Skip to content

Commit

Permalink
x86, head_32: Remove second CPUID detection from default_entry
Browse files Browse the repository at this point in the history
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@suse.de>
Link: http://lkml.kernel.org/r/1360592538-10643-4-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
  • Loading branch information
Borislav Petkov authored and H. Peter Anvin committed Feb 12, 2013
1 parent 9efb58d commit c3a22a2
Showing 1 changed file with 4 additions and 13 deletions.
17 changes: 4 additions & 13 deletions arch/x86/kernel/head_32.S
Original file line number Diff line number Diff line change
Expand Up @@ -399,18 +399,7 @@ 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 */
Expand All @@ -436,7 +425,9 @@ 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
Expand Down

0 comments on commit c3a22a2

Please sign in to comment.