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Date: Sat, 9 Feb 2013 20:52:50 +0100 From: Borislav Petkov <bp@...en8.de> To: "H. Peter Anvin" <hpa@...or.com> Cc: X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...e.de> Subject: [PATCH 1/5] x86, head_32: Remove i386 pieces From: Borislav Petkov <bp@...e.de> Remove code fragments detecting a 386 CPU since we don't support those anymore. Also, do not do alignment checks because they're done only at CPL3. Also, no need to preserve EFLAGS. Signed-off-by: Borislav Petkov <bp@...e.de> --- arch/x86/kernel/head_32.S | 22 +++++----------------- 1 file changed, 5 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 0b8c825fc264..f4d919e2cd2b 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -405,30 +405,21 @@ default_entry: jz 1f # Did we do this already? call *%eax 1: - -/* check if it is 486 or 386. */ + /* - * XXX - this does a lot of unnecessary setup. Alignment checks don't - * apply at our cpl of 0 and the stack ought to be aligned already, and - * we don't need to preserve eflags. + * Check if it is 486 */ movl $-1,X86_CPUID # -1 for no CPUID initially - movb $3,X86 # at least 386 + movb $4,X86 # at least 486 pushfl # push EFLAGS popl %eax # get EFLAGS movl %eax,%ecx # save original EFLAGS - xorl $0x240000,%eax # flip AC and ID bits in 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 - pushl %ecx # restore original EFLAGS - popfl - testl $0x40000,%eax # check if AC bit changed - je is386 - - movb $4,X86 # at least 486 testl $0x200000,%eax # check if ID bit changed je is486 @@ -456,10 +447,7 @@ default_entry: movl %edx,X86_CAPABILITY is486: movl $0x50022,%ecx # set AM, WP, NE and MP - jmp 2f - -is386: movl $2,%ecx # set MP -2: movl %cr0,%eax + movl %cr0,%eax andl $0x80000011,%eax # Save PG,PE,ET orl %ecx,%eax movl %eax,%cr0 -- 1.8.1.3.535.ga923c31 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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