diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2007-11-04 17:54:31 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2007-11-04 19:48:04 -0800 |
| commit | 9f259cc59ba45b8db401d60be9700e275676fb15 (patch) | |
| tree | dc57ec27c11c98fbb2ed4448d13030c4fc0b6cca | |
| parent | 7ed192906a2144ebc8ca2925a85d27b9c5355668 (diff) | |
x86 setup: set %ebx == %ebp == %edi == 0 on protected mode entry
In accordance with the newly formalized 32-bit boot protocol, set
%ebx == %ebp == %edi == 0 in order to support future extensions to the
protocol.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | arch/x86/boot/pmjump.S | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S index 26baeab3a4d..fa6bed1fac1 100644 --- a/arch/x86/boot/pmjump.S +++ b/arch/x86/boot/pmjump.S @@ -28,11 +28,13 @@ * void protected_mode_jump(u32 entrypoint, u32 bootparams); */ 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 movw $__BOOT_DS, %cx + xorl %ebx, %ebx # Per the 32-bit boot protocol + xorl %ebp, %ebp # Per the 32-bit boot protocol + xorl %edi, %edi # Per the 32-bit boot protocol movl %cr0, %edx orb $1, %dl # Protected mode (PE) bit |