diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2017-07-24 14:28:00 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-30 10:21:56 +0200 |
| commit | 5aa523a994d1e2850115dac11c3ea69e332a97ae (patch) | |
| tree | e2f9b3d78de46b41639a67e706b1a4794cbc32a5 /arch/powerpc/include/asm/pgtable-be-types.h | |
| parent | 5906715b93da2923d7fced66a90f45145959ab33 (diff) | |
powerpc/mm: Ensure cpumask update is ordered
commit 1a92a80ad386a1a6e3b36d576d52a1a456394b70 upstream.
There is no guarantee that the various isync's involved with
the context switch will order the update of the CPU mask with
the first TLB entry for the new context being loaded by the HW.
Be safe here and add a memory barrier to order any subsequent
load/store which may bring entries into the TLB.
The corresponding barrier on the other side already exists as
pte updates use pte_xchg() which uses __cmpxchg_u64 which has
a sync after the atomic operation.
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add comments in the code]
[mpe: Backport to 4.12, minor context change]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/include/asm/pgtable-be-types.h')
| -rw-r--r-- | arch/powerpc/include/asm/pgtable-be-types.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pgtable-be-types.h b/arch/powerpc/include/asm/pgtable-be-types.h index 49c0a5a80efa..68e087e807f8 100644 --- a/arch/powerpc/include/asm/pgtable-be-types.h +++ b/arch/powerpc/include/asm/pgtable-be-types.h @@ -87,6 +87,7 @@ static inline bool pte_xchg(pte_t *ptep, pte_t old, pte_t new) unsigned long *p = (unsigned long *)ptep; __be64 prev; + /* See comment in switch_mm_irqs_off() */ prev = (__force __be64)__cmpxchg_u64(p, (__force unsigned long)pte_raw(old), (__force unsigned long)pte_raw(new)); |