Message-ID: <53A46008.5060509@zytor.com>
Date: Fri, 20 Jun 2014 09:23:36 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Dave Hansen <dave@sr71.net>, linux-kernel@vger.kernel.org
CC: bp@alien8.de, x86@kernel.org
Subject: Re: [RFC][PATCH 3/3] x86: make MP  a required-feature on 64-bit
References: <20140620161736.D6AC16FD@viggo.jf.intel.com> <20140620161740.BFB00798@viggo.jf.intel.com>
In-Reply-To: <20140620161740.BFB00798@viggo.jf.intel.com>
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On 06/20/2014 09:17 AM, Dave Hansen wrote:
> Today, we assume that all 64-bit cpus have X86_FEATURE_MP.  It
> should be in the REQUIRED_MASK so that we do not need the #undef
> trick for it.

I don't think we enforce that the MP bit is set in CPUID, though.
Non-AMD processors will typically not set this bit at all, so the
feature validation code would have to be modified to know to not require
this bit.

	-hpa

>  
> -#define REQUIRED_MASK1	(NEED_LM|NEED_3DNOW)
> +#define REQUIRED_MASK1	(NEED_LM|NEED_3DNOW|NEED_MP)
>  

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