summaryrefslogtreecommitdiffstats
path: root/arch/mips/mm/tlb-r4k.c
blob: 965cb4c4359db6b03c8f737b0a609e6d134ad9b6 (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
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
 * Copyright (C) 1997, 1998, 1999, 2000 Ralf Baechle ralf@gnu.org
 * Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2002 MIPS Technologies, Inc.  All rights reserved.
 */
#include <linux/config.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/mm.h>

#include <asm/cpu.h>
#include <asm/bootinfo.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/system.h>

extern void build_tlb_refill_handler(void);

/*
 * Make sure all entries differ.  If they're not different
 * MIPS32 will take revenge ...
 */
#define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))

/* CP0 hazard avoidance. */
#define BARRIER __asm__ __volatile__(".set noreorder\n\t" \
				     "nop; nop; nop; nop; nop; nop;\n\t" \
				     ".set reorder\n\t")

/* Atomicity and interruptability */
#ifdef CONFIG_MIPS_MT_SMTC

#include <asm/smtc.h>
#include <asm/mipsmtregs.h>

#define ENTER_CRITICAL(flags) \
	{ \
	unsigned int mvpflags; \
	local_irq_save(flags);\
	mvpflags = dvpe()
#define EXIT_CRITICAL(flags) \
	evpe(mvpflags); \
	local_irq_restore(flags); \
	}
#else

#define ENTER_CRITICAL(flags) local_irq_save(flags)
#define EXIT_CRITICAL(flags) local_irq_restore(flags)

#endif /* CONFIG_MIPS_MT_SMTC */

void local_flush_tlb_all(void)
{
	unsigned long flags;
	unsigned long old_ctx;
	int entry;

	ENTER_CRITICAL(flags);
	/* Save old context and create impossible VPN2 value */
	old_ctx = read_c0_entryhi();
	write_c0_entrylo0(0);
	write_c0_entrylo1(0);

	entry = read_c0_wired();

	/* Blast 'em all away. */
	while (entry < current_cpu_data.tlbsize) {
		/* Make sure all entries differ. */
		write_c0_entryhi(UNIQUE_ENTRYHI(entry));
		write_c0_index(entry);
		mtc0_tlbw_hazard();
		tlb_write_indexed();
		entry++;
	}
	tlbw_use_hazard();
	write_c0_entryhi(old_ctx);
	EXIT_CRITICAL(flags);
}

/* All entries common to a mm share an asid.  To effectively flush
   these entries, we just bump the asid. */
void local_flush_tlb_mm(struct mm_struct *mm)
{
	int cpu;

	preempt_disable();

	cpu = smp_processor_id();

	if (cpu_context(cpu, mm) != 0) {
		drop_mmu_context(mm, cpu);
	}

	preempt_enable();
}

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

	if (cpu_context(cpu, mm) != 0) {
		unsigned long flags;
		int size;

		ENTER_CRITICAL(flags);
		size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
		size = (size + 1) >> 1;
		local_irq_save(flags);
		if (size <= current_cpu_data.tlbsize/2) {
			int oldpid = read_c0_entryhi();
			int newpid = cpu_asid(cpu, mm);

			start &= (PAGE_MASK << 1);
			end += ((PAGE_SIZE << 1) - 1);
			end &= (PAGE_MASK << 1);
			while (start < end) {
				int idx;

				write_c0_entryhi(start | newpid);
				start += (PAGE_SIZE << 1);
				mtc0_tlbw_hazard();
				tlb_probe();
				BARRIER;
				idx = read_c0_index();
				write_c0_entrylo0(0);
				write_c0_entrylo1(0);
				if (idx < 0)
					continue;
				/* Make sure all entries differ. */
				write_c0_entryhi(UNIQUE_ENTRYHI(idx));
				mtc0_tlbw_hazard();
				tlb_write_indexed();
			}
			tlbw_use_hazard();
			write_c0_entryhi(oldpid);
		} else {
			drop_mmu_context(mm, cpu);
		}
		EXIT_CRITICAL(flags);
	}
}

void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
	unsigned long flags;
	int size;

	ENTER_CRITICAL(flags);
	size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
	size = (size + 1) >> 1;
	if (size <= current_cpu_data.tlbsize / 2) {
		int pid = read_c0_entryhi();

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

		while (start < end) {
			int idx;

			write_c0_entryhi(start);
			start += (PAGE_SIZE << 1);
			mtc0_tlbw_hazard();
			tlb_probe();
			BARRIER;
			idx = read_c0_index();
			write_c0_entrylo0(0);
			write_c0_entrylo1(0);
			if (idx < 0)
				continue;
			/* Make sure all entries differ. */
			write_c0_entryhi(UNIQUE_ENTRYHI(idx));
			mtc0_tlbw_hazard();
			tlb_write_indexed();
		}
		tlbw_use_hazard();
		write_c0_entryhi(pid);
	} else {
		local_flush_tlb_all();
	}
	EXIT_CRITICAL(flags);
}

void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
	int cpu = smp_processor_id();

	if (cpu_context(cpu, vma->vm_mm) != 0) {
		unsigned long flags;
		int oldpid, newpid, idx;

		newpid = cpu_asid(cpu, vma->vm_mm);
		page &= (PAGE_MASK << 1);
		ENTER_CRITICAL(flags);
		oldpid = read_c0_entryhi();
		write_c0_entryhi(page | newpid);
		mtc0_tlbw_hazard();
		tlb_probe();
		BARRIER;
		idx = read_c0_index();
		write_c0_entrylo0(0);
		write_c0_entrylo1(0);
		if (idx < 0)
			goto finish;
		/* Make sure all entries differ. */
		write_c0_entryhi(UNIQUE_ENTRYHI(idx));
		mtc0_tlbw_hazard();
		tlb_write_indexed();
		tlbw_use_hazard();

	finish:
		write_c0_entryhi(oldpid);
		EXIT_CRITICAL(flags);
	}
}

/*
 * This one is only used for pages with the global bit set so we don't care
 * much about the ASID.
 */
void local_flush_tlb_one(unsigned long page)
{
	unsigned long flags;
	int oldpid, idx;

	ENTER_CRITICAL(flags);
	oldpid = read_c0_entryhi();
	page &= (PAGE_MASK << 1);
	write_c0_entryhi(page);
	mtc0_tlbw_hazard();
	tlb_probe();
	BARRIER;
	idx = read_c0_index();
	write_c0_entrylo0(0);
	write_c0_entrylo1(0);
	if (idx >= 0) {
		/* Make sure all entries differ. */
		write_c0_entryhi(UNIQUE_ENTRYHI(idx));
		mtc0_tlbw_hazard();
		tlb_write_indexed();
		tlbw_use_hazard();
	}
	write_c0_entryhi(oldpid);

	EXIT_CRITICAL(flags);
}

/*
 * We will need multiple versions of update_mmu_cache(), one that just
 * updates the TLB with the new pte(s), and another which also checks
 * for the R4k "end of page" hardware bug and does the needy.
 */
void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
{
	unsigned long flags;
	pgd_t *pgdp;
	pud_t *pudp;
	pmd_t *pmdp;
	pte_t *ptep;
	int idx, pid;

	/*
	 * Handle debugger faulting in for debugee.
	 */
	if (current->active_mm != vma->vm_mm)
		return;

	ENTER_CRITICAL(flags);

	pid = read_c0_entryhi() & ASID_MASK;
	address &= (PAGE_MASK << 1);
	write_c0_entryhi(address | pid);
	pgdp = pgd_offset(vma->vm_mm, address);
	mtc0_tlbw_hazard();
	tlb_probe();
	BARRIER;
	pudp = pud_offset(pgdp, address);
	pmdp = pmd_offset(pudp, address);
	idx = read_c0_index();
	ptep = pte_offset_map(pmdp, address);

#if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
	write_c0_entrylo0(ptep->pte_high);
	ptep++;
	write_c0_entrylo1(ptep->pte_high);
#else
	write_c0_entrylo0(pte_val(*ptep++) >> 6);
	write_c0_entrylo1(pte_val(*ptep) >> 6);
#endif
	mtc0_tlbw_hazard();
	if (idx < 0)
		tlb_write_random();
	else
		tlb_write_indexed();
	tlbw_use_hazard();
	EXIT_CRITICAL(flags);
}

#if 0
static void r4k_update_mmu_cache_hwbug(struct vm_area_struct * vma,
				       unsigned long address, pte_t pte)
{
	unsigned long flags;
	unsigned int asid;
	pgd_t *pgdp;
	pmd_t *pmdp;
	pte_t *ptep;
	int idx;

	ENTER_CRITICAL(flags);
	address &= (PAGE_MASK << 1);
	asid = read_c0_entryhi() & ASID_MASK;
	write_c0_entryhi(address | asid);
	pgdp = pgd_offset(vma->vm_mm, address);
	mtc0_tlbw_hazard();
	tlb_probe();
	BARRIER;
	pmdp = pmd_offset(pgdp, address);
	idx = read_c0_index();
	ptep = pte_offset_map(pmdp, address);
	write_c0_entrylo0(pte_val(*ptep++) >> 6);
	write_c0_entrylo1(pte_val(*ptep) >> 6);
	mtc0_tlbw_hazard();
	if (idx < 0)
		tlb_write_random();
	else
		tlb_write_indexed();
	tlbw_use_hazard();
	EXIT_CRITICAL(flags);
}
#endif

void __init add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
	unsigned long entryhi, unsigned long pagemask)
{
	unsigned long flags;
	unsigned long wired;
	unsigned long old_pagemask;
	unsigned long old_ctx;

	ENTER_CRITICAL(flags);
	/* Save old context and create impossible VPN2 value */
	old_ctx = read_c0_entryhi();
	old_pagemask = read_c0_pagemask();
	wired = read_c0_wired();
	write_c0_wired(wired + 1);
	write_c0_index(wired);
	BARRIER;
	write_c0_pagemask(pagemask);
	write_c0_entryhi(entryhi);
	write_c0_entrylo0(entrylo0);
	write_c0_entrylo1(entrylo1);
	mtc0_tlbw_hazard();
	tlb_write_indexed();
	tlbw_use_hazard();

	write_c0_entryhi(old_ctx);
	BARRIER;
	write_c0_pagemask(old_pagemask);
	local_flush_tlb_all();
	EXIT_CRITICAL(flags);
}

/*
 * Used for loading TLB entries before trap_init() has started, when we
 * don't actually want to add a wired entry which remains throughout the
 * lifetime of the system
 */

static int temp_tlb_entry __initdata;

__init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
			       unsigned long entryhi, unsigned long pagemask)
{
	int ret = 0;
	unsigned long flags;
	unsigned long wired;
	unsigned long old_pagemask;
	unsigned long old_ctx;

	ENTER_CRITICAL(flags);
	/* Save old context and create impossible VPN2 value */
	old_ctx = read_c0_entryhi();
	old_pagemask = read_c0_pagemask();
	wired = read_c0_wired();
	if (--temp_tlb_entry < wired) {
		printk(KERN_WARNING
		       "No TLB space left for add_temporary_entry\n");
		ret = -ENOSPC;
		goto out;
	}

	write_c0_index(temp_tlb_entry);
	write_c0_pagemask(pagemask);
	write_c0_entryhi(entryhi);
	write_c0_entrylo0(entrylo0);
	write_c0_entrylo1(entrylo1);
	mtc0_tlbw_hazard();
	tlb_write_indexed();
	tlbw_use_hazard();

	write_c0_entryhi(old_ctx);
	write_c0_pagemask(old_pagemask);
out:
	EXIT_CRITICAL(flags);
	return ret;
}

static void __init probe_tlb(unsigned long config)
{
	struct cpuinfo_mips *c = &current_cpu_data;
	unsigned int reg;

	/*
	 * If this isn't a MIPS32 / MIPS64 compliant CPU.  Config 1 register
	 * is not supported, we assume R4k style.  Cpu probing already figured
	 * out the number of tlb entries.
	 */
	if ((c->processor_id & 0xff0000) == PRID_COMP_LEGACY)
		return;
#ifdef CONFIG_MIPS_MT_SMTC
	/*
	 * If TLB is shared in SMTC system, total size already
	 * has been calculated and written into cpu_data tlbsize
	 */
	if((smtc_status & SMTC_TLB_SHARED) == SMTC_TLB_SHARED)
		return;
#endif /* CONFIG_MIPS_MT_SMTC */

	reg = read_c0_config1();
	if (!((config >> 7) & 3))
		panic("No TLB present");

	c->tlbsize = ((reg >> 25) & 0x3f) + 1;
}

static int __initdata ntlb = 0;
static int __init set_ntlb(char *str)
{
	get_option(&str, &ntlb);
	return 1;
}

__setup("ntlb=", set_ntlb);

void __init tlb_init(void)
{
	unsigned int config = read_c0_config();

	/*
	 * You should never change this register:
	 *   - On R4600 1.7 the tlbp never hits for pages smaller than
	 *     the value in the c0_pagemask register.
	 *   - The entire mm handling assumes the c0_pagemask register to
	 *     be set for 4kb pages.
	 */
	probe_tlb(config);
	write_c0_pagemask(PM_DEFAULT_MASK);
	write_c0_wired(0);
	write_c0_framemask(0);
	temp_tlb_entry = current_cpu_data.tlbsize - 1;

        /* From this point on the ARC firmware is dead.  */
	local_flush_tlb_all();

	/* Did I tell you that ARC SUCKS?  */

	if (ntlb) {
		if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
			int wired = current_cpu_data.tlbsize - ntlb;
			write_c0_wired(wired);
			write_c0_index(wired-1);
			printk ("Restricting TLB to %d entries\n", ntlb);
		} else
			printk("Ignoring invalid argument ntlb=%d\n", ntlb);
	}

	build_tlb_refill_handler();
}
OpenPOWER on IntegriCloud