Re: [PATCH v1 3/9] powerpc/vdso: don't clear PG_reserved

Michael Ellerman
2018-12-17T11:38:39Z

David Hildenbrand <david@redhat.com> writes:

> The VDSO is part of the kernel image and therefore the struct pages are
> marked as reserved during boot.
>
> As we install a special mapping, the actual struct pages will never be
> exposed to MM via the page tables. We can therefore leave the pages
> marked as reserved.
>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> arch/powerpc/kernel/vdso.c | 2 --
> 1 file changed, 2 deletions(-)

Thanks.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers

> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
> index 65b3bdb99f0b..d59dc2e9a695 100644
> --- a/arch/powerpc/kernel/vdso.c
> +++ b/arch/powerpc/kernel/vdso.c
> @@ -795,7 +795,6 @@ static int __init vdso_init(void)
> BUG_ON(vdso32_pagelist == NULL);
> for (i = 0; i < vdso32_pages; i++) {
> struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
> - ClearPageReserved(pg);
> get_page(pg);
> vdso32_pagelist[i] = pg;
> }
> @@ -809,7 +808,6 @@ static int __init vdso_init(void)
> BUG_ON(vdso64_pagelist == NULL);
> for (i = 0; i < vdso64_pages; i++) {
> struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
> - ClearPageReserved(pg);
> get_page(pg);
> vdso64_pagelist[i] = pg;
> }
> --
> 2.17.2