diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2016-06-17 11:32:00 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-06-17 19:47:51 +1000 |
| commit | e568006b9d828403397668864d9797dc4bfefd28 (patch) | |
| tree | 5d33a311e57ea12fecda5c04edca711b653cc845 /arch/powerpc | |
| parent | 8550e2fa34f077c8a87cf1ba2453102bbbc9ade9 (diff) | |
| download | linux-e568006b9d828403397668864d9797dc4bfefd28.tar.bz2 | |
powerpc/mm/hash: Don't add memory coherence if cache inhibited is set
H_ENTER hcall handling in qemu had assumptions that a cache inhibited
hpte entry won't have memory conference set. Also older kernel
mentioned that some version of pHyp required this (the code removed
by the below commit says:
/* Make pHyp happy */
if ((rflags & _PAGE_NO_CACHE) && !(rflags & _PAGE_WRITETHRU))
hpte_r &= ~HPTE_R_M;
But with older kernel we had some inconsistent memory conherence
mapping. We always enabled memory conherence in the page fault path and
removed memory conherence is _PAGE_NO_CACHE was set when we mapped the
page via htab_bolt_mapping. The commit mentioned below tried to
consolidate that by always enabling memory conherence. But as mentioned
above that breaks Qemu H_ENTER handling.
This patch update this such that we enable memory conherence only if
cache inhibited is not set and bring fault handling, lpar and bolt
mapping in sync.
Fixes: commit 30bda41aba4e("powerpc/mm: Drop WIMG in favour of new constant")
Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index b2740c67e172..5b22ba0b58bc 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -201,9 +201,8 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags) /* * We can't allow hardware to update hpte bits. Hence always * set 'R' bit and set 'C' if it is a write fault - * Memory coherence is always enabled */ - rflags |= HPTE_R_R | HPTE_R_M; + rflags |= HPTE_R_R; if (pteflags & _PAGE_DIRTY) rflags |= HPTE_R_C; @@ -213,10 +212,15 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags) if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_TOLERANT) rflags |= HPTE_R_I; - if ((pteflags & _PAGE_CACHE_CTL ) == _PAGE_NON_IDEMPOTENT) + else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_NON_IDEMPOTENT) rflags |= (HPTE_R_I | HPTE_R_G); - if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO) - rflags |= (HPTE_R_I | HPTE_R_W); + else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO) + rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M); + else + /* + * Add memory coherence if cache inhibited is not set + */ + rflags |= HPTE_R_M; return rflags; } |