From 123d58e1ac8a0f120b79cb5566549ff7bdf6928d Mon Sep 17 00:00:00 2001 From: Kim Phillips Date: Wed, 23 Oct 2019 10:09:54 -0500 Subject: [PATCH] perf/x86/amd/ibs: Fix reading of the IBS OpData register and thus precise RIP validity [ Upstream commit 317b96bb14303c7998dbcd5bc606bd8038fdd4b4 ] The loop that reads all the IBS MSRs into *buf stopped one MSR short of reading the IbsOpData register, which contains the RipInvalid status bit. Fix the offset_max assignment so the MSR gets read, so the RIP invalid evaluation is based on what the IBS h/w output, instead of what was left in memory. Signed-off-by: Kim Phillips Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: d47e8238cd76 ("perf/x86-ibs: Take instruction pointer from ibs sample") Link: https://lkml.kernel.org/r/20191023150955.30292-1-kim.phillips@amd.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/kernel/cpu/perf_event_amd_ibs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c index 989d3c215d2b..66ca6ec09bd4 100644 --- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c +++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c @@ -555,7 +555,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs) if (event->attr.sample_type & PERF_SAMPLE_RAW) offset_max = perf_ibs->offset_max; else if (check_rip) - offset_max = 2; + offset_max = 3; else offset_max = 1; do {