Re: [RFC 5/8] ARM64: Re-factor flush_ptrace_access
From: Oleg Nesterov
Date: Fri Jan 02 2015 - 12:52:43 EST
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.
Oleg.
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