Re: Athlon PSE/AGP Bug

[Russell King <rmk@arm.linux.org.uk>]

On Tue, Jan 22, 2002 at 01:53:21AM +0100, Andrea Arcangeli wrote:
> On Tue, Jan 22, 2002 at 12:43:59AM +0000, Russell King wrote:
> > On Tue, Jan 22, 2002 at 01:37:43AM +0100, Andrea Arcangeli wrote:
> > > On Mon, Jan 21, 2002 at 02:19:31PM -0800, David S. Miller wrote:
> > > > That's not true, see the ptrace() helper code.  Russell King pointed
> > > > this out to me last week and it's on my TODO list to fix it up.
> > > 
> > > Where? :) ptrace doesn't change pagetables, no need to flush any tlb in
> > > ptrace.
> > 
> > See:
> > 
> > int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> > {
> > ...
> >                 flush_cache_page(vma, addr);
> > ...
> > }
> > 
> > flush_cache_page() is passed a non-page aligned address.  AFAIK that is
> > the only instance where the flush_{cache,tlb}_* stuff is called with
> > non-page aligned addresses.
> 
> flush_cache_page is by no means a _tlb_ flush. It is a virtual indexed
> cache flush needed before you can access data at such address (noop on
> x86).

Sigh, I never claimed it was a tlb flush function.

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html