mm: Allow arches to provide ptep_get()
authorChristophe Leroy <christophe.leroy@csgroup.eu>
Mon, 15 Jun 2020 12:57:58 +0000 (12:57 +0000)
committerMichael Ellerman <mpe@ellerman.id.au>
Sat, 20 Jun 2020 12:14:53 +0000 (22:14 +1000)
commit481e980a7c199c5a4634fd7ea308067dd4ba75fa
tree8cb8ccaf80bd171a3745a034ac6647fc2865eeba
parent55ca22633a9faa34c6a61d99433f9cc8e28dd7cc
mm: Allow arches to provide ptep_get()

Since commit 9e343b467c70 ("READ_ONCE: Enforce atomicity for
{READ,WRITE}_ONCE() memory accesses") it is not possible anymore to
use READ_ONCE() to access complex page table entries like the one
defined for powerpc 8xx with 16k size pages.

Define a ptep_get() helper that architectures can override instead
of performing a READ_ONCE() on the page table entry pointer.

Fixes: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/087fa12b6e920e32315136b998aa834f99242695.1592225558.git.christophe.leroy@csgroup.eu
include/asm-generic/hugetlb.h
include/linux/pgtable.h
mm/gup.c