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Commit 166df91d authored by Borislav Petkov's avatar Borislav Petkov Committed by H. Peter Anvin
Browse files

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: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1360592538-10643-2-git-send-email-bp@alien8.de


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 8ecba5af

arch/x86/kernel/head_32.S

+5 −17
Original line number Diff line number Diff line
@@ -395,29 +395,20 @@ default_entry: 
	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
@@ -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 $0x80000011,%eax	# Save PG,PE,ET

	orl %ecx,%eax

	movl %eax,%cr0