Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Page table support for the Hexagon architecture
4 *
5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 */
7
8#ifndef _ASM_PGALLOC_H
9#define _ASM_PGALLOC_H
10
11#include <asm/mem-layout.h>
12#include <asm/atomic.h>
13
14#define check_pgt_cache() do {} while (0)
15
16extern unsigned long long kmap_generation;
17
18/*
19 * Page table creation interface
20 */
21static inline pgd_t *pgd_alloc(struct mm_struct *mm)
22{
23 pgd_t *pgd;
24
25 pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
26
27 /*
28 * There may be better ways to do this, but to ensure
29 * that new address spaces always contain the kernel
30 * base mapping, and to ensure that the user area is
31 * initially marked invalid, initialize the new map
32 * map with a copy of the kernel's persistent map.
33 */
34
35 memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
36 mm->context.generation = kmap_generation;
37
38 /* Physical version is what is passed to virtual machine on switch */
39 mm->context.ptbase = __pa(pgd);
40
41 return pgd;
42}
43
44static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
45{
46 free_page((unsigned long) pgd);
47}
48
49static inline struct page *pte_alloc_one(struct mm_struct *mm)
50{
51 struct page *pte;
52
53 pte = alloc_page(GFP_KERNEL | __GFP_ZERO);
54 if (!pte)
55 return NULL;
56 if (!pgtable_page_ctor(pte)) {
57 __free_page(pte);
58 return NULL;
59 }
60 return pte;
61}
62
63/* _kernel variant gets to use a different allocator */
64static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
65{
66 gfp_t flags = GFP_KERNEL | __GFP_ZERO;
67 return (pte_t *) __get_free_page(flags);
68}
69
70static inline void pte_free(struct mm_struct *mm, struct page *pte)
71{
72 pgtable_page_dtor(pte);
73 __free_page(pte);
74}
75
76static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
77{
78 free_page((unsigned long)pte);
79}
80
81static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
82 pgtable_t pte)
83{
84 /*
85 * Conveniently, zero in 3 LSB means indirect 4K page table.
86 * Not so convenient when you're trying to vary the page size.
87 */
88 set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
89 HEXAGON_L1_PTE_SIZE));
90}
91
92/*
93 * Other architectures seem to have ways of making all processes
94 * share the same pmd's for their kernel mappings, but the v0.3
95 * Hexagon VM spec has a "monolithic" L1 table for user and kernel
96 * segments. We track "generations" of the kernel map to minimize
97 * overhead, and update the "slave" copies of the kernel mappings
98 * as part of switch_mm. However, we still need to update the
99 * kernel map of the active thread who's calling pmd_populate_kernel...
100 */
101static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
102 pte_t *pte)
103{
104 extern spinlock_t kmap_gen_lock;
105 pmd_t *ppmd;
106 int pmdindex;
107
108 spin_lock(&kmap_gen_lock);
109 kmap_generation++;
110 mm->context.generation = kmap_generation;
111 current->active_mm->context.generation = kmap_generation;
112 spin_unlock(&kmap_gen_lock);
113
114 set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
115
116 /*
117 * Now the "slave" copy of the current thread.
118 * This is pointer arithmetic, not byte addresses!
119 */
120 pmdindex = (pgd_t *)pmd - mm->pgd;
121 ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
122 set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
123 if (pmdindex > max_kernel_seg)
124 max_kernel_seg = pmdindex;
125}
126
127#define __pte_free_tlb(tlb, pte, addr) \
128do { \
129 pgtable_page_dtor((pte)); \
130 tlb_remove_page((tlb), (pte)); \
131} while (0)
132
133#endif