poll + case TARGET_NR_poll: +#endif +#ifdef TARGET_NR_ppoll + case TARGET_NR_ppoll: +#endif +#if defined(TARGET_NR_select) + case TARGET_NR_select: +#endif +#ifdef TARGET_NR_pselect6 + case TARGET_NR_pselect6: +#endif +#ifdef TARGET_NR__newselect + case TARGET_NR__newselect: +#endif +#ifdef TARGET_NR_msgrcv + case TARGET_NR_msgrcv: +#endif +#ifdef TARGET_NR_msgsnd + case TARGET_NR_msgsnd: +#endif +#ifdef TARGET_NR_semop + case TARGET_NR_semop: +#endif +#ifdef TARGET_NR_ipc + case TARGET_NR_ipc: +#endif +#ifdef TARGET_NR_clock_nanosleep + case TARGET_NR_clock_nanosleep: +#endif + case TARGET_NR_rt_sigsuspend: + case TARGET_NR_rt_sigtimedwait: + case TARGET_NR_nanosleep: + case TARGET_NR_close: + /* can not be restarted */ + return 0; + } + + /* every other syscall can be restarted */ + return 1; +} + /* do_syscall() should always have a single exit point at the end so that actions, such as logging of syscall results, can be performed. All errnos that do_syscall() returns must be -TARGET_. */ @@ -5043,6 +5124,12 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, struct stat st; struct statfs stfs; void *p; + TaskState *ts = ((CPUArchState*)cpu_env)->opaque; + + if (!ts->signal_restart) { + /* remember syscall info for restart */ + ts->signal_in_syscall = 1; + } #ifdef DEBUG gemu_log("syscall %d", num); @@ -7988,7 +8075,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, cmd = target_to_host_fcntl_cmd(arg2); if (cmd == -TARGET_EINVAL) { ret = cmd; - break; + goto fail; } switch(arg2) { @@ -8733,6 +8820,7 @@ fail: #endif if(do_strace) print_syscall_ret(num, ret); + ts->signal_in_syscall = 0; return ret; efault: ret = -TARGET_EFAULT;