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.
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