[PATCH 3.16 116/127] sparc64: Switch to 4-level page tables.

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit ac55c768143aa34cc3789c4820cbb0809a76fd9c ]

This has become necessary with chips that support more than 43-bits
of physical addressing.

Based almost entirely upon a patch by Bob Picco.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/sparc/include/asm/page_64.h    |    6 +++++
 arch/sparc/include/asm/pgalloc_64.h |   28 ++++++++++++++++++++++++++-
 arch/sparc/include/asm/pgtable_64.h |   37 +++++++++++++++++++++++++++++++-----
 arch/sparc/include/asm/tsb.h        |   10 +++++++++
 arch/sparc/kernel/smp_64.c          |    7 ++++++
 arch/sparc/mm/init_64.c             |   31 ++++++++++++++++++++++++++----
 6 files changed, 109 insertions(+), 10 deletions(-)

--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -57,18 +57,21 @@ void copy_user_page(void *to, void *from
 typedef struct { unsigned long pte; } pte_t;
 typedef struct { unsigned long iopte; } iopte_t;
 typedef struct { unsigned long pmd; } pmd_t;
+typedef struct { unsigned long pud; } pud_t;
 typedef struct { unsigned long pgd; } pgd_t;
 typedef struct { unsigned long pgprot; } pgprot_t;
 
 #define pte_val(x)	((x).pte)
 #define iopte_val(x)	((x).iopte)
 #define pmd_val(x)      ((x).pmd)
+#define pud_val(x)      ((x).pud)
 #define pgd_val(x)	((x).pgd)
 #define pgprot_val(x)	((x).pgprot)
 
 #define __pte(x)	((pte_t) { (x) } )
 #define __iopte(x)	((iopte_t) { (x) } )
 #define __pmd(x)        ((pmd_t) { (x) } )
+#define __pud(x)        ((pud_t) { (x) } )
 #define __pgd(x)	((pgd_t) { (x) } )
 #define __pgprot(x)	((pgprot_t) { (x) } )
 
@@ -77,18 +80,21 @@ typedef struct { unsigned long pgprot; }
 typedef unsigned long pte_t;
 typedef unsigned long iopte_t;
 typedef unsigned long pmd_t;
+typedef unsigned long pud_t;
 typedef unsigned long pgd_t;
 typedef unsigned long pgprot_t;
 
 #define pte_val(x)	(x)
 #define iopte_val(x)	(x)
 #define pmd_val(x)      (x)
+#define pud_val(x)      (x)
 #define pgd_val(x)	(x)
 #define pgprot_val(x)	(x)
 
 #define __pte(x)	(x)
 #define __iopte(x)	(x)
 #define __pmd(x)        (x)
+#define __pud(x)        (x)
 #define __pgd(x)	(x)
 #define __pgprot(x)	(x)
 
--- a/arch/sparc/include/asm/pgalloc_64.h
+++ b/arch/sparc/include/asm/pgalloc_64.h
@@ -15,6 +15,13 @@
 
 extern struct kmem_cache *pgtable_cache;
 
+static inline void __pgd_populate(pgd_t *pgd, pud_t *pud)
+{
+	pgd_set(pgd, pud);
+}
+
+#define pgd_populate(MM, PGD, PUD)	__pgd_populate(PGD, PUD)
+
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	return kmem_cache_alloc(pgtable_cache, GFP_KERNEL);
@@ -25,7 +32,23 @@ static inline void pgd_free(struct mm_st
 	kmem_cache_free(pgtable_cache, pgd);
 }
 
-#define pud_populate(MM, PUD, PMD)	pud_set(PUD, PMD)
+static inline void __pud_populate(pud_t *pud, pmd_t *pmd)
+{
+	pud_set(pud, pmd);
+}
+
+#define pud_populate(MM, PUD, PMD)	__pud_populate(PUD, PMD)
+
+static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	return kmem_cache_alloc(pgtable_cache,
+				GFP_KERNEL|__GFP_REPEAT);
+}
+
+static inline void pud_free(struct mm_struct *mm, pud_t *pud)
+{
+	kmem_cache_free(pgtable_cache, pud);
+}
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
@@ -91,4 +114,7 @@ static inline void __pte_free_tlb(struct
 #define __pmd_free_tlb(tlb, pmd, addr)		      \
 	pgtable_free_tlb(tlb, pmd, false)
 
+#define __pud_free_tlb(tlb, pud, addr)		      \
+	pgtable_free_tlb(tlb, pud, false)
+
 #endif /* _SPARC64_PGALLOC_H */
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -20,8 +20,6 @@
 #include <asm/page.h>
 #include <asm/processor.h>
 
-#include <asm-generic/pgtable-nopud.h>
-
 /* The kernel image occupies 0x4000000 to 0x6000000 (4MB --> 96MB).
  * The page copy blockops can use 0x6000000 to 0x8000000.
  * The 8K TSB is mapped in the 0x8000000 to 0x8400000 range.
@@ -55,13 +53,21 @@
 #define PMD_MASK	(~(PMD_SIZE-1))
 #define PMD_BITS	(PAGE_SHIFT - 3)
 
-/* PGDIR_SHIFT determines what a third-level page table entry can map */
-#define PGDIR_SHIFT	(PAGE_SHIFT + (PAGE_SHIFT-3) + PMD_BITS)
+/* PUD_SHIFT determines the size of the area a third-level page
+ * table can map
+ */
+#define PUD_SHIFT	(PMD_SHIFT + PMD_BITS)
+#define PUD_SIZE	(_AC(1,UL) << PUD_SHIFT)
+#define PUD_MASK	(~(PUD_SIZE-1))
+#define PUD_BITS	(PAGE_SHIFT - 3)
+
+/* PGDIR_SHIFT determines what a fourth-level page table entry can map */
+#define PGDIR_SHIFT	(PUD_SHIFT + PUD_BITS)
 #define PGDIR_SIZE	(_AC(1,UL) << PGDIR_SHIFT)
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 #define PGDIR_BITS	(PAGE_SHIFT - 3)
 
-#if (PGDIR_SHIFT + PGDIR_BITS) != 43
+#if (PGDIR_SHIFT + PGDIR_BITS) != 53
 #error Page table parameters do not cover virtual address space properly.
 #endif
 
@@ -93,6 +99,7 @@ static inline bool kern_addr_valid(unsig
 /* Entries per page directory level. */
 #define PTRS_PER_PTE	(1UL << (PAGE_SHIFT-3))
 #define PTRS_PER_PMD	(1UL << PMD_BITS)
+#define PTRS_PER_PUD	(1UL << PUD_BITS)
 #define PTRS_PER_PGD	(1UL << PGDIR_BITS)
 
 /* Kernel has a separate 44bit address space. */
@@ -101,6 +108,9 @@ static inline bool kern_addr_valid(unsig
 #define pmd_ERROR(e)							\
 	pr_err("%s:%d: bad pmd %p(%016lx) seen at (%pS)\n",		\
 	       __FILE__, __LINE__, &(e), pmd_val(e), __builtin_return_address(0))
+#define pud_ERROR(e)							\
+	pr_err("%s:%d: bad pud %p(%016lx) seen at (%pS)\n",		\
+	       __FILE__, __LINE__, &(e), pud_val(e), __builtin_return_address(0))
 #define pgd_ERROR(e)							\
 	pr_err("%s:%d: bad pgd %p(%016lx) seen at (%pS)\n",		\
 	       __FILE__, __LINE__, &(e), pgd_val(e), __builtin_return_address(0))
@@ -779,6 +789,11 @@ static inline int pmd_present(pmd_t pmd)
 #define pud_bad(pud)			((pud_val(pud) & ~PAGE_MASK) || \
 					 !__kern_addr_valid(pud_val(pud)))
 
+#define pgd_none(pgd)			(!pgd_val(pgd))
+
+#define pgd_bad(pgd)			((pgd_val(pgd) & ~PAGE_MASK) || \
+					 !__kern_addr_valid(pgd_val(pgd)))
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 		pmd_t *pmdp, pmd_t pmd);
@@ -815,10 +830,17 @@ static inline unsigned long __pmd_page(p
 #define pmd_clear(pmdp)			(pmd_val(*(pmdp)) = 0UL)
 #define pud_present(pud)		(pud_val(pud) != 0U)
 #define pud_clear(pudp)			(pud_val(*(pudp)) = 0UL)
+#define pgd_page_vaddr(pgd)		\
+	((unsigned long) __va(pgd_val(pgd)))
+#define pgd_present(pgd)		(pgd_val(pgd) != 0U)
+#define pgd_clear(pgdp)			(pgd_val(*(pgd)) = 0UL)
 
 /* Same in both SUN4V and SUN4U.  */
 #define pte_none(pte) 			(!pte_val(pte))
 
+#define pgd_set(pgdp, pudp)	\
+	(pgd_val(*(pgdp)) = (__pa((unsigned long) (pudp))))
+
 /* to find an entry in a page-table-directory. */
 #define pgd_index(address)	(((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 #define pgd_offset(mm, address)	((mm)->pgd + pgd_index(address))
@@ -826,6 +848,11 @@ static inline unsigned long __pmd_page(p
 /* to find an entry in a kernel page-table-directory */
 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 
+/* Find an entry in the third-level page table.. */
+#define pud_index(address)	(((address) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
+#define pud_offset(pgdp, address)	\
+	((pud_t *) pgd_page_vaddr(*(pgdp)) + pud_index(address))
+
 /* Find an entry in the second-level page table.. */
 #define pmd_offset(pudp, address)	\
 	((pmd_t *) pud_page_vaddr(*(pudp)) + \
--- a/arch/sparc/include/asm/tsb.h
+++ b/arch/sparc/include/asm/tsb.h
@@ -145,6 +145,11 @@ extern struct tsb_phys_patch_entry __tsb
 	andn		REG2, 0x7, REG2; \
 	ldx		[REG1 + REG2], REG1; \
 	brz,pn		REG1, FAIL_LABEL; \
+	 sllx		VADDR, 64 - (PUD_SHIFT + PUD_BITS), REG2; \
+	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
+	andn		REG2, 0x7, REG2; \
+	ldxa		[REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
+	brz,pn		REG1, FAIL_LABEL; \
 	 sllx		VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
 	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
 	andn		REG2, 0x7, REG2; \
@@ -198,6 +203,11 @@ extern struct tsb_phys_patch_entry __tsb
 	andn		REG2, 0x7, REG2; \
 	ldxa		[PHYS_PGD + REG2] ASI_PHYS_USE_EC, REG1; \
 	brz,pn		REG1, FAIL_LABEL; \
+	 sllx		VADDR, 64 - (PUD_SHIFT + PUD_BITS), REG2; \
+	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
+	andn		REG2, 0x7, REG2; \
+	ldxa		[REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
+	brz,pn		REG1, FAIL_LABEL; \
 	 sllx		VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
 	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
 	andn		REG2, 0x7, REG2; \
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1467,6 +1467,13 @@ static void __init pcpu_populate_pte(uns
 	pud_t *pud;
 	pmd_t *pmd;
 
+	if (pgd_none(*pgd)) {
+		pud_t *new;
+
+		new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
+		pgd_populate(&init_mm, pgd, new);
+	}
+
 	pud = pud_offset(pgd, addr);
 	if (pud_none(*pud)) {
 		pmd_t *new;
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -1389,6 +1389,13 @@ static unsigned long __ref kernel_map_ra
 		pmd_t *pmd;
 		pte_t *pte;
 
+		if (pgd_none(*pgd)) {
+			pud_t *new;
+
+			new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
+			alloc_bytes += PAGE_SIZE;
+			pgd_populate(&init_mm, pgd, new);
+		}
 		pud = pud_offset(pgd, vstart);
 		if (pud_none(*pud)) {
 			pmd_t *new;
@@ -1855,7 +1862,12 @@ static void __init sun4v_linear_pte_xor_
 /* paging_init() sets up the page tables */
 
 static unsigned long last_valid_pfn;
-pgd_t swapper_pg_dir[PTRS_PER_PGD];
+
+/* These must be page aligned in order to not trigger the
+ * alignment tests of pgd_bad() and pud_bad().
+ */
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((aligned (PAGE_SIZE)));
+static pud_t swapper_pud_dir[PTRS_PER_PUD] __attribute__ ((aligned (PAGE_SIZE)));
 
 static void sun4u_pgprot_init(void);
 static void sun4v_pgprot_init(void);
@@ -1864,6 +1876,8 @@ void __init paging_init(void)
 {
 	unsigned long end_pfn, shift, phys_base;
 	unsigned long real_end, i;
+	pud_t *pud;
+	pmd_t *pmd;
 	int node;
 
 	setup_page_offset();
@@ -1960,9 +1974,18 @@ void __init paging_init(void)
 	
 	memset(swapper_low_pmd_dir, 0, sizeof(swapper_low_pmd_dir));
 
-	/* Now can init the kernel/bad page tables. */
-	pud_set(pud_offset(&swapper_pg_dir[0], 0),
-		swapper_low_pmd_dir + (shift / sizeof(pgd_t)));
+	/* The kernel page tables we publish into what the rest of the
+	 * world sees must be adjusted so that they see the PAGE_OFFSET
+	 * address of these in-kerenel data structures.  However right
+	 * here we must access them from the kernel image side, because
+	 * the trap tables haven't been taken over and therefore we cannot
+	 * take TLB misses in the PAGE_OFFSET linear mappings yet.
+	 */
+	pud = swapper_pud_dir + (shift / sizeof(pud_t));
+	pgd_set(&swapper_pg_dir[0], pud);
+
+	pmd = swapper_low_pmd_dir + (shift / sizeof(pmd_t));
+	pud_set(&swapper_pud_dir[0], pmd);
 	
 	inherit_prom_mappings();