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TOMOYO Linux Cross Reference
Linux/arch/mips/kernel/smtc.c

Version: ~ [ linux-5.2-rc5 ] ~ [ linux-5.1.12 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.53 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.128 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.182 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.182 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.68 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * This program is free software; you can redistribute it and/or
  3  * modify it under the terms of the GNU General Public License
  4  * as published by the Free Software Foundation; either version 2
  5  * of the License, or (at your option) any later version.
  6  *
  7  * This program is distributed in the hope that it will be useful,
  8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 10  * GNU General Public License for more details.
 11  *
 12  * You should have received a copy of the GNU General Public License
 13  * along with this program; if not, write to the Free Software
 14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 15  *
 16  * Copyright (C) 2004 Mips Technologies, Inc
 17  * Copyright (C) 2008 Kevin D. Kissell
 18  */
 19 
 20 #include <linux/clockchips.h>
 21 #include <linux/kernel.h>
 22 #include <linux/sched.h>
 23 #include <linux/smp.h>
 24 #include <linux/cpumask.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/kernel_stat.h>
 27 #include <linux/module.h>
 28 #include <linux/ftrace.h>
 29 #include <linux/slab.h>
 30 
 31 #include <asm/cpu.h>
 32 #include <asm/processor.h>
 33 #include <linux/atomic.h>
 34 #include <asm/hardirq.h>
 35 #include <asm/hazards.h>
 36 #include <asm/irq.h>
 37 #include <asm/mmu_context.h>
 38 #include <asm/mipsregs.h>
 39 #include <asm/cacheflush.h>
 40 #include <asm/time.h>
 41 #include <asm/addrspace.h>
 42 #include <asm/smtc.h>
 43 #include <asm/smtc_proc.h>
 44 
 45 /*
 46  * SMTC Kernel needs to manipulate low-level CPU interrupt mask
 47  * in do_IRQ. These are passed in setup_irq_smtc() and stored
 48  * in this table.
 49  */
 50 unsigned long irq_hwmask[NR_IRQS];
 51 
 52 #define LOCK_MT_PRA() \
 53         local_irq_save(flags); \
 54         mtflags = dmt()
 55 
 56 #define UNLOCK_MT_PRA() \
 57         emt(mtflags); \
 58         local_irq_restore(flags)
 59 
 60 #define LOCK_CORE_PRA() \
 61         local_irq_save(flags); \
 62         mtflags = dvpe()
 63 
 64 #define UNLOCK_CORE_PRA() \
 65         evpe(mtflags); \
 66         local_irq_restore(flags)
 67 
 68 /*
 69  * Data structures purely associated with SMTC parallelism
 70  */
 71 
 72 
 73 /*
 74  * Table for tracking ASIDs whose lifetime is prolonged.
 75  */
 76 
 77 asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS];
 78 
 79 /*
 80  * Number of InterProcessor Interrupt (IPI) message buffers to allocate
 81  */
 82 
 83 #define IPIBUF_PER_CPU 4
 84 
 85 struct smtc_ipi_q IPIQ[NR_CPUS];
 86 static struct smtc_ipi_q freeIPIq;
 87 
 88 
 89 /*
 90  * Number of FPU contexts for each VPE
 91  */
 92 
 93 static int smtc_nconf1[MAX_SMTC_VPES];
 94 
 95 
 96 /* Forward declarations */
 97 
 98 void ipi_decode(struct smtc_ipi *);
 99 static void post_direct_ipi(int cpu, struct smtc_ipi *pipi);
100 static void setup_cross_vpe_interrupts(unsigned int nvpe);
101 void init_smtc_stats(void);
102 
103 /* Global SMTC Status */
104 
105 unsigned int smtc_status;
106 
107 /* Boot command line configuration overrides */
108 
109 static int vpe0limit;
110 static int ipibuffers;
111 static int nostlb;
112 static int asidmask;
113 unsigned long smtc_asid_mask = 0xff;
114 
115 static int __init vpe0tcs(char *str)
116 {
117         get_option(&str, &vpe0limit);
118 
119         return 1;
120 }
121 
122 static int __init ipibufs(char *str)
123 {
124         get_option(&str, &ipibuffers);
125         return 1;
126 }
127 
128 static int __init stlb_disable(char *s)
129 {
130         nostlb = 1;
131         return 1;
132 }
133 
134 static int __init asidmask_set(char *str)
135 {
136         get_option(&str, &asidmask);
137         switch (asidmask) {
138         case 0x1:
139         case 0x3:
140         case 0x7:
141         case 0xf:
142         case 0x1f:
143         case 0x3f:
144         case 0x7f:
145         case 0xff:
146                 smtc_asid_mask = (unsigned long)asidmask;
147                 break;
148         default:
149                 printk("ILLEGAL ASID mask 0x%x from command line\n", asidmask);
150         }
151         return 1;
152 }
153 
154 __setup("vpe0tcs=", vpe0tcs);
155 __setup("ipibufs=", ipibufs);
156 __setup("nostlb", stlb_disable);
157 __setup("asidmask=", asidmask_set);
158 
159 #ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
160 
161 static int hang_trig;
162 
163 static int __init hangtrig_enable(char *s)
164 {
165         hang_trig = 1;
166         return 1;
167 }
168 
169 
170 __setup("hangtrig", hangtrig_enable);
171 
172 #define DEFAULT_BLOCKED_IPI_LIMIT 32
173 
174 static int timerq_limit = DEFAULT_BLOCKED_IPI_LIMIT;
175 
176 static int __init tintq(char *str)
177 {
178         get_option(&str, &timerq_limit);
179         return 1;
180 }
181 
182 __setup("tintq=", tintq);
183 
184 static int imstuckcount[MAX_SMTC_VPES][8];
185 /* vpemask represents IM/IE bits of per-VPE Status registers, low-to-high */
186 static int vpemask[MAX_SMTC_VPES][8] = {
187         {0, 0, 1, 0, 0, 0, 0, 1},
188         {0, 0, 0, 0, 0, 0, 0, 1}
189 };
190 int tcnoprog[NR_CPUS];
191 static atomic_t idle_hook_initialized = ATOMIC_INIT(0);
192 static int clock_hang_reported[NR_CPUS];
193 
194 #endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */
195 
196 /*
197  * Configure shared TLB - VPC configuration bit must be set by caller
198  */
199 
200 static void smtc_configure_tlb(void)
201 {
202         int i, tlbsiz, vpes;
203         unsigned long mvpconf0;
204         unsigned long config1val;
205 
206         /* Set up ASID preservation table */
207         for (vpes=0; vpes<MAX_SMTC_TLBS; vpes++) {
208             for(i = 0; i < MAX_SMTC_ASIDS; i++) {
209                 smtc_live_asid[vpes][i] = 0;
210             }
211         }
212         mvpconf0 = read_c0_mvpconf0();
213 
214         if ((vpes = ((mvpconf0 & MVPCONF0_PVPE)
215                         >> MVPCONF0_PVPE_SHIFT) + 1) > 1) {
216             /* If we have multiple VPEs, try to share the TLB */
217             if ((mvpconf0 & MVPCONF0_TLBS) && !nostlb) {
218                 /*
219                  * If TLB sizing is programmable, shared TLB
220                  * size is the total available complement.
221                  * Otherwise, we have to take the sum of all
222                  * static VPE TLB entries.
223                  */
224                 if ((tlbsiz = ((mvpconf0 & MVPCONF0_PTLBE)
225                                 >> MVPCONF0_PTLBE_SHIFT)) == 0) {
226                     /*
227                      * If there's more than one VPE, there had better
228                      * be more than one TC, because we need one to bind
229                      * to each VPE in turn to be able to read
230                      * its configuration state!
231                      */
232                     settc(1);
233                     /* Stop the TC from doing anything foolish */
234                     write_tc_c0_tchalt(TCHALT_H);
235                     mips_ihb();
236                     /* No need to un-Halt - that happens later anyway */
237                     for (i=0; i < vpes; i++) {
238                         write_tc_c0_tcbind(i);
239                         /*
240                          * To be 100% sure we're really getting the right
241                          * information, we exit the configuration state
242                          * and do an IHB after each rebinding.
243                          */
244                         write_c0_mvpcontrol(
245                                 read_c0_mvpcontrol() & ~ MVPCONTROL_VPC );
246                         mips_ihb();
247                         /*
248                          * Only count if the MMU Type indicated is TLB
249                          */
250                         if (((read_vpe_c0_config() & MIPS_CONF_MT) >> 7) == 1) {
251                                 config1val = read_vpe_c0_config1();
252                                 tlbsiz += ((config1val >> 25) & 0x3f) + 1;
253                         }
254 
255                         /* Put core back in configuration state */
256                         write_c0_mvpcontrol(
257                                 read_c0_mvpcontrol() | MVPCONTROL_VPC );
258                         mips_ihb();
259                     }
260                 }
261                 write_c0_mvpcontrol(read_c0_mvpcontrol() | MVPCONTROL_STLB);
262                 ehb();
263 
264                 /*
265                  * Setup kernel data structures to use software total,
266                  * rather than read the per-VPE Config1 value. The values
267                  * for "CPU 0" gets copied to all the other CPUs as part
268                  * of their initialization in smtc_cpu_setup().
269                  */
270 
271                 /* MIPS32 limits TLB indices to 64 */
272                 if (tlbsiz > 64)
273                         tlbsiz = 64;
274                 cpu_data[0].tlbsize = current_cpu_data.tlbsize = tlbsiz;
275                 smtc_status |= SMTC_TLB_SHARED;
276                 local_flush_tlb_all();
277 
278                 printk("TLB of %d entry pairs shared by %d VPEs\n",
279                         tlbsiz, vpes);
280             } else {
281                 printk("WARNING: TLB Not Sharable on SMTC Boot!\n");
282             }
283         }
284 }
285 
286 
287 /*
288  * Incrementally build the CPU map out of constituent MIPS MT cores,
289  * using the specified available VPEs and TCs.  Plaform code needs
290  * to ensure that each MIPS MT core invokes this routine on reset,
291  * one at a time(!).
292  *
293  * This version of the build_cpu_map and prepare_cpus routines assumes
294  * that *all* TCs of a MIPS MT core will be used for Linux, and that
295  * they will be spread across *all* available VPEs (to minimise the
296  * loss of efficiency due to exception service serialization).
297  * An improved version would pick up configuration information and
298  * possibly leave some TCs/VPEs as "slave" processors.
299  *
300  * Use c0_MVPConf0 to find out how many TCs are available, setting up
301  * cpu_possible_mask and the logical/physical mappings.
302  */
303 
304 int __init smtc_build_cpu_map(int start_cpu_slot)
305 {
306         int i, ntcs;
307 
308         /*
309          * The CPU map isn't actually used for anything at this point,
310          * so it's not clear what else we should do apart from set
311          * everything up so that "logical" = "physical".
312          */
313         ntcs = ((read_c0_mvpconf0() & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1;
314         for (i=start_cpu_slot; i<NR_CPUS && i<ntcs; i++) {
315                 set_cpu_possible(i, true);
316                 __cpu_number_map[i] = i;
317                 __cpu_logical_map[i] = i;
318         }
319 #ifdef CONFIG_MIPS_MT_FPAFF
320         /* Initialize map of CPUs with FPUs */
321         cpus_clear(mt_fpu_cpumask);
322 #endif
323 
324         /* One of those TC's is the one booting, and not a secondary... */
325         printk("%i available secondary CPU TC(s)\n", i - 1);
326 
327         return i;
328 }
329 
330 /*
331  * Common setup before any secondaries are started
332  * Make sure all CPUs are in a sensible state before we boot any of the
333  * secondaries.
334  *
335  * For MIPS MT "SMTC" operation, we set up all TCs, spread as evenly
336  * as possible across the available VPEs.
337  */
338 
339 static void smtc_tc_setup(int vpe, int tc, int cpu)
340 {
341         static int cp1contexts[MAX_SMTC_VPES];
342 
343         /*
344          * Make a local copy of the available FPU contexts in order
345          * to keep track of TCs that can have one.
346          */
347         if (tc == 1)
348         {
349                 /*
350                  * FIXME: Multi-core SMTC hasn't been tested and the
351                  *        maximum number of VPEs may change.
352                  */
353                 cp1contexts[0] = smtc_nconf1[0] - 1;
354                 cp1contexts[1] = smtc_nconf1[1];
355         }
356 
357         settc(tc);
358         write_tc_c0_tchalt(TCHALT_H);
359         mips_ihb();
360         write_tc_c0_tcstatus((read_tc_c0_tcstatus()
361                         & ~(TCSTATUS_TKSU | TCSTATUS_DA | TCSTATUS_IXMT))
362                         | TCSTATUS_A);
363         /*
364          * TCContext gets an offset from the base of the IPIQ array
365          * to be used in low-level code to detect the presence of
366          * an active IPI queue.
367          */
368         write_tc_c0_tccontext((sizeof(struct smtc_ipi_q) * cpu) << 16);
369 
370         /* Bind TC to VPE. */
371         write_tc_c0_tcbind(vpe);
372 
373         /* In general, all TCs should have the same cpu_data indications. */
374         memcpy(&cpu_data[cpu], &cpu_data[0], sizeof(struct cpuinfo_mips));
375 
376         /* Check to see if there is a FPU context available for this TC. */
377         if (!cp1contexts[vpe])
378                 cpu_data[cpu].options &= ~MIPS_CPU_FPU;
379         else
380                 cp1contexts[vpe]--;
381 
382         /* Store the TC and VPE into the cpu_data structure. */
383         cpu_data[cpu].vpe_id = vpe;
384         cpu_data[cpu].tc_id = tc;
385 
386         /* FIXME: Multi-core SMTC hasn't been tested, but be prepared. */
387         cpu_data[cpu].core = (read_vpe_c0_ebase() >> 1) & 0xff;
388 }
389 
390 /*
391  * Tweak to get Count registers synced as closely as possible. The
392  * value seems good for 34K-class cores.
393  */
394 
395 #define CP0_SKEW 8
396 
397 void smtc_prepare_cpus(int cpus)
398 {
399         int i, vpe, tc, ntc, nvpe, tcpervpe[NR_CPUS], slop, cpu;
400         unsigned long flags;
401         unsigned long val;
402         int nipi;
403         struct smtc_ipi *pipi;
404 
405         /* disable interrupts so we can disable MT */
406         local_irq_save(flags);
407         /* disable MT so we can configure */
408         dvpe();
409         dmt();
410 
411         spin_lock_init(&freeIPIq.lock);
412 
413         /*
414          * We probably don't have as many VPEs as we do SMP "CPUs",
415          * but it's possible - and in any case we'll never use more!
416          */
417         for (i=0; i<NR_CPUS; i++) {
418                 IPIQ[i].head = IPIQ[i].tail = NULL;
419                 spin_lock_init(&IPIQ[i].lock);
420                 IPIQ[i].depth = 0;
421                 IPIQ[i].resched_flag = 0; /* No reschedules queued initially */
422         }
423 
424         /* cpu_data index starts at zero */
425         cpu = 0;
426         cpu_data[cpu].vpe_id = 0;
427         cpu_data[cpu].tc_id = 0;
428         cpu_data[cpu].core = (read_c0_ebase() >> 1) & 0xff;
429         cpu++;
430 
431         /* Report on boot-time options */
432         mips_mt_set_cpuoptions();
433         if (vpelimit > 0)
434                 printk("Limit of %d VPEs set\n", vpelimit);
435         if (tclimit > 0)
436                 printk("Limit of %d TCs set\n", tclimit);
437         if (nostlb) {
438                 printk("Shared TLB Use Inhibited - UNSAFE for Multi-VPE Operation\n");
439         }
440         if (asidmask)
441                 printk("ASID mask value override to 0x%x\n", asidmask);
442 
443         /* Temporary */
444 #ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
445         if (hang_trig)
446                 printk("Logic Analyser Trigger on suspected TC hang\n");
447 #endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */
448 
449         /* Put MVPE's into 'configuration state' */
450         write_c0_mvpcontrol( read_c0_mvpcontrol() | MVPCONTROL_VPC );
451 
452         val = read_c0_mvpconf0();
453         nvpe = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
454         if (vpelimit > 0 && nvpe > vpelimit)
455                 nvpe = vpelimit;
456         ntc = ((val & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1;
457         if (ntc > NR_CPUS)
458                 ntc = NR_CPUS;
459         if (tclimit > 0 && ntc > tclimit)
460                 ntc = tclimit;
461         slop = ntc % nvpe;
462         for (i = 0; i < nvpe; i++) {
463                 tcpervpe[i] = ntc / nvpe;
464                 if (slop) {
465                         if((slop - i) > 0) tcpervpe[i]++;
466                 }
467         }
468         /* Handle command line override for VPE0 */
469         if (vpe0limit > ntc) vpe0limit = ntc;
470         if (vpe0limit > 0) {
471                 int slopslop;
472                 if (vpe0limit < tcpervpe[0]) {
473                     /* Reducing TC count - distribute to others */
474                     slop = tcpervpe[0] - vpe0limit;
475                     slopslop = slop % (nvpe - 1);
476                     tcpervpe[0] = vpe0limit;
477                     for (i = 1; i < nvpe; i++) {
478                         tcpervpe[i] += slop / (nvpe - 1);
479                         if(slopslop && ((slopslop - (i - 1) > 0)))
480                                 tcpervpe[i]++;
481                     }
482                 } else if (vpe0limit > tcpervpe[0]) {
483                     /* Increasing TC count - steal from others */
484                     slop = vpe0limit - tcpervpe[0];
485                     slopslop = slop % (nvpe - 1);
486                     tcpervpe[0] = vpe0limit;
487                     for (i = 1; i < nvpe; i++) {
488                         tcpervpe[i] -= slop / (nvpe - 1);
489                         if(slopslop && ((slopslop - (i - 1) > 0)))
490                                 tcpervpe[i]--;
491                     }
492                 }
493         }
494 
495         /* Set up shared TLB */
496         smtc_configure_tlb();
497 
498         for (tc = 0, vpe = 0 ; (vpe < nvpe) && (tc < ntc) ; vpe++) {
499                 /* Get number of CP1 contexts for each VPE. */
500                 if (tc == 0)
501                 {
502                         /*
503                          * Do not call settc() for TC0 or the FPU context
504                          * value will be incorrect. Besides, we know that
505                          * we are TC0 anyway.
506                          */
507                         smtc_nconf1[0] = ((read_vpe_c0_vpeconf1() &
508                                 VPECONF1_NCP1) >> VPECONF1_NCP1_SHIFT);
509                         if (nvpe == 2)
510                         {
511                                 settc(1);
512                                 smtc_nconf1[1] = ((read_vpe_c0_vpeconf1() &
513                                         VPECONF1_NCP1) >> VPECONF1_NCP1_SHIFT);
514                                 settc(0);
515                         }
516                 }
517                 if (tcpervpe[vpe] == 0)
518                         continue;
519                 if (vpe != 0)
520                         printk(", ");
521                 printk("VPE %d: TC", vpe);
522                 for (i = 0; i < tcpervpe[vpe]; i++) {
523                         /*
524                          * TC 0 is bound to VPE 0 at reset,
525                          * and is presumably executing this
526                          * code.  Leave it alone!
527                          */
528                         if (tc != 0) {
529                                 smtc_tc_setup(vpe, tc, cpu);
530                                 if (vpe != 0) {
531                                         /*
532                                          * Set MVP bit (possibly again).  Do it
533                                          * here to catch CPUs that have no TCs
534                                          * bound to the VPE at reset.  In that
535                                          * case, a TC must be bound to the VPE
536                                          * before we can set VPEControl[MVP]
537                                          */
538                                         write_vpe_c0_vpeconf0(
539                                                 read_vpe_c0_vpeconf0() |
540                                                 VPECONF0_MVP);
541                                 }
542                                 cpu++;
543                         }
544                         printk(" %d", tc);
545                         tc++;
546                 }
547                 if (vpe != 0) {
548                         /*
549                          * Allow this VPE to control others.
550                          */
551                         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() |
552                                               VPECONF0_MVP);
553 
554                         /*
555                          * Clear any stale software interrupts from VPE's Cause
556                          */
557                         write_vpe_c0_cause(0);
558 
559                         /*
560                          * Clear ERL/EXL of VPEs other than 0
561                          * and set restricted interrupt enable/mask.
562                          */
563                         write_vpe_c0_status((read_vpe_c0_status()
564                                 & ~(ST0_BEV | ST0_ERL | ST0_EXL | ST0_IM))
565                                 | (STATUSF_IP0 | STATUSF_IP1 | STATUSF_IP7
566                                 | ST0_IE));
567                         /*
568                          * set config to be the same as vpe0,
569                          *  particularly kseg0 coherency alg
570                          */
571                         write_vpe_c0_config(read_c0_config());
572                         /* Clear any pending timer interrupt */
573                         write_vpe_c0_compare(0);
574                         /* Propagate Config7 */
575                         write_vpe_c0_config7(read_c0_config7());
576                         write_vpe_c0_count(read_c0_count() + CP0_SKEW);
577                         ehb();
578                 }
579                 /* enable multi-threading within VPE */
580                 write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() | VPECONTROL_TE);
581                 /* enable the VPE */
582                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
583         }
584 
585         /*
586          * Pull any physically present but unused TCs out of circulation.
587          */
588         while (tc < (((val & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1)) {
589                 set_cpu_possible(tc, false);
590                 set_cpu_present(tc, false);
591                 tc++;
592         }
593 
594         /* release config state */
595         write_c0_mvpcontrol( read_c0_mvpcontrol() & ~ MVPCONTROL_VPC );
596 
597         printk("\n");
598 
599         /* Set up coprocessor affinity CPU mask(s) */
600 
601 #ifdef CONFIG_MIPS_MT_FPAFF
602         for (tc = 0; tc < ntc; tc++) {
603                 if (cpu_data[tc].options & MIPS_CPU_FPU)
604                         cpu_set(tc, mt_fpu_cpumask);
605         }
606 #endif
607 
608         /* set up ipi interrupts... */
609 
610         /* If we have multiple VPEs running, set up the cross-VPE interrupt */
611 
612         setup_cross_vpe_interrupts(nvpe);
613 
614         /* Set up queue of free IPI "messages". */
615         nipi = NR_CPUS * IPIBUF_PER_CPU;
616         if (ipibuffers > 0)
617                 nipi = ipibuffers;
618 
619         pipi = kmalloc(nipi *sizeof(struct smtc_ipi), GFP_KERNEL);
620         if (pipi == NULL)
621                 panic("kmalloc of IPI message buffers failed");
622         else
623                 printk("IPI buffer pool of %d buffers\n", nipi);
624         for (i = 0; i < nipi; i++) {
625                 smtc_ipi_nq(&freeIPIq, pipi);
626                 pipi++;
627         }
628 
629         /* Arm multithreading and enable other VPEs - but all TCs are Halted */
630         emt(EMT_ENABLE);
631         evpe(EVPE_ENABLE);
632         local_irq_restore(flags);
633         /* Initialize SMTC /proc statistics/diagnostics */
634         init_smtc_stats();
635 }
636 
637 
638 /*
639  * Setup the PC, SP, and GP of a secondary processor and start it
640  * running!
641  * smp_bootstrap is the place to resume from
642  * __KSTK_TOS(idle) is apparently the stack pointer
643  * (unsigned long)idle->thread_info the gp
644  *
645  */
646 void __cpuinit smtc_boot_secondary(int cpu, struct task_struct *idle)
647 {
648         extern u32 kernelsp[NR_CPUS];
649         unsigned long flags;
650         int mtflags;
651 
652         LOCK_MT_PRA();
653         if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) {
654                 dvpe();
655         }
656         settc(cpu_data[cpu].tc_id);
657 
658         /* pc */
659         write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
660 
661         /* stack pointer */
662         kernelsp[cpu] = __KSTK_TOS(idle);
663         write_tc_gpr_sp(__KSTK_TOS(idle));
664 
665         /* global pointer */
666         write_tc_gpr_gp((unsigned long)task_thread_info(idle));
667 
668         smtc_status |= SMTC_MTC_ACTIVE;
669         write_tc_c0_tchalt(0);
670         if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) {
671                 evpe(EVPE_ENABLE);
672         }
673         UNLOCK_MT_PRA();
674 }
675 
676 void smtc_init_secondary(void)
677 {
678 }
679 
680 void smtc_smp_finish(void)
681 {
682         int cpu = smp_processor_id();
683 
684         /*
685          * Lowest-numbered CPU per VPE starts a clock tick.
686          * Like per_cpu_trap_init() hack, this assumes that
687          * SMTC init code assigns TCs consdecutively and
688          * in ascending order across available VPEs.
689          */
690         if (cpu > 0 && (cpu_data[cpu].vpe_id != cpu_data[cpu - 1].vpe_id))
691                 write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ);
692 
693         local_irq_enable();
694 
695         printk("TC %d going on-line as CPU %d\n",
696                 cpu_data[smp_processor_id()].tc_id, smp_processor_id());
697 }
698 
699 void smtc_cpus_done(void)
700 {
701 }
702 
703 /*
704  * Support for SMTC-optimized driver IRQ registration
705  */
706 
707 /*
708  * SMTC Kernel needs to manipulate low-level CPU interrupt mask
709  * in do_IRQ. These are passed in setup_irq_smtc() and stored
710  * in this table.
711  */
712 
713 int setup_irq_smtc(unsigned int irq, struct irqaction * new,
714                         unsigned long hwmask)
715 {
716 #ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
717         unsigned int vpe = current_cpu_data.vpe_id;
718 
719         vpemask[vpe][irq - MIPS_CPU_IRQ_BASE] = 1;
720 #endif
721         irq_hwmask[irq] = hwmask;
722 
723         return setup_irq(irq, new);
724 }
725 
726 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
727 /*
728  * Support for IRQ affinity to TCs
729  */
730 
731 void smtc_set_irq_affinity(unsigned int irq, cpumask_t affinity)
732 {
733         /*
734          * If a "fast path" cache of quickly decodable affinity state
735          * is maintained, this is where it gets done, on a call up
736          * from the platform affinity code.
737          */
738 }
739 
740 void smtc_forward_irq(struct irq_data *d)
741 {
742         unsigned int irq = d->irq;
743         int target;
744 
745         /*
746          * OK wise guy, now figure out how to get the IRQ
747          * to be serviced on an authorized "CPU".
748          *
749          * Ideally, to handle the situation where an IRQ has multiple
750          * eligible CPUS, we would maintain state per IRQ that would
751          * allow a fair distribution of service requests.  Since the
752          * expected use model is any-or-only-one, for simplicity
753          * and efficiency, we just pick the easiest one to find.
754          */
755 
756         target = cpumask_first(d->affinity);
757 
758         /*
759          * We depend on the platform code to have correctly processed
760          * IRQ affinity change requests to ensure that the IRQ affinity
761          * mask has been purged of bits corresponding to nonexistent and
762          * offline "CPUs", and to TCs bound to VPEs other than the VPE
763          * connected to the physical interrupt input for the interrupt
764          * in question.  Otherwise we have a nasty problem with interrupt
765          * mask management.  This is best handled in non-performance-critical
766          * platform IRQ affinity setting code,  to minimize interrupt-time
767          * checks.
768          */
769 
770         /* If no one is eligible, service locally */
771         if (target >= NR_CPUS)
772                 do_IRQ_no_affinity(irq);
773         else
774                 smtc_send_ipi(target, IRQ_AFFINITY_IPI, irq);
775 }
776 
777 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */
778 
779 /*
780  * IPI model for SMTC is tricky, because interrupts aren't TC-specific.
781  * Within a VPE one TC can interrupt another by different approaches.
782  * The easiest to get right would probably be to make all TCs except
783  * the target IXMT and set a software interrupt, but an IXMT-based
784  * scheme requires that a handler must run before a new IPI could
785  * be sent, which would break the "broadcast" loops in MIPS MT.
786  * A more gonzo approach within a VPE is to halt the TC, extract
787  * its Restart, Status, and a couple of GPRs, and program the Restart
788  * address to emulate an interrupt.
789  *
790  * Within a VPE, one can be confident that the target TC isn't in
791  * a critical EXL state when halted, since the write to the Halt
792  * register could not have issued on the writing thread if the
793  * halting thread had EXL set. So k0 and k1 of the target TC
794  * can be used by the injection code.  Across VPEs, one can't
795  * be certain that the target TC isn't in a critical exception
796  * state. So we try a two-step process of sending a software
797  * interrupt to the target VPE, which either handles the event
798  * itself (if it was the target) or injects the event within
799  * the VPE.
800  */
801 
802 static void smtc_ipi_qdump(void)
803 {
804         int i;
805         struct smtc_ipi *temp;
806 
807         for (i = 0; i < NR_CPUS ;i++) {
808                 pr_info("IPIQ[%d]: head = 0x%x, tail = 0x%x, depth = %d\n",
809                         i, (unsigned)IPIQ[i].head, (unsigned)IPIQ[i].tail,
810                         IPIQ[i].depth);
811                 temp = IPIQ[i].head;
812 
813                 while (temp != IPIQ[i].tail) {
814                         pr_debug("%d %d %d: ", temp->type, temp->dest,
815                                (int)temp->arg);
816 #ifdef  SMTC_IPI_DEBUG
817                     pr_debug("%u %lu\n", temp->sender, temp->stamp);
818 #else
819                     pr_debug("\n");
820 #endif
821                     temp = temp->flink;
822                 }
823         }
824 }
825 
826 /*
827  * The standard atomic.h primitives don't quite do what we want
828  * here: We need an atomic add-and-return-previous-value (which
829  * could be done with atomic_add_return and a decrement) and an
830  * atomic set/zero-and-return-previous-value (which can't really
831  * be done with the atomic.h primitives). And since this is
832  * MIPS MT, we can assume that we have LL/SC.
833  */
834 static inline int atomic_postincrement(atomic_t *v)
835 {
836         unsigned long result;
837 
838         unsigned long temp;
839 
840         __asm__ __volatile__(
841         "1:     ll      %0, %2                                  \n"
842         "       addu    %1, %0, 1                               \n"
843         "       sc      %1, %2                                  \n"
844         "       beqz    %1, 1b                                  \n"
845         __WEAK_LLSC_MB
846         : "=&r" (result), "=&r" (temp), "=m" (v->counter)
847         : "m" (v->counter)
848         : "memory");
849 
850         return result;
851 }
852 
853 void smtc_send_ipi(int cpu, int type, unsigned int action)
854 {
855         int tcstatus;
856         struct smtc_ipi *pipi;
857         unsigned long flags;
858         int mtflags;
859         unsigned long tcrestart;
860         extern void r4k_wait_irqoff(void), __pastwait(void);
861         int set_resched_flag = (type == LINUX_SMP_IPI &&
862                                 action == SMP_RESCHEDULE_YOURSELF);
863 
864         if (cpu == smp_processor_id()) {
865                 printk("Cannot Send IPI to self!\n");
866                 return;
867         }
868         if (set_resched_flag && IPIQ[cpu].resched_flag != 0)
869                 return; /* There is a reschedule queued already */
870 
871         /* Set up a descriptor, to be delivered either promptly or queued */
872         pipi = smtc_ipi_dq(&freeIPIq);
873         if (pipi == NULL) {
874                 bust_spinlocks(1);
875                 mips_mt_regdump(dvpe());
876                 panic("IPI Msg. Buffers Depleted");
877         }
878         pipi->type = type;
879         pipi->arg = (void *)action;
880         pipi->dest = cpu;
881         if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) {
882                 /* If not on same VPE, enqueue and send cross-VPE interrupt */
883                 IPIQ[cpu].resched_flag |= set_resched_flag;
884                 smtc_ipi_nq(&IPIQ[cpu], pipi);
885                 LOCK_CORE_PRA();
886                 settc(cpu_data[cpu].tc_id);
887                 write_vpe_c0_cause(read_vpe_c0_cause() | C_SW1);
888                 UNLOCK_CORE_PRA();
889         } else {
890                 /*
891                  * Not sufficient to do a LOCK_MT_PRA (dmt) here,
892                  * since ASID shootdown on the other VPE may
893                  * collide with this operation.
894                  */
895                 LOCK_CORE_PRA();
896                 settc(cpu_data[cpu].tc_id);
897                 /* Halt the targeted TC */
898                 write_tc_c0_tchalt(TCHALT_H);
899                 mips_ihb();
900 
901                 /*
902                  * Inspect TCStatus - if IXMT is set, we have to queue
903                  * a message. Otherwise, we set up the "interrupt"
904                  * of the other TC
905                  */
906                 tcstatus = read_tc_c0_tcstatus();
907 
908                 if ((tcstatus & TCSTATUS_IXMT) != 0) {
909                         /*
910                          * If we're in the the irq-off version of the wait
911                          * loop, we need to force exit from the wait and
912                          * do a direct post of the IPI.
913                          */
914                         if (cpu_wait == r4k_wait_irqoff) {
915                                 tcrestart = read_tc_c0_tcrestart();
916                                 if (tcrestart >= (unsigned long)r4k_wait_irqoff
917                                     && tcrestart < (unsigned long)__pastwait) {
918                                         write_tc_c0_tcrestart(__pastwait);
919                                         tcstatus &= ~TCSTATUS_IXMT;
920                                         write_tc_c0_tcstatus(tcstatus);
921                                         goto postdirect;
922                                 }
923                         }
924                         /*
925                          * Otherwise we queue the message for the target TC
926                          * to pick up when he does a local_irq_restore()
927                          */
928                         write_tc_c0_tchalt(0);
929                         UNLOCK_CORE_PRA();
930                         IPIQ[cpu].resched_flag |= set_resched_flag;
931                         smtc_ipi_nq(&IPIQ[cpu], pipi);
932                 } else {
933 postdirect:
934                         post_direct_ipi(cpu, pipi);
935                         write_tc_c0_tchalt(0);
936                         UNLOCK_CORE_PRA();
937                 }
938         }
939 }
940 
941 /*
942  * Send IPI message to Halted TC, TargTC/TargVPE already having been set
943  */
944 static void post_direct_ipi(int cpu, struct smtc_ipi *pipi)
945 {
946         struct pt_regs *kstack;
947         unsigned long tcstatus;
948         unsigned long tcrestart;
949         extern u32 kernelsp[NR_CPUS];
950         extern void __smtc_ipi_vector(void);
951 //printk("%s: on %d for %d\n", __func__, smp_processor_id(), cpu);
952 
953         /* Extract Status, EPC from halted TC */
954         tcstatus = read_tc_c0_tcstatus();
955         tcrestart = read_tc_c0_tcrestart();
956         /* If TCRestart indicates a WAIT instruction, advance the PC */
957         if ((tcrestart & 0x80000000)
958             && ((*(unsigned int *)tcrestart & 0xfe00003f) == 0x42000020)) {
959                 tcrestart += 4;
960         }
961         /*
962          * Save on TC's future kernel stack
963          *
964          * CU bit of Status is indicator that TC was
965          * already running on a kernel stack...
966          */
967         if (tcstatus & ST0_CU0)  {
968                 /* Note that this "- 1" is pointer arithmetic */
969                 kstack = ((struct pt_regs *)read_tc_gpr_sp()) - 1;
970         } else {
971                 kstack = ((struct pt_regs *)kernelsp[cpu]) - 1;
972         }
973 
974         kstack->cp0_epc = (long)tcrestart;
975         /* Save TCStatus */
976         kstack->cp0_tcstatus = tcstatus;
977         /* Pass token of operation to be performed kernel stack pad area */
978         kstack->pad0[4] = (unsigned long)pipi;
979         /* Pass address of function to be called likewise */
980         kstack->pad0[5] = (unsigned long)&ipi_decode;
981         /* Set interrupt exempt and kernel mode */
982         tcstatus |= TCSTATUS_IXMT;
983         tcstatus &= ~TCSTATUS_TKSU;
984         write_tc_c0_tcstatus(tcstatus);
985         ehb();
986         /* Set TC Restart address to be SMTC IPI vector */
987         write_tc_c0_tcrestart(__smtc_ipi_vector);
988 }
989 
990 static void ipi_resched_interrupt(void)
991 {
992         scheduler_ipi();
993 }
994 
995 static void ipi_call_interrupt(void)
996 {
997         /* Invoke generic function invocation code in smp.c */
998         smp_call_function_interrupt();
999 }
1000 
1001 DECLARE_PER_CPU(struct clock_event_device, mips_clockevent_device);
1002 
1003 static void __irq_entry smtc_clock_tick_interrupt(void)
1004 {
1005         unsigned int cpu = smp_processor_id();
1006         struct clock_event_device *cd;
1007         int irq = MIPS_CPU_IRQ_BASE + 1;
1008 
1009         irq_enter();
1010         kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
1011         cd = &per_cpu(mips_clockevent_device, cpu);
1012         cd->event_handler(cd);
1013         irq_exit();
1014 }
1015 
1016 void ipi_decode(struct smtc_ipi *pipi)
1017 {
1018         void *arg_copy = pipi->arg;
1019         int type_copy = pipi->type;
1020 
1021         smtc_ipi_nq(&freeIPIq, pipi);
1022 
1023         switch (type_copy) {
1024         case SMTC_CLOCK_TICK:
1025                 smtc_clock_tick_interrupt();
1026                 break;
1027 
1028         case LINUX_SMP_IPI:
1029                 switch ((int)arg_copy) {
1030                 case SMP_RESCHEDULE_YOURSELF:
1031                         ipi_resched_interrupt();
1032                         break;
1033                 case SMP_CALL_FUNCTION:
1034                         ipi_call_interrupt();
1035                         break;
1036                 default:
1037                         printk("Impossible SMTC IPI Argument %p\n", arg_copy);
1038                         break;
1039                 }
1040                 break;
1041 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
1042         case IRQ_AFFINITY_IPI:
1043                 /*
1044                  * Accept a "forwarded" interrupt that was initially
1045                  * taken by a TC who doesn't have affinity for the IRQ.
1046                  */
1047                 do_IRQ_no_affinity((int)arg_copy);
1048                 break;
1049 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */
1050         default:
1051                 printk("Impossible SMTC IPI Type 0x%x\n", type_copy);
1052                 break;
1053         }
1054 }
1055 
1056 /*
1057  * Similar to smtc_ipi_replay(), but invoked from context restore,
1058  * so it reuses the current exception frame rather than set up a
1059  * new one with self_ipi.
1060  */
1061 
1062 void deferred_smtc_ipi(void)
1063 {
1064         int cpu = smp_processor_id();
1065 
1066         /*
1067          * Test is not atomic, but much faster than a dequeue,
1068          * and the vast majority of invocations will have a null queue.
1069          * If irq_disabled when this was called, then any IPIs queued
1070          * after we test last will be taken on the next irq_enable/restore.
1071          * If interrupts were enabled, then any IPIs added after the
1072          * last test will be taken directly.
1073          */
1074 
1075         while (IPIQ[cpu].head != NULL) {
1076                 struct smtc_ipi_q *q = &IPIQ[cpu];
1077                 struct smtc_ipi *pipi;
1078                 unsigned long flags;
1079 
1080                 /*
1081                  * It may be possible we'll come in with interrupts
1082                  * already enabled.
1083                  */
1084                 local_irq_save(flags);
1085                 spin_lock(&q->lock);
1086                 pipi = __smtc_ipi_dq(q);
1087                 spin_unlock(&q->lock);
1088                 if (pipi != NULL) {
1089                         if (pipi->type == LINUX_SMP_IPI &&
1090                             (int)pipi->arg == SMP_RESCHEDULE_YOURSELF)
1091                                 IPIQ[cpu].resched_flag = 0;
1092                         ipi_decode(pipi);
1093                 }
1094                 /*
1095                  * The use of the __raw_local restore isn't
1096                  * as obviously necessary here as in smtc_ipi_replay(),
1097                  * but it's more efficient, given that we're already
1098                  * running down the IPI queue.
1099                  */
1100                 __arch_local_irq_restore(flags);
1101         }
1102 }
1103 
1104 /*
1105  * Cross-VPE interrupts in the SMTC prototype use "software interrupts"
1106  * set via cross-VPE MTTR manipulation of the Cause register. It would be
1107  * in some regards preferable to have external logic for "doorbell" hardware
1108  * interrupts.
1109  */
1110 
1111 static int cpu_ipi_irq = MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_IRQ;
1112 
1113 static irqreturn_t ipi_interrupt(int irq, void *dev_idm)
1114 {
1115         int my_vpe = cpu_data[smp_processor_id()].vpe_id;
1116         int my_tc = cpu_data[smp_processor_id()].tc_id;
1117         int cpu;
1118         struct smtc_ipi *pipi;
1119         unsigned long tcstatus;
1120         int sent;
1121         unsigned long flags;
1122         unsigned int mtflags;
1123         unsigned int vpflags;
1124 
1125         /*
1126          * So long as cross-VPE interrupts are done via
1127          * MFTR/MTTR read-modify-writes of Cause, we need
1128          * to stop other VPEs whenever the local VPE does
1129          * anything similar.
1130          */
1131         local_irq_save(flags);
1132         vpflags = dvpe();
1133         clear_c0_cause(0x100 << MIPS_CPU_IPI_IRQ);
1134         set_c0_status(0x100 << MIPS_CPU_IPI_IRQ);
1135         irq_enable_hazard();
1136         evpe(vpflags);
1137         local_irq_restore(flags);
1138 
1139         /*
1140          * Cross-VPE Interrupt handler: Try to directly deliver IPIs
1141          * queued for TCs on this VPE other than the current one.
1142          * Return-from-interrupt should cause us to drain the queue
1143          * for the current TC, so we ought not to have to do it explicitly here.
1144          */
1145 
1146         for_each_online_cpu(cpu) {
1147                 if (cpu_data[cpu].vpe_id != my_vpe)
1148                         continue;
1149 
1150                 pipi = smtc_ipi_dq(&IPIQ[cpu]);
1151                 if (pipi != NULL) {
1152                         if (cpu_data[cpu].tc_id != my_tc) {
1153                                 sent = 0;
1154                                 LOCK_MT_PRA();
1155                                 settc(cpu_data[cpu].tc_id);
1156                                 write_tc_c0_tchalt(TCHALT_H);
1157                                 mips_ihb();
1158                                 tcstatus = read_tc_c0_tcstatus();
1159                                 if ((tcstatus & TCSTATUS_IXMT) == 0) {
1160                                         post_direct_ipi(cpu, pipi);
1161                                         sent = 1;
1162                                 }
1163                                 write_tc_c0_tchalt(0);
1164                                 UNLOCK_MT_PRA();
1165                                 if (!sent) {
1166                                         smtc_ipi_req(&IPIQ[cpu], pipi);
1167                                 }
1168                         } else {
1169                                 /*
1170                                  * ipi_decode() should be called
1171                                  * with interrupts off
1172                                  */
1173                                 local_irq_save(flags);
1174                                 if (pipi->type == LINUX_SMP_IPI &&
1175                                     (int)pipi->arg == SMP_RESCHEDULE_YOURSELF)
1176                                         IPIQ[cpu].resched_flag = 0;
1177                                 ipi_decode(pipi);
1178                                 local_irq_restore(flags);
1179                         }
1180                 }
1181         }
1182 
1183         return IRQ_HANDLED;
1184 }
1185 
1186 static void ipi_irq_dispatch(void)
1187 {
1188         do_IRQ(cpu_ipi_irq);
1189 }
1190 
1191 static struct irqaction irq_ipi = {
1192         .handler        = ipi_interrupt,
1193         .flags          = IRQF_PERCPU,
1194         .name           = "SMTC_IPI"
1195 };
1196 
1197 static void setup_cross_vpe_interrupts(unsigned int nvpe)
1198 {
1199         if (nvpe < 1)
1200                 return;
1201 
1202         if (!cpu_has_vint)
1203                 panic("SMTC Kernel requires Vectored Interrupt support");
1204 
1205         set_vi_handler(MIPS_CPU_IPI_IRQ, ipi_irq_dispatch);
1206 
1207         setup_irq_smtc(cpu_ipi_irq, &irq_ipi, (0x100 << MIPS_CPU_IPI_IRQ));
1208 
1209         irq_set_handler(cpu_ipi_irq, handle_percpu_irq);
1210 }
1211 
1212 /*
1213  * SMTC-specific hacks invoked from elsewhere in the kernel.
1214  */
1215 
1216  /*
1217   * smtc_ipi_replay is called from raw_local_irq_restore
1218   */
1219 
1220 void smtc_ipi_replay(void)
1221 {
1222         unsigned int cpu = smp_processor_id();
1223 
1224         /*
1225          * To the extent that we've ever turned interrupts off,
1226          * we may have accumulated deferred IPIs.  This is subtle.
1227          * we should be OK:  If we pick up something and dispatch
1228          * it here, that's great. If we see nothing, but concurrent
1229          * with this operation, another TC sends us an IPI, IXMT
1230          * is clear, and we'll handle it as a real pseudo-interrupt
1231          * and not a pseudo-pseudo interrupt.  The important thing
1232          * is to do the last check for queued message *after* the
1233          * re-enabling of interrupts.
1234          */
1235         while (IPIQ[cpu].head != NULL) {
1236                 struct smtc_ipi_q *q = &IPIQ[cpu];
1237                 struct smtc_ipi *pipi;
1238                 unsigned long flags;
1239 
1240                 /*
1241                  * It's just possible we'll come in with interrupts
1242                  * already enabled.
1243                  */
1244                 local_irq_save(flags);
1245 
1246                 spin_lock(&q->lock);
1247                 pipi = __smtc_ipi_dq(q);
1248                 spin_unlock(&q->lock);
1249                 /*
1250                  ** But use a raw restore here to avoid recursion.
1251                  */
1252                 __arch_local_irq_restore(flags);
1253 
1254                 if (pipi) {
1255                         self_ipi(pipi);
1256                         smtc_cpu_stats[cpu].selfipis++;
1257                 }
1258         }
1259 }
1260 
1261 EXPORT_SYMBOL(smtc_ipi_replay);
1262 
1263 void smtc_idle_loop_hook(void)
1264 {
1265 #ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
1266         int im;
1267         int flags;
1268         int mtflags;
1269         int bit;
1270         int vpe;
1271         int tc;
1272         int hook_ntcs;
1273         /*
1274          * printk within DMT-protected regions can deadlock,
1275          * so buffer diagnostic messages for later output.
1276          */
1277         char *pdb_msg;
1278         char id_ho_db_msg[768]; /* worst-case use should be less than 700 */
1279 
1280         if (atomic_read(&idle_hook_initialized) == 0) { /* fast test */
1281                 if (atomic_add_return(1, &idle_hook_initialized) == 1) {
1282                         int mvpconf0;
1283                         /* Tedious stuff to just do once */
1284                         mvpconf0 = read_c0_mvpconf0();
1285                         hook_ntcs = ((mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1;
1286                         if (hook_ntcs > NR_CPUS)
1287                                 hook_ntcs = NR_CPUS;
1288                         for (tc = 0; tc < hook_ntcs; tc++) {
1289                                 tcnoprog[tc] = 0;
1290                                 clock_hang_reported[tc] = 0;
1291                         }
1292                         for (vpe = 0; vpe < 2; vpe++)
1293                                 for (im = 0; im < 8; im++)
1294                                         imstuckcount[vpe][im] = 0;
1295                         printk("Idle loop test hook initialized for %d TCs\n", hook_ntcs);
1296                         atomic_set(&idle_hook_initialized, 1000);
1297                 } else {
1298                         /* Someone else is initializing in parallel - let 'em finish */
1299                         while (atomic_read(&idle_hook_initialized) < 1000)
1300                                 ;
1301                 }
1302         }
1303 
1304         /* Have we stupidly left IXMT set somewhere? */
1305         if (read_c0_tcstatus() & 0x400) {
1306                 write_c0_tcstatus(read_c0_tcstatus() & ~0x400);
1307                 ehb();
1308                 printk("Dangling IXMT in cpu_idle()\n");
1309         }
1310 
1311         /* Have we stupidly left an IM bit turned off? */
1312 #define IM_LIMIT 2000
1313         local_irq_save(flags);
1314         mtflags = dmt();
1315         pdb_msg = &id_ho_db_msg[0];
1316         im = read_c0_status();
1317         vpe = current_cpu_data.vpe_id;
1318         for (bit = 0; bit < 8; bit++) {
1319                 /*
1320                  * In current prototype, I/O interrupts
1321                  * are masked for VPE > 0
1322                  */
1323                 if (vpemask[vpe][bit]) {
1324                         if (!(im & (0x100 << bit)))
1325                                 imstuckcount[vpe][bit]++;
1326                         else
1327                                 imstuckcount[vpe][bit] = 0;
1328                         if (imstuckcount[vpe][bit] > IM_LIMIT) {
1329                                 set_c0_status(0x100 << bit);
1330                                 ehb();
1331                                 imstuckcount[vpe][bit] = 0;
1332                                 pdb_msg += sprintf(pdb_msg,
1333                                         "Dangling IM %d fixed for VPE %d\n", bit,
1334                                         vpe);
1335                         }
1336                 }
1337         }
1338 
1339         emt(mtflags);
1340         local_irq_restore(flags);
1341         if (pdb_msg != &id_ho_db_msg[0])
1342                 printk("CPU%d: %s", smp_processor_id(), id_ho_db_msg);
1343 #endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */
1344 
1345         smtc_ipi_replay();
1346 }
1347 
1348 void smtc_soft_dump(void)
1349 {
1350         int i;
1351 
1352         printk("Counter Interrupts taken per CPU (TC)\n");
1353         for (i=0; i < NR_CPUS; i++) {
1354                 printk("%d: %ld\n", i, smtc_cpu_stats[i].timerints);
1355         }
1356         printk("Self-IPI invocations:\n");
1357         for (i=0; i < NR_CPUS; i++) {
1358                 printk("%d: %ld\n", i, smtc_cpu_stats[i].selfipis);
1359         }
1360         smtc_ipi_qdump();
1361         printk("%d Recoveries of \"stolen\" FPU\n",
1362                atomic_read(&smtc_fpu_recoveries));
1363 }
1364 
1365 
1366 /*
1367  * TLB management routines special to SMTC
1368  */
1369 
1370 void smtc_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
1371 {
1372         unsigned long flags, mtflags, tcstat, prevhalt, asid;
1373         int tlb, i;
1374 
1375         /*
1376          * It would be nice to be able to use a spinlock here,
1377          * but this is invoked from within TLB flush routines
1378          * that protect themselves with DVPE, so if a lock is
1379          * held by another TC, it'll never be freed.
1380          *
1381          * DVPE/DMT must not be done with interrupts enabled,
1382          * so even so most callers will already have disabled
1383          * them, let's be really careful...
1384          */
1385 
1386         local_irq_save(flags);
1387         if (smtc_status & SMTC_TLB_SHARED) {
1388                 mtflags = dvpe();
1389                 tlb = 0;
1390         } else {
1391                 mtflags = dmt();
1392                 tlb = cpu_data[cpu].vpe_id;
1393         }
1394         asid = asid_cache(cpu);
1395 
1396         do {
1397                 if (!((asid += ASID_INC) & ASID_MASK) ) {
1398                         if (cpu_has_vtag_icache)
1399                                 flush_icache_all();
1400                         /* Traverse all online CPUs (hack requires contiguous range) */
1401                         for_each_online_cpu(i) {
1402                                 /*
1403                                  * We don't need to worry about our own CPU, nor those of
1404                                  * CPUs who don't share our TLB.
1405                                  */
1406                                 if ((i != smp_processor_id()) &&
1407                                     ((smtc_status & SMTC_TLB_SHARED) ||
1408                                      (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))) {
1409                                         settc(cpu_data[i].tc_id);
1410                                         prevhalt = read_tc_c0_tchalt() & TCHALT_H;
1411                                         if (!prevhalt) {
1412                                                 write_tc_c0_tchalt(TCHALT_H);
1413                                                 mips_ihb();
1414                                         }
1415                                         tcstat = read_tc_c0_tcstatus();
1416                                         smtc_live_asid[tlb][(tcstat & ASID_MASK)] |= (asiduse)(0x1 << i);
1417                                         if (!prevhalt)
1418                                                 write_tc_c0_tchalt(0);
1419                                 }
1420                         }
1421                         if (!asid)              /* fix version if needed */
1422                                 asid = ASID_FIRST_VERSION;
1423                         local_flush_tlb_all();  /* start new asid cycle */
1424                 }
1425         } while (smtc_live_asid[tlb][(asid & ASID_MASK)]);
1426 
1427         /*
1428          * SMTC shares the TLB within VPEs and possibly across all VPEs.
1429          */
1430         for_each_online_cpu(i) {
1431                 if ((smtc_status & SMTC_TLB_SHARED) ||
1432                     (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
1433                         cpu_context(i, mm) = asid_cache(i) = asid;
1434         }
1435 
1436         if (smtc_status & SMTC_TLB_SHARED)
1437                 evpe(mtflags);
1438         else
1439                 emt(mtflags);
1440         local_irq_restore(flags);
1441 }
1442 
1443 /*
1444  * Invoked from macros defined in mmu_context.h
1445  * which must already have disabled interrupts
1446  * and done a DVPE or DMT as appropriate.
1447  */
1448 
1449 void smtc_flush_tlb_asid(unsigned long asid)
1450 {
1451         int entry;
1452         unsigned long ehi;
1453 
1454         entry = read_c0_wired();
1455 
1456         /* Traverse all non-wired entries */
1457         while (entry < current_cpu_data.tlbsize) {
1458                 write_c0_index(entry);
1459                 ehb();
1460                 tlb_read();
1461                 ehb();
1462                 ehi = read_c0_entryhi();
1463                 if ((ehi & ASID_MASK) == asid) {
1464                     /*
1465                      * Invalidate only entries with specified ASID,
1466                      * makiing sure all entries differ.
1467                      */
1468                     write_c0_entryhi(CKSEG0 + (entry << (PAGE_SHIFT + 1)));
1469                     write_c0_entrylo0(0);
1470                     write_c0_entrylo1(0);
1471                     mtc0_tlbw_hazard();
1472                     tlb_write_indexed();
1473                 }
1474                 entry++;
1475         }
1476         write_c0_index(PARKED_INDEX);
1477         tlbw_use_hazard();
1478 }
1479 
1480 /*
1481  * Support for single-threading cache flush operations.
1482  */
1483 
1484 static int halt_state_save[NR_CPUS];
1485 
1486 /*
1487  * To really, really be sure that nothing is being done
1488  * by other TCs, halt them all.  This code assumes that
1489  * a DVPE has already been done, so while their Halted
1490  * state is theoretically architecturally unstable, in
1491  * practice, it's not going to change while we're looking
1492  * at it.
1493  */
1494 
1495 void smtc_cflush_lockdown(void)
1496 {
1497         int cpu;
1498 
1499         for_each_online_cpu(cpu) {
1500                 if (cpu != smp_processor_id()) {
1501                         settc(cpu_data[cpu].tc_id);
1502                         halt_state_save[cpu] = read_tc_c0_tchalt();
1503                         write_tc_c0_tchalt(TCHALT_H);
1504                 }
1505         }
1506         mips_ihb();
1507 }
1508 
1509 /* It would be cheating to change the cpu_online states during a flush! */
1510 
1511 void smtc_cflush_release(void)
1512 {
1513         int cpu;
1514 
1515         /*
1516          * Start with a hazard barrier to ensure
1517          * that all CACHE ops have played through.
1518          */
1519         mips_ihb();
1520 
1521         for_each_online_cpu(cpu) {
1522                 if (cpu != smp_processor_id()) {
1523                         settc(cpu_data[cpu].tc_id);
1524                         write_tc_c0_tchalt(halt_state_save[cpu]);
1525                 }
1526         }
1527         mips_ihb();
1528 }
1529 

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