[PATCH 3/4] x86, head_32: Remove second CPUID detection from default_entry

From: Borislav Petkov
Date: Mon Feb 11 2013 - 09:22:58 EST


From: Borislav Petkov <bp@xxxxxxx>

We do that once earlier now and cache it into new_cpu_data.cpuid_level
so no need for the EFLAGS.ID toggling dance anymore.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kernel/head_32.S | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 73e084a6d2c5..e893ac09ca03 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -410,18 +410,7 @@ default_entry:
/*
* Check if it is 486
*/
- movl $-1,X86_CPUID # -1 for no CPUID initially
- movb $4,X86 # at least 486
- pushfl # push EFLAGS
- popl %eax # get EFLAGS
- movl %eax,%ecx # save original EFLAGS
- xorl $0x200000,%eax # flip ID bit in EFLAGS
- pushl %eax # copy to EFLAGS
- popfl # set EFLAGS
- pushfl # get new EFLAGS
- popl %eax # put it in eax
- xorl %ecx,%eax # change in flags
- testl $0x200000,%eax # check if ID bit changed
+ cmpl $-1,X86_CPUID
je is486

/* get vendor info */
@@ -447,7 +436,9 @@ default_entry:
movb %cl,X86_MASK
movl %edx,X86_CAPABILITY

-is486: movl $0x50022,%ecx # set AM, WP, NE and MP
+is486:
+ movb $4,X86
+ movl $0x50022,%ecx # set AM, WP, NE and MP
movl %cr0,%eax
andl $0x80000011,%eax # Save PG,PE,ET
orl %ecx,%eax
--
1.8.1.3.535.ga923c31

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