powerpc/mm: Drop WIMG in favour of new constants

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>

4 files changed, 14 insertions, 18 deletions

diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
index e7782862362b..675331083728 100644
--- a/arch/powerpc/mm/hash64_64k.c
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -244,7 +244,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
 		 * If so, bail out and refault as a 4k page
 		 */
 		if (!mmu_has_feature(MMU_FTR_CI_LARGE_PAGE) &&
-		    unlikely(old_pte & _PAGE_NO_CACHE))
+		    unlikely(pte_ci(pte)))
 			return 0;
 		/*
 		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 38ed869c119e..eb928d86ce01 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -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 */
 
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 125fb4b54445..db277b6d8e8b 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -38,16 +38,16 @@ static inline int is_exec_fault(void)
 
 /* We only try to do i/d cache coherency on stuff that looks like
  * reasonably "normal" PTEs. We currently require a PTE to be present
- * and we avoid _PAGE_SPECIAL and _PAGE_NO_CACHE. We also only do that
+ * and we avoid _PAGE_SPECIAL and cache inhibited pte. We also only do that
  * on userspace PTEs
  */
 static inline int pte_looks_normal(pte_t pte)
 {
 
 #if defined(CONFIG_PPC_BOOK3S_64)
-	if ((pte_val(pte) &
-	     (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE)) ==
-	    _PAGE_PRESENT) {
+	if ((pte_val(pte) & (_PAGE_PRESENT | _PAGE_SPECIAL)) == _PAGE_PRESENT) {
+		if (pte_ci(pte))
+			return 0;
 		if (pte_user(pte))
 			return 1;
 	}
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index ea60a24c17a6..b3040b4535da 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -167,10 +167,6 @@ void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
 	if ((flags & _PAGE_PRESENT) == 0)
 		flags |= pgprot_val(PAGE_KERNEL);
 
-	/* Non-cacheable page cannot be coherent */
-	if (flags & _PAGE_NO_CACHE)
-		flags &= ~_PAGE_COHERENT;
-
 	/* We don't support the 4K PFN hack with ioremap */
 	if (flags & _PAGE_4K_PFN)
 		return NULL;