[tip:x86/asm] x86, head_32: Remove second CPUID detection from default_entry
From: tip-bot for Borislav Petkov
Date: Tue Feb 12 2013 - 19:12:14 EST
Commit-ID: c3a22a26d07d928e2b74b58e2f9d2436958620f0
Gitweb: http://git.kernel.org/tip/c3a22a26d07d928e2b74b58e2f9d2436958620f0
Author: Borislav Petkov <bp@xxxxxxx>
AuthorDate: Mon, 11 Feb 2013 15:22:17 +0100
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 12 Feb 2013 15:48:42 -0800
x86, head_32: Remove second CPUID detection from default_entry
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>
Link: http://lkml.kernel.org/r/1360592538-10643-4-git-send-email-bp@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
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 e3725a0..2e8532e 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -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 */
@@ -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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/