Re: [RFC 5/8] ARM64: Re-factor flush_ptrace_access

[Pratyush Anand]

On Friday 02 January 2015 11:49 PM, Oleg Nesterov wrote:
> On 01/02, Oleg Nesterov wrote:
> > On 12/31, Pratyush Anand wrote:
> > > Re-factor flush_ptrace_access to reuse vma independent part.
> >
> > But for what? The changelog should explain this.
> >
> > > Signed-off-by: Pratyush Anand <panand@xxxxxxxxxx>
> > > ---
> > >   arch/arm64/mm/flush.c | 24 +++++++++++++++---------
> > >   1 file changed, 15 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
> > > index b6f14e8d2121..9a4dd6f39cfb 100644
> > > --- a/arch/arm64/mm/flush.c
> > > +++ b/arch/arm64/mm/flush.c
> > > @@ -34,19 +34,25 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
> > >   		__flush_icache_all();
> > >   }
> > >
> > > +static void __flush_ptrace_access(struct page *page, unsigned long uaddr,
> > > +		void *kaddr, unsigned long len)
> > > +{
> > > +	unsigned long addr = (unsigned long)kaddr;
> > > +
> > > +	if (icache_is_aliasing()) {
> > > +		__flush_dcache_area(kaddr, len);
> > > +		__flush_icache_all();
> > > +	} else {
> > > +		flush_icache_range(addr, addr + len);
> > > +	}
> > > +}
> > > +
> > >   static void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
> > >   				unsigned long uaddr, void *kaddr,
> > >   				unsigned long len)
> > >   {
> > > -	if (vma->vm_flags & VM_EXEC) {
> > > -		unsigned long addr = (unsigned long)kaddr;
> > > -		if (icache_is_aliasing()) {
> > > -			__flush_dcache_area(kaddr, len);
> > > -			__flush_icache_all();
> > > -		} else {
> > > -			flush_icache_range(addr, addr + len);
> > > -		}
> > > -	}
> > > +	if (vma->vm_flags & VM_EXEC)
> > > +		__flush_ptrace_access(page, uaddr, kaddr, len);
> > >   }
> >
> > So why uprobes can't use flush_ptrace_access() ? flush_uprobe_xol_access() is
> > called by arch_uprobe_copy_ixol(), and xol vma has VM_EXEC bit set.
>
> Ah, sorry, I forgot that arch_uprobe_copy_ixol() doesn't have "vma" so it
> can't use flush_ptrace_access()... perhaps you can update the changelog.

OK.. Will improve commit log.

~Pratyush
> Oleg.
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