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authorRobert Richter <robert.richter@amd.com>2012-06-20 20:46:36 +0200
committerIngo Molnar <mingo@kernel.org>2012-07-05 21:19:42 +0200
commitf285f92f7e4c9af20149130c8fd5027131b39b0e (patch)
tree6b8f63bb0fab1898ca46859d8706a158288d3e2c /arch/x86/kernel/cpu/perf_event.c
parentb1dc3c4820428ac6216537416b2fcd140fdc52e5 (diff)
perf/x86: Improve debug output in check_hw_exists()
It might be of interest which perfctr msr failed. Signed-off-by: Robert Richter <robert.richter@amd.com> [ added hunk to avoid GCC warn ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1340217996-2254-5-git-send-email-robert.richter@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 7b4f1e871f7c..3eb88ebcec5a 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -178,7 +178,7 @@ static void release_pmc_hardware(void) {}
static bool check_hw_exists(void)
{
- u64 val, val_new = 0;
+ u64 val, val_new = ~0;
int i, reg, ret = 0;
/*
@@ -211,8 +211,9 @@ static bool check_hw_exists(void)
* that don't trap on the MSR access and always return 0s.
*/
val = 0xabcdUL;
- ret = wrmsrl_safe(x86_pmu_event_addr(0), val);
- ret |= rdmsrl_safe(x86_pmu_event_addr(0), &val_new);
+ reg = x86_pmu_event_addr(0);
+ ret = wrmsrl_safe(reg, val);
+ ret |= rdmsrl_safe(reg, &val_new);
if (ret || val != val_new)
goto msr_fail;
@@ -229,6 +230,7 @@ bios_fail:
msr_fail:
printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
+ printk(KERN_ERR "Failed to access perfctr msr (MSR %x is %Lx)\n", reg, val_new);
return false;
}