On Thu, 2015-03-19 at 16:10 -0700, David Daney wrote:
> On 03/19/2015 03:35 PM, Kamal Mostafa wrote:
> > 3.13.11-ckt17 -stable review patch. If anyone has any objections, please let me know.
> >
>
> Read the patch commentary. It should only be applied to 3.17 and later.
>
> So: NACK.
>
Thanks very much for reviewing this, David. Dropped from 3.13-stable.
Also FYI, if you append e.g. "# 3.17+" to your Cc: stable line, that
will help the stable maintainers (more specifically, will help our
automated tools ;-) recognize where the patch should and shouldn't be
applied. Example:
Cc: <stable@xxxxxxxxxxxxxxx> # 3.17+
-Kamal
> > ------------------
> >
> > From: David Daney <david.daney@xxxxxxxxxx>
> >
> > commit 9ead8632bbf454cfc709b6205dc9cd8582fb0d64 upstream.
> >
> > The following commits:
> >
> > 5890f70f15c52d (MIPS: Use dedicated exception handler if CPU supports RI/XI exceptions)
> > 6575b1d4173eae (MIPS: kernel: cpu-probe: Detect unique RI/XI exceptions)
> >
> > break the kernel for *all* existing MIPS CPUs that implement the
> > CP0_PageGrain[IEC] bit. They cause the TLB exception handlers to be
> > generated without the legacy execute-inhibit handling, but never set
> > the CP0_PageGrain[IEC] bit to activate the use of dedicated exception
> > vectors for execute-inhibit exceptions. The result is that upon
> > detection of an execute-inhibit violation, we loop forever in the TLB
> > exception handlers instead of sending SIGSEGV to the task.
> >
> > If we are generating TLB exception handlers expecting separate
> > vectors, we must also enable the CP0_PageGrain[IEC] feature.
> >
> > The bug was introduced in kernel version 3.17.
> >
> > Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
> > Cc: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
> > Cc: linux-mips@xxxxxxxxxxxxxx
> > Patchwork: http://patchwork.linux-mips.org/patch/8880/
> > Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> > Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
> > ---
> > arch/mips/mm/tlb-r4k.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
> > index da3b0b9..d04fe4e 100644
> > --- a/arch/mips/mm/tlb-r4k.c
> > +++ b/arch/mips/mm/tlb-r4k.c
> > @@ -429,6 +429,8 @@ void tlb_init(void)
> > #ifdef CONFIG_64BIT
> > pg |= PG_ELPA;
> > #endif
> > + if (cpu_has_rixiex)
> > + pg |= PG_IEC;
> > write_c0_pagegrain(pg);
> > }
> >
> >
>
