On 07/10/2017 11:25 AM, Ram Pai wrote: > On Mon, Jul 10, 2017 at 08:41:30AM +0530, Anshuman Khandual wrote: >> On 07/06/2017 02:52 AM, Ram Pai wrote: >>> get_pte_pkey() helper returns the pkey associated with >>> a address corresponding to a given mm_struct. >>> >>> Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx> >>> --- >>> arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 ++++ >>> arch/powerpc/mm/hash_utils_64.c | 28 +++++++++++++++++++++++++ >>> 2 files changed, 33 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> index f7a6ed3..369f9ff 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> @@ -450,6 +450,11 @@ extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap, >>> int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, >>> pte_t *ptep, unsigned long trap, unsigned long flags, >>> int ssize, unsigned int shift, unsigned int mmu_psize); >>> + >>> +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS >>> +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address); >>> +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ >>> + >>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >>> extern int __hash_page_thp(unsigned long ea, unsigned long access, >>> unsigned long vsid, pmd_t *pmdp, unsigned long trap, >>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c >>> index 1e74529..591990c 100644 >>> --- a/arch/powerpc/mm/hash_utils_64.c >>> +++ b/arch/powerpc/mm/hash_utils_64.c >>> @@ -1573,6 +1573,34 @@ void hash_preload(struct mm_struct *mm, unsigned long ea, >>> local_irq_restore(flags); >>> } >>> >>> +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS >>> +/* >>> + * return the protection key associated with the given address >>> + * and the mm_struct. >>> + */ >>> +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address) >>> +{ >>> + pte_t *ptep; >>> + u16 pkey = 0; >>> + unsigned long flags; >>> + >>> + if (REGION_ID(address) == VMALLOC_REGION_ID) >>> + mm = &init_mm; >> >> IIUC, protection keys are only applicable for user space. This >> function is getting used to populate siginfo structure. Then how >> can we ever request this for any address in VMALLOC region. > > make sense. this check is not needed. > >> >>> + >>> + if (!mm || !mm->pgd) >>> + return 0; >> >> Is this really required at this stage ? > > its a sanity check to gaurd against bad inputs. See a problem? I mean its okay, thought it to be unnecessary. Your call.