xref: /openbmc/linux/arch/ia64/mm/tlb.c (revision b96fc2f3) 
1 /*
2  * TLB support routines.
3  *
4  * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
5  *	David Mosberger-Tang <davidm@hpl.hp.com>
6  *
7  * 08/02/00 A. Mallick <asit.k.mallick@intel.com>
8  *		Modified RID allocation for SMP
9  *          Goutham Rao <goutham.rao@intel.com>
10  *              IPI based ptc implementation and A-step IPI implementation.
11  * Rohit Seth <rohit.seth@intel.com>
12  * Ken Chen <kenneth.w.chen@intel.com>
13  * Christophe de Dinechin <ddd@hp.com>: Avoid ptc.e on memory allocation
14  * Copyright (C) 2007 Intel Corp
15  *	Fenghua Yu <fenghua.yu@intel.com>
16  *	Add multiple ptc.g/ptc.ga instruction support in global tlb purge.
17  */
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/smp.h>
23 #include <linux/mm.h>
24 #include <linux/bootmem.h>
25 #include <linux/slab.h>
26 
27 #include <asm/delay.h>
28 #include <asm/mmu_context.h>
29 #include <asm/pgalloc.h>
30 #include <asm/pal.h>
31 #include <asm/tlbflush.h>
32 #include <asm/dma.h>
33 #include <asm/processor.h>
34 #include <asm/sal.h>
35 #include <asm/tlb.h>
36 
37 static struct {
38 	u64 mask;		/* mask of supported purge page-sizes */
39 	unsigned long max_bits;	/* log2 of largest supported purge page-size */
40 } purge;
41 
42 struct ia64_ctx ia64_ctx = {
43 	.lock =	__SPIN_LOCK_UNLOCKED(ia64_ctx.lock),
44 	.next =	1,
45 	.max_ctx = ~0U
46 };
47 
48 DEFINE_PER_CPU(u8, ia64_need_tlb_flush);
49 DEFINE_PER_CPU(u8, ia64_tr_num);  /*Number of TR slots in current processor*/
50 DEFINE_PER_CPU(u8, ia64_tr_used); /*Max Slot number used by kernel*/
51 
52 struct ia64_tr_entry *ia64_idtrs[NR_CPUS];
53 
54 /*
55  * Initializes the ia64_ctx.bitmap array based on max_ctx+1.
56  * Called after cpu_init() has setup ia64_ctx.max_ctx based on
57  * maximum RID that is supported by boot CPU.
58  */
59 void __init
60 mmu_context_init (void)
61 {
62 	ia64_ctx.bitmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
63 	ia64_ctx.flushmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
64 }
65 
66 /*
67  * Acquire the ia64_ctx.lock before calling this function!
68  */
69 void
70 wrap_mmu_context (struct mm_struct *mm)
71 {
72 	int i, cpu;
73 	unsigned long flush_bit;
74 
75 	for (i=0; i <= ia64_ctx.max_ctx / BITS_PER_LONG; i++) {
76 		flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
77 		ia64_ctx.bitmap[i] ^= flush_bit;
78 	}
79 
80 	/* use offset at 300 to skip daemons */
81 	ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
82 				ia64_ctx.max_ctx, 300);
83 	ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
84 				ia64_ctx.max_ctx, ia64_ctx.next);
85 
86 	/*
87 	 * can't call flush_tlb_all() here because of race condition
88 	 * with O(1) scheduler [EF]
89 	 */
90 	cpu = get_cpu(); /* prevent preemption/migration */
91 	for_each_online_cpu(i)
92 		if (i != cpu)
93 			per_cpu(ia64_need_tlb_flush, i) = 1;
94 	put_cpu();
95 	local_flush_tlb_all();
96 }
97 
98 /*
99  * Implement "spinaphores" ... like counting semaphores, but they
100  * spin instead of sleeping.  If there are ever any other users for
101  * this primitive it can be moved up to a spinaphore.h header.
102  */
103 struct spinaphore {
104 	unsigned long	ticket;
105 	unsigned long	serve;
106 };
107 
108 static inline void spinaphore_init(struct spinaphore *ss, int val)
109 {
110 	ss->ticket = 0;
111 	ss->serve = val;
112 }
113 
114 static inline void down_spin(struct spinaphore *ss)
115 {
116 	unsigned long t = ia64_fetchadd(1, &ss->ticket, acq), serve;
117 
118 	if (time_before(t, ss->serve))
119 		return;
120 
121 	ia64_invala();
122 
123 	for (;;) {
124 		asm volatile ("ld8.c.nc %0=[%1]" : "=r"(serve) : "r"(&ss->serve) : "memory");
125 		if (time_before(t, serve))
126 			return;
127 		cpu_relax();
128 	}
129 }
130 
131 static inline void up_spin(struct spinaphore *ss)
132 {
133 	ia64_fetchadd(1, &ss->serve, rel);
134 }
135 
136 static struct spinaphore ptcg_sem;
137 static u16 nptcg = 1;
138 static int need_ptcg_sem = 1;
139 static int toolatetochangeptcgsem = 0;
140 
141 /*
142  * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
143  * purges which is reported from either PAL or SAL PALO.
144  *
145  * We don't have sanity checking for nptcg value. It's the user's responsibility
146  * for valid nptcg value on the platform. Otherwise, kernel may hang in some
147  * cases.
148  */
149 static int __init
150 set_nptcg(char *str)
151 {
152 	int value = 0;
153 
154 	get_option(&str, &value);
155 	setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER);
156 
157 	return 1;
158 }
159 
160 __setup("nptcg=", set_nptcg);
161 
162 /*
163  * Maximum number of simultaneous ptc.g purges in the system can
164  * be defined by PAL_VM_SUMMARY (in which case we should take
165  * the smallest value for any cpu in the system) or by the PAL
166  * override table (in which case we should ignore the value from
167  * PAL_VM_SUMMARY).
168  *
169  * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g
170  * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case,
171  * we should ignore the value from either PAL_VM_SUMMARY or PAL override table.
172  *
173  * Complicating the logic here is the fact that num_possible_cpus()
174  * isn't fully setup until we start bringing cpus online.
175  */
176 void
177 setup_ptcg_sem(int max_purges, int nptcg_from)
178 {
179 	static int kp_override;
180 	static int palo_override;
181 	static int firstcpu = 1;
182 
183 	if (toolatetochangeptcgsem) {
184 		if (nptcg_from == NPTCG_FROM_PAL && max_purges == 0)
185 			BUG_ON(1 < nptcg);
186 		else
187 			BUG_ON(max_purges < nptcg);
188 		return;
189 	}
190 
191 	if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
192 		kp_override = 1;
193 		nptcg = max_purges;
194 		goto resetsema;
195 	}
196 	if (kp_override) {
197 		need_ptcg_sem = num_possible_cpus() > nptcg;
198 		return;
199 	}
200 
201 	if (nptcg_from == NPTCG_FROM_PALO) {
202 		palo_override = 1;
203 
204 		/* In PALO max_purges == 0 really means it! */
205 		if (max_purges == 0)
206 			panic("Whoa! Platform does not support global TLB purges.\n");
207 		nptcg = max_purges;
208 		if (nptcg == PALO_MAX_TLB_PURGES) {
209 			need_ptcg_sem = 0;
210 			return;
211 		}
212 		goto resetsema;
213 	}
214 	if (palo_override) {
215 		if (nptcg != PALO_MAX_TLB_PURGES)
216 			need_ptcg_sem = (num_possible_cpus() > nptcg);
217 		return;
218 	}
219 
220 	/* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
221 	if (max_purges == 0) max_purges = 1;
222 
223 	if (firstcpu) {
224 		nptcg = max_purges;
225 		firstcpu = 0;
226 	}
227 	if (max_purges < nptcg)
228 		nptcg = max_purges;
229 	if (nptcg == PAL_MAX_PURGES) {
230 		need_ptcg_sem = 0;
231 		return;
232 	} else
233 		need_ptcg_sem = (num_possible_cpus() > nptcg);
234 
235 resetsema:
236 	spinaphore_init(&ptcg_sem, max_purges);
237 }
238 
239 void
240 ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
241 		       unsigned long end, unsigned long nbits)
242 {
243 	struct mm_struct *active_mm = current->active_mm;
244 
245 	toolatetochangeptcgsem = 1;
246 
247 	if (mm != active_mm) {
248 		/* Restore region IDs for mm */
249 		if (mm && active_mm) {
250 			activate_context(mm);
251 		} else {
252 			flush_tlb_all();
253 			return;
254 		}
255 	}
256 
257 	if (need_ptcg_sem)
258 		down_spin(&ptcg_sem);
259 
260 	do {
261 		/*
262 		 * Flush ALAT entries also.
263 		 */
264 		ia64_ptcga(start, (nbits << 2));
265 		ia64_srlz_i();
266 		start += (1UL << nbits);
267 	} while (start < end);
268 
269 	if (need_ptcg_sem)
270 		up_spin(&ptcg_sem);
271 
272         if (mm != active_mm) {
273                 activate_context(active_mm);
274         }
275 }
276 
277 void
278 local_flush_tlb_all (void)
279 {
280 	unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
281 
282 	addr    = local_cpu_data->ptce_base;
283 	count0  = local_cpu_data->ptce_count[0];
284 	count1  = local_cpu_data->ptce_count[1];
285 	stride0 = local_cpu_data->ptce_stride[0];
286 	stride1 = local_cpu_data->ptce_stride[1];
287 
288 	local_irq_save(flags);
289 	for (i = 0; i < count0; ++i) {
290 		for (j = 0; j < count1; ++j) {
291 			ia64_ptce(addr);
292 			addr += stride1;
293 		}
294 		addr += stride0;
295 	}
296 	local_irq_restore(flags);
297 	ia64_srlz_i();			/* srlz.i implies srlz.d */
298 }
299 
300 void
301 flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
302 		 unsigned long end)
303 {
304 	struct mm_struct *mm = vma->vm_mm;
305 	unsigned long size = end - start;
306 	unsigned long nbits;
307 
308 #ifndef CONFIG_SMP
309 	if (mm != current->active_mm) {
310 		mm->context = 0;
311 		return;
312 	}
313 #endif
314 
315 	nbits = ia64_fls(size + 0xfff);
316 	while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
317 			(nbits < purge.max_bits))
318 		++nbits;
319 	if (nbits > purge.max_bits)
320 		nbits = purge.max_bits;
321 	start &= ~((1UL << nbits) - 1);
322 
323 	preempt_disable();
324 #ifdef CONFIG_SMP
325 	if (mm != current->active_mm || cpumask_weight(mm_cpumask(mm)) != 1) {
326 		platform_global_tlb_purge(mm, start, end, nbits);
327 		preempt_enable();
328 		return;
329 	}
330 #endif
331 	do {
332 		ia64_ptcl(start, (nbits<<2));
333 		start += (1UL << nbits);
334 	} while (start < end);
335 	preempt_enable();
336 	ia64_srlz_i();			/* srlz.i implies srlz.d */
337 }
338 EXPORT_SYMBOL(flush_tlb_range);
339 
340 void ia64_tlb_init(void)
341 {
342 	ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
343 	u64 tr_pgbits;
344 	long status;
345 	pal_vm_info_1_u_t vm_info_1;
346 	pal_vm_info_2_u_t vm_info_2;
347 	int cpu = smp_processor_id();
348 
349 	if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
350 		printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld; "
351 		       "defaulting to architected purge page-sizes.\n", status);
352 		purge.mask = 0x115557000UL;
353 	}
354 	purge.max_bits = ia64_fls(purge.mask);
355 
356 	ia64_get_ptce(&ptce_info);
357 	local_cpu_data->ptce_base = ptce_info.base;
358 	local_cpu_data->ptce_count[0] = ptce_info.count[0];
359 	local_cpu_data->ptce_count[1] = ptce_info.count[1];
360 	local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
361 	local_cpu_data->ptce_stride[1] = ptce_info.stride[1];
362 
363 	local_flush_tlb_all();	/* nuke left overs from bootstrapping... */
364 	status = ia64_pal_vm_summary(&vm_info_1, &vm_info_2);
365 
366 	if (status) {
367 		printk(KERN_ERR "ia64_pal_vm_summary=%ld\n", status);
368 		per_cpu(ia64_tr_num, cpu) = 8;
369 		return;
370 	}
371 	per_cpu(ia64_tr_num, cpu) = vm_info_1.pal_vm_info_1_s.max_itr_entry+1;
372 	if (per_cpu(ia64_tr_num, cpu) >
373 				(vm_info_1.pal_vm_info_1_s.max_dtr_entry+1))
374 		per_cpu(ia64_tr_num, cpu) =
375 				vm_info_1.pal_vm_info_1_s.max_dtr_entry+1;
376 	if (per_cpu(ia64_tr_num, cpu) > IA64_TR_ALLOC_MAX) {
377 		static int justonce = 1;
378 		per_cpu(ia64_tr_num, cpu) = IA64_TR_ALLOC_MAX;
379 		if (justonce) {
380 			justonce = 0;
381 			printk(KERN_DEBUG "TR register number exceeds "
382 			       "IA64_TR_ALLOC_MAX!\n");
383 		}
384 	}
385 }
386 
387 /*
388  * is_tr_overlap
389  *
390  * Check overlap with inserted TRs.
391  */
392 static int is_tr_overlap(struct ia64_tr_entry *p, u64 va, u64 log_size)
393 {
394 	u64 tr_log_size;
395 	u64 tr_end;
396 	u64 va_rr = ia64_get_rr(va);
397 	u64 va_rid = RR_TO_RID(va_rr);
398 	u64 va_end = va + (1<<log_size) - 1;
399 
400 	if (va_rid != RR_TO_RID(p->rr))
401 		return 0;
402 	tr_log_size = (p->itir & 0xff) >> 2;
403 	tr_end = p->ifa + (1<<tr_log_size) - 1;
404 
405 	if (va > tr_end || p->ifa > va_end)
406 		return 0;
407 	return 1;
408 
409 }
410 
411 /*
412  * ia64_insert_tr in virtual mode. Allocate a TR slot
413  *
414  * target_mask : 0x1 : itr, 0x2 : dtr, 0x3 : idtr
415  *
416  * va 	: virtual address.
417  * pte 	: pte entries inserted.
418  * log_size: range to be covered.
419  *
420  * Return value:  <0 :  error No.
421  *
422  *		  >=0 : slot number allocated for TR.
423  * Must be called with preemption disabled.
424  */
425 int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
426 {
427 	int i, r;
428 	unsigned long psr;
429 	struct ia64_tr_entry *p;
430 	int cpu = smp_processor_id();
431 
432 	if (!ia64_idtrs[cpu]) {
433 		ia64_idtrs[cpu] = kmalloc(2 * IA64_TR_ALLOC_MAX *
434 				sizeof (struct ia64_tr_entry), GFP_KERNEL);
435 		if (!ia64_idtrs[cpu])
436 			return -ENOMEM;
437 	}
438 	r = -EINVAL;
439 	/*Check overlap with existing TR entries*/
440 	if (target_mask & 0x1) {
441 		p = ia64_idtrs[cpu];
442 		for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
443 								i++, p++) {
444 			if (p->pte & 0x1)
445 				if (is_tr_overlap(p, va, log_size)) {
446 					printk(KERN_DEBUG "Overlapped Entry"
447 						"Inserted for TR Register!!\n");
448 					goto out;
449 			}
450 		}
451 	}
452 	if (target_mask & 0x2) {
453 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX;
454 		for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
455 								i++, p++) {
456 			if (p->pte & 0x1)
457 				if (is_tr_overlap(p, va, log_size)) {
458 					printk(KERN_DEBUG "Overlapped Entry"
459 						"Inserted for TR Register!!\n");
460 					goto out;
461 				}
462 		}
463 	}
464 
465 	for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
466 		switch (target_mask & 0x3) {
467 		case 1:
468 			if (!((ia64_idtrs[cpu] + i)->pte & 0x1))
469 				goto found;
470 			continue;
471 		case 2:
472 			if (!((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
473 				goto found;
474 			continue;
475 		case 3:
476 			if (!((ia64_idtrs[cpu] + i)->pte & 0x1) &&
477 			    !((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
478 				goto found;
479 			continue;
480 		default:
481 			r = -EINVAL;
482 			goto out;
483 		}
484 	}
485 found:
486 	if (i >= per_cpu(ia64_tr_num, cpu))
487 		return -EBUSY;
488 
489 	/*Record tr info for mca hander use!*/
490 	if (i > per_cpu(ia64_tr_used, cpu))
491 		per_cpu(ia64_tr_used, cpu) = i;
492 
493 	psr = ia64_clear_ic();
494 	if (target_mask & 0x1) {
495 		ia64_itr(0x1, i, va, pte, log_size);
496 		ia64_srlz_i();
497 		p = ia64_idtrs[cpu] + i;
498 		p->ifa = va;
499 		p->pte = pte;
500 		p->itir = log_size << 2;
501 		p->rr = ia64_get_rr(va);
502 	}
503 	if (target_mask & 0x2) {
504 		ia64_itr(0x2, i, va, pte, log_size);
505 		ia64_srlz_i();
506 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i;
507 		p->ifa = va;
508 		p->pte = pte;
509 		p->itir = log_size << 2;
510 		p->rr = ia64_get_rr(va);
511 	}
512 	ia64_set_psr(psr);
513 	r = i;
514 out:
515 	return r;
516 }
517 EXPORT_SYMBOL_GPL(ia64_itr_entry);
518 
519 /*
520  * ia64_purge_tr
521  *
522  * target_mask: 0x1: purge itr, 0x2 : purge dtr, 0x3 purge idtr.
523  * slot: slot number to be freed.
524  *
525  * Must be called with preemption disabled.
526  */
527 void ia64_ptr_entry(u64 target_mask, int slot)
528 {
529 	int cpu = smp_processor_id();
530 	int i;
531 	struct ia64_tr_entry *p;
532 
533 	if (slot < IA64_TR_ALLOC_BASE || slot >= per_cpu(ia64_tr_num, cpu))
534 		return;
535 
536 	if (target_mask & 0x1) {
537 		p = ia64_idtrs[cpu] + slot;
538 		if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
539 			p->pte = 0;
540 			ia64_ptr(0x1, p->ifa, p->itir>>2);
541 			ia64_srlz_i();
542 		}
543 	}
544 
545 	if (target_mask & 0x2) {
546 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + slot;
547 		if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
548 			p->pte = 0;
549 			ia64_ptr(0x2, p->ifa, p->itir>>2);
550 			ia64_srlz_i();
551 		}
552 	}
553 
554 	for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
555 		if (((ia64_idtrs[cpu] + i)->pte & 0x1) ||
556 		    ((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
557 			break;
558 	}
559 	per_cpu(ia64_tr_used, cpu) = i;
560 }
561 EXPORT_SYMBOL_GPL(ia64_ptr_entry);
562