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[IA64] Re-implement spinaphores using ticket lock concepts
[net-next-2.6.git] / arch / ia64 / mm / tlb.c
CommitLineData
1da177e4
LT
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.
dcc17d1b
PK
11 * Rohit Seth <rohit.seth@intel.com>
12 * Ken Chen <kenneth.w.chen@intel.com>
aec103bf 13 * Christophe de Dinechin <ddd@hp.com>: Avoid ptc.e on memory allocation
2046b94e
FY
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.
1da177e4 17 */
1da177e4
LT
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>
dcc17d1b 24#include <linux/bootmem.h>
1da177e4
LT
25
26#include <asm/delay.h>
27#include <asm/mmu_context.h>
28#include <asm/pgalloc.h>
29#include <asm/pal.h>
30#include <asm/tlbflush.h>
dcc17d1b 31#include <asm/dma.h>
96651896 32#include <asm/processor.h>
2046b94e 33#include <asm/sal.h>
96651896 34#include <asm/tlb.h>
1da177e4
LT
35
36static struct {
e088a4ad 37 u64 mask; /* mask of supported purge page-sizes */
58cd9082 38 unsigned long max_bits; /* log2 of largest supported purge page-size */
1da177e4
LT
39} purge;
40
41struct ia64_ctx ia64_ctx = {
8737d595
MAC
42 .lock = __SPIN_LOCK_UNLOCKED(ia64_ctx.lock),
43 .next = 1,
44 .max_ctx = ~0U
1da177e4
LT
45};
46
47DEFINE_PER_CPU(u8, ia64_need_tlb_flush);
96651896
XZ
48DEFINE_PER_CPU(u8, ia64_tr_num); /*Number of TR slots in current processor*/
49DEFINE_PER_CPU(u8, ia64_tr_used); /*Max Slot number used by kernel*/
50
51struct ia64_tr_entry __per_cpu_idtrs[NR_CPUS][2][IA64_TR_ALLOC_MAX];
1da177e4 52
dcc17d1b
PK
53/*
54 * Initializes the ia64_ctx.bitmap array based on max_ctx+1.
55 * Called after cpu_init() has setup ia64_ctx.max_ctx based on
56 * maximum RID that is supported by boot CPU.
57 */
58void __init
59mmu_context_init (void)
60{
61 ia64_ctx.bitmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
62 ia64_ctx.flushmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
63}
64
1da177e4
LT
65/*
66 * Acquire the ia64_ctx.lock before calling this function!
67 */
68void
69wrap_mmu_context (struct mm_struct *mm)
70{
58cd9082 71 int i, cpu;
dcc17d1b 72 unsigned long flush_bit;
1da177e4 73
dcc17d1b
PK
74 for (i=0; i <= ia64_ctx.max_ctx / BITS_PER_LONG; i++) {
75 flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
76 ia64_ctx.bitmap[i] ^= flush_bit;
1da177e4 77 }
dcc17d1b
PK
78
79 /* use offset at 300 to skip daemons */
80 ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
81 ia64_ctx.max_ctx, 300);
82 ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
83 ia64_ctx.max_ctx, ia64_ctx.next);
84
58cd9082
KC
85 /*
86 * can't call flush_tlb_all() here because of race condition
87 * with O(1) scheduler [EF]
88 */
89 cpu = get_cpu(); /* prevent preemption/migration */
90 for_each_online_cpu(i)
91 if (i != cpu)
92 per_cpu(ia64_need_tlb_flush, i) = 1;
93 put_cpu();
1da177e4
LT
94 local_flush_tlb_all();
95}
96
2046b94e
FY
97/*
98 * Implement "spinaphores" ... like counting semaphores, but they
99 * spin instead of sleeping. If there are ever any other users for
100 * this primitive it can be moved up to a spinaphore.h header.
101 */
102struct spinaphore {
883a3acf
TL
103 unsigned long ticket;
104 unsigned long serve;
2046b94e
FY
105};
106
107static inline void spinaphore_init(struct spinaphore *ss, int val)
108{
883a3acf
TL
109 ss->ticket = 0;
110 ss->serve = val;
2046b94e
FY
111}
112
113static inline void down_spin(struct spinaphore *ss)
114{
883a3acf
TL
115 unsigned long t = ia64_fetchadd(1, &ss->ticket, acq), serve;
116
117 if (time_before(t, ss->serve))
118 return;
119
120 ia64_invala();
121
122 for (;;) {
123 asm volatile ("ld4.c.nc %0=[%1]" : "=r"(serve) : "r"(&ss->serve) : "memory");
124 if (time_before(t, serve))
125 return;
126 cpu_relax();
127 }
2046b94e
FY
128}
129
130static inline void up_spin(struct spinaphore *ss)
131{
883a3acf 132 ia64_fetchadd(1, &ss->serve, rel);
2046b94e
FY
133}
134
135static struct spinaphore ptcg_sem;
136static u16 nptcg = 1;
137static int need_ptcg_sem = 1;
138static int toolatetochangeptcgsem = 0;
139
a6c75b86
FY
140/*
141 * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
142 * purges which is reported from either PAL or SAL PALO.
143 *
144 * We don't have sanity checking for nptcg value. It's the user's responsibility
145 * for valid nptcg value on the platform. Otherwise, kernel may hang in some
146 * cases.
147 */
148static int __init
149set_nptcg(char *str)
150{
151 int value = 0;
152
153 get_option(&str, &value);
154 setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER);
155
156 return 1;
157}
158
159__setup("nptcg=", set_nptcg);
160
2046b94e
FY
161/*
162 * Maximum number of simultaneous ptc.g purges in the system can
163 * be defined by PAL_VM_SUMMARY (in which case we should take
164 * the smallest value for any cpu in the system) or by the PAL
165 * override table (in which case we should ignore the value from
166 * PAL_VM_SUMMARY).
167 *
a6c75b86
FY
168 * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g
169 * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case,
170 * we should ignore the value from either PAL_VM_SUMMARY or PAL override table.
171 *
2046b94e
FY
172 * Complicating the logic here is the fact that num_possible_cpus()
173 * isn't fully setup until we start bringing cpus online.
174 */
175void
a6c75b86 176setup_ptcg_sem(int max_purges, int nptcg_from)
2046b94e 177{
a6c75b86
FY
178 static int kp_override;
179 static int palo_override;
2046b94e
FY
180 static int firstcpu = 1;
181
182 if (toolatetochangeptcgsem) {
e617fce6
HS
183 if (nptcg_from == NPTCG_FROM_PAL && max_purges == 0)
184 BUG_ON(1 < nptcg);
185 else
186 BUG_ON(max_purges < nptcg);
2046b94e
FY
187 return;
188 }
189
a6c75b86
FY
190 if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
191 kp_override = 1;
192 nptcg = max_purges;
193 goto resetsema;
194 }
195 if (kp_override) {
196 need_ptcg_sem = num_possible_cpus() > nptcg;
197 return;
198 }
199
200 if (nptcg_from == NPTCG_FROM_PALO) {
201 palo_override = 1;
2046b94e
FY
202
203 /* In PALO max_purges == 0 really means it! */
204 if (max_purges == 0)
205 panic("Whoa! Platform does not support global TLB purges.\n");
206 nptcg = max_purges;
207 if (nptcg == PALO_MAX_TLB_PURGES) {
208 need_ptcg_sem = 0;
209 return;
210 }
211 goto resetsema;
212 }
a6c75b86 213 if (palo_override) {
2046b94e
FY
214 if (nptcg != PALO_MAX_TLB_PURGES)
215 need_ptcg_sem = (num_possible_cpus() > nptcg);
216 return;
217 }
218
219 /* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
220 if (max_purges == 0) max_purges = 1;
221
222 if (firstcpu) {
223 nptcg = max_purges;
224 firstcpu = 0;
225 }
226 if (max_purges < nptcg)
227 nptcg = max_purges;
228 if (nptcg == PAL_MAX_PURGES) {
229 need_ptcg_sem = 0;
230 return;
231 } else
232 need_ptcg_sem = (num_possible_cpus() > nptcg);
233
234resetsema:
235 spinaphore_init(&ptcg_sem, max_purges);
236}
237
1da177e4 238void
58cd9082
KC
239ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
240 unsigned long end, unsigned long nbits)
1da177e4 241{
aec103bf
DCIV
242 struct mm_struct *active_mm = current->active_mm;
243
2046b94e
FY
244 toolatetochangeptcgsem = 1;
245
aec103bf
DCIV
246 if (mm != active_mm) {
247 /* Restore region IDs for mm */
248 if (mm && active_mm) {
249 activate_context(mm);
250 } else {
251 flush_tlb_all();
252 return;
253 }
c1902aae
DR
254 }
255
2046b94e
FY
256 if (need_ptcg_sem)
257 down_spin(&ptcg_sem);
258
259 do {
260 /*
261 * Flush ALAT entries also.
262 */
263 ia64_ptcga(start, (nbits << 2));
264 ia64_srlz_i();
265 start += (1UL << nbits);
266 } while (start < end);
267
268 if (need_ptcg_sem)
269 up_spin(&ptcg_sem);
aec103bf
DCIV
270
271 if (mm != active_mm) {
272 activate_context(active_mm);
273 }
1da177e4
LT
274}
275
276void
277local_flush_tlb_all (void)
278{
279 unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
280
281 addr = local_cpu_data->ptce_base;
282 count0 = local_cpu_data->ptce_count[0];
283 count1 = local_cpu_data->ptce_count[1];
284 stride0 = local_cpu_data->ptce_stride[0];
285 stride1 = local_cpu_data->ptce_stride[1];
286
287 local_irq_save(flags);
288 for (i = 0; i < count0; ++i) {
289 for (j = 0; j < count1; ++j) {
290 ia64_ptce(addr);
291 addr += stride1;
292 }
293 addr += stride0;
294 }
295 local_irq_restore(flags);
296 ia64_srlz_i(); /* srlz.i implies srlz.d */
297}
298
299void
58cd9082
KC
300flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
301 unsigned long end)
1da177e4
LT
302{
303 struct mm_struct *mm = vma->vm_mm;
304 unsigned long size = end - start;
305 unsigned long nbits;
306
c1902aae 307#ifndef CONFIG_SMP
1da177e4 308 if (mm != current->active_mm) {
1da177e4 309 mm->context = 0;
1da177e4
LT
310 return;
311 }
c1902aae 312#endif
1da177e4
LT
313
314 nbits = ia64_fls(size + 0xfff);
58cd9082
KC
315 while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
316 (nbits < purge.max_bits))
1da177e4
LT
317 ++nbits;
318 if (nbits > purge.max_bits)
319 nbits = purge.max_bits;
320 start &= ~((1UL << nbits) - 1);
321
663b97f7 322 preempt_disable();
ce9eed5a 323#ifdef CONFIG_SMP
5d8c39f6 324 if (mm != current->active_mm || cpumask_weight(mm_cpumask(mm)) != 1) {
ce9eed5a
KC
325 platform_global_tlb_purge(mm, start, end, nbits);
326 preempt_enable();
327 return;
328 }
329#endif
1da177e4
LT
330 do {
331 ia64_ptcl(start, (nbits<<2));
332 start += (1UL << nbits);
333 } while (start < end);
663b97f7 334 preempt_enable();
1da177e4
LT
335 ia64_srlz_i(); /* srlz.i implies srlz.d */
336}
337EXPORT_SYMBOL(flush_tlb_range);
338
339void __devinit
340ia64_tlb_init (void)
341{
256a7e09 342 ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
e088a4ad 343 u64 tr_pgbits;
1da177e4 344 long status;
96651896
XZ
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();
1da177e4
LT
348
349 if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
c2eeb321 350 printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld; "
1da177e4
LT
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
58cd9082 363 local_flush_tlb_all(); /* nuke left overs from bootstrapping... */
96651896
XZ
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) {
a9894a4a 377 static int justonce = 1;
96651896 378 per_cpu(ia64_tr_num, cpu) = IA64_TR_ALLOC_MAX;
a9894a4a
TL
379 if (justonce) {
380 justonce = 0;
381 printk(KERN_DEBUG "TR register number exceeds "
382 "IA64_TR_ALLOC_MAX!\n");
383 }
96651896
XZ
384 }
385}
386
387/*
388 * is_tr_overlap
389 *
390 * Check overlap with inserted TRs.
391 */
392static 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 */
425int 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 r = -EINVAL;
433 /*Check overlap with existing TR entries*/
434 if (target_mask & 0x1) {
435 p = &__per_cpu_idtrs[cpu][0][0];
436 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
437 i++, p++) {
438 if (p->pte & 0x1)
439 if (is_tr_overlap(p, va, log_size)) {
440 printk(KERN_DEBUG "Overlapped Entry"
441 "Inserted for TR Reigster!!\n");
442 goto out;
443 }
444 }
445 }
446 if (target_mask & 0x2) {
447 p = &__per_cpu_idtrs[cpu][1][0];
448 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
449 i++, p++) {
450 if (p->pte & 0x1)
451 if (is_tr_overlap(p, va, log_size)) {
452 printk(KERN_DEBUG "Overlapped Entry"
453 "Inserted for TR Reigster!!\n");
454 goto out;
455 }
456 }
457 }
458
459 for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
460 switch (target_mask & 0x3) {
461 case 1:
462 if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1))
463 goto found;
464 continue;
465 case 2:
466 if (!(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
467 goto found;
468 continue;
469 case 3:
470 if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1) &&
471 !(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
472 goto found;
473 continue;
474 default:
475 r = -EINVAL;
476 goto out;
477 }
478 }
479found:
480 if (i >= per_cpu(ia64_tr_num, cpu))
481 return -EBUSY;
482
483 /*Record tr info for mca hander use!*/
484 if (i > per_cpu(ia64_tr_used, cpu))
485 per_cpu(ia64_tr_used, cpu) = i;
486
487 psr = ia64_clear_ic();
488 if (target_mask & 0x1) {
489 ia64_itr(0x1, i, va, pte, log_size);
490 ia64_srlz_i();
491 p = &__per_cpu_idtrs[cpu][0][i];
492 p->ifa = va;
493 p->pte = pte;
494 p->itir = log_size << 2;
495 p->rr = ia64_get_rr(va);
496 }
497 if (target_mask & 0x2) {
498 ia64_itr(0x2, i, va, pte, log_size);
499 ia64_srlz_i();
500 p = &__per_cpu_idtrs[cpu][1][i];
501 p->ifa = va;
502 p->pte = pte;
503 p->itir = log_size << 2;
504 p->rr = ia64_get_rr(va);
505 }
506 ia64_set_psr(psr);
507 r = i;
508out:
509 return r;
510}
511EXPORT_SYMBOL_GPL(ia64_itr_entry);
512
513/*
514 * ia64_purge_tr
515 *
516 * target_mask: 0x1: purge itr, 0x2 : purge dtr, 0x3 purge idtr.
517 * slot: slot number to be freed.
518 *
519 * Must be called with preemption disabled.
520 */
521void ia64_ptr_entry(u64 target_mask, int slot)
522{
523 int cpu = smp_processor_id();
524 int i;
525 struct ia64_tr_entry *p;
526
527 if (slot < IA64_TR_ALLOC_BASE || slot >= per_cpu(ia64_tr_num, cpu))
528 return;
529
530 if (target_mask & 0x1) {
531 p = &__per_cpu_idtrs[cpu][0][slot];
532 if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
533 p->pte = 0;
534 ia64_ptr(0x1, p->ifa, p->itir>>2);
535 ia64_srlz_i();
536 }
537 }
538
539 if (target_mask & 0x2) {
540 p = &__per_cpu_idtrs[cpu][1][slot];
541 if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
542 p->pte = 0;
543 ia64_ptr(0x2, p->ifa, p->itir>>2);
544 ia64_srlz_i();
545 }
546 }
547
548 for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
549 if ((__per_cpu_idtrs[cpu][0][i].pte & 0x1) ||
550 (__per_cpu_idtrs[cpu][1][i].pte & 0x1))
551 break;
552 }
553 per_cpu(ia64_tr_used, cpu) = i;
1da177e4 554}
96651896 555EXPORT_SYMBOL_GPL(ia64_ptr_entry);