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SubjectRe: [RFC 5/8] ARM64: Re-factor flush_ptrace_access
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@redhat.com>
> > ---
> > 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.

Oleg.



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