Hi,

On Thu, May 02, 2013 at 01:48:12PM -0700, David Daney wrote:
> From: David Daney <[email protected]>
> 
> As noted by Thomas Gleixner:
> 
>    commit cdbedc61c8 (mips: Use generic idle loop) broke MIPS as I did
>    not realize that MIPS wants to invoke the wait instructions with
>    interrupts enabled.
> 
> Instead of enabling interrupts in arch_cpu_idle() as Thomas' initial
> patch does, we follow Linus' suggestion of doing it in the assembly
> code to prevent the compiler from rearranging things.
> 
> Signed-off-by: David Daney <[email protected]>
> Reported-by: EunBong Song <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Jonas Gorski <[email protected]>
> ---
> 
> This is only very lightly tested, we need more testing before
> declaring it the definitive fix.

I wonder what is the status of this patch? Or is there some alternative
fix?

I have Octeon+ board that hangs during 3.10-rc2 boot in spawn_ksoftirqd()
without this. Also, this patch does not apply cleanly to 3.10-rc2
anymore...

A.

>  arch/mips/kernel/genex.S | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index ecb347c..57cda9a 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -132,12 +132,13 @@ LEAF(r4k_wait)
>       .set    noreorder
>       /* start of rollback region */
>       LONG_L  t0, TI_FLAGS($28)
> -     nop
>       andi    t0, _TIF_NEED_RESCHED
>       bnez    t0, 1f
>        nop
> -     nop
> -     nop
> +     /* Enable interrupts so WAIT will complete */
> +     mfc0    t0, CP0_STATUS
> +     ori     t0, ST0_IE
> +     mtc0    t0, CP0_STATUS
>       .set    mips3
>       wait
>       /* end of rollback region (the region size must be power of two) */
> -- 
> 1.7.11.7
> 
> 
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