summaryrefslogtreecommitdiffstats
path: root/arch/x86/mm/ioremap.c
blob: 9f42d7e9c15829431ed31c90fd993750adf9791f (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
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
/*
 * 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 <asm/cacheflush.h>
#include <asm/e820.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>

enum ioremap_mode {
	IOR_MODE_UNCACHED,
	IOR_MODE_CACHED,
};

#ifdef CONFIG_X86_64

unsigned long __phys_addr(unsigned long x)
{
	if (x >= __START_KERNEL_map)
		return x - __START_KERNEL_map + phys_base;
	return x - PAGE_OFFSET;
}
EXPORT_SYMBOL(__phys_addr);

#endif

int page_is_ram(unsigned long pagenr)
{
	unsigned long addr, end;
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		/*
		 * Not usable memory:
		 */
		if (e820.map[i].type != E820_RAM)
			continue;
		addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
		end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;

		/*
		 * Sanity check: Some BIOSen report areas as RAM that
		 * are not. Notably the 640->1Mb area, which is the
		 * PCI BIOS area.
		 */
		if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
		    end < (BIOS_END >> PAGE_SHIFT))
			continue;

		if ((pagenr >= addr) && (pagenr < end))
			return 1;
	}
	return 0;
}

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

	switch (mode) {
	case IOR_MODE_UNCACHED:
	default:
		err = set_memory_uc(vaddr, nrpages);
		break;
	case IOR_MODE_CACHED:
		err = set_memory_wb(vaddr, nrpages);
		break;
	}

	return err;
}

/*
 * 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(unsigned long phys_addr, unsigned long size,
			       enum ioremap_mode mode)
{
	unsigned long pfn, offset, last_addr, vaddr;
	struct vm_struct *area;
	pgprot_t prot;

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

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

	/*
	 * Don't allow anybody to remap normal RAM that we're using..
	 */
	for (pfn = phys_addr >> PAGE_SHIFT; pfn < max_pfn_mapped &&
	     (pfn << PAGE_SHIFT) < last_addr; pfn++) {
		if (page_is_ram(pfn) && pfn_valid(pfn) &&
		    !PageReserved(pfn_to_page(pfn)))
			return NULL;
	}

	switch (mode) {
	case IOR_MODE_UNCACHED:
	default:
		prot = PAGE_KERNEL_NOCACHE;
		break;
	case IOR_MODE_CACHED:
		prot = PAGE_KERNEL;
		break;
	}

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

	/*
	 * Ok, go for it..
	 */
	area = get_vm_area(size, VM_IOREMAP);
	if (!area)
		return NULL;
	area->phys_addr = phys_addr;
	vaddr = (unsigned long) area->addr;
	if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
		remove_vm_area((void *)(vaddr & PAGE_MASK));
		return NULL;
	}

	if (ioremap_change_attr(vaddr, size, mode) < 0) {
		vunmap(area->addr);
		return NULL;
	}

	return (void __iomem *) (vaddr + offset);
}

/**
 * ioremap_nocache     -   map bus memory into CPU space
 * @offset:    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(unsigned long phys_addr, unsigned long size)
{
	return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
}
EXPORT_SYMBOL(ioremap_nocache);

void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
{
	return __ioremap(phys_addr, size, IOR_MODE_CACHED);
}
EXPORT_SYMBOL(ioremap_cache);

/**
 * 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 (addr >= phys_to_virt(ISA_START_ADDRESS) &&
	    addr < phys_to_virt(ISA_END_ADDRESS))
		return;

	addr = (volatile void __iomem *)
		(PAGE_MASK & (unsigned long __force)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. */
	read_lock(&vmlist_lock);
	for (p = vmlist; p; p = p->next) {
		if (p->addr == addr)
			break;
	}
	read_unlock(&vmlist_lock);

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

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

#ifdef CONFIG_X86_32

int __initdata early_ioremap_debug;

static int __init early_ioremap_debug_setup(char *str)
{
	early_ioremap_debug = 1;

	return 0;
}
early_param("early_ioremap_debug", early_ioremap_debug_setup);

static __initdata int after_paging_init;
static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)]
				__attribute__((aligned(PAGE_SIZE)));

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)];
}

void __init early_ioremap_init(void)
{
	pmd_t *pmd;

	if (early_ioremap_debug)
		printk(KERN_INFO "early_ioremap_init()\n");

	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:
	 */
	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_ioremap_clear(void)
{
	pmd_t *pmd;

	if (early_ioremap_debug)
		printk(KERN_INFO "early_ioremap_clear()\n");

	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
	pmd_clear(pmd);
	paravirt_release_pt(__pa(bm_pte) >> PAGE_SHIFT);
	__flush_tlb_all();
}

void __init early_ioremap_reset(void)
{
	enum fixed_addresses idx;
	unsigned long addr, phys;
	pte_t *pte;

	after_paging_init = 1;
	for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
		addr = fix_to_virt(idx);
		pte = early_ioremap_pte(addr);
		if (pte_present(*pte)) {
			phys = pte_val(*pte) & PAGE_MASK;
			set_fixmap(idx, phys);
		}
	}
}

static void __init __early_set_fixmap(enum fixed_addresses idx,
				   unsigned long 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(NULL, addr, pte);
	__flush_tlb_one(addr);
}

static inline void __init early_set_fixmap(enum fixed_addresses idx,
					unsigned long phys)
{
	if (after_paging_init)
		set_fixmap(idx, phys);
	else
		__early_set_fixmap(idx, phys, PAGE_KERNEL);
}

static inline void __init early_clear_fixmap(enum fixed_addresses idx)
{
	if (after_paging_init)
		clear_fixmap(idx);
	else
		__early_set_fixmap(idx, 0, __pgprot(0));
}


int __initdata early_ioremap_nested;

static int __init check_early_ioremap_leak(void)
{
	if (!early_ioremap_nested)
		return 0;

	printk(KERN_WARNING
	       "Debug warning: early ioremap leak of %d areas detected.\n",
	       early_ioremap_nested);
	printk(KERN_WARNING
	       "please boot with early_ioremap_debug and report the dmesg.\n");
	WARN_ON(1);

	return 1;
}
late_initcall(check_early_ioremap_leak);

void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
{
	unsigned long offset, last_addr;
	unsigned int nrpages, nesting;
	enum fixed_addresses idx0, idx;

	WARN_ON(system_state != SYSTEM_BOOTING);

	nesting = early_ioremap_nested;
	if (early_ioremap_debug) {
		printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
		       phys_addr, size, nesting);
		dump_stack();
	}

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

	if (nesting >= FIX_BTMAPS_NESTING) {
		WARN_ON(1);
		return NULL;
	}
	early_ioremap_nested++;
	/*
	 * Mappings have to be page-aligned
	 */
	offset = phys_addr & ~PAGE_MASK;
	phys_addr &= PAGE_MASK;
	size = PAGE_ALIGN(last_addr) - phys_addr;

	/*
	 * Mappings have to fit in the FIX_BTMAP area.
	 */
	nrpages = size >> PAGE_SHIFT;
	if (nrpages > NR_FIX_BTMAPS) {
		WARN_ON(1);
		return NULL;
	}

	/*
	 * Ok, go for it..
	 */
	idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
	idx = idx0;
	while (nrpages > 0) {
		early_set_fixmap(idx, phys_addr);
		phys_addr += PAGE_SIZE;
		--idx;
		--nrpages;
	}
	if (early_ioremap_debug)
		printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));

	return (void *) (offset + fix_to_virt(idx0));
}

void __init early_iounmap(void *addr, unsigned long size)
{
	unsigned long virt_addr;
	unsigned long offset;
	unsigned int nrpages;
	enum fixed_addresses idx;
	unsigned int nesting;

	nesting = --early_ioremap_nested;
	WARN_ON(nesting < 0);

	if (early_ioremap_debug) {
		printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
		       size, nesting);
		dump_stack();
	}

	virt_addr = (unsigned long)addr;
	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
		WARN_ON(1);
		return;
	}
	offset = virt_addr & ~PAGE_MASK;
	nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;

	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
	while (nrpages > 0) {
		early_clear_fixmap(idx);
		--idx;
		--nrpages;
	}
}

void __this_fixmap_does_not_exist(void)
{
	WARN_ON(1);
}

#endif /* CONFIG_X86_32 */
OpenPOWER on IntegriCloud