Re: [PATCH] ARM: mm: report both sections from PMD

From: Catalin Marinas
Date: Mon Feb 10 2014 - 05:41:51 EST


On Mon, Feb 10, 2014 at 10:29:35AM +0000, Catalin Marinas wrote:
> On Sun, Feb 09, 2014 at 10:18:26PM +0000, Kees Cook wrote:
> > diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
> > index 1f7b1e13d945..ff1559f9200c 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_sect(*pmd))
> > + note_page(st, addr + SECTION_SIZE, 3, pmd_val(pmd[1]));
>
> You can use pmd_large() here as well.
>
> But I think this function is broken (the "for" statement not shown
> here). The pmd_t is 32-bit with classic MMU and it uses pmd++ while the
> address grows by PMD_SIZE (two pmd_t entries).

Actually it's ok since PTRS_PER_PMD is 1, so it only goes through this
loop once.

But in your patch shouldn't you check for pmd_large(*(pmd+1))? The first
pmd is already caught by the 'if' statement.

--
Catalin
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