1 /*
2 * SN2 Platform specific SMP Support
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2000-2006 Silicon Graphics, Inc. All rights reserved.
9 */
10
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/spinlock.h>
14 #include <linux/threads.h>
15 #include <linux/sched.h>
16 #include <linux/smp.h>
17 #include <linux/interrupt.h>
18 #include <linux/irq.h>
19 #include <linux/mmzone.h>
20 #include <linux/module.h>
21 #include <linux/bitops.h>
22 #include <linux/nodemask.h>
23 #include <linux/proc_fs.h>
24 #include <linux/seq_file.h>
25
26 #include <asm/processor.h>
27 #include <asm/irq.h>
28 #include <asm/sal.h>
29 #include <asm/delay.h>
30 #include <asm/io.h>
31 #include <asm/smp.h>
32 #include <asm/tlb.h>
33 #include <asm/numa.h>
34 #include <asm/hw_irq.h>
35 #include <asm/current.h>
36 #include <asm/sn/sn_cpuid.h>
37 #include <asm/sn/sn_sal.h>
38 #include <asm/sn/addrs.h>
39 #include <asm/sn/shub_mmr.h>
40 #include <asm/sn/nodepda.h>
41 #include <asm/sn/rw_mmr.h>
42 #include <asm/sn/sn_feature_sets.h>
43
44 DEFINE_PER_CPU(struct ptc_stats, ptcstats);
45 DECLARE_PER_CPU(struct ptc_stats, ptcstats);
46
47 static __cacheline_aligned DEFINE_SPINLOCK(sn2_global_ptc_lock);
48
49 /* 0 = old algorithm (no IPI flushes), 1 = ipi deadlock flush, 2 = ipi instead of SHUB ptc, >2 = always ipi */
50 static int sn2_flush_opt = 0;
51
52 extern unsigned long
53 sn2_ptc_deadlock_recovery_core(volatile unsigned long *, unsigned long,
54 volatile unsigned long *, unsigned long,
55 volatile unsigned long *, unsigned long);
56 void
57 sn2_ptc_deadlock_recovery(nodemask_t, short, short, int,
58 volatile unsigned long *, unsigned long,
59 volatile unsigned long *, unsigned long);
60
61 /*
62 * Note: some is the following is captured here to make degugging easier
63 * (the macros make more sense if you see the debug patch - not posted)
64 */
65 #define sn2_ptctest 0
66 #define local_node_uses_ptc_ga(sh1) ((sh1) ? 1 : 0)
67 #define max_active_pio(sh1) ((sh1) ? 32 : 7)
68 #define reset_max_active_on_deadlock() 1
69 #define PTC_LOCK(sh1) ((sh1) ? &sn2_global_ptc_lock : &sn_nodepda->ptc_lock)
70
71 struct ptc_stats {
72 unsigned long ptc_l;
73 unsigned long change_rid;
74 unsigned long shub_ptc_flushes;
75 unsigned long nodes_flushed;
76 unsigned long deadlocks;
77 unsigned long deadlocks2;
78 unsigned long lock_itc_clocks;
79 unsigned long shub_itc_clocks;
80 unsigned long shub_itc_clocks_max;
81 unsigned long shub_ptc_flushes_not_my_mm;
82 unsigned long shub_ipi_flushes;
83 unsigned long shub_ipi_flushes_itc_clocks;
84 };
85
86 #define sn2_ptctest 0
87
wait_piowc(void)88 static inline unsigned long wait_piowc(void)
89 {
90 volatile unsigned long *piows;
91 unsigned long zeroval, ws;
92
93 piows = pda->pio_write_status_addr;
94 zeroval = pda->pio_write_status_val;
95 do {
96 cpu_relax();
97 } while (((ws = *piows) & SH_PIO_WRITE_STATUS_PENDING_WRITE_COUNT_MASK) != zeroval);
98 return (ws & SH_PIO_WRITE_STATUS_WRITE_DEADLOCK_MASK) != 0;
99 }
100
101 /**
102 * sn_migrate - SN-specific task migration actions
103 * @task: Task being migrated to new CPU
104 *
105 * SN2 PIO writes from separate CPUs are not guaranteed to arrive in order.
106 * Context switching user threads which have memory-mapped MMIO may cause
107 * PIOs to issue from separate CPUs, thus the PIO writes must be drained
108 * from the previous CPU's Shub before execution resumes on the new CPU.
109 */
sn_migrate(struct task_struct * task)110 void sn_migrate(struct task_struct *task)
111 {
112 pda_t *last_pda = pdacpu(task_thread_info(task)->last_cpu);
113 volatile unsigned long *adr = last_pda->pio_write_status_addr;
114 unsigned long val = last_pda->pio_write_status_val;
115
116 /* Drain PIO writes from old CPU's Shub */
117 while (unlikely((*adr & SH_PIO_WRITE_STATUS_PENDING_WRITE_COUNT_MASK)
118 != val))
119 cpu_relax();
120 }
121
sn_tlb_migrate_finish(struct mm_struct * mm)122 void sn_tlb_migrate_finish(struct mm_struct *mm)
123 {
124 /* flush_tlb_mm is inefficient if more than 1 users of mm */
125 if (mm == current->mm && mm && atomic_read(&mm->mm_users) == 1)
126 flush_tlb_mm(mm);
127 }
128
129 static void
sn2_ipi_flush_all_tlb(struct mm_struct * mm)130 sn2_ipi_flush_all_tlb(struct mm_struct *mm)
131 {
132 unsigned long itc;
133
134 itc = ia64_get_itc();
135 smp_flush_tlb_cpumask(*mm_cpumask(mm));
136 itc = ia64_get_itc() - itc;
137 __this_cpu_add(ptcstats.shub_ipi_flushes_itc_clocks, itc);
138 __this_cpu_inc(ptcstats.shub_ipi_flushes);
139 }
140
141 /**
142 * sn2_global_tlb_purge - globally purge translation cache of virtual address range
143 * @mm: mm_struct containing virtual address range
144 * @start: start of virtual address range
145 * @end: end of virtual address range
146 * @nbits: specifies number of bytes to purge per instruction (num = 1<<(nbits & 0xfc))
147 *
148 * Purges the translation caches of all processors of the given virtual address
149 * range.
150 *
151 * Note:
152 * - cpu_vm_mask is a bit mask that indicates which cpus have loaded the context.
153 * - cpu_vm_mask is converted into a nodemask of the nodes containing the
154 * cpus in cpu_vm_mask.
155 * - if only one bit is set in cpu_vm_mask & it is the current cpu & the
156 * process is purging its own virtual address range, then only the
157 * local TLB needs to be flushed. This flushing can be done using
158 * ptc.l. This is the common case & avoids the global spinlock.
159 * - if multiple cpus have loaded the context, then flushing has to be
160 * done with ptc.g/MMRs under protection of the global ptc_lock.
161 */
162
163 void
sn2_global_tlb_purge(struct mm_struct * mm,unsigned long start,unsigned long end,unsigned long nbits)164 sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
165 unsigned long end, unsigned long nbits)
166 {
167 int i, ibegin, shub1, cnode, mynasid, cpu, lcpu = 0, nasid;
168 int mymm = (mm == current->active_mm && mm == current->mm);
169 int use_cpu_ptcga;
170 volatile unsigned long *ptc0, *ptc1;
171 unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value, old_rr = 0;
172 short nix;
173 nodemask_t nodes_flushed;
174 int active, max_active, deadlock, flush_opt = sn2_flush_opt;
175
176 if (flush_opt > 2) {
177 sn2_ipi_flush_all_tlb(mm);
178 return;
179 }
180
181 nodes_clear(nodes_flushed);
182 i = 0;
183
184 for_each_cpu(cpu, mm_cpumask(mm)) {
185 cnode = cpu_to_node(cpu);
186 node_set(cnode, nodes_flushed);
187 lcpu = cpu;
188 i++;
189 }
190
191 if (i == 0)
192 return;
193
194 preempt_disable();
195
196 if (likely(i == 1 && lcpu == smp_processor_id() && mymm)) {
197 do {
198 ia64_ptcl(start, nbits << 2);
199 start += (1UL << nbits);
200 } while (start < end);
201 ia64_srlz_i();
202 __this_cpu_inc(ptcstats.ptc_l);
203 preempt_enable();
204 return;
205 }
206
207 if (atomic_read(&mm->mm_users) == 1 && mymm) {
208 flush_tlb_mm(mm);
209 __this_cpu_inc(ptcstats.change_rid);
210 preempt_enable();
211 return;
212 }
213
214 if (flush_opt == 2) {
215 sn2_ipi_flush_all_tlb(mm);
216 preempt_enable();
217 return;
218 }
219
220 itc = ia64_get_itc();
221 nix = nodes_weight(nodes_flushed);
222
223 rr_value = (mm->context << 3) | REGION_NUMBER(start);
224
225 shub1 = is_shub1();
226 if (shub1) {
227 data0 = (1UL << SH1_PTC_0_A_SHFT) |
228 (nbits << SH1_PTC_0_PS_SHFT) |
229 (rr_value << SH1_PTC_0_RID_SHFT) |
230 (1UL << SH1_PTC_0_START_SHFT);
231 ptc0 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH1_PTC_0);
232 ptc1 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH1_PTC_1);
233 } else {
234 data0 = (1UL << SH2_PTC_A_SHFT) |
235 (nbits << SH2_PTC_PS_SHFT) |
236 (1UL << SH2_PTC_START_SHFT);
237 ptc0 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH2_PTC +
238 (rr_value << SH2_PTC_RID_SHFT));
239 ptc1 = NULL;
240 }
241
242
243 mynasid = get_nasid();
244 use_cpu_ptcga = local_node_uses_ptc_ga(shub1);
245 max_active = max_active_pio(shub1);
246
247 itc = ia64_get_itc();
248 spin_lock_irqsave(PTC_LOCK(shub1), flags);
249 itc2 = ia64_get_itc();
250
251 __this_cpu_add(ptcstats.lock_itc_clocks, itc2 - itc);
252 __this_cpu_inc(ptcstats.shub_ptc_flushes);
253 __this_cpu_add(ptcstats.nodes_flushed, nix);
254 if (!mymm)
255 __this_cpu_inc(ptcstats.shub_ptc_flushes_not_my_mm);
256
257 if (use_cpu_ptcga && !mymm) {
258 old_rr = ia64_get_rr(start);
259 ia64_set_rr(start, (old_rr & 0xff) | (rr_value << 8));
260 ia64_srlz_d();
261 }
262
263 wait_piowc();
264 do {
265 if (shub1)
266 data1 = start | (1UL << SH1_PTC_1_START_SHFT);
267 else
268 data0 = (data0 & ~SH2_PTC_ADDR_MASK) | (start & SH2_PTC_ADDR_MASK);
269 deadlock = 0;
270 active = 0;
271 ibegin = 0;
272 i = 0;
273 for_each_node_mask(cnode, nodes_flushed) {
274 nasid = cnodeid_to_nasid(cnode);
275 if (use_cpu_ptcga && unlikely(nasid == mynasid)) {
276 ia64_ptcga(start, nbits << 2);
277 ia64_srlz_i();
278 } else {
279 ptc0 = CHANGE_NASID(nasid, ptc0);
280 if (ptc1)
281 ptc1 = CHANGE_NASID(nasid, ptc1);
282 pio_atomic_phys_write_mmrs(ptc0, data0, ptc1, data1);
283 active++;
284 }
285 if (active >= max_active || i == (nix - 1)) {
286 if ((deadlock = wait_piowc())) {
287 if (flush_opt == 1)
288 goto done;
289 sn2_ptc_deadlock_recovery(nodes_flushed, ibegin, i, mynasid, ptc0, data0, ptc1, data1);
290 if (reset_max_active_on_deadlock())
291 max_active = 1;
292 }
293 active = 0;
294 ibegin = i + 1;
295 }
296 i++;
297 }
298 start += (1UL << nbits);
299 } while (start < end);
300
301 done:
302 itc2 = ia64_get_itc() - itc2;
303 __this_cpu_add(ptcstats.shub_itc_clocks, itc2);
304 if (itc2 > __this_cpu_read(ptcstats.shub_itc_clocks_max))
305 __this_cpu_write(ptcstats.shub_itc_clocks_max, itc2);
306
307 if (old_rr) {
308 ia64_set_rr(start, old_rr);
309 ia64_srlz_d();
310 }
311
312 spin_unlock_irqrestore(PTC_LOCK(shub1), flags);
313
314 if (flush_opt == 1 && deadlock) {
315 __this_cpu_inc(ptcstats.deadlocks);
316 sn2_ipi_flush_all_tlb(mm);
317 }
318
319 preempt_enable();
320 }
321
322 /*
323 * sn2_ptc_deadlock_recovery
324 *
325 * Recover from PTC deadlocks conditions. Recovery requires stepping thru each
326 * TLB flush transaction. The recovery sequence is somewhat tricky & is
327 * coded in assembly language.
328 */
329
330 void
sn2_ptc_deadlock_recovery(nodemask_t nodes,short ib,short ie,int mynasid,volatile unsigned long * ptc0,unsigned long data0,volatile unsigned long * ptc1,unsigned long data1)331 sn2_ptc_deadlock_recovery(nodemask_t nodes, short ib, short ie, int mynasid,
332 volatile unsigned long *ptc0, unsigned long data0,
333 volatile unsigned long *ptc1, unsigned long data1)
334 {
335 short nasid, i;
336 int cnode;
337 unsigned long *piows, zeroval, n;
338
339 __this_cpu_inc(ptcstats.deadlocks);
340
341 piows = (unsigned long *) pda->pio_write_status_addr;
342 zeroval = pda->pio_write_status_val;
343
344 i = 0;
345 for_each_node_mask(cnode, nodes) {
346 if (i < ib)
347 goto next;
348
349 if (i > ie)
350 break;
351
352 nasid = cnodeid_to_nasid(cnode);
353 if (local_node_uses_ptc_ga(is_shub1()) && nasid == mynasid)
354 goto next;
355
356 ptc0 = CHANGE_NASID(nasid, ptc0);
357 if (ptc1)
358 ptc1 = CHANGE_NASID(nasid, ptc1);
359
360 n = sn2_ptc_deadlock_recovery_core(ptc0, data0, ptc1, data1, piows, zeroval);
361 __this_cpu_add(ptcstats.deadlocks2, n);
362 next:
363 i++;
364 }
365
366 }
367
368 /**
369 * sn_send_IPI_phys - send an IPI to a Nasid and slice
370 * @nasid: nasid to receive the interrupt (may be outside partition)
371 * @physid: physical cpuid to receive the interrupt.
372 * @vector: command to send
373 * @delivery_mode: delivery mechanism
374 *
375 * Sends an IPI (interprocessor interrupt) to the processor specified by
376 * @physid
377 *
378 * @delivery_mode can be one of the following
379 *
380 * %IA64_IPI_DM_INT - pend an interrupt
381 * %IA64_IPI_DM_PMI - pend a PMI
382 * %IA64_IPI_DM_NMI - pend an NMI
383 * %IA64_IPI_DM_INIT - pend an INIT interrupt
384 */
sn_send_IPI_phys(int nasid,long physid,int vector,int delivery_mode)385 void sn_send_IPI_phys(int nasid, long physid, int vector, int delivery_mode)
386 {
387 long val;
388 unsigned long flags = 0;
389 volatile long *p;
390
391 p = (long *)GLOBAL_MMR_PHYS_ADDR(nasid, SH_IPI_INT);
392 val = (1UL << SH_IPI_INT_SEND_SHFT) |
393 (physid << SH_IPI_INT_PID_SHFT) |
394 ((long)delivery_mode << SH_IPI_INT_TYPE_SHFT) |
395 ((long)vector << SH_IPI_INT_IDX_SHFT) |
396 (0x000feeUL << SH_IPI_INT_BASE_SHFT);
397
398 mb();
399 if (enable_shub_wars_1_1()) {
400 spin_lock_irqsave(&sn2_global_ptc_lock, flags);
401 }
402 pio_phys_write_mmr(p, val);
403 if (enable_shub_wars_1_1()) {
404 wait_piowc();
405 spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
406 }
407
408 }
409
410 EXPORT_SYMBOL(sn_send_IPI_phys);
411
412 /**
413 * sn2_send_IPI - send an IPI to a processor
414 * @cpuid: target of the IPI
415 * @vector: command to send
416 * @delivery_mode: delivery mechanism
417 * @redirect: redirect the IPI?
418 *
419 * Sends an IPI (InterProcessor Interrupt) to the processor specified by
420 * @cpuid. @vector specifies the command to send, while @delivery_mode can
421 * be one of the following
422 *
423 * %IA64_IPI_DM_INT - pend an interrupt
424 * %IA64_IPI_DM_PMI - pend a PMI
425 * %IA64_IPI_DM_NMI - pend an NMI
426 * %IA64_IPI_DM_INIT - pend an INIT interrupt
427 */
sn2_send_IPI(int cpuid,int vector,int delivery_mode,int redirect)428 void sn2_send_IPI(int cpuid, int vector, int delivery_mode, int redirect)
429 {
430 long physid;
431 int nasid;
432
433 physid = cpu_physical_id(cpuid);
434 nasid = cpuid_to_nasid(cpuid);
435
436 /* the following is used only when starting cpus at boot time */
437 if (unlikely(nasid == -1))
438 ia64_sn_get_sapic_info(physid, &nasid, NULL, NULL);
439
440 sn_send_IPI_phys(nasid, physid, vector, delivery_mode);
441 }
442
443 #ifdef CONFIG_HOTPLUG_CPU
444 /**
445 * sn_cpu_disable_allowed - Determine if a CPU can be disabled.
446 * @cpu - CPU that is requested to be disabled.
447 *
448 * CPU disable is only allowed on SHub2 systems running with a PROM
449 * that supports CPU disable. It is not permitted to disable the boot processor.
450 */
sn_cpu_disable_allowed(int cpu)451 bool sn_cpu_disable_allowed(int cpu)
452 {
453 if (is_shub2() && sn_prom_feature_available(PRF_CPU_DISABLE_SUPPORT)) {
454 if (cpu != 0)
455 return true;
456 else
457 printk(KERN_WARNING
458 "Disabling the boot processor is not allowed.\n");
459
460 } else
461 printk(KERN_WARNING
462 "CPU disable is not supported on this system.\n");
463
464 return false;
465 }
466 #endif /* CONFIG_HOTPLUG_CPU */
467
468 #ifdef CONFIG_PROC_FS
469
470 #define PTC_BASENAME "sgi_sn/ptc_statistics"
471
sn2_ptc_seq_start(struct seq_file * file,loff_t * offset)472 static void *sn2_ptc_seq_start(struct seq_file *file, loff_t * offset)
473 {
474 if (*offset < nr_cpu_ids)
475 return offset;
476 return NULL;
477 }
478
sn2_ptc_seq_next(struct seq_file * file,void * data,loff_t * offset)479 static void *sn2_ptc_seq_next(struct seq_file *file, void *data, loff_t * offset)
480 {
481 (*offset)++;
482 if (*offset < nr_cpu_ids)
483 return offset;
484 return NULL;
485 }
486
sn2_ptc_seq_stop(struct seq_file * file,void * data)487 static void sn2_ptc_seq_stop(struct seq_file *file, void *data)
488 {
489 }
490
sn2_ptc_seq_show(struct seq_file * file,void * data)491 static int sn2_ptc_seq_show(struct seq_file *file, void *data)
492 {
493 struct ptc_stats *stat;
494 int cpu;
495
496 cpu = *(loff_t *) data;
497
498 if (!cpu) {
499 seq_printf(file,
500 "# cpu ptc_l newrid ptc_flushes nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max not_my_mm deadlock2 ipi_fluches ipi_nsec\n");
501 seq_printf(file, "# ptctest %d, flushopt %d\n", sn2_ptctest, sn2_flush_opt);
502 }
503
504 if (cpu < nr_cpu_ids && cpu_online(cpu)) {
505 stat = &per_cpu(ptcstats, cpu);
506 seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n", cpu, stat->ptc_l,
507 stat->change_rid, stat->shub_ptc_flushes, stat->nodes_flushed,
508 stat->deadlocks,
509 1000 * stat->lock_itc_clocks / per_cpu(ia64_cpu_info, cpu).cyc_per_usec,
510 1000 * stat->shub_itc_clocks / per_cpu(ia64_cpu_info, cpu).cyc_per_usec,
511 1000 * stat->shub_itc_clocks_max / per_cpu(ia64_cpu_info, cpu).cyc_per_usec,
512 stat->shub_ptc_flushes_not_my_mm,
513 stat->deadlocks2,
514 stat->shub_ipi_flushes,
515 1000 * stat->shub_ipi_flushes_itc_clocks / per_cpu(ia64_cpu_info, cpu).cyc_per_usec);
516 }
517 return 0;
518 }
519
sn2_ptc_proc_write(struct file * file,const char __user * user,size_t count,loff_t * data)520 static ssize_t sn2_ptc_proc_write(struct file *file, const char __user *user, size_t count, loff_t *data)
521 {
522 int cpu;
523 char optstr[64];
524
525 if (count == 0 || count > sizeof(optstr))
526 return -EINVAL;
527 if (copy_from_user(optstr, user, count))
528 return -EFAULT;
529 optstr[count - 1] = '\0';
530 sn2_flush_opt = simple_strtoul(optstr, NULL, 0);
531
532 for_each_online_cpu(cpu)
533 memset(&per_cpu(ptcstats, cpu), 0, sizeof(struct ptc_stats));
534
535 return count;
536 }
537
538 static const struct seq_operations sn2_ptc_seq_ops = {
539 .start = sn2_ptc_seq_start,
540 .next = sn2_ptc_seq_next,
541 .stop = sn2_ptc_seq_stop,
542 .show = sn2_ptc_seq_show
543 };
544
sn2_ptc_proc_open(struct inode * inode,struct file * file)545 static int sn2_ptc_proc_open(struct inode *inode, struct file *file)
546 {
547 return seq_open(file, &sn2_ptc_seq_ops);
548 }
549
550 static const struct file_operations proc_sn2_ptc_operations = {
551 .open = sn2_ptc_proc_open,
552 .read = seq_read,
553 .write = sn2_ptc_proc_write,
554 .llseek = seq_lseek,
555 .release = seq_release,
556 };
557
558 static struct proc_dir_entry *proc_sn2_ptc;
559
sn2_ptc_init(void)560 static int __init sn2_ptc_init(void)
561 {
562 if (!ia64_platform_is("sn2"))
563 return 0;
564
565 proc_sn2_ptc = proc_create(PTC_BASENAME, 0444,
566 NULL, &proc_sn2_ptc_operations);
567 if (!proc_sn2_ptc) {
568 printk(KERN_ERR "unable to create %s proc entry", PTC_BASENAME);
569 return -EINVAL;
570 }
571 spin_lock_init(&sn2_global_ptc_lock);
572 return 0;
573 }
574
sn2_ptc_exit(void)575 static void __exit sn2_ptc_exit(void)
576 {
577 remove_proc_entry(PTC_BASENAME, NULL);
578 }
579
580 module_init(sn2_ptc_init);
581 module_exit(sn2_ptc_exit);
582 #endif /* CONFIG_PROC_FS */
583
584