From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/6] arm64: Add support for hooks to handle undefined instructions
Date: Wed, 27 Aug 2014 17:51:59 +0100 [thread overview]
Message-ID: <20140827165159.GD17601@arm.com> (raw)
In-Reply-To: <20140827164714.GF13850@arm.com>
On Wed, Aug 27, 2014 at 05:47:14PM +0100, Catalin Marinas wrote:
> On Tue, Aug 26, 2014 at 03:30:11PM +0100, Will Deacon wrote:
> > On Tue, Aug 26, 2014 at 03:21:09PM +0100, Ard Biesheuvel wrote:
> > > You need this patch in order to be able to return from an undef
> > > exception taken in EL1:
> > >
> > > --- a/arch/arm64/kernel/entry.S
> > > +++ b/arch/arm64/kernel/entry.S
> > > @@ -287,7 +287,9 @@ el1_undef:
> > > */
> > > enable_dbg
> > > mov x0, sp
> > > - b do_undefinstr
> > > + bl do_undefinstr
> > > +
> > > + kernel_exit 1
> > > el1_dbg:
> > > /*
> > > * Debug exception handling
> >
> > Hmm, I'm surprised we don't already need something like this for KGDB...
>
> We don't expect undef exceptions at EL1, so far they are fatal as we
> don't have any hooks for them. Doesn't KGDB use dedicated breakpoint
> instructions?
Ah yeah, we use magic immediates in the BRK instruction. I was getting
confused with arch/arm/, where we actually use an undefined encoding for
the same thing. That explains why things appear to be working!
Will
next prev parent reply other threads:[~2014-08-27 16:51 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-26 10:28 [PATCH 0/6] Legacy instruction emulation for arm64 Punit Agrawal
2014-08-26 10:28 ` [PATCH 1/6] arm: Fix in-correct barrier usage in SWP{B} emulation Punit Agrawal
2014-08-26 13:04 ` Will Deacon
2014-08-27 16:40 ` Catalin Marinas
2014-08-27 17:05 ` Punit Agrawal
2014-08-26 10:28 ` [PATCH 2/6] arm64: Create arch debugfs directory Punit Agrawal
2014-08-26 10:28 ` [PATCH 3/6] arm64: Add support for hooks to handle undefined instructions Punit Agrawal
2014-08-26 13:13 ` Will Deacon
2014-08-26 14:21 ` Ard Biesheuvel
2014-08-26 14:30 ` Will Deacon
2014-08-27 16:47 ` Catalin Marinas
2014-08-27 16:51 ` Will Deacon [this message]
2014-08-26 14:56 ` Punit Agrawal
2014-08-26 18:14 ` Will Deacon
2014-08-27 16:58 ` Catalin Marinas
2014-08-26 10:28 ` [PATCH 4/6] arm64: Add AArch32 instruction set condition code checks Punit Agrawal
2014-08-26 10:28 ` [PATCH 5/6] arm64: Port SWP/SWPB emulation support from arm Punit Agrawal
2014-08-26 11:32 ` Arnd Bergmann
2014-08-26 12:25 ` Will Deacon
2014-08-26 13:26 ` Arnd Bergmann
2014-08-26 13:56 ` Will Deacon
2014-08-27 17:35 ` Punit Agrawal
2014-08-27 18:30 ` Arnd Bergmann
2014-08-28 10:21 ` Punit Agrawal
2014-08-27 17:29 ` Catalin Marinas
2014-08-26 10:28 ` [PATCH 6/6] arm64: Emulate CP15 Barrier instructions Punit Agrawal
2014-08-26 13:16 ` Will Deacon
2014-08-27 17:40 ` Catalin Marinas
2014-08-28 9:34 ` Punit Agrawal
2014-08-28 9:42 ` Catalin Marinas
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