linux-kernel - [PATCH v4] perf/x86/zhaoxin: Fix instructions error by missing fixedctr member

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250814093309.1580835-1-tanze0x01@163.com>
Date: Thu, 14 Aug 2025 17:33:09 +0800
From: tanze0x01@....com
To: peterz@...radead.org,
	mingo@...hat.com,
	acme@...nel.org
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	tanze <tanze0x01@....com>,
	Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH v4] perf/x86/zhaoxin: Fix instructions error by missing fixedctr member

From: tanze <tanze0x01@....com>

Perf's instructions event tests on Zhaoxin CPUs may exhibit:

  $perf stat -e instructions,cycles ls -l

  ......
  Performance counter stats for 'ls -l':

                 0      instructions                     #    0.00  insn per cycle
         9,488,278      cycles

       0.004365407 seconds time elapsed

       0.003303000 seconds user
       0.001099000 seconds sys

The absence of the fixedctr member leads to an incorrect hwc->event_base
value on Zhaoxin CPUs, causing a discrepancy in the instruction count
reported by perf stat. This commit resolves the instruction count issue
by properly initializing the fixedctr member.

Fixes: 149fd4712bcd ("perf/x86/intel: Support Perfmon MSRs aliasing")
Signed-off-by: tanze <tanze0x01@....com>
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>

---
v1-v3:https://lore.kernel.org/all/20250620023757.1429898-1-tanze@kylinos.cn/

This patch does not modify the previous code,
Do you have any other suggestions?

---
 arch/x86/events/zhaoxin/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/events/zhaoxin/core.c b/arch/x86/events/zhaoxin/core.c
index 4bdfcf091200..3fc3f9abece9 100644
--- a/arch/x86/events/zhaoxin/core.c
+++ b/arch/x86/events/zhaoxin/core.c
@@ -467,6 +467,7 @@ static const struct x86_pmu zhaoxin_pmu __initconst = {
 	.schedule_events	= x86_schedule_events,
 	.eventsel		= MSR_ARCH_PERFMON_EVENTSEL0,
 	.perfctr		= MSR_ARCH_PERFMON_PERFCTR0,
+	.fixedctr		= MSR_ARCH_PERFMON_FIXED_CTR0,
 	.event_map		= zhaoxin_pmu_event_map,
 	.max_events		= ARRAY_SIZE(zx_pmon_event_map),
 	.apic			= 1,
-- 
2.25.1