"H. Peter Anvin" <[EMAIL PROTECTED]> writes: > Hi Linus; please pull: > > git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup.git > for-linus > > H. Peter Anvin (1): > x86 setup: correct booting on 486DX4 > > arch/x86/boot/pmjump.S | 32 +++++++++++++++++++++----------- > 1 files changed, 21 insertions(+), 11 deletions(-) > > [Full diff and log follows]
Looks reasonable to me. > commit ac3b37b78c5f0f0be0b476a35370650f7bad482f > Author: H. Peter Anvin <[EMAIL PROTECTED]> > Date: Sun Nov 4 14:33:41 2007 -0800 > > x86 setup: correct booting on 486DX4 > > Apparently, the 486DX4 does not correctly serialize a mov to %cr0, so > we really do need the far jump immediately afterwards. This means > losing the nice separation between 16- and 32-bit code, but c'est la > vie. > > Also pass %ebx = %edi = %ebp = 0 to support future extension of the > 32-bit boot protocol. > > Signed-off-by: H. Peter Anvin <[EMAIL PROTECTED]> > > diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S > index 2e55923..17e6dec 100644 > --- a/arch/x86/boot/pmjump.S > +++ b/arch/x86/boot/pmjump.S > @@ -28,27 +28,37 @@ > * 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 > + > + xorl %edx, %edx > + movw %cs, %dx > + shll $4, %edx # Patch ljmpl instruction > + addl %edx, 2f > jmp 1f # Short jump to flush instruction q. > > 1: > movw $__BOOT_DS, %cx > + xorl %ebx, %ebx # Per protocol > + xorl %ebp, %ebp # Per protocol > + xorl %edi, %edi # Per protocol > > movl %cr0, %edx > orb $1, %dl # Protected mode (PE) bit > movl %edx, %cr0 > + > + .byte 0x66, 0xea # ljmpl opcode > +2: .long 3f # Offset > + .word __BOOT_CS # Segment > > - movw %cx, %ds > - movw %cx, %es > - movw %cx, %fs > - movw %cx, %gs > - movw %cx, %ss > + .code32 > +3: > + movl %ecx, %ds > + movl %ecx, %es > + movl %ecx, %fs > + movl %ecx, %gs > + movl %ecx, %ss > > # Jump to the 32-bit entrypoint > - .byte 0x66, 0xea # ljmpl opcode > -2: .long 0 # offset > - .word __BOOT_CS # segment > - > + jmpl *%eax > + > .size protected_mode_jump, .-protected_mode_jump - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
