xref: /openbmc/linux/arch/ia64/mm/tlb.c (revision a2818ee4) 
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/memblock.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 = memblock_alloc((ia64_ctx.max_ctx + 1) >> 3,
63 					 SMP_CACHE_BYTES);
64 	ia64_ctx.flushmap = memblock_alloc((ia64_ctx.max_ctx + 1) >> 3,
65 					   SMP_CACHE_BYTES);
66 }
67 
68 /*
69  * Acquire the ia64_ctx.lock before calling this function!
70  */
71 void
72 wrap_mmu_context (struct mm_struct *mm)
73 {
74 	int i, cpu;
75 	unsigned long flush_bit;
76 
77 	for (i=0; i <= ia64_ctx.max_ctx / BITS_PER_LONG; i++) {
78 		flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
79 		ia64_ctx.bitmap[i] ^= flush_bit;
80 	}
81 
82 	/* use offset at 300 to skip daemons */
83 	ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
84 				ia64_ctx.max_ctx, 300);
85 	ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
86 				ia64_ctx.max_ctx, ia64_ctx.next);
87 
88 	/*
89 	 * can't call flush_tlb_all() here because of race condition
90 	 * with O(1) scheduler [EF]
91 	 */
92 	cpu = get_cpu(); /* prevent preemption/migration */
93 	for_each_online_cpu(i)
94 		if (i != cpu)
95 			per_cpu(ia64_need_tlb_flush, i) = 1;
96 	put_cpu();
97 	local_flush_tlb_all();
98 }
99 
100 /*
101  * Implement "spinaphores" ... like counting semaphores, but they
102  * spin instead of sleeping.  If there are ever any other users for
103  * this primitive it can be moved up to a spinaphore.h header.
104  */
105 struct spinaphore {
106 	unsigned long	ticket;
107 	unsigned long	serve;
108 };
109 
110 static inline void spinaphore_init(struct spinaphore *ss, int val)
111 {
112 	ss->ticket = 0;
113 	ss->serve = val;
114 }
115 
116 static inline void down_spin(struct spinaphore *ss)
117 {
118 	unsigned long t = ia64_fetchadd(1, &ss->ticket, acq), serve;
119 
120 	if (time_before(t, ss->serve))
121 		return;
122 
123 	ia64_invala();
124 
125 	for (;;) {
126 		asm volatile ("ld8.c.nc %0=[%1]" : "=r"(serve) : "r"(&ss->serve) : "memory");
127 		if (time_before(t, serve))
128 			return;
129 		cpu_relax();
130 	}
131 }
132 
133 static inline void up_spin(struct spinaphore *ss)
134 {
135 	ia64_fetchadd(1, &ss->serve, rel);
136 }
137 
138 static struct spinaphore ptcg_sem;
139 static u16 nptcg = 1;
140 static int need_ptcg_sem = 1;
141 static int toolatetochangeptcgsem = 0;
142 
143 /*
144  * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
145  * purges which is reported from either PAL or SAL PALO.
146  *
147  * We don't have sanity checking for nptcg value. It's the user's responsibility
148  * for valid nptcg value on the platform. Otherwise, kernel may hang in some
149  * cases.
150  */
151 static int __init
152 set_nptcg(char *str)
153 {
154 	int value = 0;
155 
156 	get_option(&str, &value);
157 	setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER);
158 
159 	return 1;
160 }
161 
162 __setup("nptcg=", set_nptcg);
163 
164 /*
165  * Maximum number of simultaneous ptc.g purges in the system can
166  * be defined by PAL_VM_SUMMARY (in which case we should take
167  * the smallest value for any cpu in the system) or by the PAL
168  * override table (in which case we should ignore the value from
169  * PAL_VM_SUMMARY).
170  *
171  * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g
172  * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case,
173  * we should ignore the value from either PAL_VM_SUMMARY or PAL override table.
174  *
175  * Complicating the logic here is the fact that num_possible_cpus()
176  * isn't fully setup until we start bringing cpus online.
177  */
178 void
179 setup_ptcg_sem(int max_purges, int nptcg_from)
180 {
181 	static int kp_override;
182 	static int palo_override;
183 	static int firstcpu = 1;
184 
185 	if (toolatetochangeptcgsem) {
186 		if (nptcg_from == NPTCG_FROM_PAL && max_purges == 0)
187 			BUG_ON(1 < nptcg);
188 		else
189 			BUG_ON(max_purges < nptcg);
190 		return;
191 	}
192 
193 	if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
194 		kp_override = 1;
195 		nptcg = max_purges;
196 		goto resetsema;
197 	}
198 	if (kp_override) {
199 		need_ptcg_sem = num_possible_cpus() > nptcg;
200 		return;
201 	}
202 
203 	if (nptcg_from == NPTCG_FROM_PALO) {
204 		palo_override = 1;
205 
206 		/* In PALO max_purges == 0 really means it! */
207 		if (max_purges == 0)
208 			panic("Whoa! Platform does not support global TLB purges.\n");
209 		nptcg = max_purges;
210 		if (nptcg == PALO_MAX_TLB_PURGES) {
211 			need_ptcg_sem = 0;
212 			return;
213 		}
214 		goto resetsema;
215 	}
216 	if (palo_override) {
217 		if (nptcg != PALO_MAX_TLB_PURGES)
218 			need_ptcg_sem = (num_possible_cpus() > nptcg);
219 		return;
220 	}
221 
222 	/* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
223 	if (max_purges == 0) max_purges = 1;
224 
225 	if (firstcpu) {
226 		nptcg = max_purges;
227 		firstcpu = 0;
228 	}
229 	if (max_purges < nptcg)
230 		nptcg = max_purges;
231 	if (nptcg == PAL_MAX_PURGES) {
232 		need_ptcg_sem = 0;
233 		return;
234 	} else
235 		need_ptcg_sem = (num_possible_cpus() > nptcg);
236 
237 resetsema:
238 	spinaphore_init(&ptcg_sem, max_purges);
239 }
240 
241 void
242 ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
243 		       unsigned long end, unsigned long nbits)
244 {
245 	struct mm_struct *active_mm = current->active_mm;
246 
247 	toolatetochangeptcgsem = 1;
248 
249 	if (mm != active_mm) {
250 		/* Restore region IDs for mm */
251 		if (mm && active_mm) {
252 			activate_context(mm);
253 		} else {
254 			flush_tlb_all();
255 			return;
256 		}
257 	}
258 
259 	if (need_ptcg_sem)
260 		down_spin(&ptcg_sem);
261 
262 	do {
263 		/*
264 		 * Flush ALAT entries also.
265 		 */
266 		ia64_ptcga(start, (nbits << 2));
267 		ia64_srlz_i();
268 		start += (1UL << nbits);
269 	} while (start < end);
270 
271 	if (need_ptcg_sem)
272 		up_spin(&ptcg_sem);
273 
274         if (mm != active_mm) {
275                 activate_context(active_mm);
276         }
277 }
278 
279 void
280 local_flush_tlb_all (void)
281 {
282 	unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
283 
284 	addr    = local_cpu_data->ptce_base;
285 	count0  = local_cpu_data->ptce_count[0];
286 	count1  = local_cpu_data->ptce_count[1];
287 	stride0 = local_cpu_data->ptce_stride[0];
288 	stride1 = local_cpu_data->ptce_stride[1];
289 
290 	local_irq_save(flags);
291 	for (i = 0; i < count0; ++i) {
292 		for (j = 0; j < count1; ++j) {
293 			ia64_ptce(addr);
294 			addr += stride1;
295 		}
296 		addr += stride0;
297 	}
298 	local_irq_restore(flags);
299 	ia64_srlz_i();			/* srlz.i implies srlz.d */
300 }
301 
302 void
303 flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
304 		 unsigned long end)
305 {
306 	struct mm_struct *mm = vma->vm_mm;
307 	unsigned long size = end - start;
308 	unsigned long nbits;
309 
310 #ifndef CONFIG_SMP
311 	if (mm != current->active_mm) {
312 		mm->context = 0;
313 		return;
314 	}
315 #endif
316 
317 	nbits = ia64_fls(size + 0xfff);
318 	while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
319 			(nbits < purge.max_bits))
320 		++nbits;
321 	if (nbits > purge.max_bits)
322 		nbits = purge.max_bits;
323 	start &= ~((1UL << nbits) - 1);
324 
325 	preempt_disable();
326 #ifdef CONFIG_SMP
327 	if (mm != current->active_mm || cpumask_weight(mm_cpumask(mm)) != 1) {
328 		platform_global_tlb_purge(mm, start, end, nbits);
329 		preempt_enable();
330 		return;
331 	}
332 #endif
333 	do {
334 		ia64_ptcl(start, (nbits<<2));
335 		start += (1UL << nbits);
336 	} while (start < end);
337 	preempt_enable();
338 	ia64_srlz_i();			/* srlz.i implies srlz.d */
339 }
340 EXPORT_SYMBOL(flush_tlb_range);
341 
342 void ia64_tlb_init(void)
343 {
344 	ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
345 	u64 tr_pgbits;
346 	long status;
347 	pal_vm_info_1_u_t vm_info_1;
348 	pal_vm_info_2_u_t vm_info_2;
349 	int cpu = smp_processor_id();
350 
351 	if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
352 		printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld; "
353 		       "defaulting to architected purge page-sizes.\n", status);
354 		purge.mask = 0x115557000UL;
355 	}
356 	purge.max_bits = ia64_fls(purge.mask);
357 
358 	ia64_get_ptce(&ptce_info);
359 	local_cpu_data->ptce_base = ptce_info.base;
360 	local_cpu_data->ptce_count[0] = ptce_info.count[0];
361 	local_cpu_data->ptce_count[1] = ptce_info.count[1];
362 	local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
363 	local_cpu_data->ptce_stride[1] = ptce_info.stride[1];
364 
365 	local_flush_tlb_all();	/* nuke left overs from bootstrapping... */
366 	status = ia64_pal_vm_summary(&vm_info_1, &vm_info_2);
367 
368 	if (status) {
369 		printk(KERN_ERR "ia64_pal_vm_summary=%ld\n", status);
370 		per_cpu(ia64_tr_num, cpu) = 8;
371 		return;
372 	}
373 	per_cpu(ia64_tr_num, cpu) = vm_info_1.pal_vm_info_1_s.max_itr_entry+1;
374 	if (per_cpu(ia64_tr_num, cpu) >
375 				(vm_info_1.pal_vm_info_1_s.max_dtr_entry+1))
376 		per_cpu(ia64_tr_num, cpu) =
377 				vm_info_1.pal_vm_info_1_s.max_dtr_entry+1;
378 	if (per_cpu(ia64_tr_num, cpu) > IA64_TR_ALLOC_MAX) {
379 		static int justonce = 1;
380 		per_cpu(ia64_tr_num, cpu) = IA64_TR_ALLOC_MAX;
381 		if (justonce) {
382 			justonce = 0;
383 			printk(KERN_DEBUG "TR register number exceeds "
384 			       "IA64_TR_ALLOC_MAX!\n");
385 		}
386 	}
387 }
388 
389 /*
390  * is_tr_overlap
391  *
392  * Check overlap with inserted TRs.
393  */
394 static int is_tr_overlap(struct ia64_tr_entry *p, u64 va, u64 log_size)
395 {
396 	u64 tr_log_size;
397 	u64 tr_end;
398 	u64 va_rr = ia64_get_rr(va);
399 	u64 va_rid = RR_TO_RID(va_rr);
400 	u64 va_end = va + (1<<log_size) - 1;
401 
402 	if (va_rid != RR_TO_RID(p->rr))
403 		return 0;
404 	tr_log_size = (p->itir & 0xff) >> 2;
405 	tr_end = p->ifa + (1<<tr_log_size) - 1;
406 
407 	if (va > tr_end || p->ifa > va_end)
408 		return 0;
409 	return 1;
410 
411 }
412 
413 /*
414  * ia64_insert_tr in virtual mode. Allocate a TR slot
415  *
416  * target_mask : 0x1 : itr, 0x2 : dtr, 0x3 : idtr
417  *
418  * va 	: virtual address.
419  * pte 	: pte entries inserted.
420  * log_size: range to be covered.
421  *
422  * Return value:  <0 :  error No.
423  *
424  *		  >=0 : slot number allocated for TR.
425  * Must be called with preemption disabled.
426  */
427 int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
428 {
429 	int i, r;
430 	unsigned long psr;
431 	struct ia64_tr_entry *p;
432 	int cpu = smp_processor_id();
433 
434 	if (!ia64_idtrs[cpu]) {
435 		ia64_idtrs[cpu] = kmalloc_array(2 * IA64_TR_ALLOC_MAX,
436 						sizeof(struct ia64_tr_entry),
437 						GFP_KERNEL);
438 		if (!ia64_idtrs[cpu])
439 			return -ENOMEM;
440 	}
441 	r = -EINVAL;
442 	/*Check overlap with existing TR entries*/
443 	if (target_mask & 0x1) {
444 		p = ia64_idtrs[cpu];
445 		for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
446 								i++, p++) {
447 			if (p->pte & 0x1)
448 				if (is_tr_overlap(p, va, log_size)) {
449 					printk(KERN_DEBUG "Overlapped Entry"
450 						"Inserted for TR Register!!\n");
451 					goto out;
452 			}
453 		}
454 	}
455 	if (target_mask & 0x2) {
456 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX;
457 		for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
458 								i++, p++) {
459 			if (p->pte & 0x1)
460 				if (is_tr_overlap(p, va, log_size)) {
461 					printk(KERN_DEBUG "Overlapped Entry"
462 						"Inserted for TR Register!!\n");
463 					goto out;
464 				}
465 		}
466 	}
467 
468 	for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
469 		switch (target_mask & 0x3) {
470 		case 1:
471 			if (!((ia64_idtrs[cpu] + i)->pte & 0x1))
472 				goto found;
473 			continue;
474 		case 2:
475 			if (!((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
476 				goto found;
477 			continue;
478 		case 3:
479 			if (!((ia64_idtrs[cpu] + i)->pte & 0x1) &&
480 			    !((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
481 				goto found;
482 			continue;
483 		default:
484 			r = -EINVAL;
485 			goto out;
486 		}
487 	}
488 found:
489 	if (i >= per_cpu(ia64_tr_num, cpu))
490 		return -EBUSY;
491 
492 	/*Record tr info for mca hander use!*/
493 	if (i > per_cpu(ia64_tr_used, cpu))
494 		per_cpu(ia64_tr_used, cpu) = i;
495 
496 	psr = ia64_clear_ic();
497 	if (target_mask & 0x1) {
498 		ia64_itr(0x1, i, va, pte, log_size);
499 		ia64_srlz_i();
500 		p = ia64_idtrs[cpu] + i;
501 		p->ifa = va;
502 		p->pte = pte;
503 		p->itir = log_size << 2;
504 		p->rr = ia64_get_rr(va);
505 	}
506 	if (target_mask & 0x2) {
507 		ia64_itr(0x2, i, va, pte, log_size);
508 		ia64_srlz_i();
509 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i;
510 		p->ifa = va;
511 		p->pte = pte;
512 		p->itir = log_size << 2;
513 		p->rr = ia64_get_rr(va);
514 	}
515 	ia64_set_psr(psr);
516 	r = i;
517 out:
518 	return r;
519 }
520 EXPORT_SYMBOL_GPL(ia64_itr_entry);
521 
522 /*
523  * ia64_purge_tr
524  *
525  * target_mask: 0x1: purge itr, 0x2 : purge dtr, 0x3 purge idtr.
526  * slot: slot number to be freed.
527  *
528  * Must be called with preemption disabled.
529  */
530 void ia64_ptr_entry(u64 target_mask, int slot)
531 {
532 	int cpu = smp_processor_id();
533 	int i;
534 	struct ia64_tr_entry *p;
535 
536 	if (slot < IA64_TR_ALLOC_BASE || slot >= per_cpu(ia64_tr_num, cpu))
537 		return;
538 
539 	if (target_mask & 0x1) {
540 		p = ia64_idtrs[cpu] + slot;
541 		if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
542 			p->pte = 0;
543 			ia64_ptr(0x1, p->ifa, p->itir>>2);
544 			ia64_srlz_i();
545 		}
546 	}
547 
548 	if (target_mask & 0x2) {
549 		p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + slot;
550 		if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
551 			p->pte = 0;
552 			ia64_ptr(0x2, p->ifa, p->itir>>2);
553 			ia64_srlz_i();
554 		}
555 	}
556 
557 	for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
558 		if (((ia64_idtrs[cpu] + i)->pte & 0x1) ||
559 		    ((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
560 			break;
561 	}
562 	per_cpu(ia64_tr_used, cpu) = i;
563 }
564 EXPORT_SYMBOL_GPL(ia64_ptr_entry);
565