x86/boot: Don't overwrite cr4 when enabling PAE
authorMatt Fleming <matt.fleming@intel.com>
Mon, 24 Feb 2014 13:37:29 +0000 (13:37 +0000)
committerMatt Fleming <matt.fleming@intel.com>
Tue, 4 Mar 2014 21:43:59 +0000 (21:43 +0000)
commit108d3f44b16be2ecf0e44c2f2863752918eb7bce
treed7b13929ee817e10d174e5344bdcc79ca5d58b3a
parent7d453eee36ae4cf30fc2f2faae54f634c4f863b7
x86/boot: Don't overwrite cr4 when enabling PAE

Some EFI firmware makes use of the FPU during boottime services and
clearing X86_CR4_OSFXSR by overwriting %cr4 causes the firmware to
crash.

Add the PAE bit explicitly instead of trashing the existing contents,
leaving the rest of the bits as the firmware set them.

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
arch/x86/boot/compressed/head_64.S