linux-kernel - RE: [PATCH v2 03/16] x86/mce/amd: Remove smca_banks

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Message-ID: <CY8PR11MB713439C32E76A85C09C666BB89FB2@CY8PR11MB7134.namprd11.prod.outlook.com>
Date: Mon, 17 Feb 2025 07:57:47 +0000
From: "Zhuo, Qiuxu" <qiuxu.zhuo@...el.com>
To: Yazen Ghannam <yazen.ghannam@....com>, "x86@...nel.org" <x86@...nel.org>,
	"Luck, Tony" <tony.luck@...el.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
	"Smita.KoralahalliChannabasappa@....com"
	<Smita.KoralahalliChannabasappa@....com>
Subject: RE: [PATCH v2 03/16] x86/mce/amd: Remove smca_banks_map

> From: Yazen Ghannam <yazen.ghannam@....com>
> Sent: Friday, February 14, 2025 12:46 AM
> To: x86@...nel.org; Luck, Tony <tony.luck@...el.com>
> Cc: linux-kernel@...r.kernel.org; linux-edac@...r.kernel.org;
> Smita.KoralahalliChannabasappa@....com; Yazen Ghannam
> <yazen.ghannam@....com>
> Subject: [PATCH v2 03/16] x86/mce/amd: Remove smca_banks_map
> 
> The MCx_MISC0[BlkPtr] field was used on legacy systems to hold a register
> offset for the next MCx_MISC* register. In this way, an implementation-
> specific number of registers can be discovered at runtime.
> 
> The MCAX/SMCA register space simplifies this by always including the
> MCx_MISC[1-4] registers. The MCx_MISC0[BlkPtr] field is used to indicate
> (true/false) whether any MCx_MISC[1-4] registers are present.
> But it does not indicate which ones nor how many. Therefore, all the registers

s/nor/or     (suggested by AI 😊)
OR
s/does not indicate/indicates neither

> are accessed and their bits are checked.
> 
> AMD systems generally enforce a Read-as-Zero/Writes-Ignored policy for
> unused registers. Therefore, there is no harm to read an unused register. This
> is already done in practice for most of the MCx_MISC registers.
> 
> Remove the smca_banks_map variable as it is effectively redundant.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>

Aside from the small nit above,

    Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>