From: H. Peter Anvin <hpa@linux.intel.com>
Date: Wed, 21 Jan 2009 23:04:32 +0000 (-0800)
Subject: x86: unmask CPUID levels on Intel CPUs
X-Git-Tag: v2.6.29-rc3~42^2~8
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=066941bd4eeb159307a5d7d795100d0887c00442;p=pandora-kernel.git

x86: unmask CPUID levels on Intel CPUs

Impact: Fixes crashes with misconfigured BIOSes on XSAVE hardware

Avuton Olrich reported early boot crashes with v2.6.28 and
bisected it down to dc1e35c6e95e8923cf1d3510438b63c600fee1e2
("x86, xsave: enable xsave/xrstor on cpus with xsave support").

If the CPUID limit bit in MSR_IA32_MISC_ENABLE is set, clear it to
make all CPUID information available.  This is required for some
features to work, in particular XSAVE.

Reported-and-bisected-by: Avuton Olrich <avuton@gmail.com>
Tested-by: Avuton Olrich <avuton@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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