Pull percpu-dtc into release branch
[pandora-kernel.git] / arch / powerpc / kernel / traps.c
index 535f506..f786222 100644 (file)
@@ -90,51 +90,80 @@ EXPORT_SYMBOL(unregister_die_notifier);
  * Trap & Exception support
  */
 
-static DEFINE_SPINLOCK(die_lock);
+#ifdef CONFIG_PMAC_BACKLIGHT
+static void pmac_backlight_unblank(void)
+{
+       mutex_lock(&pmac_backlight_mutex);
+       if (pmac_backlight) {
+               struct backlight_properties *props;
+
+               props = &pmac_backlight->props;
+               props->brightness = props->max_brightness;
+               props->power = FB_BLANK_UNBLANK;
+               backlight_update_status(pmac_backlight);
+       }
+       mutex_unlock(&pmac_backlight_mutex);
+}
+#else
+static inline void pmac_backlight_unblank(void) { }
+#endif
 
 int die(const char *str, struct pt_regs *regs, long err)
 {
+       static struct {
+               spinlock_t lock;
+               u32 lock_owner;
+               int lock_owner_depth;
+       } die = {
+               .lock =                 __SPIN_LOCK_UNLOCKED(die.lock),
+               .lock_owner =           -1,
+               .lock_owner_depth =     0
+       };
        static int die_counter;
+       unsigned long flags;
 
        if (debugger(regs))
                return 1;
 
-       console_verbose();
-       spin_lock_irq(&die_lock);
-       bust_spinlocks(1);
-#ifdef CONFIG_PMAC_BACKLIGHT
-       mutex_lock(&pmac_backlight_mutex);
-       if (machine_is(powermac) && pmac_backlight) {
-               struct backlight_properties *props;
+       oops_enter();
 
-               down(&pmac_backlight->sem);
-               props = pmac_backlight->props;
-               props->brightness = props->max_brightness;
-               props->power = FB_BLANK_UNBLANK;
-               props->update_status(pmac_backlight);
-               up(&pmac_backlight->sem);
+       if (die.lock_owner != raw_smp_processor_id()) {
+               console_verbose();
+               spin_lock_irqsave(&die.lock, flags);
+               die.lock_owner = smp_processor_id();
+               die.lock_owner_depth = 0;
+               bust_spinlocks(1);
+               if (machine_is(powermac))
+                       pmac_backlight_unblank();
+       } else {
+               local_save_flags(flags);
        }
-       mutex_unlock(&pmac_backlight_mutex);
-#endif
-       printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
+
+       if (++die.lock_owner_depth < 3) {
+               printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 #ifdef CONFIG_PREEMPT
-       printk("PREEMPT ");
+               printk("PREEMPT ");
 #endif
 #ifdef CONFIG_SMP
-       printk("SMP NR_CPUS=%d ", NR_CPUS);
+               printk("SMP NR_CPUS=%d ", NR_CPUS);
 #endif
 #ifdef CONFIG_DEBUG_PAGEALLOC
-       printk("DEBUG_PAGEALLOC ");
+               printk("DEBUG_PAGEALLOC ");
 #endif
 #ifdef CONFIG_NUMA
-       printk("NUMA ");
+               printk("NUMA ");
 #endif
-       printk("%s\n", ppc_md.name ? "" : ppc_md.name);
+               printk("%s\n", ppc_md.name ? ppc_md.name : "");
+
+               print_modules();
+               show_regs(regs);
+       } else {
+               printk("Recursive die() failure, output suppressed\n");
+       }
 
-       print_modules();
-       show_regs(regs);
        bust_spinlocks(0);
-       spin_unlock_irq(&die_lock);
+       die.lock_owner = -1;
+       spin_unlock_irqrestore(&die.lock, flags);
 
        if (kexec_should_crash(current) ||
                kexec_sr_activated(smp_processor_id()))
@@ -147,6 +176,7 @@ int die(const char *str, struct pt_regs *regs, long err)
        if (panic_on_oops)
                panic("Fatal exception");
 
+       oops_exit();
        do_exit(err);
 
        return 0;
@@ -174,7 +204,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
         * generate the same exception over and over again and we get
         * nowhere.  Better to kill it and let the kernel panic.
         */
-       if (current->pid == 1) {
+       if (is_init(current)) {
                __sighandler_t handler;
 
                spin_lock_irq(&current->sighand->siglock);
@@ -535,34 +565,40 @@ static void emulate_single_step(struct pt_regs *regs)
        }
 }
 
-static void parse_fpe(struct pt_regs *regs)
+static inline int __parse_fpscr(unsigned long fpscr)
 {
-       int code = 0;
-       unsigned long fpscr;
-
-       flush_fp_to_thread(current);
-
-       fpscr = current->thread.fpscr.val;
+       int ret = 0;
 
        /* Invalid operation */
        if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
-               code = FPE_FLTINV;
+               ret = FPE_FLTINV;
 
        /* Overflow */
        else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
-               code = FPE_FLTOVF;
+               ret = FPE_FLTOVF;
 
        /* Underflow */
        else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
-               code = FPE_FLTUND;
+               ret = FPE_FLTUND;
 
        /* Divide by zero */
        else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
-               code = FPE_FLTDIV;
+               ret = FPE_FLTDIV;
 
        /* Inexact result */
        else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
-               code = FPE_FLTRES;
+               ret = FPE_FLTRES;
+
+       return ret;
+}
+
+static void parse_fpe(struct pt_regs *regs)
+{
+       int code = 0;
+
+       flush_fp_to_thread(current);
+
+       code = __parse_fpscr(current->thread.fpscr.val);
 
        _exception(SIGFPE, regs, code, regs->nip);
 }
@@ -739,20 +775,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)
        extern int do_mathemu(struct pt_regs *regs);
 
        /* We can now get here via a FP Unavailable exception if the core
-        * has no FPU, in that case no reason flags will be set */
-#ifdef CONFIG_MATH_EMULATION
-       /* (reason & REASON_ILLEGAL) would be the obvious thing here,
-        * but there seems to be a hardware bug on the 405GP (RevD)
-        * that means ESR is sometimes set incorrectly - either to
-        * ESR_DST (!?) or 0.  In the process of chasing this with the
-        * hardware people - not sure if it can happen on any illegal
-        * instruction or only on FP instructions, whether there is a
-        * pattern to occurences etc. -dgibson 31/Mar/2003 */
-       if (!(reason & REASON_TRAP) && do_mathemu(regs) == 0) {
-               emulate_single_step(regs);
-               return;
-       }
-#endif /* CONFIG_MATH_EMULATION */
+        * has no FPU, in that case the reason flags will be 0 */
 
        if (reason & REASON_FP) {
                /* IEEE FP exception */
@@ -778,6 +801,31 @@ void __kprobes program_check_exception(struct pt_regs *regs)
 
        local_irq_enable();
 
+#ifdef CONFIG_MATH_EMULATION
+       /* (reason & REASON_ILLEGAL) would be the obvious thing here,
+        * but there seems to be a hardware bug on the 405GP (RevD)
+        * that means ESR is sometimes set incorrectly - either to
+        * ESR_DST (!?) or 0.  In the process of chasing this with the
+        * hardware people - not sure if it can happen on any illegal
+        * instruction or only on FP instructions, whether there is a
+        * pattern to occurences etc. -dgibson 31/Mar/2003 */
+       switch (do_mathemu(regs)) {
+       case 0:
+               emulate_single_step(regs);
+               return;
+       case 1: {
+                       int code = 0;
+                       code = __parse_fpscr(current->thread.fpscr.val);
+                       _exception(SIGFPE, regs, code, regs->nip);
+                       return;
+               }
+       case -EFAULT:
+               _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
+               return;
+       }
+       /* fall through on any other errors */
+#endif /* CONFIG_MATH_EMULATION */
+
        /* Try to emulate it if we should. */
        if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
                switch (emulate_instruction(regs)) {
@@ -891,18 +939,39 @@ void SoftwareEmulation(struct pt_regs *regs)
 
 #ifdef CONFIG_MATH_EMULATION
        errcode = do_mathemu(regs);
+
+       switch (errcode) {
+       case 0:
+               emulate_single_step(regs);
+               return;
+       case 1: {
+                       int code = 0;
+                       code = __parse_fpscr(current->thread.fpscr.val);
+                       _exception(SIGFPE, regs, code, regs->nip);
+                       return;
+               }
+       case -EFAULT:
+               _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
+               return;
+       default:
+               _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
+               return;
+       }
+
 #else
        errcode = Soft_emulate_8xx(regs);
-#endif
-       if (errcode) {
-               if (errcode > 0)
-                       _exception(SIGFPE, regs, 0, 0);
-               else if (errcode == -EFAULT)
-                       _exception(SIGSEGV, regs, 0, 0);
-               else
-                       _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
-       } else
+       switch (errcode) {
+       case 0:
                emulate_single_step(regs);
+               return;
+       case 1:
+               _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
+               return;
+       case -EFAULT:
+               _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
+               return;
+       }
+#endif
 }
 #endif /* CONFIG_8xx */