linux-kernel - RE: [PATCH -next v4 2/3] x86/mce: rename MCE_IN_KERNEL_COPYIN to MCE_IN_KERNEL_COPY

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Date: Fri, 2 Feb 2024 18:44:32 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: Borislav Petkov <bp@...en8.de>, Tong Tiangen <tongtiangen@...wei.com>
CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	"wangkefeng.wang@...wei.com" <wangkefeng.wang@...wei.com>, Dave Hansen
	<dave.hansen@...ux.intel.com>, "x86@...nel.org" <x86@...nel.org>, "H. Peter
 Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...nel.org>, Peter Zijlstra
	<peterz@...radead.org>, Andrew Morton <akpm@...ux-foundation.org>, "Naoya
 Horiguchi" <naoya.horiguchi@....com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-edac@...r.kernel.org"
	<linux-edac@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org>,
	Guohanjun <guohanjun@...wei.com>
Subject: RE: [PATCH -next v4 2/3] x86/mce: rename MCE_IN_KERNEL_COPYIN to
 MCE_IN_KERNEL_COPY_MC

> So you have, for example:
>
>  unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len)
>
> Now imagine you get a MCE for *dst which is some kernel page which
> cannot be poisoned: direct map, kernel text, and so on.

At least on Intel you can only get a machine check for operation on poison data LOAD.
Not for a STORE. I believe that is generally true - other arches to confirm.

So there can't me a machine check on "*dst".

-Tony