powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM

[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]

powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nicholas Piggin 2020-09-14 14:52:17 +10:00 committed by Greg Kroah-Hartman
parent b664645274
commit 19da77b901
2 changed files with 2 additions and 1 deletions

View file

@ -152,6 +152,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_EXTABLE_SORT

View file

@ -204,7 +204,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
switch_mm(prev, next, current);
switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */