Le 31/10/2023 à 11:15, Aneesh Kumar K.V a écrit :
> Christophe Leroy <christophe.le...@csgroup.eu> writes:
>
>> pte_user() is now only used in pte_access_permitted() to check
>> access on vmas. User flag is cleared to make a page unreadable.
>>
>> So rename it pte_read() and remove pte_user() which isn't used
>> anymore.
>>
>> For the time being it checks _PAGE_USER but in the near futur
>> all plateforms will be converted to _PAGE_READ so lets support
>> both for now.
>>
>> Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
>> ---
>> arch/powerpc/include/asm/nohash/32/pte-8xx.h | 7 -------
>> arch/powerpc/include/asm/nohash/pgtable.h | 13 +++++++------
>> arch/powerpc/mm/ioremap.c | 4 ----
>> 3 files changed, 7 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> index 62c965a4511a..1ee38befd29a 100644
>> --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> @@ -112,13 +112,6 @@ static inline pte_t pte_mkwrite_novma(pte_t pte)
>>
>> #define pte_mkwrite_novma pte_mkwrite_novma
>>
>> -static inline bool pte_user(pte_t pte)
>> -{
>> - return !(pte_val(pte) & _PAGE_SH);
>> -}
>> -
>> -#define pte_user pte_user
>> -
>> static inline pte_t pte_mkhuge(pte_t pte)
>> {
>> return __pte(pte_val(pte) | _PAGE_SPS | _PAGE_HUGE);
>> diff --git a/arch/powerpc/include/asm/nohash/pgtable.h
>> b/arch/powerpc/include/asm/nohash/pgtable.h
>> index ee677162f9e6..aba56fe3b1c6 100644
>> --- a/arch/powerpc/include/asm/nohash/pgtable.h
>> +++ b/arch/powerpc/include/asm/nohash/pgtable.h
>> @@ -160,9 +160,6 @@ static inline int pte_write(pte_t pte)
>> return pte_val(pte) & _PAGE_WRITE;
>> }
>> #endif
>> -#ifndef pte_read
>> -static inline int pte_read(pte_t pte) { return 1; }
>> -#endif
>> static inline int pte_dirty(pte_t pte) { return pte_val(pte) &
>> _PAGE_DIRTY; }
>> static inline int pte_special(pte_t pte) { return pte_val(pte) &
>> _PAGE_SPECIAL; }
>> static inline int pte_none(pte_t pte) { return (pte_val(pte)
>> & ~_PTE_NONE_MASK) == 0; }
>> @@ -190,10 +187,14 @@ static inline int pte_young(pte_t pte)
>> * and PTE_64BIT, PAGE_KERNEL_X contains _PAGE_BAP_SR which is also in
>> * _PAGE_USER. Need to explicitly match _PAGE_BAP_UR bit in that case too.
>> */
>> -#ifndef pte_user
>> -static inline bool pte_user(pte_t pte)
>> +#ifndef pte_read
>> +static inline bool pte_read(pte_t pte)
>> {
>> +#ifdef _PAGE_READ
>> + return (pte_val(pte) & _PAGE_READ) == _PAGE_READ;
>> +#else
>> return (pte_val(pte) & _PAGE_USER) == _PAGE_USER;
>> +#endif
>> }
>> #endif
>>
>> @@ -208,7 +209,7 @@ static inline bool pte_access_permitted(pte_t pte, bool
>> write)
>> * A read-only access is controlled by _PAGE_USER bit.
>> * We have _PAGE_READ set for WRITE and EXECUTE
>> */
>> - if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
>> + if (!pte_present(pte) || !pte_read(pte))
>> return false;
>>
>> if (write && !pte_write(pte))
>> diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c
>> index 7823c38f09de..7b0afcabd89f 100644
>> --- a/arch/powerpc/mm/ioremap.c
>> +++ b/arch/powerpc/mm/ioremap.c
>> @@ -50,10 +50,6 @@ void __iomem *ioremap_prot(phys_addr_t addr, size_t size,
>> unsigned long flags)
>> if (pte_write(pte))
>> pte = pte_mkdirty(pte);
>>
>> - /* we don't want to let _PAGE_USER leak out */
>> - if (WARN_ON(pte_user(pte)))
>> - return NULL;
>>
>
> This check is still valid right? I understand that we want to remove
> _PAGE_USER. But then loosing this check is ok?
Well, we may have to think about it for book3s/64. For all others
_PAGE_USER is gone and replaced by a check of addresses versus TASK_SIZE.
As ioremap() will map into vmalloc space that address is necesserally
correct.
>
>> -
>> if (iowa_is_active())
>> return iowa_ioremap(addr, size, pte_pgprot(pte), caller);
>> return __ioremap_caller(addr, size, pte_pgprot(pte), caller);
>> --
>> 2.41.0
