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From: "H. Peter Anvin" <hpa@zytor.com>
To: mingo@kernel.org, linux-kernel@vger.kernel.org,
	aravind.gopalakrishnan@amd.com, tglx@linutronix.de, bp@suse.de,
	hpa@linux.intel.com, linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/urgent] x86, cpu, amd: Add workaround for family 16h, erratum 793
Date: Tue, 14 Jan 2014 16:54:41 -0800	[thread overview]
Message-ID: <52D5DC51.9010606@zytor.com> (raw)
In-Reply-To: <tip-3b56496865f9f7d9bcb2f93b44c63f274f08e3b6@git.kernel.org>

On 01/14/2014 04:45 PM, tip-bot for Borislav Petkov wrote:
> +		rdmsrl(MSR_AMD64_LS_CFG, val);
> +		if (!(val & BIT(15)))
> +			wrmsrl(MSR_AMD64_LS_CFG, val | BIT(15));

Incidentally, I'm wondering if we shouldn't have a
set_in_msr()/clear_in_msr() set of functions which would incorporate the
above construct:

void set_in_msr(u32 msr, u64 mask)
{
	u64 old, new;

	old = rdmsrl(msr);
	new = old | mask;
	if (old != new)
		wrmsrl(msr, new);
}

... and the obvious equivalent for clear_in_msr().

The perhaps only question is if it should be "set/clear_bit_in_msr()"
rather than having to haul a full 64-bit mask in the common case.

	-hpa



  reply	other threads:[~2014-01-15  0:55 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-14 11:41 AMD errata 793 (CVE-2013-6885) needs a workaround in Linux? Henrique de Moraes Holschuh
2014-01-14 11:55 ` Borislav Petkov
2014-01-14 15:14   ` H. Peter Anvin
2014-01-14 15:35     ` Borislav Petkov
2014-01-14 16:27       ` [PATCH] x86, CPU, AMD: Add workaround for family 16h, erratum 793 Borislav Petkov
2014-01-14 16:30         ` H. Peter Anvin
2014-01-14 16:42           ` Borislav Petkov
2014-01-14 17:46             ` H. Peter Anvin
2014-01-14 23:07               ` [PATCH -v1.1] " Borislav Petkov
2014-01-15  0:38                 ` H. Peter Anvin
2014-01-15 11:10                   ` [PATCH -v1.2] " Borislav Petkov
2014-01-15  0:45                 ` [tip:x86/urgent] x86, cpu, amd: " tip-bot for Borislav Petkov
2014-01-15  0:54                   ` H. Peter Anvin [this message]
2014-01-15  6:28                     ` Ingo Molnar
2014-01-15 13:36                       ` Borislav Petkov
2014-01-15 13:52                         ` H. Peter Anvin
2014-01-15 18:38                           ` Ingo Molnar
2014-01-16  4:11                             ` H. Peter Anvin
     [not found]         ` <52D59ACC.3090100@amd.com>
2014-01-14 20:38           ` [PATCH] x86, CPU, AMD: " Borislav Petkov
2014-01-16 17:58             ` Aravind Gopalakrishnan
2014-01-16 18:10               ` Borislav Petkov
2014-01-17  0:21               ` Henrique de Moraes Holschuh
2014-01-17  0:25                 ` H. Peter Anvin
2014-01-17 10:18                 ` Borislav Petkov
2014-01-17 16:23                   ` H. Peter Anvin
2014-01-17 17:02                     ` Borislav Petkov
2014-01-17 17:36                       ` Aravind Gopalakrishnan
2014-01-17 17:42                       ` H. Peter Anvin
2014-01-17 18:05                         ` Aravind Gopalakrishnan
2014-01-17 18:25                           ` Borislav Petkov
2014-01-17 22:28         ` Pavel Machek
2014-01-17 22:50           ` Borislav Petkov
2014-01-17 22:51             ` H. Peter Anvin
2014-01-17 22:57               ` Borislav Petkov
2014-01-18  0:29               ` Pavel Machek
2014-01-18  1:21                 ` H. Peter Anvin
2014-01-18  2:01                   ` Pavel Machek
2014-01-18 10:42                     ` Borislav Petkov
2014-01-18 11:08                       ` Pavel Machek
2014-01-18 11:26                         ` Borislav Petkov
2014-01-18 11:31                           ` Pavel Machek

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