From: Borislav Petkov <bp@alien8.de>
To: silviazhao-oc <silviazhao-oc@zhaoxin.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@kernel.org, namhyung@kernel.org, tglx@linutronix.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
cobechen@zhaoxin.com, louisqi@zhaoxin.com,
silviazhao@zhaoxin.com, 8vvbbqzo567a@nospam.xutrox.com
Subject: Re: [PATCH] x86/perf: Fixed kernel panic during boot on Nano processor.
Date: Thu, 3 Nov 2022 11:07:28 +0100 [thread overview]
Message-ID: <Y2OS4PgqfavavMKY@zn.tnic> (raw)
In-Reply-To: <20221103032304.27753-1-silviazhao-oc@zhaoxin.com>
On Thu, Nov 03, 2022 at 11:23:04AM +0800, silviazhao-oc wrote:
> Nano processor may not fully support rdpmc instruction,
What does that even mean? Not fully support?
> it works well for reading general pmc counter, but will lead
> GP(general protection) when accessing fixed pmc counter.
RDPMC will #GP when the perf counter specified cannot be read.
AFAICT, that is RCX: 0000000040000001 which looks like perf counter
index 1 with INTEL_PMC_FIXED_RDPMC_BASE ORed in.
> Furthermore, family/mode information is same between Nano processor
> and ZX-C processor, it leads to zhaoxin pmu driver is wrongly loaded
> for Nano processor, which resulting boot kernal fail.
So *that* is the real problem - it tries to access perf counters
thinking it is running on architectural perf counters implementation but
nano doesn't have that.
> To solve this problem, stepping information will be checked to distinguish
> between Nano processor and ZX-C processor.
Why doesn't that ZXC thing doesn't have a CPUID flag to check instead of
looking at models and steppings and thus confusing it with a nano CPU?
> [https://bugzilla.kernel.org/show_bug.cgi?id=212389]
>
> Reported-by: Arjan <8vvbbqzo567a@nospam.xutrox.com>
Does Arjan have a last name?
> Signed-off-by: silviazhao-oc <silviazhao-oc@zhaoxin.com>
I'm assuming your name is properly spelled "Silvia Zhao" and not in a
single word with a "-oc" string appended at the end, yes?
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-11-03 10:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 3:23 [PATCH] x86/perf: Fixed kernel panic during boot on Nano processor silviazhao-oc
2022-11-03 10:07 ` Borislav Petkov [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-06-07 1:31 Cody Yao-oc
2021-06-30 4:38 ` Codyyao-oc
2022-10-13 13:49 ` Thorsten Leemhuis
2022-10-13 13:59 ` Peter Zijlstra
2022-10-13 15:07 ` Peter Zijlstra
2022-10-16 9:53 ` Arjan
2022-10-16 9:59 ` Peter Zijlstra
2022-10-16 10:56 ` 8vvbbqzo567a
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