aboutsummaryrefslogtreecommitdiffstats
path: root/arch/avr32/mm/tlb.c
blob: 06677be98ffba5fcb0143dac626bf96235fd1e16 (plain) (blame)
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
/*
 * AVR32 TLB operations
 *
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/mm.h>

#include <asm/mmu_context.h>

/* TODO: Get the correct number from the CONFIG1 system register */
#define NR_TLB_ENTRIES 32

static void show_dtlb_entry(unsigned int index)
{
	u32 tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
	unsigned long flags;

	local_irq_save(flags);
	mmucr_save = sysreg_read(MMUCR);
	tlbehi_save = sysreg_read(TLBEHI);
	mmucr = SYSREG_BFINS(DRP, index, mmucr_save);
	sysreg_write(MMUCR, mmucr);

	__builtin_tlbr();
	cpu_sync_pipeline();

	tlbehi = sysreg_read(TLBEHI);
	tlbelo = sysreg_read(TLBELO);

	printk("%2u: %c %c %02x   %05x %05x %o  %o  %c %c %c %c\n",
	       index,
	       SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
	       SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
	       SYSREG_BFEXT(ASID, tlbehi),
	       SYSREG_BFEXT(VPN, tlbehi) >> 2,
	       SYSREG_BFEXT(PFN, tlbelo) >> 2,
	       SYSREG_BFEXT(AP, tlbelo),
	       SYSREG_BFEXT(SZ, tlbelo),
	       SYSREG_BFEXT(TLBELO_C, tlbelo) ? 'C' : ' ',
	       SYSREG_BFEXT(B, tlbelo) ? 'B' : ' ',
	       SYSREG_BFEXT(W, tlbelo) ? 'W' : ' ',
	       SYSREG_BFEXT(TLBELO_D, tlbelo) ? 'D' : ' ');

	sysreg_write(MMUCR, mmucr_save);
	sysreg_write(TLBEHI, tlbehi_save);
	cpu_sync_pipeline();
	local_irq_restore(flags);
}

void dump_dtlb(void)
{
	unsigned int i;

	printk("ID  V G ASID VPN   PFN   AP SZ C B W D\n");
	for (i = 0; i < NR_TLB_ENTRIES; i++)
		show_dtlb_entry(i);
}

static void update_dtlb(unsigned long address, pte_t pte)
{
	u32 tlbehi;
	u32 mmucr;

	/*
	 * We're not changing the ASID here, so no need to flush the
	 * pipeline.
	 */
	tlbehi = sysreg_read(TLBEHI);
	tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
	tlbehi |= address & MMU_VPN_MASK;
	tlbehi |= SYSREG_BIT(TLBEHI_V);
	sysreg_write(TLBEHI, tlbehi);

	/* Does this mapping already exist? */
	__builtin_tlbs();
	mmucr = sysreg_read(MMUCR);

	if (mmucr & SYSREG_BIT(MMUCR_N)) {
		/* Not found -- pick a not-recently-accessed entry */
		unsigned int rp;
		u32 tlbar = sysreg_read(TLBARLO);

		rp = 32 - fls(tlbar);
		if (rp == 32) {
			rp = 0;
			sysreg_write(TLBARLO, -1L);
		}

		mmucr = SYSREG_BFINS(DRP, rp, mmucr);
		sysreg_write(MMUCR, mmucr);
	}

	sysreg_write(TLBELO, pte_val(pte) & _PAGE_FLAGS_HARDWARE_MASK);

	/* Let's go */
	__builtin_tlbw();
}

void update_mmu_cache(struct vm_area_struct *vma,
		      unsigned long address, pte_t pte)
{
	unsigned long flags;

	/* ptrace may call this routine */
	if (vma && current->active_mm != vma->vm_mm)
		return;

	local_irq_save(flags);
	update_dtlb(address, pte);
	local_irq_restore(flags);
}

static void __flush_tlb_page(unsigned long asid, unsigned long page)
{
	u32 mmucr, tlbehi;

	/*
	 * Caller is responsible for masking out non-PFN bits in page
	 * and changing the current ASID if necessary. This means that
	 * we don't need to flush the pipeline after writing TLBEHI.
	 */
	tlbehi = page | asid;
	sysreg_write(TLBEHI, tlbehi);

	__builtin_tlbs();
	mmucr = sysreg_read(MMUCR);

	if (!(mmucr & SYSREG_BIT(MMUCR_N))) {
		unsigned int entry;
		u32 tlbarlo;

		/* Clear the "valid" bit */
		sysreg_write(TLBEHI, tlbehi);

		/* mark the entry as "not accessed" */
		entry = SYSREG_BFEXT(DRP, mmucr);
		tlbarlo = sysreg_read(TLBARLO);
		tlbarlo |= (0x80000000UL >> entry);
		sysreg_write(TLBARLO, tlbarlo);

		/* update the entry with valid bit clear */
		__builtin_tlbw();
	}
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
	if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
		unsigned long flags, asid;
		unsigned long saved_asid = MMU_NO_ASID;

		asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
		page &= PAGE_MASK;

		local_irq_save(flags);
		if (vma->vm_mm != current->mm) {
			saved_asid = get_asid();
			set_asid(asid);
		}

		__flush_tlb_page(asid, page);

		if (saved_asid != MMU_NO_ASID)
			set_asid(saved_asid);
		local_irq_restore(flags);
	}
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
		     unsigned long end)
{
	struct mm_struct *mm = vma->vm_mm;

	if (mm->context != NO_CONTEXT) {
		unsigned long flags;
		int size;

		local_irq_save(flags);
		size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;

		if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
			mm->context = NO_CONTEXT;
			if (mm == current->mm)
				activate_context(mm);
		} else {
			unsigned long asid;
			unsigned long saved_asid;

			asid = mm->context & MMU_CONTEXT_ASID_MASK;
			saved_asid = MMU_NO_ASID;

			start &= PAGE_MASK;
			end += (PAGE_SIZE - 1);
			end &= PAGE_MASK;

			if (mm != current->mm) {
				saved_asid = get_asid();
				set_asid(asid);
			}

			while (start < end) {
				__flush_tlb_page(asid, start);
				start += PAGE_SIZE;
			}
			if (saved_asid != MMU_NO_ASID)
				set_asid(saved_asid);
		}
		local_irq_restore(flags);
	}
}

/*
 * This function depends on the pages to be flushed having the G
 * (global) bit set in their pte. This is true for all
 * PAGE_KERNEL(_RO) pages.
 */
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
	unsigned long flags;
	int size;

	size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
	if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
		flush_tlb_all();
	} else {
		unsigned long asid;

		local_irq_save(flags);
		asid = get_asid();

		start &= PAGE_MASK;
		end += (PAGE_SIZE - 1);
		end &= PAGE_MASK;

		while (start < end) {
			__flush_tlb_page(asid, start);
			start += PAGE_SIZE;
		}
		local_irq_restore(flags);
	}
}

void flush_tlb_mm(struct mm_struct *mm)
{
	/* Invalidate all TLB entries of this process by getting a new ASID */
	if (mm->context != NO_CONTEXT) {
		unsigned long flags;

		local_irq_save(flags);
		mm->context = NO_CONTEXT;
		if (mm == current->mm)
			activate_context(mm);
		local_irq_restore(flags);
	}
}

void flush_tlb_all(void)
{
	unsigned long flags;

	local_irq_save(flags);
	sysreg_write(MMUCR, sysreg_read(MMUCR) | SYSREG_BIT(MMUCR_I));
	local_irq_restore(flags);
}

#ifdef CONFIG_PROC_FS

#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/init.h>

static void *tlb_start(struct seq_file *tlb, loff_t *pos)
{
	static unsigned long tlb_index;

	if (*pos >= NR_TLB_ENTRIES)
		return NULL;

	tlb_index = 0;
	return &tlb_index;
}

static void *tlb_next(struct seq_file *tlb, void *v, loff_t *pos)
{
	unsigned long *index = v;

	if (*index >= NR_TLB_ENTRIES - 1)
		return NULL;

	++*pos;
	++*index;
	return index;
}

static void tlb_stop(struct seq_file *tlb, void *v)
{

}

static int tlb_show(struct seq_file *tlb, void *v)
{
	unsigned int tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
	unsigned long flags;
	unsigned long *index = v;

	if (*index == 0)
		seq_puts(tlb, "ID  V G ASID VPN   PFN   AP SZ C B W D\n");

	BUG_ON(*index >= NR_TLB_ENTRIES);

	local_irq_save(flags);
	mmucr_save = sysreg_read(MMUCR);
	tlbehi_save = sysreg_read(TLBEHI);
	mmucr = SYSREG_BFINS(DRP, *index, mmucr_save);
	sysreg_write(MMUCR, mmucr);

	/* TLBR might change the ASID */
	__builtin_tlbr();
	cpu_sync_pipeline();

	tlbehi = sysreg_read(TLBEHI);
	tlbelo = sysreg_read(TLBELO);

	sysreg_write(MMUCR, mmucr_save);
	sysreg_write(TLBEHI, tlbehi_save);
	cpu_sync_pipeline();
	local_irq_restore(flags);

	seq_printf(tlb, "%2lu: %c %c %02x   %05x %05x %o  %o  %c %c %c %c\n",
		   *index,
		   SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
		   SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
		   SYSREG_BFEXT(ASID, tlbehi),
		   SYSREG_BFEXT(VPN, tlbehi) >> 2,
		   SYSREG_BFEXT(PFN, tlbelo) >> 2,
		   SYSREG_BFEXT(AP, tlbelo),
		   SYSREG_BFEXT(SZ, tlbelo),
		   SYSREG_BFEXT(TLBELO_C, tlbelo) ? '1' : '0',
		   SYSREG_BFEXT(B, tlbelo) ? '1' : '0',
		   SYSREG_BFEXT(W, tlbelo) ? '1' : '0',
		   SYSREG_BFEXT(TLBELO_D, tlbelo) ? '1' : '0');

	return 0;
}

static const struct seq_operations tlb_ops = {
	.start		= tlb_start,
	.next		= tlb_next,
	.stop		= tlb_stop,
	.show		= tlb_show,
};

static int tlb_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &tlb_ops);
}

static const struct file_operations proc_tlb_operations = {
	.open		= tlb_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int __init proctlb_init(void)
{
	proc_create("tlb", 0, NULL, &proc_tlb_operations);
	return 0;
}
late_initcall(proctlb_init);
#endif /* CONFIG_PROC_FS */