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
 16#include "pgalloc-track.h"
 17
 18#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 19static int __read_mostly ioremap_p4d_capable;
 20static int __read_mostly ioremap_pud_capable;
 21static int __read_mostly ioremap_pmd_capable;
 22static int __read_mostly ioremap_huge_disabled;
 23
 24static int __init set_nohugeiomap(char *str)
 25{
 26	ioremap_huge_disabled = 1;
 27	return 0;
 28}
 29early_param("nohugeiomap", set_nohugeiomap);
 30
 31void __init ioremap_huge_init(void)
 32{
 33	if (!ioremap_huge_disabled) {
 34		if (arch_ioremap_p4d_supported())
 35			ioremap_p4d_capable = 1;
 36		if (arch_ioremap_pud_supported())
 37			ioremap_pud_capable = 1;
 38		if (arch_ioremap_pmd_supported())
 39			ioremap_pmd_capable = 1;
 40	}
 41}
 42
 43static inline int ioremap_p4d_enabled(void)
 44{
 45	return ioremap_p4d_capable;
 46}
 47
 48static inline int ioremap_pud_enabled(void)
 49{
 50	return ioremap_pud_capable;
 51}
 52
 53static inline int ioremap_pmd_enabled(void)
 54{
 55	return ioremap_pmd_capable;
 56}
 57
 58#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 59static inline int ioremap_p4d_enabled(void) { return 0; }
 60static inline int ioremap_pud_enabled(void) { return 0; }
 61static inline int ioremap_pmd_enabled(void) { return 0; }
 62#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 63
 64static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
 65		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
 66		pgtbl_mod_mask *mask)
 67{
 68	pte_t *pte;
 69	u64 pfn;
 70
 71	pfn = phys_addr >> PAGE_SHIFT;
 72	pte = pte_alloc_kernel_track(pmd, addr, mask);
 73	if (!pte)
 74		return -ENOMEM;
 75	do {
 76		BUG_ON(!pte_none(*pte));
 77		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
 78		pfn++;
 79	} while (pte++, addr += PAGE_SIZE, addr != end);
 80	*mask |= PGTBL_PTE_MODIFIED;
 81	return 0;
 82}
 83
 84static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
 85				unsigned long end, phys_addr_t phys_addr,
 86				pgprot_t prot)
 87{
 88	if (!ioremap_pmd_enabled())
 89		return 0;
 90
 91	if ((end - addr) != PMD_SIZE)
 92		return 0;
 93
 94	if (!IS_ALIGNED(addr, PMD_SIZE))
 95		return 0;
 96
 97	if (!IS_ALIGNED(phys_addr, PMD_SIZE))
 98		return 0;
 99
100	if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
101		return 0;
102
103	return pmd_set_huge(pmd, phys_addr, prot);
104}
105
106static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
107		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
108		pgtbl_mod_mask *mask)
109{
110	pmd_t *pmd;
111	unsigned long next;
112
113	pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
114	if (!pmd)
115		return -ENOMEM;
116	do {
117		next = pmd_addr_end(addr, end);
118
119		if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
120			*mask |= PGTBL_PMD_MODIFIED;
121			continue;
122		}
123
124		if (ioremap_pte_range(pmd, addr, next, phys_addr, prot, mask))
125			return -ENOMEM;
126	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
127	return 0;
128}
129
130static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
131				unsigned long end, phys_addr_t phys_addr,
132				pgprot_t prot)
133{
134	if (!ioremap_pud_enabled())
135		return 0;
136
137	if ((end - addr) != PUD_SIZE)
138		return 0;
139
140	if (!IS_ALIGNED(addr, PUD_SIZE))
141		return 0;
142
143	if (!IS_ALIGNED(phys_addr, PUD_SIZE))
144		return 0;
145
146	if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
147		return 0;
148
149	return pud_set_huge(pud, phys_addr, prot);
150}
151
152static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
153		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
154		pgtbl_mod_mask *mask)
155{
156	pud_t *pud;
157	unsigned long next;
158
159	pud = pud_alloc_track(&init_mm, p4d, addr, mask);
160	if (!pud)
161		return -ENOMEM;
162	do {
163		next = pud_addr_end(addr, end);
164
165		if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
166			*mask |= PGTBL_PUD_MODIFIED;
167			continue;
168		}
169
170		if (ioremap_pmd_range(pud, addr, next, phys_addr, prot, mask))
171			return -ENOMEM;
172	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
173	return 0;
174}
175
176static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
177				unsigned long end, phys_addr_t phys_addr,
178				pgprot_t prot)
179{
180	if (!ioremap_p4d_enabled())
181		return 0;
182
183	if ((end - addr) != P4D_SIZE)
184		return 0;
185
186	if (!IS_ALIGNED(addr, P4D_SIZE))
187		return 0;
188
189	if (!IS_ALIGNED(phys_addr, P4D_SIZE))
190		return 0;
191
192	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
193		return 0;
194
195	return p4d_set_huge(p4d, phys_addr, prot);
196}
197
198static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
199		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
200		pgtbl_mod_mask *mask)
201{
202	p4d_t *p4d;
203	unsigned long next;
204
205	p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
206	if (!p4d)
207		return -ENOMEM;
208	do {
209		next = p4d_addr_end(addr, end);
210
211		if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
212			*mask |= PGTBL_P4D_MODIFIED;
213			continue;
214		}
215
216		if (ioremap_pud_range(p4d, addr, next, phys_addr, prot, mask))
217			return -ENOMEM;
218	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
219	return 0;
220}
221
222int ioremap_page_range(unsigned long addr,
223		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
224{
225	pgd_t *pgd;
226	unsigned long start;
227	unsigned long next;
228	int err;
229	pgtbl_mod_mask mask = 0;
230
231	might_sleep();
232	BUG_ON(addr >= end);
233
234	start = addr;
235	pgd = pgd_offset_k(addr);
236	do {
237		next = pgd_addr_end(addr, end);
238		err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot,
239					&mask);
240		if (err)
241			break;
242	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
243
244	flush_cache_vmap(start, end);
245
246	if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
247		arch_sync_kernel_mappings(start, end);
248
249	return err;
250}
251
252#ifdef CONFIG_GENERIC_IOREMAP
253void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
254{
255	unsigned long offset, vaddr;
256	phys_addr_t last_addr;
257	struct vm_struct *area;
258
259	/* Disallow wrap-around or zero size */
260	last_addr = addr + size - 1;
261	if (!size || last_addr < addr)
262		return NULL;
263
264	/* Page-align mappings */
265	offset = addr & (~PAGE_MASK);
266	addr -= offset;
267	size = PAGE_ALIGN(size + offset);
268
269	area = get_vm_area_caller(size, VM_IOREMAP,
270			__builtin_return_address(0));
271	if (!area)
272		return NULL;
273	vaddr = (unsigned long)area->addr;
274
275	if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
276		free_vm_area(area);
277		return NULL;
278	}
279
280	return (void __iomem *)(vaddr + offset);
281}
282EXPORT_SYMBOL(ioremap_prot);
283
284void iounmap(volatile void __iomem *addr)
285{
286	vunmap((void *)((unsigned long)addr & PAGE_MASK));
287}
288EXPORT_SYMBOL(iounmap);
289#endif /* CONFIG_GENERIC_IOREMAP */