From: Kim Phillips kim.phillips@amd.com
stable inclusion from linux-4.19.155 commit a1c59cb6a944bd0eab88af1af681a166163ac213
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commit 680d69635005ba0e58fe3f4c52fc162b8fc743b0 upstream.
get_ibs_op_count() adds hardware's current count (IbsOpCurCnt) bits to its count regardless of hardware's valid status.
According to the PPR for AMD Family 17h Model 31h B0 55803 Rev 0.54, if the counter rolls over, valid status is set, and the lower 7 bits of IbsOpCurCnt are randomized by hardware.
Don't include those bits in the driver's event count.
Fixes: 8b1e13638d46 ("perf/x86-ibs: Fix usage of IBS op current count") Signed-off-by: Kim Phillips kim.phillips@amd.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/x86/events/amd/ibs.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c index 801c50be8e1d..e58a3cfeab39 100644 --- a/arch/x86/events/amd/ibs.c +++ b/arch/x86/events/amd/ibs.c @@ -347,11 +347,15 @@ static u64 get_ibs_op_count(u64 config) { u64 count = 0;
+ /* + * If the internal 27-bit counter rolled over, the count is MaxCnt + * and the lower 7 bits of CurCnt are randomized. + * Otherwise CurCnt has the full 27-bit current counter value. + */ if (config & IBS_OP_VAL) - count += (config & IBS_OP_MAX_CNT) << 4; /* cnt rolled over */ - - if (ibs_caps & IBS_CAPS_RDWROPCNT) - count += (config & IBS_OP_CUR_CNT) >> 32; + count = (config & IBS_OP_MAX_CNT) << 4; + else if (ibs_caps & IBS_CAPS_RDWROPCNT) + count = (config & IBS_OP_CUR_CNT) >> 32;
return count; }