[tip:x86/asm] x86, head_32: Remove i386 pieces
Commit-ID: 166df91daf38f619d4ca90b58ff90983de6e40d2 Gitweb: http://git.kernel.org/tip/166df91daf38f619d4ca90b58ff90983de6e40d2 Author: Borislav Petkov AuthorDate: Mon, 11 Feb 2013 15:22:15 +0100 Committer: H. Peter Anvin CommitDate: Tue, 12 Feb 2013 15:48:40 -0800 x86, head_32: Remove i386 pieces 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 Link: http://lkml.kernel.org/r/1360592538-10643-2-git-send-email...@alien8.de Signed-off-by: H. Peter Anvin --- 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 c8932c7..a9c5cc8 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -394,30 +394,21 @@ 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 $0x24,%eax # flip AC and ID bits in EFLAGS + xorl $0x20,%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 $0x4,%eax # check if AC bit changed - je is386 - - movb $4,X86 # at least 486 testl $0x20,%eax# check if ID bit changed je is486 @@ -445,10 +436,7 @@ 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 $0x8011,%eax # Save PG,PE,ET orl %ecx,%eax movl %eax,%cr0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[tip:x86/asm] x86, head_32: Remove i386 pieces
Commit-ID: 166df91daf38f619d4ca90b58ff90983de6e40d2 Gitweb: http://git.kernel.org/tip/166df91daf38f619d4ca90b58ff90983de6e40d2 Author: Borislav Petkov b...@suse.de AuthorDate: Mon, 11 Feb 2013 15:22:15 +0100 Committer: H. Peter Anvin h...@linux.intel.com CommitDate: Tue, 12 Feb 2013 15:48:40 -0800 x86, head_32: Remove i386 pieces 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 b...@suse.de Link: http://lkml.kernel.org/r/1360592538-10643-2-git-send-email...@alien8.de Signed-off-by: H. Peter Anvin h...@linux.intel.com --- 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 c8932c7..a9c5cc8 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -394,30 +394,21 @@ 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 $0x24,%eax # flip AC and ID bits in EFLAGS + xorl $0x20,%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 $0x4,%eax # check if AC bit changed - je is386 - - movb $4,X86 # at least 486 testl $0x20,%eax# check if ID bit changed je is486 @@ -445,10 +436,7 @@ 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 $0x8011,%eax # Save PG,PE,ET orl %ecx,%eax movl %eax,%cr0 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
