powerpc/mm/hash64: Fix subpage protection with 4K HPTE config

[pandora-kernel.git] / arch / powerpc / mm / hash_utils_64.c

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 26b2872..e9a8b8c 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -27,6 +27,7 @@
 #include <linux/proc_fs.h>
 #include <linux/stat.h>
 #include <linux/sysctl.h>
+#include <linux/export.h>
 #include <linux/ctype.h>
 #include <linux/cache.h>
 #include <linux/init.h>
@@ -105,9 +106,6 @@ int mmu_kernel_ssize = MMU_SEGSIZE_256M;
 int mmu_highuser_ssize = MMU_SEGSIZE_256M;
 u16 mmu_slb_size = 64;
 EXPORT_SYMBOL_GPL(mmu_slb_size);
-#ifdef CONFIG_HUGETLB_PAGE
-unsigned int HPAGE_SHIFT;
-#endif
 #ifdef CONFIG_PPC_64K_PAGES
 int mmu_ci_restrictions;
 #endif
@@ -534,11 +532,11 @@ static unsigned long __init htab_get_table_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-void create_section_mapping(unsigned long start, unsigned long end)
+int create_section_mapping(unsigned long start, unsigned long end)
 {
-       BUG_ON(htab_bolt_mapping(start, end, __pa(start),
+       return htab_bolt_mapping(start, end, __pa(start),
                                 pgprot_val(PAGE_KERNEL), mmu_linear_psize,
-                                mmu_kernel_ssize));
+                                mmu_kernel_ssize);
 }
 
 int remove_section_mapping(unsigned long start, unsigned long end)
@@ -1076,6 +1074,30 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
 }
 EXPORT_SYMBOL_GPL(hash_page);
 
+#ifdef CONFIG_PPC_MM_SLICES
+static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
+{
+       int psize = get_slice_psize(mm, ea);
+
+       /* We only prefault standard pages for now */
+       if (unlikely(psize != mm->context.user_psize))
+               return false;
+
+       /*
+        * Don't prefault if subpage protection is enabled for the EA.
+        */
+       if (unlikely((psize == MMU_PAGE_4K) && subpage_protection(mm, ea)))
+               return false;
+
+       return true;
+}
+#else
+static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
+{
+       return true;
+}
+#endif
+
 void hash_preload(struct mm_struct *mm, unsigned long ea,
                  unsigned long access, unsigned long trap)
 {
@@ -1087,11 +1109,8 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 
        BUG_ON(REGION_ID(ea) != USER_REGION_ID);
 
-#ifdef CONFIG_PPC_MM_SLICES
-       /* We only prefault standard pages for now */
-       if (unlikely(get_slice_psize(mm, ea) != mm->context.user_psize))
+       if (!should_hash_preload(mm, ea))
                return;
-#endif
 
        DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
                " trap=%lx\n", mm, mm->pgd, ea, access, trap);