diff options
Diffstat (limited to 'accel/tcg/user-exec.c')
| -rw-r--r-- | accel/tcg/user-exec.c | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c index f42285ea1c..c973752562 100644 --- a/accel/tcg/user-exec.c +++ b/accel/tcg/user-exec.c @@ -57,12 +57,13 @@ static void cpu_exit_tb_from_sighandler(CPUState *cpu, sigset_t *old_set) the effective address of the memory exception. 'is_write' is 1 if a write caused the exception and otherwise 0'. 'old_set' is the signal set which should be restored */ -static inline int handle_cpu_signal(uintptr_t pc, unsigned long address, +static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info, int is_write, sigset_t *old_set) { CPUState *cpu = current_cpu; CPUClass *cc; int ret; + unsigned long address = (unsigned long)info->si_addr; /* We must handle PC addresses from two different sources: * a call return address and a signal frame address. @@ -103,7 +104,18 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address, pc, address, is_write, *(unsigned long *)old_set); #endif /* XXX: locking issue */ - if (is_write && h2g_valid(address)) { + /* Note that it is important that we don't call page_unprotect() unless + * this is really a "write to nonwriteable page" fault, because + * page_unprotect() assumes that if it is called for an access to + * a page that's writeable this means we had two threads racing and + * another thread got there first and already made the page writeable; + * so we will retry the access. If we were to call page_unprotect() + * for some other kind of fault that should really be passed to the + * guest, we'd end up in an infinite loop of retrying the faulting + * access. + */ + if (is_write && info->si_signo == SIGSEGV && info->si_code == SEGV_ACCERR && + h2g_valid(address)) { switch (page_unprotect(h2g(address), pc)) { case 0: /* Fault not caused by a page marked unwritable to protect @@ -215,9 +227,8 @@ int cpu_signal_handler(int host_signum, void *pinfo, #endif pc = EIP_sig(uc); trapno = TRAP_sig(uc); - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - trapno == 0xe ? - (ERROR_sig(uc) >> 1) & 1 : 0, + return handle_cpu_signal(pc, info, + trapno == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0, &MASK_sig(uc)); } @@ -261,9 +272,8 @@ int cpu_signal_handler(int host_signum, void *pinfo, #endif pc = PC_sig(uc); - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - TRAP_sig(uc) == 0xe ? - (ERROR_sig(uc) >> 1) & 1 : 0, + return handle_cpu_signal(pc, info, + TRAP_sig(uc) == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0, &MASK_sig(uc)); } @@ -341,8 +351,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, is_write = 1; } #endif - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #elif defined(__alpha__) @@ -372,8 +381,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, is_write = 1; } - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #elif defined(__sparc__) @@ -432,8 +440,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, break; } } - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, sigmask); + return handle_cpu_signal(pc, info, is_write, sigmask); } #elif defined(__arm__) @@ -466,9 +473,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, * later processor; on v5 we will always report this as a read). */ is_write = extract32(uc->uc_mcontext.error_code, 11, 1); - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, - &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #elif defined(__aarch64__) @@ -495,8 +500,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, void *puc) /* Ignore bits 23 & 24, controlling indexing. */ || (insn & 0x3a400000) == 0x28000000); /* C3.3.7,14-16 */ - return handle_cpu_signal(pc, (uintptr_t)info->si_addr, - is_write, &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #elif defined(__ia64) @@ -529,9 +533,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, void *puc) default: break; } - return handle_cpu_signal(ip, (unsigned long)info->si_addr, - is_write, - (sigset_t *)&uc->uc_sigmask); + return handle_cpu_signal(ip, info, is_write, (sigset_t *)&uc->uc_sigmask); } #elif defined(__s390__) @@ -583,8 +585,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, } break; } - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #elif defined(__mips__) @@ -599,8 +600,7 @@ int cpu_signal_handler(int host_signum, void *pinfo, /* XXX: compute is_write */ is_write = 0; - return handle_cpu_signal(pc, (unsigned long)info->si_addr, - is_write, &uc->uc_sigmask); + return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask); } #else |