diff options
| author | Matt Fleming <matt.fleming@intel.com> | 2014-02-24 13:37:29 +0000 |
|---|---|---|
| committer | Matt Fleming <matt.fleming@intel.com> | 2014-03-04 21:43:59 +0000 |
| commit | 108d3f44b16be2ecf0e44c2f2863752918eb7bce (patch) | |
| tree | d7b13929ee817e10d174e5344bdcc79ca5d58b3a /arch/x86/boot | |
| parent | 7d453eee36ae4cf30fc2f2faae54f634c4f863b7 (diff) | |
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>
Diffstat (limited to 'arch/x86/boot')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 37c741b0d2ac..4f40cddd025d 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -113,7 +113,8 @@ ENTRY(startup_32) lgdt gdt(%ebp) /* Enable PAE mode */ - movl $(X86_CR4_PAE), %eax + movl %cr4, %eax + orl $X86_CR4_PAE, %eax movl %eax, %cr4 /* |