better signal/exception support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@42 c046a42c-6fe2-441c-8c8c-71466251a162

better signal/exception support
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@42 c046a42c-6fe2-441c-8c8c-71466251a162
bellard
1 parent 66fb9763
Showing 15 changed files with 642 additions and 206 deletions
TODO
cpu-i386.h
exec-i386.c
exec-i386.h
linux-user/elfload.c
linux-user/ioctls.h
linux-user/main.c
linux-user/qemu.h
linux-user/signal.c
linux-user/syscall.c
linux-user/syscall_defs.h
op-i386.c
syscall-i386.h
tests/testsig.c
translate-i386.c
-- asynchronous signal interrupt / clear synchronous signal handling
-- add eflags restore in emulator
-- finish signal handing (fp87 state)
-- verify thread support (clone() and various locks)
 - optimize translated cache chaining (DLL PLT-like system)
+- more syscalls (in particular all 64 bit ones, IPCs, fix 64 bit issues)
+- finish signal handing (fp87 state, more siginfo conversions)
+- verify thread support (clone() and various locks)
 - vm86 syscall support
 - overrides/16bit for string ops
-- more syscalls (in particular all 64 bit ones)
 - make it self runnable (use same trick as ld.so : include its own relocator and libc)
 - improved 16 bit support 
 - fix FPU exceptions (in particular: gen_op_fpush not before mem load)
@@ -68,7 +68,7 @@
 #define EXCP11_ALGN	18
 #define EXCP12_MCHK	19
-#define EXCP_SIGNAL	256 /* async signal */
+#define EXCP_INTERRUPT 	256 /* async interruption */
 enum {
     CC_OP_DYNAMIC, /* must use dynamic code to get cc_op */
@@ -170,9 +170,10 @@ typedef struct CPUX86State {
     /* various CPU modes */
     int vm86;
-    /* exception handling */
+    /* exception/interrupt handling */
     jmp_buf jmp_env;
     int exception_index;
+    int interrupt_request;
 } CPUX86State;
 /* all CPU memory access use these macros */
@@ -383,11 +384,19 @@ int cpu_x86_inl(int addr);
 CPUX86State *cpu_x86_init(void);
 int cpu_x86_exec(CPUX86State *s);
+void cpu_x86_interrupt(CPUX86State *s);
 void cpu_x86_close(CPUX86State *s);
 /* needed to load some predefinied segment registers */
 void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector);
+/* you can call these signal handler from you SIGBUS and SIGSEGV
+   signal handlers to inform the virtual CPU of exceptions. non zero
+   is returned if the signal was handled by the virtual CPU.  */
+struct siginfo;
+int cpu_x86_signal_handler(int host_signum, struct siginfo *info, 
+                           void *puc);
+
 /* internal functions */
 #define GEN_FLAG_CODE32_SHIFT 0
@@ -21,6 +21,7 @@
 //#define DEBUG_EXEC
 #define DEBUG_FLUSH
+//#define DEBUG_SIGNAL
 /* main execution loop */
@@ -98,7 +99,41 @@ void cpu_unlock(void)
     global_cpu_lock = 0;
 }
-#ifdef DEBUG_EXEC
+/* exception support */
+/* NOTE: not static to force relocation generation by GCC */
+void raise_exception(int exception_index)
+{
+    /* NOTE: the register at this point must be saved by hand because
+       longjmp restore them */
+#ifdef reg_EAX
+    env->regs[R_EAX] = EAX;
+#endif
+#ifdef reg_ECX
+    env->regs[R_ECX] = ECX;
+#endif
+#ifdef reg_EDX
+    env->regs[R_EDX] = EDX;
+#endif
+#ifdef reg_EBX
+    env->regs[R_EBX] = EBX;
+#endif
+#ifdef reg_ESP
+    env->regs[R_ESP] = ESP;
+#endif
+#ifdef reg_EBP
+    env->regs[R_EBP] = EBP;
+#endif
+#ifdef reg_ESI
+    env->regs[R_ESI] = ESI;
+#endif
+#ifdef reg_EDI
+    env->regs[R_EDI] = EDI;
+#endif
+    env->exception_index = exception_index;
+    longjmp(env->jmp_env, 1);
+}
+
+#if defined(DEBUG_EXEC)
 static const char *cc_op_str[] = {
     "DYNAMIC",
     "EFLAGS",
@@ -132,15 +167,16 @@ static const char *cc_op_str[] = {
     "SARL",
 };
-static void cpu_x86_dump_state(void)
+static void cpu_x86_dump_state(FILE *f)
 {
     int eflags;
     eflags = cc_table[CC_OP].compute_all();
     eflags |= (DF & DIRECTION_FLAG);
-    fprintf(logfile, 
+    fprintf(f, 
             "EAX=%08x EBX=%08X ECX=%08x EDX=%08x\n"
             "ESI=%08x EDI=%08X EBP=%08x ESP=%08x\n"
-            "CCS=%08x CCD=%08x CCO=%-8s EFL=%c%c%c%c%c%c%c\n",
+            "CCS=%08x CCD=%08x CCO=%-8s EFL=%c%c%c%c%c%c%c\n"
+            "EIP=%08x\n",
             env->regs[R_EAX], env->regs[R_EBX], env->regs[R_ECX], env->regs[R_EDX], 
             env->regs[R_ESI], env->regs[R_EDI], env->regs[R_EBP], env->regs[R_ESP], 
             env->cc_src, env->cc_dst, cc_op_str[env->cc_op],
@@ -150,10 +186,10 @@ static void cpu_x86_dump_state(void)
             eflags & CC_Z ? 'Z' : '-',
             eflags & CC_A ? 'A' : '-',
             eflags & CC_P ? 'P' : '-',
-            eflags & CC_C ? 'C' : '-'
-            );
+            eflags & CC_C ? 'C' : '-',
+            env->eip);
 #if 1
-    fprintf(logfile, "ST0=%f ST1=%f ST2=%f ST3=%f\n", 
+    fprintf(f, "ST0=%f ST1=%f ST2=%f ST3=%f\n", 
             (double)ST0, (double)ST1, (double)ST(2), (double)ST(3));
 #endif
 }
@@ -185,10 +221,11 @@ static void tb_flush(void)
 }
 /* find a translation block in the translation cache. If not found,
-   allocate a new one */
-static inline TranslationBlock *tb_find_and_alloc(unsigned long pc, 
-                                                  unsigned long cs_base,
-                                                  unsigned int flags)
+   return NULL and the pointer to the last element of the list in pptb */
+static inline TranslationBlock *tb_find(TranslationBlock ***pptb,
+                                        unsigned long pc, 
+                                        unsigned long cs_base,
+                                        unsigned int flags)
 {
     TranslationBlock **ptb, *tb;
     unsigned int h;
@@ -203,16 +240,19 @@ static inline TranslationBlock *tb_find_and_alloc(unsigned long pc,
             return tb;
         ptb = &tb->hash_next;
     }
+    *pptb = ptb;
+    return NULL;
+}
+
+/* allocate a new translation block. flush the translation buffer if
+   too many translation blocks or too much generated code */
+static inline TranslationBlock *tb_alloc(void)
+{
+    TranslationBlock *tb;
     if (nb_tbs >= CODE_GEN_MAX_BLOCKS || 
         (code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE)
         tb_flush();
     tb = &tbs[nb_tbs++];
-    *ptb = tb;
-    tb->pc = pc;
-    tb->cs_base = cs_base;
-    tb->flags = flags;
-    tb->tc_ptr = NULL;
-    tb->hash_next = NULL;
     return tb;
 }
@@ -246,7 +286,7 @@ int cpu_x86_exec(CPUX86State *env1)
 #endif
     int code_gen_size, ret;
     void (*gen_func)(void);
-    TranslationBlock *tb;
+    TranslationBlock *tb, **ptb;
     uint8_t *tc_ptr, *cs_base, *pc;
     unsigned int flags;
@@ -289,12 +329,21 @@ int cpu_x86_exec(CPUX86State *env1)
     EDI = env->regs[R_EDI];
 #endif
+    /* put eflags in CPU temporary format */
+    T0 = env->eflags;
+    op_movl_eflags_T0();
+    CC_OP = CC_OP_EFLAGS;
+    env->interrupt_request = 0;
+    
     /* prepare setjmp context for exception handling */
     if (setjmp(env->jmp_env) == 0) {
         for(;;) {
+            if (env->interrupt_request) {
+                raise_exception(EXCP_INTERRUPT);
+            }
 #ifdef DEBUG_EXEC
             if (loglevel) {
-                cpu_x86_dump_state();
+                cpu_x86_dump_state(logfile);
             }
 #endif
             /* we compute the CPU state. We assume it will not
@@ -307,28 +356,43 @@ int cpu_x86_exec(CPUX86State *env1)
                 GEN_FLAG_ADDSEG_SHIFT;
             cs_base = env->seg_cache[R_CS].base;
             pc = cs_base + env->eip;
-            tb = tb_find_and_alloc((unsigned long)pc, (unsigned long)cs_base, 
-                                   flags);
-            tc_ptr = tb->tc_ptr;
-            if (!tb->tc_ptr) {
+            tb = tb_find(&ptb, (unsigned long)pc, (unsigned long)cs_base, 
+                         flags);
+            if (!tb) {
                 /* if no translated code available, then translate it now */
                 /* XXX: very inefficient: we lock all the cpus when
                    generating code */
                 cpu_lock();
                 tc_ptr = code_gen_ptr;
-                cpu_x86_gen_code(code_gen_ptr, CODE_GEN_MAX_SIZE, 
-                                 &code_gen_size, pc, cs_base, flags);
+                ret = cpu_x86_gen_code(code_gen_ptr, CODE_GEN_MAX_SIZE, 
+                                       &code_gen_size, pc, cs_base, flags);
+                /* if invalid instruction, signal it */
+                if (ret != 0) {
+                    cpu_unlock();
+                    raise_exception(EXCP06_ILLOP);
+                }
+                tb = tb_alloc();
+                *ptb = tb;
+                tb->pc = (unsigned long)pc;
+                tb->cs_base = (unsigned long)cs_base;
+                tb->flags = flags;
                 tb->tc_ptr = tc_ptr;
+                tb->hash_next = NULL;
                 code_gen_ptr = (void *)(((unsigned long)code_gen_ptr + code_gen_size + CODE_GEN_ALIGN - 1) & ~(CODE_GEN_ALIGN - 1));
                 cpu_unlock();
             }
             /* execute the generated code */
+            tc_ptr = tb->tc_ptr;
             gen_func = (void *)tc_ptr;
             gen_func();
         }
     }
     ret = env->exception_index;
+    /* restore flags in standard format */
+    op_movl_T0_eflags();
+    env->eflags = T0;
+
     /* restore global registers */
 #ifdef reg_EAX
     EAX = saved_EAX;
@@ -361,6 +425,12 @@ int cpu_x86_exec(CPUX86State *env1)
     return ret;
 }
+void cpu_x86_interrupt(CPUX86State *s)
+{
+    s->interrupt_request = 1;
+}
+
+
 void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector)
 {
     CPUX86State *saved_env;
@@ -370,3 +440,56 @@ void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector)
     load_seg(seg_reg, selector);
     env = saved_env;
 }
+
+#undef EAX
+#undef ECX
+#undef EDX
+#undef EBX
+#undef ESP
+#undef EBP
+#undef ESI
+#undef EDI
+#undef EIP
+#include <signal.h>
+#include <sys/ucontext.h>
+
+static inline int handle_cpu_signal(unsigned long pc,
+                                    sigset_t *old_set)
+{
+#ifdef DEBUG_SIGNAL
+    printf("gemu: SIGSEGV pc=0x%08lx oldset=0x%08lx\n", 
+           pc, *(unsigned long *)old_set);
+#endif
+    if (pc >= (unsigned long)code_gen_buffer &&
+        pc < (unsigned long)code_gen_buffer + CODE_GEN_BUFFER_SIZE) {
+        /* the PC is inside the translated code. It means that we have
+           a virtual CPU fault */
+        /* we restore the process signal mask as the sigreturn should
+           do it */
+        sigprocmask(SIG_SETMASK, old_set, NULL);
+        /* XXX: need to compute virtual pc position by retranslating
+           code. The rest of the CPU state should be correct. */
+        raise_exception(EXCP0D_GPF);
+        /* never comes here */
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+int cpu_x86_signal_handler(int host_signum, struct siginfo *info, 
+                           void *puc)
+{
+#if defined(__i386__)
+    struct ucontext *uc = puc;
+    unsigned long pc;
+    sigset_t *pold_set;
+    
+    pc = uc->uc_mcontext.gregs[EIP];
+    pold_set = &uc->uc_sigmask;
+    return handle_cpu_signal(pc, pold_set);
+#else
+#warning No CPU specific signal handler: cannot handle target SIGSEGV events
+    return 0;
+#endif
+}
@@ -141,3 +141,7 @@ extern CCTable cc_table[];
 void load_seg(int seg_reg, int selector);
 void cpu_lock(void);
 void cpu_unlock(void);
+void raise_exception(int exception_index);
+
+void OPPROTO op_movl_eflags_T0(void);
+void OPPROTO op_movl_T0_eflags(void);
@@ -261,6 +261,9 @@ unsigned long setup_arg_pages(unsigned long p, struct linux_binprm * bprm,
     /* Create enough stack to hold everything.  If we don't use
      * it for args, we'll use it for something else...
      */
+    /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
+       we allocate a bigger stack. Need a better solution, for example
+       by remapping the process stack directly at the right place */
     if(x86_stack_size >  MAX_ARG_PAGES*X86_PAGE_SIZE) {
         if((long)mmap4k((void *)(X86_STACK_TOP-x86_stack_size), x86_stack_size + X86_PAGE_SIZE,
     		     PROT_READ | PROT_WRITE,
      /* emulated ioctl list */
      IOCTL(TCGETS, IOC_R, MK_PTR(MK_STRUCT(STRUCT_termios)))
-     IOCTL(TCGETS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
+     IOCTL(TCSETS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
      IOCTL(TCSETSF, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
      IOCTL(TCSETSW, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
      IOCTL(TIOCGWINSZ, IOC_R, MK_PTR(MK_STRUCT(STRUCT_winsize)))
@@ -199,8 +199,12 @@
   IOCTL(SNDCTL_TMR_METRONOME, IOC_W, MK_PTR(TYPE_INT))
   IOCTL(SNDCTL_TMR_SELECT, IOC_W, MK_PTR(TYPE_INT))
   IOCTL(SNDCTL_TMR_SOURCE, IOC_RW, MK_PTR(TYPE_INT))
+#if 0
+     /* we invalidate these defines because they have a same number as
+        termios ioctls */
   IOCTL(SNDCTL_TMR_START, 0, TYPE_NULL)
   IOCTL(SNDCTL_TMR_STOP, 0, TYPE_NULL)
+#endif
   IOCTL(SNDCTL_TMR_TEMPO, IOC_RW, MK_PTR(TYPE_INT))
   IOCTL(SNDCTL_TMR_TIMEBASE, IOC_RW, MK_PTR(TYPE_INT))
@@ -33,7 +33,10 @@
 FILE *logfile = NULL;
 int loglevel;
-unsigned long x86_stack_size;
+/* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
+   we allocate a bigger stack. Need a better solution, for example
+   by remapping the process stack directly at the right place */
+unsigned long x86_stack_size = 512 * 1024;
 unsigned long stktop;
 void gemu_log(const char *fmt, ...)
@@ -102,10 +105,11 @@ uint64_t gdt_table[6];
 void cpu_loop(struct CPUX86State *env)
 {
+    int err;
+    uint8_t *pc;
+    target_siginfo_t info;
+    
     for(;;) {
-        int err;
-        uint8_t *pc;
-        
         err = cpu_x86_exec(env);
         pc = env->seg_cache[R_CS].base + env->eip;
         switch(err) {
@@ -122,12 +126,42 @@ void cpu_loop(struct CPUX86State *env)
                                               env->regs[R_EDI],
                                               env->regs[R_EBP]);
             } else {
-                goto trap_error;
+                /* XXX: more precise info */
+                info.si_signo = SIGSEGV;
+                info.si_errno = 0;
+                info.si_code = 0;
+                info._sifields._sigfault._addr = 0;
+                queue_signal(info.si_signo, &info);
             }
             break;
+        case EXCP00_DIVZ:
+            /* division by zero */
+            info.si_signo = SIGFPE;
+            info.si_errno = 0;
+            info.si_code = TARGET_FPE_INTDIV;
+            info._sifields._sigfault._addr = env->eip;
+            queue_signal(info.si_signo, &info);
+            break;
+        case EXCP04_INTO:
+        case EXCP05_BOUND:
+            info.si_signo = SIGSEGV;
+            info.si_errno = 0;
+            info.si_code = 0;
+            info._sifields._sigfault._addr = 0;
+            queue_signal(info.si_signo, &info);
+            break;
+        case EXCP06_ILLOP:
+            info.si_signo = SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_ILLOPN;
+            info._sifields._sigfault._addr = env->eip;
+            queue_signal(info.si_signo, &info);
+            break;
+        case EXCP_INTERRUPT:
+            /* just indicate that signals should be handled asap */
+            break;
         default:
-        trap_error:
-            fprintf(stderr, "0x%08lx: Unknown exception %d, aborting\n", 
+            fprintf(stderr, "0x%08lx: Unknown exception CPU %d, aborting\n", 
                     (long)pc, err);
             abort();
         }
@@ -144,6 +178,9 @@ void usage(void)
     exit(1);
 }
+/* XXX: currently only used for async signals (see signal.c) */
+CPUX86State *global_env;
+
 int main(int argc, char **argv)
 {
     const char *filename;
@@ -199,6 +236,7 @@ int main(int argc, char **argv)
     signal_init();
     env = cpu_x86_init();
+    global_env = env;
     /* linux register setup */
     env->regs[R_EAX] = regs->eax;
@@ -3,30 +3,12 @@
 #include "thunk.h"
-#ifdef TARGET_I386
-
-/* default linux values for the selectors */
-#define __USER_CS	(0x23)
-#define __USER_DS	(0x2B)
-
-struct target_pt_regs {
-	long ebx;
-	long ecx;
-	long edx;
-	long esi;
-	long edi;
-	long ebp;
-	long eax;
-	int  xds;
-	int  xes;
-	long orig_eax;
-	long eip;
-	int  xcs;
-	long eflags;
-	long esp;
-	int  xss;
-};
+#include <signal.h>
+#include "syscall_defs.h"
+#ifdef TARGET_I386
+#include "cpu-i386.h"
+#include "syscall-i386.h"
 #endif
 /* This struct is used to hold certain information about the image.
@@ -59,9 +41,10 @@ void syscall_init(void);
 long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3, 
                 long arg4, long arg5, long arg6);
 void gemu_log(const char *fmt, ...) __attribute__((format(printf,1,2)));
-struct CPUX86State;
-void cpu_loop(struct CPUX86State *env);
+extern CPUX86State *global_env;
+void cpu_loop(CPUX86State *env);
 void process_pending_signals(void *cpu_env);
 void signal_init(void);
+int queue_signal(int sig, target_siginfo_t *info);
 #endif
@@ -27,13 +27,6 @@
 #include "gemu.h"
-#include "syscall_defs.h"
-
-#ifdef TARGET_I386
-#include "cpu-i386.h"
-#include "syscall-i386.h"
-#endif
-
 /* signal handling inspired from em86. */
 //#define DEBUG_SIGNAL
@@ -42,7 +35,7 @@
 struct sigqueue {
     struct sigqueue *next;
-    siginfo_t info;
+    target_siginfo_t info;
 };
 struct emulated_sigaction {
@@ -101,20 +94,66 @@ void target_to_host_old_sigset(sigset_t *sigset,
     *(unsigned long *)sigset = tswapl(*old_sigset);
 }
-/* XXX: finish it */
-void host_to_target_siginfo(target_siginfo_t *tinfo, siginfo_t *info)
+/* siginfo conversion */
+
+static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, 
+                                                 const siginfo_t *info)
 {
-    tinfo->si_signo = tswap32(info->si_signo);
+    int sig;
+    sig = host_to_target_signal(info->si_signo);
+    tinfo->si_signo = sig;
+    tinfo->si_errno = 0;
+    tinfo->si_code = 0;
+    if (sig == SIGILL || sig == SIGFPE || sig == SIGSEGV || sig == SIGBUS) {
+        /* should never come here, but who knows. The information for
+           the target is irrelevant */
+        tinfo->_sifields._sigfault._addr = 0;
+    } else if (sig >= TARGET_SIGRTMIN) {
+        tinfo->_sifields._rt._pid = info->si_pid;
+        tinfo->_sifields._rt._uid = info->si_uid;
+        /* XXX: potential problem if 64 bit */
+        tinfo->_sifields._rt._sigval.sival_ptr = 
+            (target_ulong)info->si_value.sival_ptr;
+    }
+}
+
+static void tswap_siginfo(target_siginfo_t *tinfo, 
+                          const target_siginfo_t *info)
+{
+    int sig;
+    sig = info->si_signo;
+    tinfo->si_signo = tswap32(sig);
     tinfo->si_errno = tswap32(info->si_errno);
     tinfo->si_code = tswap32(info->si_code);
+    if (sig == SIGILL || sig == SIGFPE || sig == SIGSEGV || sig == SIGBUS) {
+        tinfo->_sifields._sigfault._addr = 
+            tswapl(info->_sifields._sigfault._addr);
+    } else if (sig >= TARGET_SIGRTMIN) {
+        tinfo->_sifields._rt._pid = tswap32(info->_sifields._rt._pid);
+        tinfo->_sifields._rt._uid = tswap32(info->_sifields._rt._uid);
+        tinfo->_sifields._rt._sigval.sival_ptr = 
+            tswapl(info->_sifields._rt._sigval.sival_ptr);
+    }
+}
+
+
+void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
+{
+    host_to_target_siginfo_noswap(tinfo, info);
+    tswap_siginfo(tinfo, tinfo);
 }
-/* XXX: finish it */
-void target_to_host_siginfo(siginfo_t *info, target_siginfo_t *tinfo)
+/* XXX: we support only POSIX RT signals are used. */
+/* XXX: find a solution for 64 bit (additionnal malloced data is needed) */
+void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
 {
     info->si_signo = tswap32(tinfo->si_signo);
     info->si_errno = tswap32(tinfo->si_errno);
     info->si_code = tswap32(tinfo->si_code);
+    info->si_pid = tswap32(tinfo->_sifields._rt._pid);
+    info->si_uid = tswap32(tinfo->_sifields._rt._uid);
+    info->si_value.sival_ptr = 
+        (void *)tswapl(tinfo->_sifields._rt._sigval.sival_ptr);
 }
 void signal_init(void)
@@ -122,8 +161,9 @@ void signal_init(void)
     struct sigaction act;
     int i;
-    /* set all host signal handlers */
-    sigemptyset(&act.sa_mask);
+    /* set all host signal handlers. ALL signals are blocked during
+       the handlers to serialize them. */
+    sigfillset(&act.sa_mask);
     act.sa_flags = SA_SIGINFO;
     act.sa_sigaction = host_signal_handler;
     for(i = 1; i < NSIG; i++) {
@@ -155,56 +195,40 @@ static inline void free_sigqueue(struct sigqueue *q)
     first_free = q;
 }
-static int queue_signal(struct emulated_sigaction *k, int sig, siginfo_t *info)
-{
-    struct sigqueue *q, **pq;
-
-    pq = &k->first;
-    if (!k->pending || sig < TARGET_SIGRTMIN) {
-        /* first signal or non real time signal */
-        q = &k->info;
-    } else {
-        q = alloc_sigqueue();
-        if (!q)
-            return -EAGAIN;
-        while (*pq != NULL)
-            pq = &(*pq)->next;
-    }
-    *pq = q;
-    q->info = *info;
-    q->next = NULL;
-    k->pending = 1;
-    /* signal that a new signal is pending */
-    signal_pending = 1;
-    return 0;
-}
-
-void force_sig(int sig)
+/* abort execution with signal */
+void __attribute((noreturn)) force_sig(int sig)
 {
     int host_sig;
-    /* abort execution with signal */
     host_sig = target_to_host_signal(sig);
     fprintf(stderr, "gemu: uncaught target signal %d (%s) - exiting\n", 
             sig, strsignal(host_sig));
+#if 1
     _exit(-host_sig);
+#else
+    {
+        struct sigaction act;
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_SIGINFO;
+        act.sa_sigaction = SIG_DFL;
+        sigaction(SIGABRT, &act, NULL);
+        abort();
+    }
+#endif
 }
-
-static void host_signal_handler(int host_signum, siginfo_t *info, 
-                                void *puc)
+/* queue a signal so that it will be send to the virtual CPU as soon
+   as possible */
+int queue_signal(int sig, target_siginfo_t *info)
 {
     struct emulated_sigaction *k;
-    int sig;
+    struct sigqueue *q, **pq;
     target_ulong handler;
-    /* get target signal number */
-    sig = host_to_target_signal(host_signum);
-    if (sig < 1 || sig > TARGET_NSIG)
-        return;
-    k = &sigact_table[sig - 1];
-#ifdef DEBUG_SIGNAL
-    fprintf(stderr, "gemu: got signal %d\n", sig);
+#if defined(DEBUG_SIGNAL)
+    fprintf(stderr, "queue_sigal: sig=%d\n", 
+            sig);
 #endif
+    k = &sigact_table[sig - 1];
     handler = k->sa._sa_handler;
     if (handler == TARGET_SIG_DFL) {
         /* default handler : ignore some signal. The other are fatal */
@@ -212,13 +236,96 @@ static void host_signal_handler(int host_signum, siginfo_t *info,
             sig != TARGET_SIGURG && 
             sig != TARGET_SIGWINCH) {
             force_sig(sig);
+        } else {
+            return 0; /* indicate ignored */
         }
     } else if (handler == TARGET_SIG_IGN) {
         /* ignore signal */
+        return 0;
     } else if (handler == TARGET_SIG_ERR) {
         force_sig(sig);
     } else {
-        queue_signal(k, sig, info);
+        pq = &k->first;
+        if (sig < TARGET_SIGRTMIN) {
+            /* if non real time signal, we queue exactly one signal */
+            if (!k->pending)
+                q = &k->info;
+            else
+                return 0;
+        } else {
+            if (!k->pending) {
+                /* first signal */
+                q = &k->info;
+            } else {
+                q = alloc_sigqueue();
+                if (!q)
+                    return -EAGAIN;
+                while (*pq != NULL)
+                    pq = &(*pq)->next;
+            }
+        }
+        *pq = q;
+        q->info = *info;
+        q->next = NULL;
+        k->pending = 1;
+        /* signal that a new signal is pending */
+        signal_pending = 1;
+        return 1; /* indicates that the signal was queued */
+    }
+}
+
+#if defined(DEBUG_SIGNAL)
+#ifdef __i386__
+static void dump_regs(struct ucontext *uc)
+{
+    fprintf(stderr, 
+            "EAX=%08x EBX=%08x ECX=%08x EDX=%08x\n"
+            "ESI=%08x EDI=%08x EBP=%08x ESP=%08x\n"
+            "EFL=%08x EIP=%08x\n",
+            uc->uc_mcontext.gregs[EAX],
+            uc->uc_mcontext.gregs[EBX],
+            uc->uc_mcontext.gregs[ECX],
+            uc->uc_mcontext.gregs[EDX],
+            uc->uc_mcontext.gregs[ESI],
+            uc->uc_mcontext.gregs[EDI],
+            uc->uc_mcontext.gregs[EBP],
+            uc->uc_mcontext.gregs[ESP],
+            uc->uc_mcontext.gregs[EFL],
+            uc->uc_mcontext.gregs[EIP]);
+}
+#else
+static void dump_regs(struct ucontext *uc)
+{
+}
+#endif
+
+#endif
+
+static void host_signal_handler(int host_signum, siginfo_t *info, 
+                                void *puc)
+{
+    int sig;
+    target_siginfo_t tinfo;
+
+    /* the CPU emulator uses some host signals to detect exceptions,
+       we we forward to it some signals */
+    if (host_signum == SIGSEGV || host_signum == SIGBUS) {
+        if (cpu_x86_signal_handler(host_signum, info, puc))
+            return;
+    }
+
+    /* get target signal number */
+    sig = host_to_target_signal(host_signum);
+    if (sig < 1 || sig > TARGET_NSIG)
+        return;
+#if defined(DEBUG_SIGNAL)
+    fprintf(stderr, "gemu: got signal %d\n", sig);
+    dump_regs(puc);
+#endif
+    host_to_target_siginfo_noswap(&tinfo, info);
+    if (queue_signal(sig, &tinfo) == 1) {
+        /* interrupt the virtual CPU as soon as possible */
+        cpu_x86_interrupt(global_env);
     }
 }
@@ -388,9 +495,10 @@ struct rt_sigframe
     0;\
 })
-static inline int copy_siginfo_to_user(target_siginfo_t *tinfo, siginfo_t *info)
+static inline int copy_siginfo_to_user(target_siginfo_t *tinfo, 
+                                       const target_siginfo_t *info)
 {
-    host_to_target_siginfo(tinfo, info);
+    tswap_siginfo(tinfo, info);
     return 0;
 }
@@ -531,7 +639,8 @@ give_sigsegv:
 	force_sig(TARGET_SIGSEGV /* , current */);
 }
-static void setup_rt_frame(int sig, struct emulated_sigaction *ka, siginfo_t *info,
+static void setup_rt_frame(int sig, struct emulated_sigaction *ka, 
+                           target_siginfo_t *info,
 			   target_sigset_t *set, CPUX86State *env)
 {
 	struct rt_sigframe *frame;
@@ -734,7 +843,8 @@ void process_pending_signals(void *cpu_env)
 {
     int sig;
     target_ulong handler;
-    target_sigset_t set;
+    sigset_t set, old_set;
+    target_sigset_t target_old_set;
     struct emulated_sigaction *k;
     struct sigqueue *q;
@@ -774,12 +884,24 @@ void process_pending_signals(void *cpu_env)
     } else if (handler == TARGET_SIG_ERR) {
         force_sig(sig);
     } else {
-        set = k->sa.sa_mask;
-        /* send the signal to the CPU */
+        /* compute the blocked signals during the handler execution */
+        target_to_host_sigset(&set, &k->sa.sa_mask);
+        /* SA_NODEFER indicates that the current signal should not be
+           blocked during the handler */
+        if (!(k->sa.sa_flags & TARGET_SA_NODEFER))
+            sigaddset(&set, target_to_host_signal(sig));
+        
+        /* block signals in the handler using Linux */
+        sigprocmask(SIG_BLOCK, &set, &old_set);
+        /* save the previous blocked signal state to restore it at the
+           end of the signal execution (see do_sigreturn) */
+        host_to_target_sigset(&target_old_set, &old_set);
+
+        /* prepare the stack frame of the virtual CPU */
         if (k->sa.sa_flags & TARGET_SA_SIGINFO)
-            setup_rt_frame(sig, k, &q->info, &set, cpu_env);
+            setup_rt_frame(sig, k, &q->info, &target_old_set, cpu_env);
         else
-            setup_frame(sig, k, &set, cpu_env);
+            setup_frame(sig, k, &target_old_set, cpu_env);
 	if (k->sa.sa_flags & TARGET_SA_RESETHAND)
             k->sa._sa_handler = TARGET_SIG_DFL;
     }
@@ -38,6 +38,7 @@
 #include <sched.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
+#include <sys/poll.h>
 //#include <sys/user.h>
 #define termios host_termios
@@ -68,15 +69,8 @@
 #define	VFAT_IOCTL_READDIR_BOTH		_IOR('r', 1, struct dirent [2])
 #define	VFAT_IOCTL_READDIR_SHORT	_IOR('r', 2, struct dirent [2])
-#include "syscall_defs.h"
-
-#ifdef TARGET_I386
-#include "cpu-i386.h"
-#include "syscall-i386.h"
-#endif
-
-void host_to_target_siginfo(target_siginfo_t *tinfo, siginfo_t *info);
-void target_to_host_siginfo(siginfo_t *info, target_siginfo_t *tinfo);
+void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info);
+void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo);
 long do_sigreturn(CPUX86State *env);
 long do_rt_sigreturn(CPUX86State *env);
@@ -106,6 +100,9 @@ _syscall2(int,sys_fstatfs,int,fd,struct kernel_statfs *,buf)
 _syscall3(int,sys_rt_sigqueueinfo,int,pid,int,sig,siginfo_t *,uinfo)
 extern int personality(int);
+extern int flock(int, int);
+extern int setfsuid(int);
+extern int setfsgid(int);
 static inline long get_errno(long ret)
 {
@@ -437,7 +434,7 @@ static long do_ioctl(long fd, long cmd, long arg)
         ie++;
     }
     arg_type = ie->arg_type;
-#ifdef DEBUG
+#if defined(DEBUG)
     gemu_log("ioctl: cmd=0x%04lx (%s)\n", cmd, ie->name);
 #endif
     switch(arg_type[0]) {
@@ -1244,9 +1241,30 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
         ret = get_errno(sethostname((const char *)arg1, arg2));
         break;
     case TARGET_NR_setrlimit:
-        goto unimplemented;
+        {
+            /* XXX: convert resource ? */
+            int resource = arg1;
+            struct target_rlimit *target_rlim = (void *)arg2;
+            struct rlimit rlim;
+            rlim.rlim_cur = tswapl(target_rlim->rlim_cur);
+            rlim.rlim_max = tswapl(target_rlim->rlim_max);
+            ret = get_errno(setrlimit(resource, &rlim));
+        }
+        break;
     case TARGET_NR_getrlimit:
-        goto unimplemented;
+        {
+            /* XXX: convert resource ? */
+            int resource = arg1;
+            struct target_rlimit *target_rlim = (void *)arg2;
+            struct rlimit rlim;
+            
+            ret = get_errno(getrlimit(resource, &rlim));
+            if (!is_error(ret)) {
+                target_rlim->rlim_cur = tswapl(rlim.rlim_cur);
+                target_rlim->rlim_max = tswapl(rlim.rlim_max);
+            }
+        }
+        break;
     case TARGET_NR_getrusage:
         goto unimplemented;
     case TARGET_NR_gettimeofday:
@@ -1317,6 +1335,27 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
     case TARGET_NR_munmap:
         ret = get_errno(munmap((void *)arg1, arg2));
         break;
+    case TARGET_NR_mprotect:
+        ret = get_errno(mprotect((void *)arg1, arg2, arg3));
+        break;
+    case TARGET_NR_mremap:
+        ret = get_errno((long)mremap((void *)arg1, arg2, arg3, arg4));
+        break;
+    case TARGET_NR_msync:
+        ret = get_errno(msync((void *)arg1, arg2, arg3));
+        break;
+    case TARGET_NR_mlock:
+        ret = get_errno(mlock((void *)arg1, arg2));
+        break;
+    case TARGET_NR_munlock:
+        ret = get_errno(munlock((void *)arg1, arg2));
+        break;
+    case TARGET_NR_mlockall:
+        ret = get_errno(mlockall(arg1));
+        break;
+    case TARGET_NR_munlockall:
+        ret = get_errno(munlockall());
+        break;
     case TARGET_NR_truncate:
         ret = get_errno(truncate((const char *)arg1, arg2));
         break;
@@ -1506,9 +1545,6 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
 #endif
     case TARGET_NR_adjtimex:
         goto unimplemented;
-    case TARGET_NR_mprotect:
-        ret = get_errno(mprotect((void *)arg1, arg2, arg3));
-        break;
     case TARGET_NR_create_module:
     case TARGET_NR_init_module:
     case TARGET_NR_delete_module:
@@ -1532,9 +1568,11 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
     case TARGET_NR_afs_syscall:
         goto unimplemented;
     case TARGET_NR_setfsuid:
-        goto unimplemented;
+        ret = get_errno(setfsuid(arg1));
+        break;
     case TARGET_NR_setfsgid:
-        goto unimplemented;
+        ret = get_errno(setfsgid(arg1));
+        break;
     case TARGET_NR__llseek:
         {
             int64_t res;
@@ -1596,10 +1634,31 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
         ret = do_select(arg1, (void *)arg2, (void *)arg3, (void *)arg4, 
                         (void *)arg5);
         break;
+    case TARGET_NR_poll:
+        {
+            struct target_pollfd *target_pfd = (void *)arg1;
+            unsigned int nfds = arg2;
+            int timeout = arg3;
+            struct pollfd *pfd;
+            int i;
+
+            pfd = alloca(sizeof(struct pollfd) * nfds);
+            for(i = 0; i < nfds; i++) {
+                pfd->fd = tswap32(target_pfd->fd);
+                pfd->events = tswap16(target_pfd->events);
+            }
+            ret = get_errno(poll(pfd, nfds, timeout));
+            if (!is_error(ret)) {
+                for(i = 0; i < nfds; i++) {
+                    target_pfd->revents = tswap16(pfd->revents);
+                }
+            }
+        }
+        break;
     case TARGET_NR_flock:
-        goto unimplemented;
-    case TARGET_NR_msync:
-        ret = get_errno(msync((void *)arg1, arg2, arg3));
+        /* NOTE: the flock constant seems to be the same for every
+           Linux platform */
+        ret = get_errno(flock(arg1, arg2));
         break;
     case TARGET_NR_readv:
         {
@@ -1638,18 +1697,6 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
         goto unimplemented;
     case TARGET_NR__sysctl:
         goto unimplemented;
-    case TARGET_NR_mlock:
-        ret = get_errno(mlock((void *)arg1, arg2));
-        break;
-    case TARGET_NR_munlock:
-        ret = get_errno(munlock((void *)arg1, arg2));
-        break;
-    case TARGET_NR_mlockall:
-        ret = get_errno(mlockall(arg1));
-        break;
-    case TARGET_NR_munlockall:
-        ret = get_errno(munlockall());
-        break;
     case TARGET_NR_sched_setparam:
         goto unimplemented;
     case TARGET_NR_sched_getparam:
@@ -1681,12 +1728,10 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
         }
         break;
-    case TARGET_NR_mremap:
     case TARGET_NR_setresuid:
     case TARGET_NR_getresuid:
     case TARGET_NR_vm86:
     case TARGET_NR_query_module:
-    case TARGET_NR_poll:
     case TARGET_NR_nfsservctl:
     case TARGET_NR_setresgid:
     case TARGET_NR_getresgid:
@@ -1800,7 +1845,7 @@ long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3,
         goto unimplemented;
     default:
     unimplemented:
-        gemu_log("Unsupported syscall: %d\n", num);
+        gemu_log("gemu: Unsupported syscall: %d\n", num);
         ret = -ENOSYS;
         break;
     }
@@ -150,6 +150,17 @@ struct target_sigaction;
 int do_sigaction(int sig, const struct target_sigaction *act,
                  struct target_sigaction *oact);
+struct target_rlimit {
+        target_ulong   rlim_cur;
+        target_ulong   rlim_max;
+};
+
+struct target_pollfd {
+    int fd;           /* file descriptor */
+    short events;     /* requested events */
+    short revents;    /* returned events */
+};
+
 /* Networking ioctls */
 #define TARGET_SIOCADDRT       0x890B          /* add routing table entry */
 #define TARGET_SIOCDELRT       0x890C          /* delete routing table entry */
@@ -119,40 +119,6 @@ static inline int lshift(int x, int n)
         return x >> (-n);
 }
-/* exception support */
-/* NOTE: not static to force relocation generation by GCC */
-void raise_exception(int exception_index)
-{
-    /* NOTE: the register at this point must be saved by hand because
-       longjmp restore them */
-#ifdef reg_EAX
-    env->regs[R_EAX] = EAX;
-#endif
-#ifdef reg_ECX
-    env->regs[R_ECX] = ECX;
-#endif
-#ifdef reg_EDX
-    env->regs[R_EDX] = EDX;
-#endif
-#ifdef reg_EBX
-    env->regs[R_EBX] = EBX;
-#endif
-#ifdef reg_ESP
-    env->regs[R_ESP] = ESP;
-#endif
-#ifdef reg_EBP
-    env->regs[R_EBP] = EBP;
-#endif
-#ifdef reg_ESI
-    env->regs[R_ESI] = ESI;
-#endif
-#ifdef reg_EDI
-    env->regs[R_EDI] = EDI;
-#endif
-    env->exception_index = exception_index;
-    longjmp(env->jmp_env, 1);
-}
-
 /* we define the various pieces of code used by the JIT */
 #define REG EAX
@@ -391,13 +357,15 @@ void OPPROTO op_imull_T0_T1(void)
 }
 /* division, flags are undefined */
-/* XXX: add exceptions for overflow & div by zero */
+/* XXX: add exceptions for overflow */
 void OPPROTO op_divb_AL_T0(void)
 {
     unsigned int num, den, q, r;
     num = (EAX & 0xffff);
     den = (T0 & 0xff);
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den) & 0xff;
     r = (num % den) & 0xff;
     EAX = (EAX & 0xffff0000) | (r << 8) | q;
@@ -409,6 +377,8 @@ void OPPROTO op_idivb_AL_T0(void)
     num = (int16_t)EAX;
     den = (int8_t)T0;
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den) & 0xff;
     r = (num % den) & 0xff;
     EAX = (EAX & 0xffff0000) | (r << 8) | q;
@@ -420,6 +390,8 @@ void OPPROTO op_divw_AX_T0(void)
     num = (EAX & 0xffff) | ((EDX & 0xffff) << 16);
     den = (T0 & 0xffff);
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den) & 0xffff;
     r = (num % den) & 0xffff;
     EAX = (EAX & 0xffff0000) | q;
@@ -432,6 +404,8 @@ void OPPROTO op_idivw_AX_T0(void)
     num = (EAX & 0xffff) | ((EDX & 0xffff) << 16);
     den = (int16_t)T0;
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den) & 0xffff;
     r = (num % den) & 0xffff;
     EAX = (EAX & 0xffff0000) | q;
@@ -445,6 +419,8 @@ void OPPROTO op_divl_EAX_T0(void)
     num = EAX | ((uint64_t)EDX << 32);
     den = T0;
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den);
     r = (num % den);
     EAX = q;
@@ -458,6 +434,8 @@ void OPPROTO op_idivl_EAX_T0(void)
     num = EAX | ((uint64_t)EDX << 32);
     den = T0;
+    if (den == 0)
+        raise_exception(EXCP00_DIVZ);
     q = (num / den);
     r = (num % den);
     EAX = q;
@@ -359,7 +359,7 @@ struct target_sigaction {
 typedef union target_sigval {
 	int sival_int;
-	void *sival_ptr;
+        target_ulong sival_ptr;
 } target_sigval_t;
 #define TARGET_SI_MAX_SIZE	128
@@ -389,7 +389,7 @@ typedef struct target_siginfo {
 		struct {
 			pid_t _pid;		/* sender's pid */
 			uid_t _uid;		/* sender's uid */
-			sigval_t _sigval;
+			target_sigval_t _sigval;
 		} _rt;
 		/* SIGCHLD */
@@ -403,7 +403,7 @@ typedef struct target_siginfo {
 		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 		struct {
-			void *_addr; /* faulting insn/memory ref. */
+			target_ulong _addr; /* faulting insn/memory ref. */
 		} _sigfault;
 		/* SIGPOLL */
@@ -414,6 +414,46 @@ typedef struct target_siginfo {
 	} _sifields;
 } target_siginfo_t;
+/*
+ * SIGILL si_codes
+ */
+#define TARGET_ILL_ILLOPN	(2)	/* illegal operand */
+
+/*
+ * SIGFPE si_codes
+ */
+#define TARGET_FPE_INTDIV      (1)  /* integer divide by zero */
+#define TARGET_FPE_INTOVF      (2)  /* integer overflow */
+#define TARGET_FPE_FLTDIV      (3)  /* floating point divide by zero */
+#define TARGET_FPE_FLTOVF      (4)  /* floating point overflow */
+#define TARGET_FPE_FLTUND      (5)  /* floating point underflow */
+#define TARGET_FPE_FLTRES      (6)  /* floating point inexact result */
+#define TARGET_FPE_FLTINV      (7)  /* floating point invalid operation */
+#define TARGET_FPE_FLTSUB      (8)  /* subscript out of range */
+#define TARGET_NSIGFPE         8
+
+/* default linux values for the selectors */
+#define __USER_CS	(0x23)
+#define __USER_DS	(0x2B)
+
+struct target_pt_regs {
+	long ebx;
+	long ecx;
+	long edx;
+	long esi;
+	long edi;
+	long ebp;
+	long eax;
+	int  xds;
+	int  xes;
+	long orig_eax;
+	long eip;
+	int  xcs;
+	long eflags;
+	long esp;
+	int  xss;
+};
+
 /* ioctls */
 /*
+#define _GNU_SOURCE
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <signal.h>
 #include <unistd.h>
+#include <setjmp.h>
+#include <sys/ucontext.h>
+
+jmp_buf jmp_env;
 void alarm_handler(int sig)
 {
@@ -9,15 +15,82 @@ void alarm_handler(int sig)
     alarm(1);
 }
+void dump_regs(struct ucontext *uc)
+{
+    printf("EAX=%08x EBX=%08x ECX=%08x EDX=%08x\n"
+           "ESI=%08x EDI=%08x EBP=%08x ESP=%08x\n"
+           "EFL=%08x EIP=%08x\n",
+           uc->uc_mcontext.gregs[EAX],
+           uc->uc_mcontext.gregs[EBX],
+           uc->uc_mcontext.gregs[ECX],
+           uc->uc_mcontext.gregs[EDX],
+           uc->uc_mcontext.gregs[ESI],
+           uc->uc_mcontext.gregs[EDI],
+           uc->uc_mcontext.gregs[EBP],
+           uc->uc_mcontext.gregs[ESP],
+           uc->uc_mcontext.gregs[EFL],
+           uc->uc_mcontext.gregs[EIP]);
+}
+
+void sig_handler(int sig, siginfo_t *info, void *puc)
+{
+    struct ucontext *uc = puc;
+
+    printf("%s: si_signo=%d si_errno=%d si_code=%d si_addr=0x%08lx\n",
+           strsignal(info->si_signo),
+           info->si_signo, info->si_errno, info->si_code, 
+           (unsigned long)info->si_addr);
+    dump_regs(uc);
+    longjmp(jmp_env, 1);
+}
+
+int v1;
+
 int main(int argc, char **argv)
 {
     struct sigaction act;
+    int i;
+    
+    /* test division by zero reporting */
+    if (setjmp(jmp_env) == 0) {
+        act.sa_sigaction = sig_handler;
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_SIGINFO | SA_ONESHOT;
+        sigaction(SIGFPE, &act, NULL);
+        
+        /* now divide by zero */
+        v1 = 0;
+        v1 = 2 / v1;
+    }
+
+    /* test illegal instruction reporting */
+    if (setjmp(jmp_env) == 0) {
+        act.sa_sigaction = sig_handler;
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_SIGINFO | SA_ONESHOT;
+        sigaction(SIGILL, &act, NULL);
+        
+        /* now execute an invalid instruction */
+        asm volatile("ud2");
+    }
+    
+    /* test SEGV reporting */
+    if (setjmp(jmp_env) == 0) {
+        act.sa_sigaction = sig_handler;
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_SIGINFO | SA_ONESHOT;
+        sigaction(SIGSEGV, &act, NULL);
+        
+        /* now store in an invalid address */
+        *(char *)0x1234 = 1;
+    }
+    
     act.sa_handler = alarm_handler;
     sigemptyset(&act.sa_mask);
     act.sa_flags = 0;
     sigaction(SIGALRM, &act, NULL);
     alarm(1);
-    for(;;) {
+    for(i = 0;i < 2; i++) {
         sleep(1);
     }
     return 0;
@@ -22,6 +22,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <inttypes.h>
+#include <signal.h>
 #include <assert.h>
 #define DEBUG_DISAS
@@ -3487,7 +3488,8 @@ static void dump_ops(const uint16_t *opc_buf)
 static uint16_t gen_opc_buf[OPC_BUF_SIZE];
 static uint32_t gen_opparam_buf[OPPARAM_BUF_SIZE];
-/* return the next pc */
+/* return non zero if the very first instruction is invalid so that
+   the virtual CPU can trigger an exception. */
 int cpu_x86_gen_code(uint8_t *gen_code_buf, int max_code_size, 
                      int *gen_code_size_ptr,
                      uint8_t *pc_start,  uint8_t *cs_base, int flags)
@@ -3519,9 +3521,13 @@ int cpu_x86_gen_code(uint8_t *gen_code_buf, int max_code_size,
     do {
         ret = disas_insn(dc, pc_ptr);
         if (ret == -1) {
-            fprintf(stderr, "unknown instruction at PC=0x%08lx B=%02x %02x %02x", 
-                    (long)pc_ptr, pc_ptr[0], pc_ptr[1], pc_ptr[2]);
-            abort();
+            /* we trigger an illegal instruction operation only if it
+               is the first instruction. Otherwise, we simply stop
+               generating the code just before it */
+            if (pc_ptr == pc_start)
+                return -1;
+            else
+                break;
         }
         pc_ptr = (void *)ret;
     } while (!dc->is_jmp && gen_opc_ptr < gen_opc_end);
@@ -3640,8 +3646,7 @@ CPUX86State *cpu_x86_init(void)
         env->fptags[i] = 1;
     env->fpuc = 0x37f;
     /* flags setup */
-    env->cc_op = CC_OP_EFLAGS;
-    env->df = 1;
+    env->eflags = 0;
     /* init various static tables */
     if (!inited) {