Messages in this thread | | | Date | Mon, 22 Dec 2014 11:25:39 +0100 | From | leroy christophe <> | Subject | Re: [v2 PATCH 1/2] powerpc32: adds handling of _PAGE_RO |
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Le 18/12/2014 03:14, Scott Wood a écrit : > On Wed, 2014-12-17 at 10:14 +0100, Christophe Leroy wrote: >> Some powerpc like the 8xx don't have a RW bit in PTE bits but a RO (Read Only) bit. >> This patch implements the handling of a _PAGE_RO flag to be used in place of _PAGE_RW >> >> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >> >> --- >> v2 is a complete rework compared to v1 >> >> arch/powerpc/include/asm/pgtable-ppc32.h | 11 ++++++----- >> arch/powerpc/include/asm/pgtable.h | 10 +++++++--- >> arch/powerpc/include/asm/pte-common.h | 27 ++++++++++++++++++--------- >> arch/powerpc/mm/gup.c | 2 ++ >> arch/powerpc/mm/mem.c | 2 +- >> arch/powerpc/mm/pgtable_32.c | 24 ++++++++++++++++++++---- >> 6 files changed, 54 insertions(+), 22 deletions(-) >> >> diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h >> index 543bb8e..64ed9e1 100644 >> --- a/arch/powerpc/include/asm/pgtable-ppc32.h >> +++ b/arch/powerpc/include/asm/pgtable-ppc32.h >> @@ -125,7 +125,7 @@ extern int icache_44x_need_flush; >> #ifndef __ASSEMBLY__ >> >> #define pte_clear(mm, addr, ptep) \ >> - do { pte_update(ptep, ~_PAGE_HASHPTE, 0); } while (0) >> + do { pte_update(ptep, ~_PAGE_HASHPTE, _PAGE_RO); } while (0) > Is this really necessary? It's already clearing the valid bit. > > Likewise in several other places that set or check for _PAGE_RO on pages > for which no access is permitted. > > You are right, this is not needed. I needed it because I had defined pte_none() as requiring _PAGE_RO set. But we can keep value 0 as pte_none. Taken into account in v3
Christophe
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