Re: [RFC PATCH 2/5] powerpc: Exception hooks for context trackingsubsystem
From: Li Zhong
Date: Sat Feb 16 2013 - 04:41:52 EST
On Sun, 2013-02-10 at 15:10 +0100, Frederic Weisbecker wrote:
> 2013/2/1 Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>:
> > This is the exception hooks for context tracking subsystem, including
> > data access, program check, single step, instruction breakpoint, machine check,
> > alignment, fp unavailable, altivec assist, unknown exception, whose handlers
> > might use RCU.
> > This patch corresponds to
> > [PATCH] x86: Exception hooks for userspace RCU extended QS
> > commit 6ba3c97a38803883c2eee489505796cb0a727122
> > Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
> Looks good!
> I guess we should move exception_enter/exit definition to the generic
> code. They should be the same for all archs after all.
> Also we are
> relying on user_mode(regs) but this may be buggy with some corner
> cases. For example if an exception happen after a call to user_exit()
I guess you mean user_enter() here, or am I confused?
> (on syscall exit) but before we actually resume in userspace, the
> exception will exit in kernel mode from the context tracking POV.
> So instead on relying on the regs, which are not sync with the context
> tracking state, we should use something like:
> prev_state = exception_enter();
> Also preempt_schedule_irq() is concerned as well by this problem. So I
> should convert it to that scheme as well. I'm going to prepare some
> Feel free to merge this patch in the powerpc tree, I'll do the
> conversion along the way.
Or if your patches gets merged earlier than these, I can update my code
according to yours.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/