x86/boot: Don't overwrite cr4 when enabling PAE

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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>

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This commit is contained in:

Matt Fleming 2014-02-24 13:37:29 +00:00

parent 7d453eee36

commit 108d3f44b1

1 changed files with 2 additions and 1 deletions

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arch/x86/boot/compressed/head_64.S

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