Commit-ID: 108d3f44b16be2ecf0e44c2f2863752918eb7bce Gitweb: http://git.kernel.org/tip/108d3f44b16be2ecf0e44c2f2863752918eb7bce Author: Matt Fleming <matt.fleming@xxxxxxxxx> AuthorDate: Mon, 24 Feb 2014 13:37:29 +0000 Committer: Matt Fleming <matt.fleming@xxxxxxxxx> CommitDate: Tue, 4 Mar 2014 21:43:59 +0000 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@xxxxxxxxx> Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx> --- arch/x86/boot/compressed/head_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 37c741b..4f40cdd 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 /* -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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