powerpc/mm: Use _PAGE_READ to indicate Read access

This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also
removes the dependency on _PAGE_USER for implying read only. Few things
to note here is that, we have read implied with write and execute
permission. Hence we should always find _PAGE_READ set on hash pte
fault.

We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on
marking a prot none pte _PAGE_WRITE. (For more details look at
b191f9b106ea "mm: numa: preserve PTE write permissions across a NUMA
hinting fault")

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

8 files changed, 16 insertions, 16 deletions

diff --git a/arch/powerpc/mm/hash64_4k.c b/arch/powerpc/mm/hash64_4k.c
index dbd3133a8562..491b7d137cd8 100644
--- a/arch/powerpc/mm/hash64_4k.c
+++ b/arch/powerpc/mm/hash64_4k.c
@@ -45,7 +45,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 		 * also add _PAGE_COMBO
 		 */
 		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
-		if (access & _PAGE_RW)
+		if (access & _PAGE_WRITE)
 			new_pte |= _PAGE_DIRTY;
 	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
 
diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
index 292f40705674..2d3472173d79 100644
--- a/arch/powerpc/mm/hash64_64k.c
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -77,7 +77,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 		 * also add _PAGE_COMBO
 		 */
 		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_COMBO;
-		if (access & _PAGE_RW)
+		if (access & _PAGE_WRITE)
 			new_pte |= _PAGE_DIRTY;
 	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
 
@@ -251,7 +251,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
 		 * a write access.
 		 */
 		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
-		if (access & _PAGE_RW)
+		if (access & _PAGE_WRITE)
 			new_pte |= _PAGE_DIRTY;
 	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
 
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 7635b1c6b5da..ed190e42bbc5 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -175,8 +175,9 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
 	 * or PP=0x3 for read-only (including writeable but clean pages).
 	 */
 	if (pteflags & _PAGE_USER) {
-		rflags |= 0x2;
-		if (!((pteflags & _PAGE_RW) && (pteflags & _PAGE_DIRTY)))
+		if (pteflags & _PAGE_RWX)
+			rflags |= 0x2;
+		if (!((pteflags & _PAGE_WRITE) && (pteflags & _PAGE_DIRTY)))
 			rflags |= 0x1;
 	}
 	/*
@@ -1209,7 +1210,7 @@ EXPORT_SYMBOL_GPL(hash_page);
 int __hash_page(unsigned long ea, unsigned long msr, unsigned long trap,
 		unsigned long dsisr)
 {
-	unsigned long access = _PAGE_PRESENT;
+	unsigned long access = _PAGE_PRESENT | _PAGE_READ;
 	unsigned long flags = 0;
 	struct mm_struct *mm = current->mm;
 
@@ -1220,7 +1221,7 @@ int __hash_page(unsigned long ea, unsigned long msr, unsigned long trap,
 		flags |= HPTE_NOHPTE_UPDATE;
 
 	if (dsisr & DSISR_ISSTORE)
-		access |= _PAGE_RW;
+		access |= _PAGE_WRITE;
 	/*
 	 * We need to set the _PAGE_USER bit if MSR_PR is set or if we are
 	 * accessing a userspace segment (even from the kernel). We assume
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index 92c3c1858707..b4b6668d1b24 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -47,7 +47,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
 		 * a write access
 		 */
 		new_pmd = old_pmd | _PAGE_BUSY | _PAGE_ACCESSED;
-		if (access & _PAGE_RW)
+		if (access & _PAGE_WRITE)
 			new_pmd |= _PAGE_DIRTY;
 	} while (!pmd_xchg(pmdp, __pmd(old_pmd), __pmd(new_pmd)));
 
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index 9c0518761279..cdca743cdaf1 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -55,7 +55,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
 		/* Try to lock the PTE, add ACCESSED and DIRTY if it was
 		 * a write access */
 		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
-		if (access & _PAGE_RW)
+		if (access & _PAGE_WRITE)
 			new_pte |= _PAGE_DIRTY;
 	} while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
 
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index d991b9e80dbb..0bf269b00de9 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -1003,9 +1003,9 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 		end = pte_end;
 
 	pte = READ_ONCE(*ptep);
-	mask = _PAGE_PRESENT | _PAGE_USER;
+	mask = _PAGE_PRESENT | _PAGE_USER | _PAGE_READ;
 	if (write)
-		mask |= _PAGE_RW;
+		mask |= _PAGE_WRITE;
 
 	if ((pte_val(pte) & mask) != mask)
 		return 0;
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index de37ff445362..ef7b922c655c 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -177,8 +177,8 @@ void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 	 * _PAGE_PRESENT, but we can be sure that it is not in hpte.
 	 * Hence we can use set_pte_at for them.
 	 */
-	VM_WARN_ON((pte_val(*ptep) & (_PAGE_PRESENT | _PAGE_USER)) ==
-		(_PAGE_PRESENT | _PAGE_USER));
+	VM_WARN_ON(pte_present(*ptep) && !pte_protnone(*ptep));
+
 	/*
 	 * Add the pte bit when tryint set a pte
 	 */
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 494fc111ef90..16bc751f10df 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -277,7 +277,7 @@ void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size,
 	void *caller = __builtin_return_address(0);
 
 	/* writeable implies dirty for kernel addresses */
-	if (flags & _PAGE_RW)
+	if (flags & _PAGE_WRITE)
 		flags |= _PAGE_DIRTY;
 
 	/* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
@@ -676,8 +676,7 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 		pmd_t *pmdp, pmd_t pmd)
 {
 #ifdef CONFIG_DEBUG_VM
-	WARN_ON((pmd_val(*pmdp) & (_PAGE_PRESENT | _PAGE_USER)) ==
-		(_PAGE_PRESENT | _PAGE_USER));
+	WARN_ON(pte_present(pmd_pte(*pmdp)) && !pte_protnone(pmd_pte(*pmdp)));
 	assert_spin_locked(&mm->page_table_lock);
 	WARN_ON(!pmd_trans_huge(pmd));
 #endif