1 files changed, 19 insertions, 52 deletions

diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
index edea388e9d3f..85753e32a4de 100644
--- a/arch/powerpc/mm/pageattr.c
+++ b/arch/powerpc/mm/pageattr.c
@@ -15,12 +15,14 @@
 #include <asm/pgtable.h>
 
 
+static pte_basic_t pte_update_delta(pte_t *ptep, unsigned long addr,
+				    unsigned long old, unsigned long new)
+{
+	return pte_update(&init_mm, addr, ptep, old & ~new, new & ~old, 0);
+}
+
 /*
- * Updates the attributes of a page in three steps:
- *
- * 1. take the page_table_lock
- * 2. install the new entry with the updated attributes
- * 3. flush the TLB
+ * Updates the attributes of a page atomically.
  *
  * This sequence is safe against concurrent updates, and also allows updating the
  * attributes of a page currently being executed or accessed.
@@ -28,41 +30,39 @@
 static int change_page_attr(pte_t *ptep, unsigned long addr, void *data)
 {
 	long action = (long)data;
-	pte_t pte;
 
-	spin_lock(&init_mm.page_table_lock);
-
-	pte = ptep_get(ptep);
-
-	/* modify the PTE bits as desired, then apply */
+	/* modify the PTE bits as desired */
 	switch (action) {
 	case SET_MEMORY_RO:
-		pte = pte_wrprotect(pte);
+		/* Don't clear DIRTY bit */
+		pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, _PAGE_KERNEL_RO);
 		break;
 	case SET_MEMORY_RW:
-		pte = pte_mkwrite(pte_mkdirty(pte));
+		pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_RW);
 		break;
 	case SET_MEMORY_NX:
-		pte = pte_exprotect(pte);
+		pte_update_delta(ptep, addr, _PAGE_KERNEL_ROX, _PAGE_KERNEL_RO);
 		break;
 	case SET_MEMORY_X:
-		pte = pte_mkexec(pte);
+		pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_ROX);
+		break;
+	case SET_MEMORY_NP:
+		pte_update(&init_mm, addr, ptep, _PAGE_PRESENT, 0, 0);
+		break;
+	case SET_MEMORY_P:
+		pte_update(&init_mm, addr, ptep, 0, _PAGE_PRESENT, 0);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		break;
 	}
 
-	pte_update(&init_mm, addr, ptep, ~0UL, pte_val(pte), 0);
-
 	/* See ptesync comment in radix__set_pte_at() */
 	if (radix_enabled())
 		asm volatile("ptesync": : :"memory");
 
 	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 
-	spin_unlock(&init_mm.page_table_lock);
-
 	return 0;
 }
 
@@ -96,36 +96,3 @@ int change_memory_attr(unsigned long addr, int numpages, long action)
 	return apply_to_existing_page_range(&init_mm, start, size,
 					    change_page_attr, (void *)action);
 }
-
-/*
- * Set the attributes of a page:
- *
- * This function is used by PPC32 at the end of init to set final kernel memory
- * protection. It includes changing the maping of the page it is executing from
- * and data pages it is using.
- */
-static int set_page_attr(pte_t *ptep, unsigned long addr, void *data)
-{
-	pgprot_t prot = __pgprot((unsigned long)data);
-
-	spin_lock(&init_mm.page_table_lock);
-
-	set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot));
-	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-
-	spin_unlock(&init_mm.page_table_lock);
-
-	return 0;
-}
-
-int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot)
-{
-	unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
-	unsigned long sz = numpages * PAGE_SIZE;
-
-	if (numpages <= 0)
-		return 0;
-
-	return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr,
-					    (void *)pgprot_val(prot));
-}