On Fri, 2010-02-05 at 00:53 +0800, Li Yang wrote: > We can't just clear the user read permission in book3e pte, because > that will also clear supervisor read permission. This surely isn't > desired. Fix the problem by adding the supervisor read back. > > Signed-off-by: Li Yang <le...@freescale.com> > --- > arch/powerpc/mm/pgtable_32.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c > index cb96cb2..aff7c04 100644 > --- a/arch/powerpc/mm/pgtable_32.c > +++ b/arch/powerpc/mm/pgtable_32.c > @@ -144,6 +144,11 @@ ioremap_flags(phys_addr_t addr, unsigned long size, > unsigned long flags) > /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ > flags &= ~(_PAGE_USER | _PAGE_EXEC); > > +#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_PTE_64BIT) > + /* supervisor read permission has just been cleared, add back */ > + flags |= _PAGE_BAP_SR; > +#endif > +
So this is a bit fishy indeed. pgtable_64.c seems to have the same problem in fact. It boils down to the "hack" I have in the new PTE format which consists of having _SR be part of _PAGE_USER. I wonder if I should change that instead. Kumar, what do you reckon ? _Maybe_ an option is to have _PAGE_NO_USER that defaults to be ~_PAGE_USER in pte-common.h and can be set in pte-book3e.h to only strip out UR and UW ? Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev