linux-kernel - Re: [PATCH v1 07/12] tools/x86/kcpuid: Add rudimentary CPU vendor detection

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 for Android: free password hash cracker in your pocket

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

Message-ID: <0ada12f8-4fdb-4dad-90f7-b044993e829c@intel.com>
Date: Thu, 6 Mar 2025 14:00:52 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: "Ahmed S. Darwish" <darwi@...utronix.de>, Borislav Petkov <bp@...en8.de>,
 Ingo Molnar <mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
 Andrew Cooper <andrew.cooper3@...rix.com>, "H. Peter Anvin" <hpa@...or.com>,
 x86@...nel.org, John Ogness <john.ogness@...utronix.de>,
 x86-cpuid@...ts.linux.dev, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 07/12] tools/x86/kcpuid: Add rudimentary CPU vendor
 detection

On 3/6/25 12:49, Ahmed S. Darwish wrote:
> +/*
> + * Leaf 0x0 EDX output, CPU vendor ID string bytes 4 - 7.
> + */
> +enum {
> +	EDX_INTEL	= fourcc('i', 'n', 'e', 'I'),	/* Genu_ineI_ntel */
> +	EDX_AMD		= fourcc('e', 'n', 't', 'i'),	/* Auth_enti_cAMD */
> +	EDX_HYGON	= fourcc('n', 'G', 'e', 'n'),	/* Hygo_nGen_uine */
> +	EDX_TRANSMETA	= fourcc('i', 'n', 'e', 'T'),	/* Genu_ineT_Mx86 */
> +	EDX_CENTAUR	= fourcc('a', 'u', 'r', 'H'),	/* Cent_aurH_auls */
> +	EDX_ZHAOXIN	= fourcc('a', 'n', 'g', 'h'),	/*   Sh_angh_ai	  */
> +};

So, this is cute and all. But isn't it a _wee_ bit too clever for its
own good?

Why not just have a dumb array:

	{ INTEL, "GenuineIntel" },
	{ AMD,   "AuthenticAMD" ],
	...

Are we really looking to save a few dozen CPU cycles in this thing? It
took me at least a minute or two of staring at this thing to figure out
what the heck it was doing.