pageattr.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2024 Loongson Technology Corporation Limited
  4 */
  5
  6#include <linux/memblock.h>
  7#include <linux/pagewalk.h>
  8#include <linux/pgtable.h>
  9#include <asm/set_memory.h>
 10#include <asm/tlbflush.h>
 11
 12struct pageattr_masks {
 13	pgprot_t set_mask;
 14	pgprot_t clear_mask;
 15};
 16
 17static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
 18{
 19	unsigned long new_val = val;
 20	struct pageattr_masks *masks = walk->private;
 21
 22	new_val &= ~(pgprot_val(masks->clear_mask));
 23	new_val |= (pgprot_val(masks->set_mask));
 24
 25	return new_val;
 26}
 27
 28static int pageattr_pgd_entry(pgd_t *pgd, unsigned long addr,
 29			      unsigned long next, struct mm_walk *walk)
 30{
 31	pgd_t val = pgdp_get(pgd);
 32
 33	if (pgd_leaf(val)) {
 34		val = __pgd(set_pageattr_masks(pgd_val(val), walk));
 35		set_pgd(pgd, val);
 36	}
 37
 38	return 0;
 39}
 40
 41static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
 42			      unsigned long next, struct mm_walk *walk)
 43{
 44	p4d_t val = p4dp_get(p4d);
 45
 46	if (p4d_leaf(val)) {
 47		val = __p4d(set_pageattr_masks(p4d_val(val), walk));
 48		set_p4d(p4d, val);
 49	}
 50
 51	return 0;
 52}
 53
 54static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
 55			      unsigned long next, struct mm_walk *walk)
 56{
 57	pud_t val = pudp_get(pud);
 58
 59	if (pud_leaf(val)) {
 60		val = __pud(set_pageattr_masks(pud_val(val), walk));
 61		set_pud(pud, val);
 62	}
 63
 64	return 0;
 65}
 66
 67static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
 68			      unsigned long next, struct mm_walk *walk)
 69{
 70	pmd_t val = pmdp_get(pmd);
 71
 72	if (pmd_leaf(val)) {
 73		val = __pmd(set_pageattr_masks(pmd_val(val), walk));
 74		set_pmd(pmd, val);
 75	}
 76
 77	return 0;
 78}
 79
 80static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
 81			      unsigned long next, struct mm_walk *walk)
 82{
 83	pte_t val = ptep_get(pte);
 84
 85	val = __pte(set_pageattr_masks(pte_val(val), walk));
 86	set_pte(pte, val);
 87
 88	return 0;
 89}
 90
 91static int pageattr_pte_hole(unsigned long addr, unsigned long next,
 92			     int depth, struct mm_walk *walk)
 93{
 94	return 0;
 95}
 96
 97static const struct mm_walk_ops pageattr_ops = {
 98	.pgd_entry = pageattr_pgd_entry,
 99	.p4d_entry = pageattr_p4d_entry,
100	.pud_entry = pageattr_pud_entry,
101	.pmd_entry = pageattr_pmd_entry,
102	.pte_entry = pageattr_pte_entry,
103	.pte_hole = pageattr_pte_hole,
104	.walk_lock = PGWALK_RDLOCK,
105};
106
107static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask, pgprot_t clear_mask)
108{
109	int ret;
110	unsigned long start = addr;
111	unsigned long end = start + PAGE_SIZE * numpages;
112	struct pageattr_masks masks = {
113		.set_mask = set_mask,
114		.clear_mask = clear_mask
115	};
116
117	if (!numpages)
118		return 0;
119
120	mmap_write_lock(&init_mm);
121	ret = walk_kernel_page_table_range(start, end, &pageattr_ops, NULL, &masks);
122	mmap_write_unlock(&init_mm);
123
124	flush_tlb_kernel_range(start, end);
125
126	return ret;
127}
128
129int set_memory_x(unsigned long addr, int numpages)
130{
131	if (addr < vm_map_base)
132		return 0;
133
134	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_NO_EXEC));
135}
136
137int set_memory_nx(unsigned long addr, int numpages)
138{
139	if (addr < vm_map_base)
140		return 0;
141
142	return __set_memory(addr, numpages, __pgprot(_PAGE_NO_EXEC), __pgprot(0));
143}
144
145int set_memory_ro(unsigned long addr, int numpages)
146{
147	if (addr < vm_map_base)
148		return 0;
149
150	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_WRITE | _PAGE_DIRTY));
151}
152
153int set_memory_rw(unsigned long addr, int numpages)
154{
155	if (addr < vm_map_base)
156		return 0;
157
158	return __set_memory(addr, numpages, __pgprot(_PAGE_WRITE | _PAGE_DIRTY), __pgprot(0));
159}
160
161bool kernel_page_present(struct page *page)
162{
163	pgd_t *pgd;
164	p4d_t *p4d;
165	pud_t *pud;
166	pmd_t *pmd;
167	pte_t *pte;
168	unsigned long addr = (unsigned long)page_address(page);
169
170	if (addr < vm_map_base)
171		return memblock_is_memory(__pa(addr));
172
173	pgd = pgd_offset_k(addr);
174	if (pgd_none(pgdp_get(pgd)))
175		return false;
176	if (pgd_leaf(pgdp_get(pgd)))
177		return true;
178
179	p4d = p4d_offset(pgd, addr);
180	if (p4d_none(p4dp_get(p4d)))
181		return false;
182	if (p4d_leaf(p4dp_get(p4d)))
183		return true;
184
185	pud = pud_offset(p4d, addr);
186	if (pud_none(pudp_get(pud)))
187		return false;
188	if (pud_leaf(pudp_get(pud)))
189		return true;
190
191	pmd = pmd_offset(pud, addr);
192	if (pmd_none(pmdp_get(pmd)))
193		return false;
194	if (pmd_leaf(pmdp_get(pmd)))
195		return true;
196
197	pte = pte_offset_kernel(pmd, addr);
198	return pte_present(ptep_get(pte));
199}
200
201int set_direct_map_default_noflush(struct page *page)
202{
203	unsigned long addr = (unsigned long)page_address(page);
204
205	if (addr < vm_map_base)
206		return 0;
207
208	return __set_memory(addr, 1, PAGE_KERNEL, __pgprot(0));
209}
210
211int set_direct_map_invalid_noflush(struct page *page)
212{
213	unsigned long addr = (unsigned long)page_address(page);
214
215	if (addr < vm_map_base)
216		return 0;
217
218	return __set_memory(addr, 1, __pgprot(0), __pgprot(_PAGE_PRESENT | _PAGE_VALID));
219}
220
221int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid)
222{
223	unsigned long addr = (unsigned long)page_address(page);
224	pgprot_t set, clear;
225
226	if (addr < vm_map_base)
227		return 0;
228
229	if (valid) {
230		set = PAGE_KERNEL;
231		clear = __pgprot(0);
232	} else {
233		set = __pgprot(0);
234		clear = __pgprot(_PAGE_PRESENT | _PAGE_VALID);
235	}
236
237	return __set_memory(addr, 1, set, clear);
238}