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#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */
15
16#define check_pgt_cache() do {} while (0)
17
18extern unsigned long long kmap_generation;
19
20/*
21 * Page table creation interface
22 */
23static inline pgd_t *pgd_alloc(struct mm_struct *mm)
24{
25 pgd_t *pgd;
26
27 pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
28
29 /*
30 * There may be better ways to do this, but to ensure
31 * that new address spaces always contain the kernel
32 * base mapping, and to ensure that the user area is
33 * initially marked invalid, initialize the new map
34 * map with a copy of the kernel's persistent map.
35 */
36
37 memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
38 mm->context.generation = kmap_generation;
39
40 /* Physical version is what is passed to virtual machine on switch */
41 mm->context.ptbase = __pa(pgd);
42
43 return pgd;
44}
45
46static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
47{
48 free_page((unsigned long) pgd);
49}
50
51static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
52 pgtable_t pte)
53{
54 /*
55 * Conveniently, zero in 3 LSB means indirect 4K page table.
56 * Not so convenient when you're trying to vary the page size.
57 */
58 set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
59 HEXAGON_L1_PTE_SIZE));
60}
61
62/*
63 * Other architectures seem to have ways of making all processes
64 * share the same pmd's for their kernel mappings, but the v0.3
65 * Hexagon VM spec has a "monolithic" L1 table for user and kernel
66 * segments. We track "generations" of the kernel map to minimize
67 * overhead, and update the "slave" copies of the kernel mappings
68 * as part of switch_mm. However, we still need to update the
69 * kernel map of the active thread who's calling pmd_populate_kernel...
70 */
71static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
72 pte_t *pte)
73{
74 extern spinlock_t kmap_gen_lock;
75 pmd_t *ppmd;
76 int pmdindex;
77
78 spin_lock(&kmap_gen_lock);
79 kmap_generation++;
80 mm->context.generation = kmap_generation;
81 current->active_mm->context.generation = kmap_generation;
82 spin_unlock(&kmap_gen_lock);
83
84 set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
85
86 /*
87 * Now the "slave" copy of the current thread.
88 * This is pointer arithmetic, not byte addresses!
89 */
90 pmdindex = (pgd_t *)pmd - mm->pgd;
91 ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
92 set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
93 if (pmdindex > max_kernel_seg)
94 max_kernel_seg = pmdindex;
95}
96
97#define __pte_free_tlb(tlb, pte, addr) \
98do { \
99 pgtable_page_dtor((pte)); \
100 tlb_remove_page((tlb), (pte)); \
101} while (0)
102
103#endif