Réf. : does the linux kernel use k0, k1 regs?

Réf. : does the linux kernel use k0, k1 regs?

[Florian DELIZY]

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k0, k1 registers are used in SAVE_ALL and RESTORE_ALL macros mainly, to 
save all registers on the kernel stack,
once all registered are properly saved, you can use them, and restore them 
after, that's why kernel interrupt code does not 
uise k0,k1, and let them for critical interruption code (save/restore 
context)


Have a look in include/asm-mips/stackframe.h (grep is your friend)

-- Florian Delizy






zhuzhenhua <zzh.hust@gmail.com>

Envoyé par : linux-mips-bounce@linux-mips.org
13/01/2006 03:39
Remis le : 15/01/2006 19:29

 
        Pour :  linux-mips <linux-mips@linux-mips.org>
        cc :    (ccc : Florian DELIZY/EXT/SAGEM)
        Objet : does the linux kernel use k0, k1 regs?



i have to handle a NMI interrupt in bootloader(0xBFC00000),
 and i want to return to linux after the NMI interrupt,  i think other
regs maybe be useing by linux-kernel, i think the NMI handle only can
use K0, K1.

and i do not find the use of K0, K1 in linux-kernel interrupt or
exception handle
so i think if the NMI interrupt a linux interrupt handle, there is
still no conflict.

i am not sure my thinking is right, anyone can give some hints?

Best regards

zhuzhenhua




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Re: Réf. : does the linux kernel use k0, k1 regs?

[zhuzhenhua]

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thanks for all
now in my NMI interrupt, i first move k0 value to Desave, then use k0 to
handle, and then eret.
it can work.

On 1/16/06, Florian DELIZY <florian.delizy@sagem.com> wrote:
>
>
> k0, k1 registers are used in SAVE_ALL and RESTORE_ALL macros mainly, to
> save all registers on the kernel stack,
> once all registered are properly saved, you can use them, and restore them
> after, that's why kernel interrupt code does not
> uise k0,k1, and let them for critical interruption code (save/restore
> context)
>
>
> Have a look in include/asm-mips/stackframe.h (grep is your friend)
>
> -- Florian Delizy
>
>
>
>
>
> *zhuzhenhua <zzh.hust@gmail.com>*
>
> Envoyé par : linux-mips-bounce@linux-mips.org
>
> 13/01/2006 03:39
> Remis le : 15/01/2006 19:29
>
>         Pour :        linux-mips <linux-mips@linux-mips.org>
>         cc :        (ccc : Florian DELIZY/EXT/SAGEM)
>         Objet :        does the linux kernel use k0, k1 regs?
>
>
>
> i have to handle a NMI interrupt in bootloader(0xBFC00000),
> and i want to return to linux after the NMI interrupt,  i think other
> regs maybe be useing by linux-kernel, i think the NMI handle only can
> use K0, K1.
>
> and i do not find the use of K0, K1 in linux-kernel interrupt or
> exception handle
> so i think if the NMI interrupt a linux interrupt handle, there is
> still no conflict.
>
> i am not sure my thinking is right, anyone can give some hints?
>
> Best regards
>
> zhuzhenhua
>
>
>
>

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Re: Réf. : does the linux kernel use k0, k1 regs?

[Kevin D. Kissell]

zhuzhenhua wrote:
> thanks for all
> now in my NMI interrupt, i first move k0 value to Desave, then use k0 to
> handle, and then eret.
> it can work.

It can work as long as you understand that you can't use
EJTAG breakpoints or (more difficult to avoid) handle DINT
events that happen during your NMI handler.

		Regards,

		Kevin K.