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 
47 LIST_HEAD(static_vmlist);
48 
find_static_vm_paddr(phys_addr_t paddr,size_t size,unsigned int mtype)49 static 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 
find_static_vm_vaddr(void * vaddr)72 struct 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 
add_static_vm_early(struct static_vm * svm)91 void __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(&svm->list, &curr_svm->list);
108 }
109 
ioremap_page(unsigned long virt,unsigned long phys,const struct mem_type * mtype)110 int ioremap_page(unsigned long virt, unsigned long phys,
111 		 const struct mem_type *mtype)
112 {
113 	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
114 				  __pgprot(mtype->prot_pte));
115 }
116 EXPORT_SYMBOL(ioremap_page);
117 
__check_vmalloc_seq(struct mm_struct * mm)118 void __check_vmalloc_seq(struct mm_struct *mm)
119 {
120 	int seq;
121 
122 	do {
123 		seq = atomic_read(&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(&mm->context.vmalloc_seq, seq);
134 	} while (seq != atomic_read(&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  */
unmap_area_sections(unsigned long virt,unsigned long size)148 static 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 
187 static int
remap_area_sections(unsigned long virt,unsigned long pfn,size_t size,const struct mem_type * type)188 remap_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 
214 static int
remap_area_supersections(unsigned long virt,unsigned long pfn,size_t size,const struct mem_type * type)215 remap_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 
__arm_ioremap_pfn_caller(unsigned long pfn,unsigned long offset,size_t size,unsigned int mtype,void * caller)249 static 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(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, addr + size, paddr,
316 					 __pgprot(type->prot_pte));
317 
318 	if (err) {
319  		vunmap((void *)addr);
320  		return NULL;
321  	}
322 
323 	flush_cache_vmap(addr, addr + size);
324 	return (void __iomem *) (offset + addr);
325 }
326 
__arm_ioremap_caller(phys_addr_t phys_addr,size_t size,unsigned int mtype,void * caller)327 void __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  */
354 void __iomem *
__arm_ioremap_pfn(unsigned long pfn,unsigned long offset,size_t size,unsigned int mtype)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 					__builtin_return_address(0));
360 }
361 EXPORT_SYMBOL(__arm_ioremap_pfn);
362 
363 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
364 				      unsigned int, void *) =
365 	__arm_ioremap_caller;
366 
ioremap(resource_size_t res_cookie,size_t size)367 void __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 }
372 EXPORT_SYMBOL(ioremap);
373 
ioremap_cache(resource_size_t res_cookie,size_t size)374 void __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 }
379 EXPORT_SYMBOL(ioremap_cache);
380 
ioremap_wc(resource_size_t res_cookie,size_t size)381 void __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 }
386 EXPORT_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  */
395 void __iomem *
__arm_ioremap_exec(phys_addr_t phys_addr,size_t size,bool cached)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 			__builtin_return_address(0));
407 }
408 
__arm_iomem_set_ro(void __iomem * ptr,size_t size)409 void __arm_iomem_set_ro(void __iomem *ptr, size_t size)
410 {
411 	set_memory_ro((unsigned long)ptr, PAGE_ALIGN(size) / PAGE_SIZE);
412 }
413 
arch_memremap_wb(phys_addr_t phys_addr,size_t size)414 void *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 
__iounmap(volatile void __iomem * io_addr)421 void __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(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 }
449 
450 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
451 
iounmap(volatile void __iomem * cookie)452 void iounmap(volatile void __iomem *cookie)
453 {
454 	arch_iounmap(cookie);
455 }
456 EXPORT_SYMBOL(iounmap);
457 
458 #if defined(CONFIG_PCI) || IS_ENABLED(CONFIG_PCMCIA)
459 static int pci_ioremap_mem_type = MT_DEVICE;
460 
pci_ioremap_set_mem_type(int mem_type)461 void pci_ioremap_set_mem_type(int mem_type)
462 {
463 	pci_ioremap_mem_type = mem_type;
464 }
465 
pci_remap_iospace(const struct resource * res,phys_addr_t phys_addr)466 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
467 {
468 	unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
469 
470 	if (!(res->flags & IORESOURCE_IO))
471 		return -EINVAL;
472 
473 	if (res->end > IO_SPACE_LIMIT)
474 		return -EINVAL;
475 
476 	return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
477 				  __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
478 }
479 EXPORT_SYMBOL(pci_remap_iospace);
480 
pci_remap_cfgspace(resource_size_t res_cookie,size_t size)481 void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
482 {
483 	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
484 				   __builtin_return_address(0));
485 }
486 EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
487 #endif
488 
489 /*
490  * Must be called after early_fixmap_init
491  */
early_ioremap_init(void)492 void __init early_ioremap_init(void)
493 {
494 	early_ioremap_setup();
495 }
496 
arch_memremap_can_ram_remap(resource_size_t offset,size_t size,unsigned long flags)497 bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
498 				 unsigned long flags)
499 {
500 	unsigned long pfn = PHYS_PFN(offset);
501 
502 	return memblock_is_map_memory(pfn);
503 }
504