Re: [linuxsh-dev] PCMCIA patch & question

[Greg B. <gb...@po...>]

NIIBE Yutaka wrote:
> 
> NIIBE Yutaka wrote:
>  > I think that wired TLB entry is better.  Some (or most) drivers don't
>  > expect TLB fault would occur with I/O access functions.
> 
> Reading test10-pre2, I've changed my mind.  It reads:
> 
> --- v2.4.0-test9/linux/arch/i386/mm/fault.c     Wed May 24 18:38:26 2000
> +++ linux/arch/i386/mm/fault.c  Thu Oct 12 12:57:31 2000
> @@ -130,6 +130,19 @@
>         __asm__("movl %%cr2,%0":"=r" (address));
> 
>         tsk = current;
> +
> +       /*
> +        * We fault-in kernel-space virtual memory on-demand. The
> +        * 'reference' page table is init_mm.pgd.
> +        *
> +        * NOTE! We MUST NOT take any locks for this case. We may
> +        * be in an interrupt or a critical region, and should
> +        * only copy the information from the master page table,
> +        * nothing more.
> +        */
> +       if (address >= TASK_SIZE)
> +               goto vmalloc_fault;
> +
> -------------------------------
> 
> It explicitly says this fault may occur in a interrupt handler or in a
> critical region.  I _was_ afraid of exactly on this issue (TLB falut
> in interrupt handler or a critical region), I now understand that we
> should implement the TLB fault handler with this condition.
> 
> Please go ahead on your original TLB implementation.  Please include
> ChangeLog entries when commit.
> 
> I'll do the changes of optimizing PGD and removing set_pgdir for SuperH.

  Ok.

  Last night I submitted the host bridge driver to David Hinds.

Greg.
-- 
These are my opinions not PPIs.