Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Re-map IO memory to kernel address space so that we can access it.
4 * This is needed for high PCI addresses that aren't mapped in the
5 * 640k-1MB IO memory area on PC's
6 *
7 * (C) Copyright 1995 1996 Linus Torvalds
8 */
9#include <linux/vmalloc.h>
10#include <linux/mm.h>
11#include <linux/sched.h>
12#include <linux/io.h>
13#include <linux/export.h>
14#include <asm/cacheflush.h>
15#include <asm/pgtable.h>
16
17#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
18static int __read_mostly ioremap_p4d_capable;
19static int __read_mostly ioremap_pud_capable;
20static int __read_mostly ioremap_pmd_capable;
21static int __read_mostly ioremap_huge_disabled;
22
23static int __init set_nohugeiomap(char *str)
24{
25 ioremap_huge_disabled = 1;
26 return 0;
27}
28early_param("nohugeiomap", set_nohugeiomap);
29
30void __init ioremap_huge_init(void)
31{
32 if (!ioremap_huge_disabled) {
33 if (arch_ioremap_p4d_supported())
34 ioremap_p4d_capable = 1;
35 if (arch_ioremap_pud_supported())
36 ioremap_pud_capable = 1;
37 if (arch_ioremap_pmd_supported())
38 ioremap_pmd_capable = 1;
39 }
40}
41
42static inline int ioremap_p4d_enabled(void)
43{
44 return ioremap_p4d_capable;
45}
46
47static inline int ioremap_pud_enabled(void)
48{
49 return ioremap_pud_capable;
50}
51
52static inline int ioremap_pmd_enabled(void)
53{
54 return ioremap_pmd_capable;
55}
56
57#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
58static inline int ioremap_p4d_enabled(void) { return 0; }
59static inline int ioremap_pud_enabled(void) { return 0; }
60static inline int ioremap_pmd_enabled(void) { return 0; }
61#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
62
63static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
64 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
65{
66 pte_t *pte;
67 u64 pfn;
68
69 pfn = phys_addr >> PAGE_SHIFT;
70 pte = pte_alloc_kernel(pmd, addr);
71 if (!pte)
72 return -ENOMEM;
73 do {
74 BUG_ON(!pte_none(*pte));
75 set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
76 pfn++;
77 } while (pte++, addr += PAGE_SIZE, addr != end);
78 return 0;
79}
80
81static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
82 unsigned long end, phys_addr_t phys_addr,
83 pgprot_t prot)
84{
85 if (!ioremap_pmd_enabled())
86 return 0;
87
88 if ((end - addr) != PMD_SIZE)
89 return 0;
90
91 if (!IS_ALIGNED(addr, PMD_SIZE))
92 return 0;
93
94 if (!IS_ALIGNED(phys_addr, PMD_SIZE))
95 return 0;
96
97 if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
98 return 0;
99
100 return pmd_set_huge(pmd, phys_addr, prot);
101}
102
103static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
104 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
105{
106 pmd_t *pmd;
107 unsigned long next;
108
109 pmd = pmd_alloc(&init_mm, pud, addr);
110 if (!pmd)
111 return -ENOMEM;
112 do {
113 next = pmd_addr_end(addr, end);
114
115 if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot))
116 continue;
117
118 if (ioremap_pte_range(pmd, addr, next, phys_addr, prot))
119 return -ENOMEM;
120 } while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
121 return 0;
122}
123
124static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
125 unsigned long end, phys_addr_t phys_addr,
126 pgprot_t prot)
127{
128 if (!ioremap_pud_enabled())
129 return 0;
130
131 if ((end - addr) != PUD_SIZE)
132 return 0;
133
134 if (!IS_ALIGNED(addr, PUD_SIZE))
135 return 0;
136
137 if (!IS_ALIGNED(phys_addr, PUD_SIZE))
138 return 0;
139
140 if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
141 return 0;
142
143 return pud_set_huge(pud, phys_addr, prot);
144}
145
146static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
147 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
148{
149 pud_t *pud;
150 unsigned long next;
151
152 pud = pud_alloc(&init_mm, p4d, addr);
153 if (!pud)
154 return -ENOMEM;
155 do {
156 next = pud_addr_end(addr, end);
157
158 if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot))
159 continue;
160
161 if (ioremap_pmd_range(pud, addr, next, phys_addr, prot))
162 return -ENOMEM;
163 } while (pud++, phys_addr += (next - addr), addr = next, addr != end);
164 return 0;
165}
166
167static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
168 unsigned long end, phys_addr_t phys_addr,
169 pgprot_t prot)
170{
171 if (!ioremap_p4d_enabled())
172 return 0;
173
174 if ((end - addr) != P4D_SIZE)
175 return 0;
176
177 if (!IS_ALIGNED(addr, P4D_SIZE))
178 return 0;
179
180 if (!IS_ALIGNED(phys_addr, P4D_SIZE))
181 return 0;
182
183 if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
184 return 0;
185
186 return p4d_set_huge(p4d, phys_addr, prot);
187}
188
189static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
190 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
191{
192 p4d_t *p4d;
193 unsigned long next;
194
195 p4d = p4d_alloc(&init_mm, pgd, addr);
196 if (!p4d)
197 return -ENOMEM;
198 do {
199 next = p4d_addr_end(addr, end);
200
201 if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot))
202 continue;
203
204 if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))
205 return -ENOMEM;
206 } while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
207 return 0;
208}
209
210int ioremap_page_range(unsigned long addr,
211 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
212{
213 pgd_t *pgd;
214 unsigned long start;
215 unsigned long next;
216 int err;
217
218 might_sleep();
219 BUG_ON(addr >= end);
220
221 start = addr;
222 pgd = pgd_offset_k(addr);
223 do {
224 next = pgd_addr_end(addr, end);
225 err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot);
226 if (err)
227 break;
228 } while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
229
230 flush_cache_vmap(start, end);
231
232 return err;
233}
234
235#ifdef CONFIG_GENERIC_IOREMAP
236void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
237{
238 unsigned long offset, vaddr;
239 phys_addr_t last_addr;
240 struct vm_struct *area;
241
242 /* Disallow wrap-around or zero size */
243 last_addr = addr + size - 1;
244 if (!size || last_addr < addr)
245 return NULL;
246
247 /* Page-align mappings */
248 offset = addr & (~PAGE_MASK);
249 addr -= offset;
250 size = PAGE_ALIGN(size + offset);
251
252 area = get_vm_area_caller(size, VM_IOREMAP,
253 __builtin_return_address(0));
254 if (!area)
255 return NULL;
256 vaddr = (unsigned long)area->addr;
257
258 if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
259 free_vm_area(area);
260 return NULL;
261 }
262
263 return (void __iomem *)(vaddr + offset);
264}
265EXPORT_SYMBOL(ioremap_prot);
266
267void iounmap(volatile void __iomem *addr)
268{
269 vunmap((void *)((unsigned long)addr & PAGE_MASK));
270}
271EXPORT_SYMBOL(iounmap);
272#endif /* CONFIG_GENERIC_IOREMAP */