From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: benh@kernel.crashing.org
Cc: Daniel Jacobowitz <drow@false.org>,
gdb@sourceware.org, linuxppc-embedded@ozlabs.org,
Matt Mackall <mpm@selenic.com>
Subject: Re: Apparent kernel bug with GDB on ppc405
Date: Sat, 27 Oct 2007 01:40:00 -0000 [thread overview]
Message-ID: <1193448456.25515.63.camel@localhost.localdomain> (raw)
In-Reply-To: <1193448983.18243.16.camel@pasglop>
On Sat, 2007-10-27 at 11:36 +1000, Benjamin Herrenschmidt wrote:
> On Fri, 2007-10-26 at 15:41 -0500, Josh Boyer wrote:
> > On Fri, 26 Oct 2007 11:51:22 +1000
> > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> >
> > >
> > > On Wed, 2007-10-24 at 18:41 -0400, Daniel Jacobowitz wrote:
> > > > On Wed, Oct 24, 2007 at 05:32:50PM -0500, Matt Mackall wrote:
> > > > > Not completely implausible, but a) why isn't this seen on basically
> > > > > every machine with software TLB? b) why does -local- GDB, which is
> > > > > presumably doing much less work than gdbserver + network stack, not fail?
> > > >
> > > > You said it yourself. Local gdb does more work -> blows through more
> > > > TLB entries.
> > > >
> > > > I can't answer you about the other half, but I'm pretty sure TLB
> > > > invalidation is already supposed to be happening... somewhere.
> > >
> > > Yes. do_wp_page() -> ptep_clear_flush() -> flush_tlb_page()
> >
> > Aren't there cases in do_wp_page that don't call ptep_clear_flush?
> > Seems anonymous pages, and possibly shared writeable pages skip that
> > step if reuse is true.
>
> Nah, if that was broken, everybody would be in bad shape. I think I know
> what's up, see my other email.
Yeah, I figured that out after I sent this anyway. In those cases it
should likely get flushed from ptep_set_access_flags.
josh
next prev parent reply other threads:[~2007-10-27 1:40 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-24 19:46 Matt Mackall
2007-10-24 20:28 ` Grant Likely
2007-10-24 20:42 ` Matt Mackall
2007-10-24 20:46 ` Grant Likely
2007-10-24 21:54 ` Matt Mackall
2007-10-24 22:28 ` Grant Likely
2007-10-24 22:33 ` Matt Mackall
2007-10-24 22:39 ` Grant Likely
2007-10-24 22:40 ` Grant Likely
2007-10-26 1:51 ` Benjamin Herrenschmidt
2007-10-24 22:41 ` Daniel Jacobowitz
2007-10-26 1:51 ` Benjamin Herrenschmidt
2007-10-26 20:41 ` Josh Boyer
2007-10-27 1:36 ` Benjamin Herrenschmidt
2007-10-27 1:40 ` Josh Boyer [this message]
2007-10-24 20:34 ` David Daney
2007-10-26 1:52 ` Benjamin Herrenschmidt
2007-10-26 1:47 ` Benjamin Herrenschmidt
2007-10-26 2:45 ` Grant Likely
2007-10-26 3:23 ` Benjamin Herrenschmidt
2007-10-26 14:42 ` Matt Mackall
2007-10-27 1:31 ` Benjamin Herrenschmidt
[not found] ` <1193470322.18243.63.camel@pasglop>
[not found] ` <20071029070824.72854629@weaponx.rchland.ibm.com>
[not found] ` <20071029151546.5af0e843@weaponx.rchland.ibm.com>
[not found] ` <1193690106.9928.32.camel@pasglop>
2007-10-29 21:19 ` [PATCH/RFC] powerpc: Pass PID argument to _tlbie (WAS: Apparent kernel bug with GDB on ppc405) Matt Mackall
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