Commit e2aaae2d authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/mm: add set_pXd()/set_pte() helper functions 



Add set_pXd()/set_pte() helper functions which must be used to update
page table entries. The new helpers use WRITE_ONCE() to make sure that
a page table entry is written to only once.

Without this the compiler could otherwise generate code which writes
several times to a page table entry when updating its contents from
invalid to valid, which could lead to surprising results especially
for multithreaded processes...

Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent f0003a9e

arch/s390/include/asm/pgtable.h

+25 −0
Original line number Diff line number Diff line
@@ -881,6 +881,31 @@ static inline pgprot_t pte_pgprot(pte_t pte) 
 * pgd/pmd/pte modification functions

 */



static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)

{

	WRITE_ONCE(*pgdp, pgd);

}



static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)

{

	WRITE_ONCE(*p4dp, p4d);

}



static inline void set_pud(pud_t *pudp, pud_t pud)

{

	WRITE_ONCE(*pudp, pud);

}



static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)

{

	WRITE_ONCE(*pmdp, pmd);

}



static inline void set_pte(pte_t *ptep, pte_t pte)

{

	WRITE_ONCE(*ptep, pte);

}



static inline void pgd_clear(pgd_t *pgd)

{

	if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1)