aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/mm/ioremap.c
blob: baff1da354e0ecfaf371b4e9f30ac6533d657a28 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
/*
 * Re-map IO memory to kernel address space so that we can access it.
 * This is needed for high PCI addresses that aren't mapped in the
 * 640k-1MB IO memory area on PC's
 *
 * (C) Copyright 1995 1996 Linus Torvalds
 */

#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mmiotrace.h>

#include <asm/cacheflush.h>
#include <asm/e820.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/pat.h>

#include "physaddr.h"

/*
 * Fix up the linear direct mapping of the kernel to avoid cache attribute
 * conflicts.
 */
int ioremap_change_attr(unsigned long vaddr, unsigned long size,
			       unsigned long prot_val)
{
	unsigned long nrpages = size >> PAGE_SHIFT;
	int err;

	switch (prot_val) {
	case _PAGE_CACHE_UC:
	default:
		err = _set_memory_uc(vaddr, nrpages);
		break;
	case _PAGE_CACHE_WC:
		err = _set_memory_wc(vaddr, nrpages);
		break;
	case _PAGE_CACHE_WB:
		err = _set_memory_wb(vaddr, nrpages);
		break;
	}

	return err;
}

static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
			       void *arg)
{
	unsigned long i;

	for (i = 0; i < nr_pages; ++i)
		if (pfn_valid(start_pfn + i) &&
		    !PageReserved(pfn_to_page(start_pfn + i)))
			return 1;

	WARN_ONCE(1, "ioremap on RAM pfn 0x%lx\n", start_pfn);

	return 0;
}

/*
 * Remap an arbitrary physical address space into the kernel virtual
 * address space. Needed when the kernel wants to access high addresses
 * directly.
 *
 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 * have to convert them into an offset in a page-aligned mapping, but the
 * caller shouldn't need to know that small detail.
 */
static void __iomem *__ioremap_caller(resource_size_t phys_addr,
		unsigned long size, unsigned long prot_val, void *caller)
{
	unsigned long offset, vaddr;
	resource_size_t pfn, last_pfn, last_addr;
	const resource_size_t unaligned_phys_addr = phys_addr;
	const unsigned long unaligned_size = size;
	struct vm_struct *area;
	unsigned long new_prot_val;
	pgprot_t prot;
	int retval;
	void __iomem *ret_addr;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;
	if (!size || last_addr < phys_addr)
		return NULL;

	if (!phys_addr_valid(phys_addr)) {
		printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
		       (unsigned long long)phys_addr);
		WARN_ON_ONCE(1);
		return NULL;
	}

	/*
	 * Don't remap the low PCI/ISA area, it's always mapped..
	 */
	if (is_ISA_range(phys_addr, last_addr))
		return (__force void __iomem *)phys_to_virt(phys_addr);

	/*
	 * Don't allow anybody to remap normal RAM that we're using..
	 */
	pfn      = phys_addr >> PAGE_SHIFT;
	last_pfn = last_addr >> PAGE_SHIFT;
	if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
				  __ioremap_check_ram) == 1)
		return NULL;

	/*
	 * Mappings have to be page-aligned
	 */
	offset = phys_addr & ~PAGE_MASK;
	phys_addr &= PHYSICAL_PAGE_MASK;
	size = PAGE_ALIGN(last_addr+1) - phys_addr;

	retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
						prot_val, &new_prot_val);
	if (retval) {
		printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval);
		return NULL;
	}

	if (prot_val != new_prot_val) {
		if (!is_new_memtype_allowed(phys_addr, size,
					    prot_val, new_prot_val)) {
			printk(KERN_ERR
		"ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
				(unsigned long long)phys_addr,
				(unsigned long long)(phys_addr + size),
				prot_val, new_prot_val);
			goto err_free_memtype;
		}
		prot_val = new_prot_val;
	}

	switch (prot_val) {
	case _PAGE_CACHE_UC:
	default:
		prot = PAGE_KERNEL_IO_NOCACHE;
		break;
	case _PAGE_CACHE_UC_MINUS:
		prot = PAGE_KERNEL_IO_UC_MINUS;
		break;
	case _PAGE_CACHE_WC:
		prot = PAGE_KERNEL_IO_WC;
		break;
	case _PAGE_CACHE_WB:
		prot = PAGE_KERNEL_IO;
		break;
	}

	/*
	 * Ok, go for it..
	 */
	area = get_vm_area_caller(size, VM_IOREMAP, caller);
	if (!area)
		goto err_free_memtype;
	area->phys_addr = phys_addr;
	vaddr = (unsigned long) area->addr;

	if (kernel_map_sync_memtype(phys_addr, size, prot_val))
		goto err_free_area;

	if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot))
		goto err_free_area;

	ret_addr = (void __iomem *) (vaddr + offset);
	mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);

	/*
	 * Check if the request spans more than any BAR in the iomem resource
	 * tree.
	 */
	WARN_ONCE(iomem_map_sanity_check(unaligned_phys_addr, unaligned_size),
		  KERN_INFO "Info: mapping multiple BARs. Your kernel is fine.");

	return ret_addr;
err_free_area:
	free_vm_area(area);
err_free_memtype:
	free_memtype(phys_addr, phys_addr + size);
	return NULL;
}

/**
 * ioremap_nocache     -   map bus memory into CPU space
 * @phys_addr:    bus address of the memory
 * @size:      size of the resource to map
 *
 * ioremap_nocache performs a platform specific sequence of operations to
 * make bus memory CPU accessible via the readb/readw/readl/writeb/
 * writew/writel functions and the other mmio helpers. The returned
 * address is not guaranteed to be usable directly as a virtual
 * address.
 *
 * This version of ioremap ensures that the memory is marked uncachable
 * on the CPU as well as honouring existing caching rules from things like
 * the PCI bus. Note that there are other caches and buffers on many
 * busses. In particular driver authors should read up on PCI writes
 *
 * It's useful if some control registers are in such an area and
 * write combining or read caching is not desirable:
 *
 * Must be freed with iounmap.
 */
void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
{
	/*
	 * Ideally, this should be:
	 *	pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS;
	 *
	 * Till we fix all X drivers to use ioremap_wc(), we will use
	 * UC MINUS.
	 */
	unsigned long val = _PAGE_CACHE_UC_MINUS;

	return __ioremap_caller(phys_addr, size, val,
				__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_nocache);

/**
 * ioremap_wc	-	map memory into CPU space write combined
 * @phys_addr:	bus address of the memory
 * @size:	size of the resource to map
 *
 * This version of ioremap ensures that the memory is marked write combining.
 * Write combining allows faster writes to some hardware devices.
 *
 * Must be freed with iounmap.
 */
void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
{
	if (pat_enabled)
		return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC,
					__builtin_return_address(0));
	else
		return ioremap_nocache(phys_addr, size);
}
EXPORT_SYMBOL(ioremap_wc);

void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
{
	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB,
				__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_cache);

void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
				unsigned long prot_val)
{
	return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK),
				__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_prot);

/**
 * iounmap - Free a IO remapping
 * @addr: virtual address from ioremap_*
 *
 * Caller must ensure there is only one unmapping for the same pointer.
 */
void iounmap(volatile void __iomem *addr)
{
	struct vm_struct *p, *o;

	if ((void __force *)addr <= high_memory)
		return;

	/*
	 * __ioremap special-cases the PCI/ISA range by not instantiating a
	 * vm_area and by simply returning an address into the kernel mapping
	 * of ISA space.   So handle that here.
	 */
	if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) &&
	    (void __force *)addr < phys_to_virt(ISA_END_ADDRESS))
		return;

	addr = (volatile void __iomem *)
		(PAGE_MASK & (unsigned long __force)addr);

	mmiotrace_iounmap(addr);

	/* Use the vm area unlocked, assuming the caller
	   ensures there isn't another iounmap for the same address
	   in parallel. Reuse of the virtual address is prevented by
	   leaving it in the global lists until we're done with it.
	   cpa takes care of the direct mappings. */
	p = find_vm_area((void __force *)addr);

	if (!p) {
		printk(KERN_ERR "iounmap: bad address %p\n", addr);
		dump_stack();
		return;
	}

	free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p));

	/* Finally remove it */
	o = remove_vm_area((void __force *)addr);
	BUG_ON(p != o || o == NULL);
	kfree(p);
}
EXPORT_SYMBOL(iounmap);

/*
 * Convert a physical pointer to a virtual kernel pointer for /dev/mem
 * access
 */
void *xlate_dev_mem_ptr(unsigned long phys)
{
	void *addr;
	unsigned long start = phys & PAGE_MASK;

	/* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
	if (page_is_ram(start >> PAGE_SHIFT))
		return __va(phys);

	addr = (void __force *)ioremap_cache(start, PAGE_SIZE);
	if (addr)
		addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));

	return addr;
}

void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
{
	if (page_is_ram(phys >> PAGE_SHIFT))
		return;

	iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
	return;
}

static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;

static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
{
	/* Don't assume we're using swapper_pg_dir at this point */
	pgd_t *base = __va(read_cr3());
	pgd_t *pgd = &base[pgd_index(addr)];
	pud_t *pud = pud_offset(pgd, addr);
	pmd_t *pmd = pmd_offset(pud, addr);

	return pmd;
}

static inline pte_t * __init early_ioremap_pte(unsigned long addr)
{
	return &bm_pte[pte_index(addr)];
}

bool __init is_early_ioremap_ptep(pte_t *ptep)
{
	return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)];
}

void __init early_ioremap_init(void)
{
	pmd_t *pmd;

#ifdef CONFIG_X86_64
	BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1));
#else
	WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1));
#endif

	early_ioremap_setup();

	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
	memset(bm_pte, 0, sizeof(bm_pte));
	pmd_populate_kernel(&init_mm, pmd, bm_pte);

	/*
	 * The boot-ioremap range spans multiple pmds, for which
	 * we are not prepared:
	 */
#define __FIXADDR_TOP (-PAGE_SIZE)
	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
#undef __FIXADDR_TOP
	if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
		WARN_ON(1);
		printk(KERN_WARNING "pmd %p != %p\n",
		       pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
		printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
			fix_to_virt(FIX_BTMAP_BEGIN));
		printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END):   %08lx\n",
			fix_to_virt(FIX_BTMAP_END));

		printk(KERN_WARNING "FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
		printk(KERN_WARNING "FIX_BTMAP_BEGIN:     %d\n",
		       FIX_BTMAP_BEGIN);
	}
}

void __init __early_set_fixmap(enum fixed_addresses idx,
			       phys_addr_t phys, pgprot_t flags)
{
	unsigned long addr = __fix_to_virt(idx);
	pte_t *pte;

	if (idx >= __end_of_fixed_addresses) {
		BUG();
		return;
	}
	pte = early_ioremap_pte(addr);

	if (pgprot_val(flags))
		set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
	else
		pte_clear(&init_mm, addr, pte);
	__flush_tlb_one(addr);
}

Privacy Policy