Rework PowerPC exceptions model to make it more versatile:

* don't use exception vectors as the exception number.
  Use vectors numbers as defined in the PowerPC embedded specification instead
  and extend this model to cover all emulated PowerPC variants exceptions.
* add some missing exceptions definitions, from PowerPC 2.04 specification
  and actual PowerPC implementations.
* add code provision for hypervisor exceptions handling.
* define exception vectors and prefix in CPUPPCState to emulate BookE exception
  vectors without any hacks.
* define per CPU model valid exception vectors.
* handle all known exceptions in user-mode only emulations.
* fix hardware interrupts priorities in most cases.
* change RET_EXCP macros name into GEN_EXCP as they don't return.
* do not stop translation on most instructions that are not defined as
  context-synchronizing in PowerPC specification.
* fix PowerPC 64 jump targets and link register update when in 32 bits mode.
* Fix PowerPC 464 and 464F definitions.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3261 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 279 insertions, 179 deletions

diff --git a/linux-user/main.c b/linux-user/main.c
index b70c070c3f..fb424ad887 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -723,6 +723,16 @@ int ppc_dcr_write (ppc_dcr_t *dcr_env, int dcrn, target_ulong val)
     return -1;
 }
 
+#define EXCP_DUMP(env, fmt, args...)                                         \
+do {                                                                          \
+    fprintf(stderr, fmt , ##args);                                            \
+    cpu_dump_state(env, stderr, fprintf, 0);                                  \
+    if (loglevel != 0) {                                                      \
+        fprintf(logfile, fmt , ##args);                                       \
+        cpu_dump_state(env, logfile, fprintf, 0);                             \
+    }                                                                         \
+} while (0)
+
 void cpu_loop(CPUPPCState *env)
 {
     target_siginfo_t info;
@@ -731,60 +741,22 @@ void cpu_loop(CPUPPCState *env)
 
     for(;;) {
         trapnr = cpu_ppc_exec(env);
-        if (trapnr != EXCP_SYSCALL_USER && trapnr != EXCP_BRANCH &&
-            trapnr != EXCP_TRACE) {
-            if (loglevel > 0) {
-                cpu_dump_state(env, logfile, fprintf, 0);
-            }
-        }
         switch(trapnr) {
-        case EXCP_NONE:
+        case POWERPC_EXCP_NONE:
+            /* Just go on */
             break;
-        case EXCP_SYSCALL_USER:
-            /* system call */
-            /* WARNING:
-             * PPC ABI uses overflow flag in cr0 to signal an error
-             * in syscalls.
-             */
-#if 0
-            printf("syscall %d 0x%08x 0x%08x 0x%08x 0x%08x\n", env->gpr[0],
-                   env->gpr[3], env->gpr[4], env->gpr[5], env->gpr[6]);
-#endif
-            env->crf[0] &= ~0x1;
-            ret = do_syscall(env, env->gpr[0], env->gpr[3], env->gpr[4],
-                             env->gpr[5], env->gpr[6], env->gpr[7],
-                             env->gpr[8]);
-            if (ret > (uint32_t)(-515)) {
-                env->crf[0] |= 0x1;
-                ret = -ret;
-            }
-            env->gpr[3] = ret;
-#if 0
-            printf("syscall returned 0x%08x (%d)\n", ret, ret);
-#endif
+        case POWERPC_EXCP_CRITICAL: /* Critical input                        */
+            cpu_abort(env, "Critical interrupt while in user mode. "
+                      "Aborting\n");
             break;
-        case EXCP_RESET:
-            /* Should not happen ! */
-            fprintf(stderr, "RESET asked... Stop emulation\n");
-            if (loglevel)
-                fprintf(logfile, "RESET asked... Stop emulation\n");
-            abort();
-        case EXCP_MACHINE_CHECK:
-            fprintf(stderr, "Machine check exeption...  Stop emulation\n");
-            if (loglevel)
-                fprintf(logfile, "Machine check exception. Stop emulation\n");
-            info.si_signo = TARGET_SIGBUS;
-            info.si_errno = 0;
-            info.si_code = TARGET_BUS_OBJERR;
-            info._sifields._sigfault._addr = env->nip - 4;
-            queue_signal(info.si_signo, &info);
-        case EXCP_DSI:
-            fprintf(stderr, "Invalid data memory access: 0x" ADDRX "\n",
-                    env->spr[SPR_DAR]);
-            if (loglevel) {
-                fprintf(logfile, "Invalid data memory access: 0x" ADDRX "\n",
-                        env->spr[SPR_DAR]);
-            }
+        case POWERPC_EXCP_MCHECK:   /* Machine check exception               */
+            cpu_abort(env, "Machine check exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_DSI:      /* Data storage exception                */
+            EXCP_DUMP(env, "Invalid data memory access: 0x" ADDRX "\n",
+                      env->spr[SPR_DAR]);
+            /* XXX: check this. Seems bugged */
             switch (env->error_code & 0xFF000000) {
             case 0x40000000:
                 info.si_signo = TARGET_SIGSEGV;
@@ -803,12 +775,8 @@ void cpu_loop(CPUPPCState *env)
                 break;
             default:
                 /* Let's send a regular segfault... */
-                fprintf(stderr, "Invalid segfault errno (%02x)\n",
-                        env->error_code);
-                if (loglevel) {
-                    fprintf(logfile, "Invalid segfault errno (%02x)\n",
-                            env->error_code);
-                }
+                EXCP_DUMP(env, "Invalid segfault errno (%02x)\n",
+                          env->error_code);
                 info.si_signo = TARGET_SIGSEGV;
                 info.si_errno = 0;
                 info.si_code = TARGET_SEGV_MAPERR;
@@ -817,10 +785,10 @@ void cpu_loop(CPUPPCState *env)
             info._sifields._sigfault._addr = env->nip;
             queue_signal(info.si_signo, &info);
             break;
-        case EXCP_ISI:
-            fprintf(stderr, "Invalid instruction fetch\n");
-            if (loglevel)
-                fprintf(logfile, "Invalid instruction fetch\n");
+        case POWERPC_EXCP_ISI:      /* Instruction storage exception         */
+            EXCP_DUMP(env, "Invalid instruction fetch: 0x\n" ADDRX "\n",
+                      env->spr[SPR_DAR]);
+            /* XXX: check this */
             switch (env->error_code & 0xFF000000) {
             case 0x40000000:
                 info.si_signo = TARGET_SIGSEGV;
@@ -835,12 +803,8 @@ void cpu_loop(CPUPPCState *env)
                 break;
             default:
                 /* Let's send a regular segfault... */
-                fprintf(stderr, "Invalid segfault errno (%02x)\n",
-                        env->error_code);
-                if (loglevel) {
-                    fprintf(logfile, "Invalid segfault errno (%02x)\n",
-                            env->error_code);
-                }
+                EXCP_DUMP(env, "Invalid segfault errno (%02x)\n",
+                          env->error_code);
                 info.si_signo = TARGET_SIGSEGV;
                 info.si_errno = 0;
                 info.si_code = TARGET_SEGV_MAPERR;
@@ -849,28 +813,24 @@ void cpu_loop(CPUPPCState *env)
             info._sifields._sigfault._addr = env->nip - 4;
             queue_signal(info.si_signo, &info);
             break;
-        case EXCP_EXTERNAL:
-            /* Should not happen ! */
-            fprintf(stderr, "External interruption... Stop emulation\n");
-            if (loglevel)
-                fprintf(logfile, "External interruption... Stop emulation\n");
-            abort();
-        case EXCP_ALIGN:
-            fprintf(stderr, "Invalid unaligned memory access\n");
-            if (loglevel)
-                fprintf(logfile, "Invalid unaligned memory access\n");
+        case POWERPC_EXCP_EXTERNAL: /* External input                        */
+            cpu_abort(env, "External interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_ALIGN:    /* Alignment exception                   */
+            EXCP_DUMP(env, "Unaligned memory access\n");
+            /* XXX: check this */
             info.si_signo = TARGET_SIGBUS;
             info.si_errno = 0;
             info.si_code = TARGET_BUS_ADRALN;
             info._sifields._sigfault._addr = env->nip - 4;
             queue_signal(info.si_signo, &info);
             break;
-        case EXCP_PROGRAM:
+        case POWERPC_EXCP_PROGRAM:  /* Program exception                     */
+            /* XXX: check this */
             switch (env->error_code & ~0xF) {
-            case EXCP_FP:
-            fprintf(stderr, "Program exception\n");
-                if (loglevel)
-                    fprintf(logfile, "Program exception\n");
+            case POWERPC_EXCP_FP:
+                EXCP_DUMP(env, "Floating point program exception\n");
                 /* Set FX */
                 env->fpscr[7] |= 0x8;
                 /* Finally, update FEX */
@@ -880,155 +840,138 @@ void cpu_loop(CPUPPCState *env)
                 info.si_signo = TARGET_SIGFPE;
                 info.si_errno = 0;
                 switch (env->error_code & 0xF) {
-                case EXCP_FP_OX:
+                case POWERPC_EXCP_FP_OX:
                     info.si_code = TARGET_FPE_FLTOVF;
                     break;
-                case EXCP_FP_UX:
+                case POWERPC_EXCP_FP_UX:
                     info.si_code = TARGET_FPE_FLTUND;
                     break;
-                case EXCP_FP_ZX:
-                case EXCP_FP_VXZDZ:
+                case POWERPC_EXCP_FP_ZX:
+                case POWERPC_EXCP_FP_VXZDZ:
                     info.si_code = TARGET_FPE_FLTDIV;
                     break;
-                case EXCP_FP_XX:
+                case POWERPC_EXCP_FP_XX:
                     info.si_code = TARGET_FPE_FLTRES;
                     break;
-                case EXCP_FP_VXSOFT:
+                case POWERPC_EXCP_FP_VXSOFT:
                     info.si_code = TARGET_FPE_FLTINV;
                     break;
-                case EXCP_FP_VXNAN:
-                case EXCP_FP_VXISI:
-                case EXCP_FP_VXIDI:
-                case EXCP_FP_VXIMZ:
-                case EXCP_FP_VXVC:
-                case EXCP_FP_VXSQRT:
-                case EXCP_FP_VXCVI:
+                case POWERPC_EXCP_FP_VXNAN:
+                case POWERPC_EXCP_FP_VXISI:
+                case POWERPC_EXCP_FP_VXIDI:
+                case POWERPC_EXCP_FP_VXIMZ:
+                case POWERPC_EXCP_FP_VXVC:
+                case POWERPC_EXCP_FP_VXSQRT:
+                case POWERPC_EXCP_FP_VXCVI:
                     info.si_code = TARGET_FPE_FLTSUB;
                     break;
                 default:
-                    fprintf(stderr, "Unknown floating point exception "
-                            "(%02x)\n", env->error_code);
-                    if (loglevel) {
-                        fprintf(logfile, "Unknown floating point exception "
-                                "(%02x)\n", env->error_code & 0xF);
-                    }
+                    EXCP_DUMP(env, "Unknown floating point exception (%02x)\n",
+                              env->error_code);
+                    break;
                 }
-            break;
-        case EXCP_INVAL:
-                fprintf(stderr, "Invalid instruction\n");
-                if (loglevel)
-                    fprintf(logfile, "Invalid instruction\n");
+                break;
+            case POWERPC_EXCP_INVAL:
+                EXCP_DUMP(env, "Invalid instruction\n");
                 info.si_signo = TARGET_SIGILL;
                 info.si_errno = 0;
                 switch (env->error_code & 0xF) {
-                case EXCP_INVAL_INVAL:
+                case POWERPC_EXCP_INVAL_INVAL:
                     info.si_code = TARGET_ILL_ILLOPC;
                     break;
-                case EXCP_INVAL_LSWX:
+                case POWERPC_EXCP_INVAL_LSWX:
                     info.si_code = TARGET_ILL_ILLOPN;
                     break;
-                case EXCP_INVAL_SPR:
+                case POWERPC_EXCP_INVAL_SPR:
                     info.si_code = TARGET_ILL_PRVREG;
                     break;
-                case EXCP_INVAL_FP:
+                case POWERPC_EXCP_INVAL_FP:
                     info.si_code = TARGET_ILL_COPROC;
                     break;
                 default:
-                    fprintf(stderr, "Unknown invalid operation (%02x)\n",
-                            env->error_code & 0xF);
-                    if (loglevel) {
-                        fprintf(logfile, "Unknown invalid operation (%02x)\n",
-                                env->error_code & 0xF);
-                    }
+                    EXCP_DUMP(env, "Unknown invalid operation (%02x)\n",
+                              env->error_code & 0xF);
                     info.si_code = TARGET_ILL_ILLADR;
                     break;
                 }
                 break;
-            case EXCP_PRIV:
-                fprintf(stderr, "Privilege violation\n");
-                if (loglevel)
-                    fprintf(logfile, "Privilege violation\n");
+            case POWERPC_EXCP_PRIV:
+                EXCP_DUMP(env, "Privilege violation\n");
                 info.si_signo = TARGET_SIGILL;
                 info.si_errno = 0;
                 switch (env->error_code & 0xF) {
-                case EXCP_PRIV_OPC:
+                case POWERPC_EXCP_PRIV_OPC:
                     info.si_code = TARGET_ILL_PRVOPC;
                     break;
-                case EXCP_PRIV_REG:
+                case POWERPC_EXCP_PRIV_REG:
                     info.si_code = TARGET_ILL_PRVREG;
-                break;
+                    break;
                 default:
-                    fprintf(stderr, "Unknown privilege violation (%02x)\n",
-                            env->error_code & 0xF);
+                    EXCP_DUMP(env, "Unknown privilege violation (%02x)\n",
+                              env->error_code & 0xF);
                     info.si_code = TARGET_ILL_PRVOPC;
                     break;
                 }
                 break;
-            case EXCP_TRAP:
-                fprintf(stderr, "Tried to call a TRAP\n");
-                if (loglevel)
-                    fprintf(logfile, "Tried to call a TRAP\n");
-                abort();
+            case POWERPC_EXCP_TRAP:
+                cpu_abort(env, "Tried to call a TRAP\n");
+                break;
             default:
                 /* Should not happen ! */
-                fprintf(stderr, "Unknown program exception (%02x)\n",
-                        env->error_code);
-                if (loglevel) {
-                    fprintf(logfile, "Unknwon program exception (%02x)\n",
-                            env->error_code);
-                }
-                abort();
+                cpu_abort(env, "Unknown program exception (%02x)\n",
+                          env->error_code);
+                break;
             }
             info._sifields._sigfault._addr = env->nip - 4;
             queue_signal(info.si_signo, &info);
             break;
-        case EXCP_NO_FP:
-            fprintf(stderr, "No floating point allowed\n");
-            if (loglevel)
-                fprintf(logfile, "No floating point allowed\n");
+        case POWERPC_EXCP_FPU:      /* Floating-point unavailable exception  */
+            EXCP_DUMP(env, "No floating point allowed\n");
             info.si_signo = TARGET_SIGILL;
             info.si_errno = 0;
             info.si_code = TARGET_ILL_COPROC;
             info._sifields._sigfault._addr = env->nip - 4;
             queue_signal(info.si_signo, &info);
             break;
-        case EXCP_DECR:
-            /* Should not happen ! */
-            fprintf(stderr, "Decrementer exception\n");
-            if (loglevel)
-                fprintf(logfile, "Decrementer exception\n");
-            abort();
-        case EXCP_TRACE:
-            /* Do nothing: we use this to trace execution */
-            break;
-        case EXCP_FP_ASSIST:
-            /* Should not happen ! */
-            fprintf(stderr, "Floating point assist exception\n");
-            if (loglevel)
-                fprintf(logfile, "Floating point assist exception\n");
-            abort();
-        case EXCP_MTMSR:
-            /* We reloaded the msr, just go on */
-            if (msr_pr == 0) {
-                fprintf(stderr, "Tried to go into supervisor mode !\n");
-                if (loglevel)
-                    fprintf(logfile, "Tried to go into supervisor mode !\n");
-                abort();
-            }
+        case POWERPC_EXCP_SYSCALL:  /* System call exception                 */
+            cpu_abort(env, "Syscall exception while in user mode. "
+                      "Aborting\n");
             break;
-        case EXCP_BRANCH:
-            /* We stopped because of a jump... */
+        case POWERPC_EXCP_APU:      /* Auxiliary processor unavailable       */
+            EXCP_DUMP(env, "No APU instruction allowed\n");
+            info.si_signo = TARGET_SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_COPROC;
+            info._sifields._sigfault._addr = env->nip - 4;
+            queue_signal(info.si_signo, &info);
             break;
-        case EXCP_INTERRUPT:
-            /* Don't know why this should ever happen... */
+        case POWERPC_EXCP_DECR:     /* Decrementer exception                 */
+            cpu_abort(env, "Decrementer interrupt while in user mode. "
+                      "Aborting\n");
             break;
-        case EXCP_DEBUG:
+        case POWERPC_EXCP_FIT:      /* Fixed-interval timer interrupt        */
+            cpu_abort(env, "Fix interval timer interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_WDT:      /* Watchdog timer interrupt              */
+            cpu_abort(env, "Watchdog timer interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_DTLB:     /* Data TLB error                        */
+            cpu_abort(env, "Data TLB exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_ITLB:     /* Instruction TLB error                 */
+            cpu_abort(env, "Instruction TLB exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_DEBUG:    /* Debug interrupt                       */
+            /* XXX: check this */
             {
                 int sig;
 
-                sig = gdb_handlesig (env, TARGET_SIGTRAP);
-                if (sig)
-                  {
+                sig = gdb_handlesig(env, TARGET_SIGTRAP);
+                if (sig) {
                     info.si_signo = sig;
                     info.si_errno = 0;
                     info.si_code = TARGET_TRAP_BRKPT;
@@ -1036,14 +979,171 @@ void cpu_loop(CPUPPCState *env)
                   }
             }
             break;
-        default:
-            fprintf(stderr, "qemu: unhandled CPU exception 0x%x - aborting\n",
-                    trapnr);
-            if (loglevel) {
-                fprintf(logfile, "qemu: unhandled CPU exception 0x%02x - "
-                        "0x%02x - aborting\n", trapnr, env->error_code);
+#if defined(TARGET_PPCEMB)
+        case POWERPC_EXCP_SPEU:     /* SPE/embedded floating-point unavail.  */
+            EXCP_DUMP(env, "No SPE/floating-point instruction allowed\n");
+            info.si_signo = TARGET_SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_COPROC;
+            info._sifields._sigfault._addr = env->nip - 4;
+            queue_signal(info.si_signo, &info);
+            break;
+        case POWERPC_EXCP_EFPDI:    /* Embedded floating-point data IRQ      */
+            cpu_abort(env, "Embedded floating-point data IRQ not handled\n");
+            break;
+        case POWERPC_EXCP_EFPRI:    /* Embedded floating-point round IRQ     */
+            cpu_abort(env, "Embedded floating-point round IRQ not handled\n");
+            break;
+        case POWERPC_EXCP_EPERFM:   /* Embedded performance monitor IRQ      */
+            cpu_abort(env, "Performance monitor exception not handled\n");
+            break;
+        case POWERPC_EXCP_DOORI:    /* Embedded doorbell interrupt           */
+            cpu_abort(env, "Doorbell interrupt while in user mode. "
+                       "Aborting\n");
+            break;
+        case POWERPC_EXCP_DOORCI:   /* Embedded doorbell critical interrupt  */
+            cpu_abort(env, "Doorbell critical interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_RESET:    /* System reset exception                */
+            cpu_abort(env, "Reset interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+#endif /* defined(TARGET_PPCEMB) */
+#if defined(TARGET_PPC64) /* PowerPC 64 */
+        case POWERPC_EXCP_DSEG:     /* Data segment exception                */
+            cpu_abort(env, "Data segment exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_ISEG:     /* Instruction segment exception         */
+            cpu_abort(env, "Instruction segment exception "
+                      "while in user mode. Aborting\n");
+            break;
+#endif /* defined(TARGET_PPC64) */
+#if defined(TARGET_PPC64H) /* PowerPC 64 with hypervisor mode support */
+        case POWERPC_EXCP_HDECR:    /* Hypervisor decrementer exception      */
+            cpu_abort(env, "Hypervisor decrementer interrupt "
+                      "while in user mode. Aborting\n");
+            break;
+#endif /* defined(TARGET_PPC64H) */
+        case POWERPC_EXCP_TRACE:    /* Trace exception                       */
+            /* Nothing to do:
+             * we use this exception to emulate step-by-step execution mode.
+             */
+            break;
+#if defined(TARGET_PPC64H) /* PowerPC 64 with hypervisor mode support */
+        case POWERPC_EXCP_HDSI:     /* Hypervisor data storage exception     */
+            cpu_abort(env, "Hypervisor data storage exception "
+                      "while in user mode. Aborting\n");
+            break;
+        case POWERPC_EXCP_HISI:     /* Hypervisor instruction storage excp   */
+            cpu_abort(env, "Hypervisor instruction storage exception "
+                      "while in user mode. Aborting\n");
+            break;
+        case POWERPC_EXCP_HDSEG:    /* Hypervisor data segment exception     */
+            cpu_abort(env, "Hypervisor data segment exception "
+                      "while in user mode. Aborting\n");
+            break;
+        case POWERPC_EXCP_HISEG:    /* Hypervisor instruction segment excp   */
+            cpu_abort(env, "Hypervisor instruction segment exception "
+                      "while in user mode. Aborting\n");
+            break;
+#endif /* defined(TARGET_PPC64H) */
+        case POWERPC_EXCP_VPU:      /* Vector unavailable exception          */
+            EXCP_DUMP(env, "No Altivec instructions allowed\n");
+            info.si_signo = TARGET_SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_COPROC;
+            info._sifields._sigfault._addr = env->nip - 4;
+            queue_signal(info.si_signo, &info);
+            break;
+        case POWERPC_EXCP_PIT:      /* Programmable interval timer IRQ       */
+            cpu_abort(env, "Programable interval timer interrupt "
+                      "while in user mode. Aborting\n");
+            break;
+        case POWERPC_EXCP_IO:       /* IO error exception                    */
+            cpu_abort(env, "IO error exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_RUNM:     /* Run mode exception                    */
+            cpu_abort(env, "Run mode exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_EMUL:     /* Emulation trap exception              */
+            cpu_abort(env, "Emulation trap exception not handled\n");
+            break;
+        case POWERPC_EXCP_IFTLB:    /* Instruction fetch TLB error           */
+            cpu_abort(env, "Instruction fetch TLB exception "
+                      "while in user-mode. Aborting");
+            break;
+        case POWERPC_EXCP_DLTLB:    /* Data load TLB miss                    */
+            cpu_abort(env, "Data load TLB exception while in user-mode. "
+                      "Aborting");
+            break;
+        case POWERPC_EXCP_DSTLB:    /* Data store TLB miss                   */
+            cpu_abort(env, "Data store TLB exception while in user-mode. "
+                      "Aborting");
+            break;
+        case POWERPC_EXCP_FPA:      /* Floating-point assist exception       */
+            cpu_abort(env, "Floating-point assist exception not handled\n");
+            break;
+        case POWERPC_EXCP_IABR:     /* Instruction address breakpoint        */
+            cpu_abort(env, "Instruction address breakpoint exception "
+                      "not handled\n");
+            break;
+        case POWERPC_EXCP_SMI:      /* System management interrupt           */
+            cpu_abort(env, "System management interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_THERM:    /* Thermal interrupt                     */
+            cpu_abort(env, "Thermal interrupt interrupt while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_PERFM:   /* Embedded performance monitor IRQ      */
+            cpu_abort(env, "Performance monitor exception not handled\n");
+            break;
+        case POWERPC_EXCP_VPUA:     /* Vector assist exception               */
+            cpu_abort(env, "Vector assist exception not handled\n");
+            break;
+        case POWERPC_EXCP_SOFTP:    /* Soft patch exception                  */
+            cpu_abort(env, "Soft patch exception not handled\n");
+            break;
+        case POWERPC_EXCP_MAINT:    /* Maintenance exception                 */
+            cpu_abort(env, "Maintenance exception while in user mode. "
+                      "Aborting\n");
+            break;
+        case POWERPC_EXCP_STOP:     /* stop translation                      */
+            /* We did invalidate the instruction cache. Go on */
+            break;
+        case POWERPC_EXCP_BRANCH:   /* branch instruction:                   */
+            /* We just stopped because of a branch. Go on */
+            break;
+        case POWERPC_EXCP_SYSCALL_USER:
+            /* system call in user-mode emulation */
+            /* WARNING:
+             * PPC ABI uses overflow flag in cr0 to signal an error
+             * in syscalls.
+             */
+#if 0
+            printf("syscall %d 0x%08x 0x%08x 0x%08x 0x%08x\n", env->gpr[0],
+                   env->gpr[3], env->gpr[4], env->gpr[5], env->gpr[6]);
+#endif
+            env->crf[0] &= ~0x1;
+            ret = do_syscall(env, env->gpr[0], env->gpr[3], env->gpr[4],
+                             env->gpr[5], env->gpr[6], env->gpr[7],
+                             env->gpr[8]);
+            if (ret > (uint32_t)(-515)) {
+                env->crf[0] |= 0x1;
+                ret = -ret;
             }
-            abort();
+            env->gpr[3] = ret;
+#if 0
+            printf("syscall returned 0x%08x (%d)\n", ret, ret);
+#endif
+            break;
+        default:
+            cpu_abort(env, "Unknown exception 0x%d. Aborting\n", trapnr);
+            break;
         }
         process_pending_signals(env);
     }