5 files changed, 48 insertions, 3 deletions

diff --git a/include/asm-powerpc/mmu-hash64.h b/include/asm-powerpc/mmu-hash64.h
index 2a1b4040e20d..2864fa3989ea 100644
--- a/include/asm-powerpc/mmu-hash64.h
+++ b/include/asm-powerpc/mmu-hash64.h
@@ -265,7 +265,7 @@ static inline unsigned long hpt_hash(unsigned long va, unsigned int shift,
 
 extern int __hash_page_4K(unsigned long ea, unsigned long access,
                           unsigned long vsid, pte_t *ptep, unsigned long trap,
-                          unsigned int local, int ssize);
+                          unsigned int local, int ssize, int subpage_prot);
 extern int __hash_page_64K(unsigned long ea, unsigned long access,
                            unsigned long vsid, pte_t *ptep, unsigned long trap,
                            unsigned int local, int ssize);
@@ -279,6 +279,7 @@ extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
                              unsigned long pstart, unsigned long mode,
                              int psize, int ssize);
 extern void set_huge_psize(int psize);
+extern void demote_segment_4k(struct mm_struct *mm, unsigned long addr);
 
 extern void htab_initialize(void);
 extern void htab_initialize_secondary(void);
diff --git a/include/asm-powerpc/pgalloc-64.h b/include/asm-powerpc/pgalloc-64.h
index 94d0294341d6..43214c8085b7 100644
--- a/include/asm-powerpc/pgalloc-64.h
+++ b/include/asm-powerpc/pgalloc-64.h
@@ -12,6 +12,10 @@
 #include <linux/cpumask.h>
 #include <linux/percpu.h>
 
+#ifndef CONFIG_PPC_SUBPAGE_PROT
+static inline void subpage_prot_free(pgd_t *pgd) {}
+#endif
+
 extern struct kmem_cache *pgtable_cache[];
 
 #define PGD_CACHE_NUM           0
@@ -27,6 +31,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 
 static inline void pgd_free(pgd_t *pgd)
 {
+        subpage_prot_free(pgd);
         kmem_cache_free(pgtable_cache[PGD_CACHE_NUM], pgd);
 }
 
diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h
index bd54b772fbc6..1cbd6b377eea 100644
--- a/include/asm-powerpc/pgtable-64k.h
+++ b/include/asm-powerpc/pgtable-64k.h
@@ -13,12 +13,49 @@
 #define PTE_TABLE_SIZE  (sizeof(real_pte_t) << PTE_INDEX_SIZE)
 #define PMD_TABLE_SIZE  (sizeof(pmd_t) << PMD_INDEX_SIZE)
 #define PGD_TABLE_SIZE  (sizeof(pgd_t) << PGD_INDEX_SIZE)
-#endif  /* __ASSEMBLY__ */
 
 #define PTRS_PER_PTE    (1 << PTE_INDEX_SIZE)
 #define PTRS_PER_PMD    (1 << PMD_INDEX_SIZE)
 #define PTRS_PER_PGD    (1 << PGD_INDEX_SIZE)
 
+#ifdef CONFIG_PPC_SUBPAGE_PROT
+/*
+ * For the sub-page protection option, we extend the PGD with one of
+ * these.  Basically we have a 3-level tree, with the top level being
+ * the protptrs array.  To optimize speed and memory consumption when
+ * only addresses < 4GB are being protected, pointers to the first
+ * four pages of sub-page protection words are stored in the low_prot
+ * array.
+ * Each page of sub-page protection words protects 1GB (4 bytes
+ * protects 64k).  For the 3-level tree, each page of pointers then
+ * protects 8TB.
+ */
+struct subpage_prot_table {
+        unsigned long maxaddr;  /* only addresses < this are protected */
+        unsigned int **protptrs[2];
+        unsigned int *low_prot[4];
+};
+
+#undef PGD_TABLE_SIZE
+#define PGD_TABLE_SIZE          ((sizeof(pgd_t) << PGD_INDEX_SIZE) + \
+                                 sizeof(struct subpage_prot_table))
+
+#define SBP_L1_BITS             (PAGE_SHIFT - 2)
+#define SBP_L2_BITS             (PAGE_SHIFT - 3)
+#define SBP_L1_COUNT            (1 << SBP_L1_BITS)
+#define SBP_L2_COUNT            (1 << SBP_L2_BITS)
+#define SBP_L2_SHIFT            (PAGE_SHIFT + SBP_L1_BITS)
+#define SBP_L3_SHIFT            (SBP_L2_SHIFT + SBP_L2_BITS)
+
+extern void subpage_prot_free(pgd_t *pgd);
+
+static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd)
+{
+        return (struct subpage_prot_table *)(pgd + PTRS_PER_PGD);
+}
+#endif /* CONFIG_PPC_SUBPAGE_PROT */
+#endif  /* __ASSEMBLY__ */
+
 /* With 4k base page size, hugepage PTEs go at the PMD level */
 #define MIN_HUGEPTE_SHIFT       PAGE_SHIFT
 
diff --git a/include/asm-powerpc/systbl.h b/include/asm-powerpc/systbl.h
index 11d5383b2f09..0c8b0d679139 100644
--- a/include/asm-powerpc/systbl.h
+++ b/include/asm-powerpc/systbl.h
@@ -313,3 +313,4 @@ COMPAT_SYS_SPU(timerfd)
 SYSCALL_SPU(eventfd)
 COMPAT_SYS_SPU(sync_file_range2)
 COMPAT_SYS(fallocate)
+SYSCALL(subpage_prot)
diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h
index 97d82b6a9406..fedc4b8e49e2 100644
--- a/include/asm-powerpc/unistd.h
+++ b/include/asm-powerpc/unistd.h
@@ -332,10 +332,11 @@
 #define __NR_eventfd            307
 #define __NR_sync_file_range2   308
 #define __NR_fallocate          309
+#define __NR_subpage_prot       310
 
 #ifdef __KERNEL__
 
-#define __NR_syscalls           310
+#define __NR_syscalls           311
 
 #define __NR__exit __NR_exit
 #define NR_syscalls     __NR_syscalls