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powerpc/mm: Drop WIMG in favour of new constants

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PowerISA 3.0 introduces two pte bits with the below meaning for radix:
  00 -> Normal Memory
  01 -> Strong Access Order (SAO)
  10 -> Non idempotent I/O (Cache inhibited and guarded)
  11 -> Tolerant I/O (Cache inhibited)

We drop the existing WIMG bits in the Linux page table in favour of the
above constants. We loose _PAGE_WRITETHRU with this conversion. We only
use writethru via pgprot_cached_wthru() which is used by
fbdev/controlfb.c which is Apple control display and also PPC32.

With respect to _PAGE_COHERENCE, we have been marking hpte always
coherent for some time now. htab_convert_pte_flags() always added
HPTE_R_M.

NOTE: KVM changes need closer review.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V
2016-04-29 23:25:38 +10:00
committed by Michael Ellerman
parent 72176dd0ad
commit 30bda41aba
9 changed files with 66 additions and 90 deletions
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18
arch/powerpc/mm/hash_utils_64.c
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@@ -192,12 +192,13 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
/*
* Add in WIG bits
*/
if (pteflags & _PAGE_WRITETHRU)
rflags |= HPTE_R_W;
if (pteflags & _PAGE_NO_CACHE)
if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_TOLERANT)
rflags |= HPTE_R_I;
if (pteflags & _PAGE_GUARDED)
rflags |= HPTE_R_G;
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);
return rflags;
}
@@ -1142,8 +1143,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
/* If this PTE is non-cacheable and we have restrictions on
* using non cacheable large pages, then we switch to 4k
*/
if (mmu_ci_restrictions && psize == MMU_PAGE_64K &&
(pte_val(*ptep) & _PAGE_NO_CACHE)) {
if (mmu_ci_restrictions && psize == MMU_PAGE_64K && pte_ci(*ptep)) {
if (user_region) {
demote_segment_4k(mm, ea);
psize = MMU_PAGE_4K;
@@ -1297,13 +1297,13 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
WARN_ON(hugepage_shift);
#ifdef CONFIG_PPC_64K_PAGES
/* If either _PAGE_4K_PFN or _PAGE_NO_CACHE is set (and we are on
/* If either _PAGE_4K_PFN or cache inhibited is set (and we are on
* a 64K kernel), then we don't preload, hash_page() will take
* care of it once we actually try to access the page.
* That way we don't have to duplicate all of the logic for segment
* page size demotion here
*/
if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_NO_CACHE))
if ((pte_val(*ptep) & _PAGE_4K_PFN) || pte_ci(*ptep))
goto out_exit;
#endif /* CONFIG_PPC_64K_PAGES */