1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/mm/ioremap.c
4 *
5 * Re-map IO memory to kernel address space so that we can access it.
6 *
7 * (C) Copyright 1995 1996 Linus Torvalds
8 *
9 * Hacked for ARM by Phil Blundell <philb@gnu.org>
10 * Hacked to allow all architectures to build, and various cleanups
11 * by Russell King
12 *
13 * This allows a driver to remap an arbitrary region of bus memory into
14 * virtual space. One should *only* use readl, writel, memcpy_toio and
15 * so on with such remapped areas.
16 *
17 * Because the ARM only has a 32-bit address space we can't address the
18 * whole of the (physical) PCI space at once. PCI huge-mode addressing
19 * allows us to circumvent this restriction by splitting PCI space into
20 * two 2GB chunks and mapping only one at a time into processor memory.
21 * We use MMU protection domains to trap any attempt to access the bank
22 * that is not currently mapped. (This isn't fully implemented yet.)
23 */
24#include <linux/module.h>
25#include <linux/errno.h>
26#include <linux/mm.h>
27#include <linux/vmalloc.h>
28#include <linux/io.h>
29#include <linux/sizes.h>
30#include <linux/memblock.h>
31
32#include <asm/cp15.h>
33#include <asm/cputype.h>
34#include <asm/cacheflush.h>
35#include <asm/early_ioremap.h>
36#include <asm/mmu_context.h>
37#include <asm/pgalloc.h>
38#include <asm/tlbflush.h>
39#include <asm/set_memory.h>
40#include <asm/system_info.h>
41
42#include <asm/mach/map.h>
43#include <asm/mach/pci.h>
44#include "mm.h"
45
46
47LIST_HEAD(static_vmlist);
48
49static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
50 size_t size, unsigned int mtype)
51{
52 struct static_vm *svm;
53 struct vm_struct *vm;
54
55 list_for_each_entry(svm, &static_vmlist, list) {
56 vm = &svm->vm;
57 if (!(vm->flags & VM_ARM_STATIC_MAPPING))
58 continue;
59 if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
60 continue;
61
62 if (vm->phys_addr > paddr ||
63 paddr + size - 1 > vm->phys_addr + vm->size - 1)
64 continue;
65
66 return svm;
67 }
68
69 return NULL;
70}
71
72struct static_vm *find_static_vm_vaddr(void *vaddr)
73{
74 struct static_vm *svm;
75 struct vm_struct *vm;
76
77 list_for_each_entry(svm, &static_vmlist, list) {
78 vm = &svm->vm;
79
80 /* static_vmlist is ascending order */
81 if (vm->addr > vaddr)
82 break;
83
84 if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
85 return svm;
86 }
87
88 return NULL;
89}
90
91void __init add_static_vm_early(struct static_vm *svm)
92{
93 struct static_vm *curr_svm;
94 struct vm_struct *vm;
95 void *vaddr;
96
97 vm = &svm->vm;
98 vm_area_add_early(vm);
99 vaddr = vm->addr;
100
101 list_for_each_entry(curr_svm, &static_vmlist, list) {
102 vm = &curr_svm->vm;
103
104 if (vm->addr > vaddr)
105 break;
106 }
107 list_add_tail(new: &svm->list, head: &curr_svm->list);
108}
109
110int ioremap_page(unsigned long virt, unsigned long phys,
111 const struct mem_type *mtype)
112{
113 return vmap_page_range(addr: virt, end: virt + PAGE_SIZE, phys_addr: phys,
114 __pgprot(mtype->prot_pte));
115}
116EXPORT_SYMBOL(ioremap_page);
117
118void __check_vmalloc_seq(struct mm_struct *mm)
119{
120 int seq;
121
122 do {
123 seq = atomic_read(v: &init_mm.context.vmalloc_seq);
124 memcpy(pgd_offset(mm, VMALLOC_START),
125 pgd_offset_k(VMALLOC_START),
126 sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
127 pgd_index(VMALLOC_START)));
128 /*
129 * Use a store-release so that other CPUs that observe the
130 * counter's new value are guaranteed to see the results of the
131 * memcpy as well.
132 */
133 atomic_set_release(v: &mm->context.vmalloc_seq, i: seq);
134 } while (seq != atomic_read(v: &init_mm.context.vmalloc_seq));
135}
136
137#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
138/*
139 * Section support is unsafe on SMP - If you iounmap and ioremap a region,
140 * the other CPUs will not see this change until their next context switch.
141 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
142 * which requires the new ioremap'd region to be referenced, the CPU will
143 * reference the _old_ region.
144 *
145 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
146 * mask the size back to 1MB aligned or we will overflow in the loop below.
147 */
148static void unmap_area_sections(unsigned long virt, unsigned long size)
149{
150 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
151 pmd_t *pmdp = pmd_off_k(addr);
152
153 do {
154 pmd_t pmd = *pmdp;
155
156 if (!pmd_none(pmd)) {
157 /*
158 * Clear the PMD from the page table, and
159 * increment the vmalloc sequence so others
160 * notice this change.
161 *
162 * Note: this is still racy on SMP machines.
163 */
164 pmd_clear(pmdp);
165 atomic_inc_return_release(&init_mm.context.vmalloc_seq);
166
167 /*
168 * Free the page table, if there was one.
169 */
170 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
171 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
172 }
173
174 addr += PMD_SIZE;
175 pmdp += 2;
176 } while (addr < end);
177
178 /*
179 * Ensure that the active_mm is up to date - we want to
180 * catch any use-after-iounmap cases.
181 */
182 check_vmalloc_seq(current->active_mm);
183
184 flush_tlb_kernel_range(virt, end);
185}
186
187static int
188remap_area_sections(unsigned long virt, unsigned long pfn,
189 size_t size, const struct mem_type *type)
190{
191 unsigned long addr = virt, end = virt + size;
192 pmd_t *pmd = pmd_off_k(addr);
193
194 /*
195 * Remove and free any PTE-based mapping, and
196 * sync the current kernel mapping.
197 */
198 unmap_area_sections(virt, size);
199
200 do {
201 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
202 pfn += SZ_1M >> PAGE_SHIFT;
203 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
204 pfn += SZ_1M >> PAGE_SHIFT;
205 flush_pmd_entry(pmd);
206
207 addr += PMD_SIZE;
208 pmd += 2;
209 } while (addr < end);
210
211 return 0;
212}
213
214static int
215remap_area_supersections(unsigned long virt, unsigned long pfn,
216 size_t size, const struct mem_type *type)
217{
218 unsigned long addr = virt, end = virt + size;
219 pmd_t *pmd = pmd_off_k(addr);
220
221 /*
222 * Remove and free any PTE-based mapping, and
223 * sync the current kernel mapping.
224 */
225 unmap_area_sections(virt, size);
226 do {
227 unsigned long super_pmd_val, i;
228
229 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
230 PMD_SECT_SUPER;
231 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
232
233 for (i = 0; i < 8; i++) {
234 pmd[0] = __pmd(super_pmd_val);
235 pmd[1] = __pmd(super_pmd_val);
236 flush_pmd_entry(pmd);
237
238 addr += PMD_SIZE;
239 pmd += 2;
240 }
241
242 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
243 } while (addr < end);
244
245 return 0;
246}
247#endif
248
249static void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
250 unsigned long offset, size_t size, unsigned int mtype, void *caller)
251{
252 const struct mem_type *type;
253 int err;
254 unsigned long addr;
255 struct vm_struct *area;
256 phys_addr_t paddr = __pfn_to_phys(pfn);
257
258#ifndef CONFIG_ARM_LPAE
259 /*
260 * High mappings must be supersection aligned
261 */
262 if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
263 return NULL;
264#endif
265
266 type = get_mem_type(type: mtype);
267 if (!type)
268 return NULL;
269
270 /*
271 * Page align the mapping size, taking account of any offset.
272 */
273 size = PAGE_ALIGN(offset + size);
274
275 /*
276 * Try to reuse one of the static mapping whenever possible.
277 */
278 if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
279 struct static_vm *svm;
280
281 svm = find_static_vm_paddr(paddr, size, mtype);
282 if (svm) {
283 addr = (unsigned long)svm->vm.addr;
284 addr += paddr - svm->vm.phys_addr;
285 return (void __iomem *) (offset + addr);
286 }
287 }
288
289 /*
290 * Don't allow RAM to be mapped with mismatched attributes - this
291 * causes problems with ARMv6+
292 */
293 if (WARN_ON(memblock_is_map_memory(PFN_PHYS(pfn)) &&
294 mtype != MT_MEMORY_RW))
295 return NULL;
296
297 area = get_vm_area_caller(size, VM_IOREMAP, caller);
298 if (!area)
299 return NULL;
300 addr = (unsigned long)area->addr;
301 area->phys_addr = paddr;
302
303#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
304 if (DOMAIN_IO == 0 &&
305 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
306 cpu_is_xsc3()) && pfn >= 0x100000 &&
307 !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
308 area->flags |= VM_ARM_SECTION_MAPPING;
309 err = remap_area_supersections(addr, pfn, size, type);
310 } else if (!((paddr | size | addr) & ~PMD_MASK)) {
311 area->flags |= VM_ARM_SECTION_MAPPING;
312 err = remap_area_sections(addr, pfn, size, type);
313 } else
314#endif
315 err = ioremap_page_range(addr, end: addr + size, phys_addr: paddr,
316 __pgprot(type->prot_pte));
317
318 if (err) {
319 vunmap(addr: (void *)addr);
320 return NULL;
321 }
322
323 flush_cache_vmap(start: addr, end: addr + size);
324 return (void __iomem *) (offset + addr);
325}
326
327void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
328 unsigned int mtype, void *caller)
329{
330 phys_addr_t last_addr;
331 unsigned long offset = phys_addr & ~PAGE_MASK;
332 unsigned long pfn = __phys_to_pfn(phys_addr);
333
334 /*
335 * Don't allow wraparound or zero size
336 */
337 last_addr = phys_addr + size - 1;
338 if (!size || last_addr < phys_addr)
339 return NULL;
340
341 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
342 caller);
343}
344
345/*
346 * Remap an arbitrary physical address space into the kernel virtual
347 * address space. Needed when the kernel wants to access high addresses
348 * directly.
349 *
350 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
351 * have to convert them into an offset in a page-aligned mapping, but the
352 * caller shouldn't need to know that small detail.
353 */
354void __iomem *
355__arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
356 unsigned int mtype)
357{
358 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
359 caller: __builtin_return_address(0));
360}
361EXPORT_SYMBOL(__arm_ioremap_pfn);
362
363void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
364 unsigned int, void *) =
365 __arm_ioremap_caller;
366
367void __iomem *ioremap(resource_size_t res_cookie, size_t size)
368{
369 return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
370 __builtin_return_address(0));
371}
372EXPORT_SYMBOL(ioremap);
373
374void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
375{
376 return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
377 __builtin_return_address(0));
378}
379EXPORT_SYMBOL(ioremap_cache);
380
381void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
382{
383 return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
384 __builtin_return_address(0));
385}
386EXPORT_SYMBOL(ioremap_wc);
387
388/*
389 * Remap an arbitrary physical address space into the kernel virtual
390 * address space as memory. Needed when the kernel wants to execute
391 * code in external memory. This is needed for reprogramming source
392 * clocks that would affect normal memory for example. Please see
393 * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
394 */
395void __iomem *
396__arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
397{
398 unsigned int mtype;
399
400 if (cached)
401 mtype = MT_MEMORY_RWX;
402 else
403 mtype = MT_MEMORY_RWX_NONCACHED;
404
405 return __arm_ioremap_caller(phys_addr, size, mtype,
406 caller: __builtin_return_address(0));
407}
408
409void __arm_iomem_set_ro(void __iomem *ptr, size_t size)
410{
411 set_memory_ro(addr: (unsigned long)ptr, PAGE_ALIGN(size) / PAGE_SIZE);
412}
413
414void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
415{
416 return (__force void *)arch_ioremap_caller(phys_addr, size,
417 MT_MEMORY_RW,
418 __builtin_return_address(0));
419}
420
421void iounmap(volatile void __iomem *io_addr)
422{
423 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
424 struct static_vm *svm;
425
426 /* If this is a static mapping, we must leave it alone */
427 svm = find_static_vm_vaddr(vaddr: addr);
428 if (svm)
429 return;
430
431#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
432 {
433 struct vm_struct *vm;
434
435 vm = find_vm_area(addr);
436
437 /*
438 * If this is a section based mapping we need to handle it
439 * specially as the VM subsystem does not know how to handle
440 * such a beast.
441 */
442 if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
443 unmap_area_sections((unsigned long)vm->addr, vm->size);
444 }
445#endif
446
447 vunmap(addr);
448}
449EXPORT_SYMBOL(iounmap);
450
451#if defined(CONFIG_PCI) || IS_ENABLED(CONFIG_PCMCIA)
452static int pci_ioremap_mem_type = MT_DEVICE;
453
454void pci_ioremap_set_mem_type(int mem_type)
455{
456 pci_ioremap_mem_type = mem_type;
457}
458
459int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
460{
461 unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
462
463 if (!(res->flags & IORESOURCE_IO))
464 return -EINVAL;
465
466 if (res->end > IO_SPACE_LIMIT)
467 return -EINVAL;
468
469 return vmap_page_range(addr: vaddr, end: vaddr + resource_size(res), phys_addr,
470 __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
471}
472EXPORT_SYMBOL(pci_remap_iospace);
473
474void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
475{
476 return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
477 __builtin_return_address(0));
478}
479EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
480#endif
481
482/*
483 * Must be called after early_fixmap_init
484 */
485void __init early_ioremap_init(void)
486{
487 early_ioremap_setup();
488}
489
490bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
491 unsigned long flags)
492{
493 unsigned long pfn = PHYS_PFN(offset);
494
495 return memblock_is_map_memory(addr: pfn);
496}
497

source code of linux/arch/arm/mm/ioremap.c