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authorH. Peter Anvin <hpa@zytor.com>2007-11-04 17:50:12 -0800
committerH. Peter Anvin <hpa@zytor.com>2007-11-04 19:47:46 -0800
commit7ed192906a2144ebc8ca2925a85d27b9c5355668 (patch)
tree350af59996f750ae2a2d7d7ccf2ffbb596a571e8
parentb55d1b1814c52463c11707f53dbdc223e09b2924 (diff)
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: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--arch/x86/boot/pmjump.S4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S
index 2e559233725a..26baeab3a4d4 100644
--- a/arch/x86/boot/pmjump.S
+++ b/arch/x86/boot/pmjump.S
@@ -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