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SubjectRe: [PATCH 12/20] x86_64: wakeup.S Misc cleanup

> o Various cleanups. One of the main purpose of cleanups is that make
> wakeup.S as close as possible to trampoline.S.
> o Following are the changes
> - Indentations for comments.
> - Changed the gdt table to compact form and to resemble the
> one in trampoline.S
> - Take the jump to 32bit from real mode using ljmpl. Makes code
> more readable.
> - After enabling long mode, directly take a long jump for 64bit
> mode. No need to take an extra jump to "reach_comaptibility_mode"
> - Stack is not used after real mode. So don't load stack in
> 32 bit mode.
> - No need to enable PGE here.
> - No need to do extra EFER read, anyway we trash the read contents.
> - No need to enable system call (EFER_SCE). Anyway it will be
> enabled when original EFER is restored.
> - No need to set MP, ET, NE, WP, AM bits in cr0. Very soon we will
> reload the original cr0 while restroing the processor state.
> Signed-off-by: Eric W. Biederman <>
> Signed-off-by: Vivek Goyal <>

ACK, minor nitpicks:

> + /* ??? Why I need the accessed bit set in order for this to work? */

Yes, I'd like to know :-).

> + .quad 0x00cf9b000000ffff # __KERNEL32_CS
> + .quad 0x00af9b000000ffff # __KERNEL_CS
> + .quad 0x00cf93000000ffff # __KERNEL_DS

Can we get a comment telling us what to keep it in sync with?

(cesky, pictures)
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