Commit 7ed19290 authored by H. Peter Anvin's avatar H. Peter Anvin
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x86 setup: add a near jump to serialize %cr0 on 386/486 



The 386 and 486 needs a jump immediately after setting %cr0 in order
to serialize the pipeline.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent b55d1b18

arch/x86/boot/pmjump.S

+2 −2
Original line number Diff line number Diff line
@@ -31,14 +31,14 @@ protected_mode_jump: 
	xorl	%ebx, %ebx		# Flag to indicate this is a boot

	movl	%edx, %esi		# Pointer to boot_params table

	movl	%eax, 2f		# Patch ljmpl instruction

	jmp	1f			# Short jump to flush instruction q.



1:

	movw	$__BOOT_DS, %cx



	movl	%cr0, %edx

	orb	$1, %dl			# Protected mode (PE) bit

	movl	%edx, %cr0

	jmp	1f			# Short jump to serialize on 386/486

1:



	movw	%cx, %ds

	movw	%cx, %es