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SubjectRe: [PATCH v3] ARM: mm: report both sections from PMD
On Thu, Feb 13, 2014 at 11:52:30AM -0800, Kees Cook wrote:
> On 2-level page table systems, the PMD has 2 section entries. Report
> these, otherwise ARM_PTDUMP will miss reporting permission changes on
> odd section boundaries.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> v3:
> - re-reorganize, drop use of pmd_sect; suggested by Catalin Marinas.
> v2:
> - reorganize, suggested by Catalin Marinas.
> ---
> arch/arm/mm/dump.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
> index 2b342177f5de..61cc78ae9f21 100644
> --- a/arch/arm/mm/dump.c
> +++ b/arch/arm/mm/dump.c
> @@ -264,6 +264,9 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
> note_page(st, addr, 3, pmd_val(*pmd));
> else
> walk_pte(st, pmd, addr);
> +
> + if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1]))
> + note_page(st, addr + SECTION_SIZE, 3, pmd_val(pmd[1]));
> }
> }
>
> --
> 1.7.9.5

This picks up an odd megabyte aligned section on my Arndale board with
short descriptors on 3.14-rc2. Behaves as expected with long descriptors
too (does nothing).

FWIW:
Tested-by: Steve Capper <steve.capper@linaro.org>

Cheers,
--
Steve

>
>
> --
> Kees Cook
> Chrome OS Security
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


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