[PATCH] Make interrupt handler works for all cases

[PATCH] Make interrupt handler works for all cases

[Franck Bui-Huu]

specially when the kernel is mapped.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>


---

 arch/mips/kernel/genex.S |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

72821cd1fc2a6e31e31c2babf338425b29e8f11f
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index ff7af36..50cb0c2 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -132,7 +132,8 @@ NESTED(handle_int, PT_SIZE, sp)

 	PTR_LA	ra, ret_from_irq
 	move	a0, sp
-	j	plat_irq_dispatch
+	PTR_LA	k0, plat_irq_dispatch
+	jr	k0
 	END(handle_int)

 	__INIT
--
1.3.0.g2473

Re: [PATCH] Make interrupt handler works for all cases

[Ralf Baechle]

On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:

> specially when the kernel is mapped.

At which time you're on very fragile ice because TLB instructions should
better be executed from an unmapped address ...

  Ralf

Re: [PATCH] Make interrupt handler works for all cases

[Franck Bui-Huu]

2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
>
> > specially when the kernel is mapped.
>
> At which time you're on very fragile ice because TLB instructions should
> better be executed from an unmapped address ...
>

well TLB entry used by the kernel is wired, so it should work fined,
shouldn't it ?

Thanks
--
               Franck

Re: [PATCH] Make interrupt handler works for all cases

[Thiemo Seufer]

Franck Bui-Huu wrote:
> 2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> >On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
> >
> >> specially when the kernel is mapped.
> >
> >At which time you're on very fragile ice because TLB instructions should
> >better be executed from an unmapped address ...
> >
> 
> well TLB entry used by the kernel is wired, so it should work fined,
> shouldn't it ?

The architecture spec doesn't guarantee it will.


Thiemo

Re: [PATCH] Make interrupt handler works for all cases

[Franck Bui-Huu]

2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
>
> > specially when the kernel is mapped.
>
> At which time you're on very fragile ice because TLB instructions should
> better be executed from an unmapped address ...
>

So does it mean that MIPS arch can't provide reliable support for
running mapped kernel ?

--
               Franck

Re: [PATCH] Make interrupt handler works for all cases

[Franck Bui-Huu]

2006/5/2, Thiemo Seufer <ths@networkno.de>:
> Franck Bui-Huu wrote:
> > 2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> > >On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
> > >
> > >> specially when the kernel is mapped.
> > >
> > >At which time you're on very fragile ice because TLB instructions should
> > >better be executed from an unmapped address ...
> > >
> >
> > well TLB entry used by the kernel is wired, so it should work fined,
> > shouldn't it ?
>
> The architecture spec doesn't guarantee it will.
>

having a quick look at the TLB handling code, it seems that the code
assumes it will...

--
               Franck

Re: [PATCH] Make interrupt handler works for all cases

[Thiemo Seufer]

Franck Bui-Huu wrote:
> 2006/5/2, Thiemo Seufer <ths@networkno.de>:
> >Franck Bui-Huu wrote:
> >> 2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> >> >On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
> >> >
> >> >> specially when the kernel is mapped.
> >> >
> >> >At which time you're on very fragile ice because TLB instructions should
> >> >better be executed from an unmapped address ...
> >> >
> >>
> >> well TLB entry used by the kernel is wired, so it should work fined,
> >> shouldn't it ?
> >
> >The architecture spec doesn't guarantee it will.
> 
> having a quick look at the TLB handling code, it seems that the code
> assumes it will...

I don't know which code you are looking at, but the kernel's TLB
handling doesn't run in mapped space. (The ip27 is an exception,
I assume the R1x000 allows for mapped TLB handling.)


Thiemo

Re: [PATCH] Make interrupt handler works for all cases

[Franck Bui-Huu]

2006/5/2, Thiemo Seufer <ths@networkno.de>:
> Franck Bui-Huu wrote:
> > 2006/5/2, Thiemo Seufer <ths@networkno.de>:
> > >Franck Bui-Huu wrote:
> > >> 2006/5/2, Ralf Baechle <ralf@linux-mips.org>:
> > >> >On Tue, May 02, 2006 at 09:55:51AM +0200, Franck Bui-Huu wrote:
> > >> >
> > >> >> specially when the kernel is mapped.
> > >> >
> > >> >At which time you're on very fragile ice because TLB instructions should
> > >> >better be executed from an unmapped address ...
> > >> >
> > >>
> > >> well TLB entry used by the kernel is wired, so it should work fined,
> > >> shouldn't it ?
> > >
> > >The architecture spec doesn't guarantee it will.
> >
> > having a quick look at the TLB handling code, it seems that the code
> > assumes it will...
>
> I don't know which code you are looking at, but the kernel's TLB
> handling doesn't run in mapped space. (The ip27 is an exception,
> I assume the R1x000 allows for mapped TLB handling.)
>

I have assumed the same for r4k cpu and it seems to work fine...
Anyways, Ralf can you apply this patch ?

Thanks
--
               Franck