powerpc/perf: Fix finding overflowed PMC in interrupt

[pandora-kernel.git] / arch / powerpc / perf / core-book3s.c

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index aa2465e..53fc7b8 100644 (file)
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1412,11 +1412,8 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs)
                return regs->nip;
 }
 
-static bool pmc_overflow(unsigned long val)
+static bool pmc_overflow_power7(unsigned long val)
 {
-       if ((int)val < 0)
-               return true;
-
        /*
         * Events on POWER7 can roll back if a speculative event doesn't
         * eventually complete. Unfortunately in some rare cases they will
@@ -1428,7 +1425,15 @@ static bool pmc_overflow(unsigned long val)
         * PMCs because a user might set a period of less than 256 and we
         * don't want to mistakenly reset them.
         */
-       if (pvr_version_is(PVR_POWER7) && ((0x80000000 - val) <= 256))
+       if ((0x80000000 - val) <= 256)
+               return true;
+
+       return false;
+}
+
+static bool pmc_overflow(unsigned long val)
+{
+       if ((int)val < 0)
                return true;
 
        return false;
@@ -1439,11 +1444,11 @@ static bool pmc_overflow(unsigned long val)
  */
 static void perf_event_interrupt(struct pt_regs *regs)
 {
-       int i;
+       int i, j;
        struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
        struct perf_event *event;
-       unsigned long val;
-       int found = 0;
+       unsigned long val[8];
+       int found, active;
        int nmi;
 
        if (cpuhw->n_limited)
@@ -1458,33 +1463,53 @@ static void perf_event_interrupt(struct pt_regs *regs)
        else
                irq_enter();
 
-       for (i = 0; i < cpuhw->n_events; ++i) {
-               event = cpuhw->event[i];
-               if (!event->hw.idx || is_limited_pmc(event->hw.idx))
+       /* Read all the PMCs since we'll need them a bunch of times */
+       for (i = 0; i < ppmu->n_counter; ++i)
+               val[i] = read_pmc(i + 1);
+
+       /* Try to find what caused the IRQ */
+       found = 0;
+       for (i = 0; i < ppmu->n_counter; ++i) {
+               if (!pmc_overflow(val[i]))
                        continue;
-               val = read_pmc(event->hw.idx);
-               if ((int)val < 0) {
-                       /* event has overflowed */
-                       found = 1;
-                       record_and_restart(event, val, regs);
+               if (is_limited_pmc(i + 1))
+                       continue; /* these won't generate IRQs */
+               /*
+                * We've found one that's overflowed.  For active
+                * counters we need to log this.  For inactive
+                * counters, we need to reset it anyway
+                */
+               found = 1;
+               active = 0;
+               for (j = 0; j < cpuhw->n_events; ++j) {
+                       event = cpuhw->event[j];
+                       if (event->hw.idx == (i + 1)) {
+                               active = 1;
+                               record_and_restart(event, val[i], regs);
+                               break;
+                       }
                }
+               if (!active)
+                       /* reset non active counters that have overflowed */
+                       write_pmc(i + 1, 0);
        }
-
-       /*
-        * In case we didn't find and reset the event that caused
-        * the interrupt, scan all events and reset any that are
-        * negative, to avoid getting continual interrupts.
-        * Any that we processed in the previous loop will not be negative.
-        */
-       if (!found) {
-               for (i = 0; i < ppmu->n_counter; ++i) {
-                       if (is_limited_pmc(i + 1))
+       if (!found && pvr_version_is(PVR_POWER7)) {
+               /* check active counters for special buggy p7 overflow */
+               for (i = 0; i < cpuhw->n_events; ++i) {
+                       event = cpuhw->event[i];
+                       if (!event->hw.idx || is_limited_pmc(event->hw.idx))
                                continue;
-                       val = read_pmc(i + 1);
-                       if (pmc_overflow(val))
-                               write_pmc(i + 1, 0);
+                       if (pmc_overflow_power7(val[event->hw.idx - 1])) {
+                               /* event has overflowed in a buggy way*/
+                               found = 1;
+                               record_and_restart(event,
+                                                  val[event->hw.idx - 1],
+                                                  regs);
+                       }
                }
        }
+       if ((!found) && printk_ratelimit())
+               printk(KERN_WARNING "Can't find PMC that caused IRQ\n");
 
        /*
         * Reset MMCR0 to its normal value.  This will set PMXE and