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authorNicolas Pitre <nicolas.pitre@linaro.org>2011-03-27 22:47:51 -0400
committerNicolas Pitre <nicolas.pitre@linaro.org>2011-03-27 22:47:51 -0400
commit0e9882b4fb8703f13921279fe4a6592574f92c62 (patch)
tree001ea9826ec3011e19986eb81cc7597d58f4f999 /arch/powerpc
parentc4bb07ec0084e26323047bcbe446d59ac352e07f (diff)
parent24d6a9d07f7da6c635530688a43086ea293bf9dc (diff)
downloadlinux-2.6.38-lt-ux500-0e9882b4fb8703f13921279fe4a6592574f92c62.tar.gz
Merge commit 'v2.6.38.1' into linaro-2.6.38
Conflicts: drivers/usb/core/hcd-pci.c drivers/usb/host/isp1760-hcd.c include/linux/usb/ch9.h
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/reg.h1
-rw-r--r--arch/powerpc/kernel/perf_event.c24
2 files changed, 24 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 125fc1ad665..7626fa78e1f 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -880,6 +880,7 @@
#define PV_970 0x0039
#define PV_POWER5 0x003A
#define PV_POWER5p 0x003B
+#define PV_POWER7 0x003F
#define PV_970FX 0x003C
#define PV_630 0x0040
#define PV_630p 0x0041
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index ab6f6beadb5..97e0ae41494 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/arch/powerpc/kernel/perf_event.c
@@ -1269,6 +1269,28 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs)
return ip;
}
+static bool pmc_overflow(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
+ * raise a performance monitor exception. We need to catch this to
+ * ensure we reset the PMC. In all cases the PMC will be 256 or less
+ * cycles from overflow.
+ *
+ * We only do this if the first pass fails to find any overflowing
+ * PMCs because a user might set a period of less than 256 and we
+ * don't want to mistakenly reset them.
+ */
+ if (__is_processor(PV_POWER7) && ((0x80000000 - val) <= 256))
+ return true;
+
+ return false;
+}
+
/*
* Performance monitor interrupt stuff
*/
@@ -1316,7 +1338,7 @@ static void perf_event_interrupt(struct pt_regs *regs)
if (is_limited_pmc(i + 1))
continue;
val = read_pmc(i + 1);
- if ((int)val < 0)
+ if (pmc_overflow(val))
write_pmc(i + 1, 0);
}
}