1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 *   This program is free software; you can redistribute it and/or
5 *   modify it under the terms of the GNU General Public License
6 *   as published by the Free Software Foundation, version 2.
7 *
8 *   This program is distributed in the hope that it will be useful, but
9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 *   NON INFRINGEMENT.  See the GNU General Public License for
12 *   more details.
13 *
14 */
15
16#ifndef _ASM_TILE_PGTABLE_32_H
17#define _ASM_TILE_PGTABLE_32_H
18
19/*
20 * The level-1 index is defined by the huge page size.  A PGD is composed
21 * of PTRS_PER_PGD pgd_t's and is the top level of the page table.
22 */
23#define PGDIR_SHIFT	HPAGE_SHIFT
24#define PGDIR_SIZE	HPAGE_SIZE
25#define PGDIR_MASK	(~(PGDIR_SIZE-1))
26#define PTRS_PER_PGD	_HV_L1_ENTRIES(HPAGE_SHIFT)
27#define PGD_INDEX(va)	_HV_L1_INDEX(va, HPAGE_SHIFT)
28#define SIZEOF_PGD	_HV_L1_SIZE(HPAGE_SHIFT)
29
30/*
31 * The level-2 index is defined by the difference between the huge
32 * page size and the normal page size.  A PTE is composed of
33 * PTRS_PER_PTE pte_t's and is the bottom level of the page table.
34 * Note that the hypervisor docs use PTE for what we call pte_t, so
35 * this nomenclature is somewhat confusing.
36 */
37#define PTRS_PER_PTE	_HV_L2_ENTRIES(HPAGE_SHIFT, PAGE_SHIFT)
38#define PTE_INDEX(va)	_HV_L2_INDEX(va, HPAGE_SHIFT, PAGE_SHIFT)
39#define SIZEOF_PTE	_HV_L2_SIZE(HPAGE_SHIFT, PAGE_SHIFT)
40
41#ifndef __ASSEMBLY__
42
43/*
44 * Right now we initialize only a single pte table. It can be extended
45 * easily, subsequent pte tables have to be allocated in one physical
46 * chunk of RAM.
47 *
48 * HOWEVER, if we are using an allocation scheme with slop after the
49 * end of the page table (e.g. where our L2 page tables are 2KB but
50 * our pages are 64KB and we are allocating via the page allocator)
51 * we can't extend it easily.
52 */
53#define LAST_PKMAP PTRS_PER_PTE
54
55#define PKMAP_BASE   ((FIXADDR_BOOT_START - PAGE_SIZE*LAST_PKMAP) & PGDIR_MASK)
56
57#ifdef CONFIG_HIGHMEM
58# define _VMALLOC_END	(PKMAP_BASE & ~(HPAGE_SIZE-1))
59#else
60# define _VMALLOC_END	(FIXADDR_START & ~(HPAGE_SIZE-1))
61#endif
62
63/*
64 * Align the vmalloc area to an L2 page table, and leave a guard page
65 * at the beginning and end.  The vmalloc code also puts in an internal
66 * guard page between each allocation.
67 */
68#define VMALLOC_END	(_VMALLOC_END - PAGE_SIZE)
69extern unsigned long VMALLOC_RESERVE /* = CONFIG_VMALLOC_RESERVE */;
70#define _VMALLOC_START	(_VMALLOC_END - VMALLOC_RESERVE)
71#define VMALLOC_START	(_VMALLOC_START + PAGE_SIZE)
72
73/* This is the maximum possible amount of lowmem. */
74#define MAXMEM		(_VMALLOC_START - PAGE_OFFSET)
75
76/* We have no pmd or pud since we are strictly a two-level page table */
77#include <asm-generic/pgtable-nopmd.h>
78
79static inline int pud_huge_page(pud_t pud)	{ return 0; }
80
81/* We don't define any pgds for these addresses. */
82static inline int pgd_addr_invalid(unsigned long addr)
83{
84	return addr >= MEM_HV_START;
85}
86
87/*
88 * Provide versions of these routines that can be used safely when
89 * the hypervisor may be asynchronously modifying dirty/accessed bits.
90 * ptep_get_and_clear() matches the generic one but we provide it to
91 * be parallel with the 64-bit code.
92 */
93#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
94#define __HAVE_ARCH_PTEP_SET_WRPROTECT
95
96extern int ptep_test_and_clear_young(struct vm_area_struct *,
97				     unsigned long addr, pte_t *);
98extern void ptep_set_wrprotect(struct mm_struct *,
99			       unsigned long addr, pte_t *);
100
101#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
102static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
103				       unsigned long addr, pte_t *ptep)
104{
105	pte_t pte = *ptep;
106	pte_clear(_mm, addr, ptep);
107	return pte;
108}
109
110/*
111 * pmds are wrappers around pgds, which are the same as ptes.
112 * It's often convenient to "cast" back and forth and use the pte methods,
113 * which are the methods supplied by the hypervisor.
114 */
115#define pmd_pte(pmd) ((pmd).pud.pgd)
116#define pmdp_ptep(pmdp) (&(pmdp)->pud.pgd)
117#define pte_pmd(pte) ((pmd_t){ { (pte) } })
118
119#endif /* __ASSEMBLY__ */
120
121#endif /* _ASM_TILE_PGTABLE_32_H */
122