arch/powerpc/platforms/iseries/lpevents.c

   1 /*
   2  * Copyright (C) 2001 Mike Corrigan  IBM Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include <linux/stddef.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/module.h>
  17
  18 #include <asm/system.h>
  19 #include <asm/paca.h>
  20 #include <asm/iSeries/ItLpQueue.h>
  21 #include <asm/iSeries/HvLpEvent.h>
  22 #include <asm/iSeries/HvCallEvent.h>
  23 #include <asm/iSeries/ItLpNaca.h>
  24
  25 /*
  26  * The LpQueue is used to pass event data from the hypervisor to
  27  * the partition.  This is where I/O interrupt events are communicated.
  28  *
  29  * It is written to by the hypervisor so cannot end up in the BSS.
  30  */
  31 struct hvlpevent_queue hvlpevent_queue __attribute__((__section__(".data")));
  32
  33 DEFINE_PER_CPU(unsigned long[HvLpEvent_Type_NumTypes], hvlpevent_counts);
  34
  35 static char *event_types[HvLpEvent_Type_NumTypes] = {
  36         "Hypervisor",
  37         "Machine Facilities",
  38         "Session Manager",
  39         "SPD I/O",
  40         "Virtual Bus",
  41         "PCI I/O",
  42         "RIO I/O",
  43         "Virtual Lan",
  44         "Virtual I/O"
  45 };
  46
  47 /* Array of LpEvent handler functions */
  48 static LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
  49 static unsigned lpEventHandlerPaths[HvLpEvent_Type_NumTypes];
  50
  51 static struct HvLpEvent * get_next_hvlpevent(void)
  52 {
  53         struct HvLpEvent * event;
  54         event = (struct HvLpEvent *)hvlpevent_queue.xSlicCurEventPtr;
  55
  56         if (event->xFlags.xValid) {
  57                 /* rmb() needed only for weakly consistent machines (regatta) */
  58                 rmb();
  59                 /* Set pointer to next potential event */
  60                 hvlpevent_queue.xSlicCurEventPtr += ((event->xSizeMinus1 +
  61                                 LpEventAlign) / LpEventAlign) * LpEventAlign;
  62
  63                 /* Wrap to beginning if no room at end */
  64                 if (hvlpevent_queue.xSlicCurEventPtr >
  65                                 hvlpevent_queue.xSlicLastValidEventPtr) {
  66                         hvlpevent_queue.xSlicCurEventPtr =
  67                                 hvlpevent_queue.xSlicEventStackPtr;
  68                 }
  69         } else {
  70                 event = NULL;
  71         }
  72
  73         return event;
  74 }
  75
  76 static unsigned long spread_lpevents = NR_CPUS;
  77
  78 int hvlpevent_is_pending(void)
  79 {
  80         struct HvLpEvent *next_event;
  81
  82         if (smp_processor_id() >= spread_lpevents)
  83                 return 0;
  84
  85         next_event = (struct HvLpEvent *)hvlpevent_queue.xSlicCurEventPtr;
  86
  87         return next_event->xFlags.xValid |
  88                 hvlpevent_queue.xPlicOverflowIntPending;
  89 }
  90
  91 static void hvlpevent_clear_valid(struct HvLpEvent * event)
  92 {
  93         /* Tell the Hypervisor that we're done with this event.
  94          * Also clear bits within this event that might look like valid bits.
  95          * ie. on 64-byte boundaries.
  96          */
  97         struct HvLpEvent *tmp;
  98         unsigned extra = ((event->xSizeMinus1 + LpEventAlign) /
  99                                                  LpEventAlign) - 1;
 100
 101         switch (extra) {
 102         case 3:
 103                 tmp = (struct HvLpEvent*)((char*)event + 3 * LpEventAlign);
 104                 tmp->xFlags.xValid = 0;
 105         case 2:
 106                 tmp = (struct HvLpEvent*)((char*)event + 2 * LpEventAlign);
 107                 tmp->xFlags.xValid = 0;
 108         case 1:
 109                 tmp = (struct HvLpEvent*)((char*)event + 1 * LpEventAlign);
 110                 tmp->xFlags.xValid = 0;
 111         }
 112
 113         mb();
 114
 115         event->xFlags.xValid = 0;
 116 }
 117
 118 void process_hvlpevents(struct pt_regs *regs)
 119 {
 120         struct HvLpEvent * event;
 121
 122         /* If we have recursed, just return */
 123         if (!spin_trylock(&hvlpevent_queue.lock))
 124                 return;
 125
 126         for (;;) {
 127                 event = get_next_hvlpevent();
 128                 if (event) {
 129                         /* Call appropriate handler here, passing
 130                          * a pointer to the LpEvent.  The handler
 131                          * must make a copy of the LpEvent if it
 132                          * needs it in a bottom half. (perhaps for
 133                          * an ACK)
 134                          *
 135                          *  Handlers are responsible for ACK processing
 136                          *
 137                          * The Hypervisor guarantees that LpEvents will
 138                          * only be delivered with types that we have
 139                          * registered for, so no type check is necessary
 140                          * here!
 141                          */
 142                         if (event->xType < HvLpEvent_Type_NumTypes)
 143                                 __get_cpu_var(hvlpevent_counts)[event->xType]++;
 144                         if (event->xType < HvLpEvent_Type_NumTypes &&
 145                                         lpEventHandler[event->xType])
 146                                 lpEventHandler[event->xType](event, regs);
 147                         else
 148                                 printk(KERN_INFO "Unexpected Lp Event type=%d\n", event->xType );
 149
 150                         hvlpevent_clear_valid(event);
 151                 } else if (hvlpevent_queue.xPlicOverflowIntPending)
 152                         /*
 153                          * No more valid events. If overflow events are
 154                          * pending process them
 155                          */
 156                         HvCallEvent_getOverflowLpEvents(hvlpevent_queue.xIndex);
 157                 else
 158                         break;
 159         }
 160
 161         spin_unlock(&hvlpevent_queue.lock);
 162 }
 163
 164 static int set_spread_lpevents(char *str)
 165 {
 166         unsigned long val = simple_strtoul(str, NULL, 0);
 167
 168         /*
 169          * The parameter is the number of processors to share in processing
 170          * lp events.
 171          */
 172         if (( val > 0) && (val <= NR_CPUS)) {
 173                 spread_lpevents = val;
 174                 printk("lpevent processing spread over %ld processors\n", val);
 175         } else {
 176                 printk("invalid spread_lpevents %ld\n", val);
 177         }
 178
 179         return 1;
 180 }
 181 __setup("spread_lpevents=", set_spread_lpevents);
 182
 183 void setup_hvlpevent_queue(void)
 184 {
 185         void *eventStack;
 186
 187         /*
 188          * Allocate a page for the Event Stack. The Hypervisor needs the
 189          * absolute real address, so we subtract out the KERNELBASE and add
 190          * in the absolute real address of the kernel load area.
 191          */
 192         eventStack = alloc_bootmem_pages(LpEventStackSize);
 193         memset(eventStack, 0, LpEventStackSize);
 194
 195         /* Invoke the hypervisor to initialize the event stack */
 196         HvCallEvent_setLpEventStack(0, eventStack, LpEventStackSize);
 197
 198         hvlpevent_queue.xSlicEventStackPtr = (char *)eventStack;
 199         hvlpevent_queue.xSlicCurEventPtr = (char *)eventStack;
 200         hvlpevent_queue.xSlicLastValidEventPtr = (char *)eventStack +
 201                                         (LpEventStackSize - LpEventMaxSize);
 202         hvlpevent_queue.xIndex = 0;
 203 }
 204
 205 /* Register a handler for an LpEvent type */
 206 int HvLpEvent_registerHandler(HvLpEvent_Type eventType, LpEventHandler handler)
 207 {
 208         if (eventType < HvLpEvent_Type_NumTypes) {
 209                 lpEventHandler[eventType] = handler;
 210                 return 0;
 211         }
 212         return 1;
 213 }
 214 EXPORT_SYMBOL(HvLpEvent_registerHandler);
 215
 216 int HvLpEvent_unregisterHandler(HvLpEvent_Type eventType)
 217 {
 218         might_sleep();
 219
 220         if (eventType < HvLpEvent_Type_NumTypes) {
 221                 if (!lpEventHandlerPaths[eventType]) {
 222                         lpEventHandler[eventType] = NULL;
 223                         /*
 224                          * We now sleep until all other CPUs have scheduled.
 225                          * This ensures that the deletion is seen by all
 226                          * other CPUs, and that the deleted handler isn't
 227                          * still running on another CPU when we return.
 228                          */
 229                         synchronize_rcu();
 230                         return 0;
 231                 }
 232         }
 233         return 1;
 234 }
 235 EXPORT_SYMBOL(HvLpEvent_unregisterHandler);
 236
 237 /*
 238  * lpIndex is the partition index of the target partition.
 239  * needed only for VirtualIo, VirtualLan and SessionMgr.  Zero
 240  * indicates to use our partition index - for the other types.
 241  */
 242 int HvLpEvent_openPath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 243 {
 244         if ((eventType < HvLpEvent_Type_NumTypes) &&
 245                         lpEventHandler[eventType]) {
 246                 if (lpIndex == 0)
 247                         lpIndex = itLpNaca.xLpIndex;
 248                 HvCallEvent_openLpEventPath(lpIndex, eventType);
 249                 ++lpEventHandlerPaths[eventType];
 250                 return 0;
 251         }
 252         return 1;
 253 }
 254
 255 int HvLpEvent_closePath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 256 {
 257         if ((eventType < HvLpEvent_Type_NumTypes) &&
 258                         lpEventHandler[eventType] &&
 259                         lpEventHandlerPaths[eventType]) {
 260                 if (lpIndex == 0)
 261                         lpIndex = itLpNaca.xLpIndex;
 262                 HvCallEvent_closeLpEventPath(lpIndex, eventType);
 263                 --lpEventHandlerPaths[eventType];
 264                 return 0;
 265         }
 266         return 1;
 267 }
 268
 269 static int proc_lpevents_show(struct seq_file *m, void *v)
 270 {
 271         int cpu, i;
 272         unsigned long sum;
 273         static unsigned long cpu_totals[NR_CPUS];
 274
 275         /* FIXME: do we care that there's no locking here? */
 276         sum = 0;
 277         for_each_online_cpu(cpu) {
 278                 cpu_totals[cpu] = 0;
 279                 for (i = 0; i < HvLpEvent_Type_NumTypes; i++) {
 280                         cpu_totals[cpu] += per_cpu(hvlpevent_counts, cpu)[i];
 281                 }
 282                 sum += cpu_totals[cpu];
 283         }
 284
 285         seq_printf(m, "LpEventQueue 0\n");
 286         seq_printf(m, "  events processed:\t%lu\n", sum);
 287
 288         for (i = 0; i < HvLpEvent_Type_NumTypes; ++i) {
 289                 sum = 0;
 290                 for_each_online_cpu(cpu) {
 291                         sum += per_cpu(hvlpevent_counts, cpu)[i];
 292                 }
 293
 294                 seq_printf(m, "    %-20s %10lu\n", event_types[i], sum);
 295         }
 296
 297         seq_printf(m, "\n  events processed by processor:\n");
 298
 299         for_each_online_cpu(cpu) {
 300                 seq_printf(m, "    CPU%02d  %10lu\n", cpu, cpu_totals[cpu]);
 301         }
 302
 303         return 0;
 304 }
 305
 306 static int proc_lpevents_open(struct inode *inode, struct file *file)
 307 {
 308         return single_open(file, proc_lpevents_show, NULL);
 309 }
 310
 311 static struct file_operations proc_lpevents_operations = {
 312         .open           = proc_lpevents_open,
 313         .read           = seq_read,
 314         .llseek         = seq_lseek,
 315         .release        = single_release,
 316 };
 317
 318 static int __init proc_lpevents_init(void)
 319 {
 320         struct proc_dir_entry *e;
 321
 322         e = create_proc_entry("iSeries/lpevents", S_IFREG|S_IRUGO, NULL);
 323         if (e)
 324                 e->proc_fops = &proc_lpevents_operations;
 325
 326         return 0;
 327 }
 328 __initcall(proc_lpevents_init);
 329