Messages in this thread | | | Subject | Re: [PATCH 2/2] powerpc/mm/autonuma: Switch ppc64 to its own implementeation of saved write | From | "Aneesh Kumar K.V" <> | Date | Thu, 16 Feb 2017 07:42:46 +0530 |
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On Thursday 16 February 2017 03:16 AM, Andrew Morton wrote: > On Thu, 9 Feb 2017 08:30:59 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote: > >> With this our protnone becomes a present pte with READ/WRITE/EXEC bit cleared. >> By default we also set _PAGE_PRIVILEGED on such pte. This is now used to help >> us identify a protnone pte that as saved write bit. For such pte, we will clear >> the _PAGE_PRIVILEGED bit. The pte still remain non-accessible from both user >> and kernel. > I don't see how these patches differ from the ones which are presently > in -mm. > > It helps to have a [0/n] email for a patch series and to put a version > number in there as well. > >> +#define pte_mk_savedwrite pte_mk_savedwrite >> +static inline pte_t pte_mk_savedwrite(pte_t pte) >> +{ >> + /* >> + * Used by Autonuma subsystem to preserve the write bit >> + * while marking the pte PROT_NONE. Only allow this >> + * on PROT_NONE pte >> + */ >> + VM_BUG_ON((pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_RWX | _PAGE_PRIVILEGED)) != >> + cpu_to_be64(_PAGE_PRESENT | _PAGE_PRIVILEGED)); >> + return __pte(pte_val(pte) & ~_PAGE_PRIVILEGED); >> +} >> + >> +#define pte_savedwrite pte_savedwrite >> +static inline bool pte_savedwrite(pte_t pte) >> +{ >> + /* >> + * Saved write ptes are prot none ptes that doesn't have >> + * privileged bit sit. We mark prot none as one which has >> + * present and pviliged bit set and RWX cleared. To mark >> + * protnone which used to have _PAGE_WRITE set we clear >> + * the privileged bit. >> + */ >> + return !(pte_raw(pte) & cpu_to_be64(_PAGE_RWX | _PAGE_PRIVILEGED)); >> +} >> + >> static inline pte_t pte_mkdevmap(pte_t pte) >> { >> return __pte(pte_val(pte) | _PAGE_SPECIAL|_PAGE_DEVMAP); > arch/powerpc/include/asm/book3s/64/pgtable.h doesn't have > pte_mkdevmap(). What tree are you patching here? > >
I did post a V2 of this for which you replied https://lkml.kernel.org/r/20170214162008.bd592c747fc5e167c10ce7b8@linux-foundation.org
I actually found the issue with this patch. I will be sending V3 after more testing.
-aneesh
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