From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Kim Phillips <kim.phillips@amd.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>,
linux-perf-users@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 3/5] perf/x86/amd/ibs: Work around erratum #1197
Date: Mon, 30 Aug 2021 08:00:51 -0400 [thread overview]
Message-ID: <20210830120053.1018205-3-sashal@kernel.org> (raw)
In-Reply-To: <20210830120053.1018205-1-sashal@kernel.org>
From: Kim Phillips <kim.phillips@amd.com>
[ Upstream commit 26db2e0c51fe83e1dd852c1321407835b481806e ]
Erratum #1197 "IBS (Instruction Based Sampling) Register State May be
Incorrect After Restore From CC6" is published in a document:
"Revision Guide for AMD Family 19h Models 00h-0Fh Processors" 56683 Rev. 1.04 July 2021
https://bugzilla.kernel.org/show_bug.cgi?id=206537
Implement the erratum's suggested workaround and ignore IBS samples if
MSRC001_1031 == 0.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210817221048.88063-3-kim.phillips@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/events/amd/ibs.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index f6e57bebbc6b..5c6aad14cdd9 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -89,6 +89,7 @@ struct perf_ibs {
unsigned long offset_mask[1];
int offset_max;
unsigned int fetch_count_reset_broken : 1;
+ unsigned int fetch_ignore_if_zero_rip : 1;
struct cpu_perf_ibs __percpu *pcpu;
struct attribute **format_attrs;
@@ -673,6 +674,10 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
if (check_rip && (ibs_data.regs[2] & IBS_RIP_INVALID)) {
regs.flags &= ~PERF_EFLAGS_EXACT;
} else {
+ /* Workaround for erratum #1197 */
+ if (perf_ibs->fetch_ignore_if_zero_rip && !(ibs_data.regs[1]))
+ goto out;
+
set_linear_ip(®s, ibs_data.regs[1]);
regs.flags |= PERF_EFLAGS_EXACT;
}
@@ -766,6 +771,9 @@ static __init void perf_event_ibs_init(void)
if (boot_cpu_data.x86 >= 0x16 && boot_cpu_data.x86 <= 0x18)
perf_ibs_fetch.fetch_count_reset_broken = 1;
+ if (boot_cpu_data.x86 == 0x19 && boot_cpu_data.x86_model < 0x10)
+ perf_ibs_fetch.fetch_ignore_if_zero_rip = 1;
+
perf_ibs_pmu_init(&perf_ibs_fetch, "ibs_fetch");
if (ibs_caps & IBS_CAPS_OPCNT) {
--
2.30.2
next prev parent reply other threads:[~2021-08-30 12:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-30 12:00 [PATCH AUTOSEL 4.9 1/5] qed: Fix the VF msix vectors flow Sasha Levin
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 2/5] qede: Fix memset corruption Sasha Levin
2021-08-30 12:00 ` Sasha Levin [this message]
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 4/5] net: fix NULL pointer reference in cipso_v4_doi_free Sasha Levin
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 5/5] cryptoloop: add a deprecation warning Sasha Levin
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