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From: Borislav Petkov <bp@alien8.de>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/4] x86/mce: Get rid of msr_ops
Date: Wed, 22 Sep 2021 17:57:52 +0200	[thread overview]
Message-ID: <YUtSgEa8O5vyALSj@zn.tnic> (raw)
In-Reply-To: <f73c2f6790d6428393348869bc7c7e73@intel.com>

On Wed, Sep 22, 2021 at 03:22:01PM +0000, Luck, Tony wrote:
> Also:
> 
> 	switch (enum) {
> 	actions for every value of that enum
> 	}
> 
> doesn't need a default: option

Right, my thought was to catch silly stuff like this here:

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index b355ce737543..dfecf65e5407 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1714,6 +1714,7 @@ static void __mcheck_cpu_init_clear_banks(void)
 			continue;
 		wrmsrl(mca_msr_reg(i, MCA_CTL), b->ctl);
 		wrmsrl(mca_msr_reg(i, MCA_STATUS), 0);
+		wrmsrl(mca_msr_reg(i, 12), 0);
 	}
 }
 

but we already warn nicely there:

[    0.146457] unchecked MSR access error: WRMSR to 0x0 (tried to write 0x0000000000000000) at rIP: 0xffffffff8103234b (__mcheck_cpu_init_clear_banks+0x6b/0xe0)
[    0.147550] Call Trace:
[    0.147836]  mcheck_cpu_init+0x16c/0x4a0
[    0.148234]  identify_cpu+0x3fe/0x670
[    0.148607]  identify_boot_cpu+0xc/0x94
[    0.148995]  check_bugs+0x26/0xaef
[    0.149353]  ? __get_locked_pte+0x14a/0x200
[    0.149777]  start_kernel+0x602/0x621
[    0.150153]  secondary_startup_64_no_verify+0xb0/0xbb

and the mce_rd/wrmsrl() wrappers even panic.

So default case gone.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-09-22 15:58 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-17 10:53 [PATCH 0/4] x86/mce: Remove indirect calls Borislav Petkov
2021-09-17 10:53 ` [PATCH 1/4] x86/mce: Get rid of the mce_severity function pointer Borislav Petkov
2021-09-17 10:53 ` [PATCH 2/4] x86/mce: Get rid of machine_check_vector Borislav Petkov
2021-09-20  4:57   ` Luck, Tony
2021-09-20  7:42     ` Rasmus Villemoes
2021-09-20  8:15       ` Borislav Petkov
2021-09-20  8:12     ` Borislav Petkov
2021-09-20 16:04       ` Luck, Tony
2021-09-20 16:32         ` Borislav Petkov
2021-09-17 10:53 ` [PATCH 3/4] x86/mce: Get rid of msr_ops Borislav Petkov
2021-09-20  4:47   ` Luck, Tony
2021-09-20  8:32     ` Borislav Petkov
2021-09-22 12:16       ` Borislav Petkov
2021-09-22 13:23         ` Luck, Tony
2021-09-22 13:55           ` Borislav Petkov
2021-09-22 15:22             ` Luck, Tony
2021-09-22 15:57               ` Borislav Petkov [this message]
2021-09-17 10:53 ` [PATCH 4/4] x86/mce: Get rid of the ->quirk_no_way_out() indirect call Borislav Petkov
2021-09-20  5:06   ` Luck, Tony
2021-09-20  8:34     ` Borislav Petkov
2021-09-23 14:51   ` Yazen Ghannam
2021-09-23 15:11     ` Borislav Petkov
2021-09-24 20:04       ` Yazen Ghannam

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