arch/powerpc/perf/8xx-pmu.c

   1 /*
   2  * Performance event support - PPC 8xx
   3  *
   4  * Copyright 2016 Christophe Leroy, CS Systemes d'Information
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/perf_event.h>
  15 #include <linux/percpu.h>
  16 #include <linux/hardirq.h>
  17 #include <asm/pmc.h>
  18 #include <asm/machdep.h>
  19 #include <asm/firmware.h>
  20 #include <asm/ptrace.h>
  21 #include <asm/code-patching.h>
  22
  23 #define PERF_8xx_ID_CPU_CYCLES          1
  24 #define PERF_8xx_ID_HW_INSTRUCTIONS     2
  25 #define PERF_8xx_ID_ITLB_LOAD_MISS      3
  26 #define PERF_8xx_ID_DTLB_LOAD_MISS      4
  27
  28 #define C(x)    PERF_COUNT_HW_CACHE_##x
  29 #define DTLB_LOAD_MISS  (C(DTLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  30 #define ITLB_LOAD_MISS  (C(ITLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  31
  32 extern unsigned long itlb_miss_counter, dtlb_miss_counter;
  33 extern atomic_t instruction_counter;
  34
  35 static atomic_t insn_ctr_ref;
  36 static atomic_t itlb_miss_ref;
  37 static atomic_t dtlb_miss_ref;
  38
  39 static s64 get_insn_ctr(void)
  40 {
  41         int ctr;
  42         unsigned long counta;
  43
  44         do {
  45                 ctr = atomic_read(&instruction_counter);
  46                 counta = mfspr(SPRN_COUNTA);
  47         } while (ctr != atomic_read(&instruction_counter));
  48
  49         return ((s64)ctr << 16) | (counta >> 16);
  50 }
  51
  52 static int event_type(struct perf_event *event)
  53 {
  54         switch (event->attr.type) {
  55         case PERF_TYPE_HARDWARE:
  56                 if (event->attr.config == PERF_COUNT_HW_CPU_CYCLES)
  57                         return PERF_8xx_ID_CPU_CYCLES;
  58                 if (event->attr.config == PERF_COUNT_HW_INSTRUCTIONS)
  59                         return PERF_8xx_ID_HW_INSTRUCTIONS;
  60                 break;
  61         case PERF_TYPE_HW_CACHE:
  62                 if (event->attr.config == ITLB_LOAD_MISS)
  63                         return PERF_8xx_ID_ITLB_LOAD_MISS;
  64                 if (event->attr.config == DTLB_LOAD_MISS)
  65                         return PERF_8xx_ID_DTLB_LOAD_MISS;
  66                 break;
  67         case PERF_TYPE_RAW:
  68                 break;
  69         default:
  70                 return -ENOENT;
  71         }
  72         return -EOPNOTSUPP;
  73 }
  74
  75 static int mpc8xx_pmu_event_init(struct perf_event *event)
  76 {
  77         int type = event_type(event);
  78
  79         if (type < 0)
  80                 return type;
  81         return 0;
  82 }
  83
  84 static int mpc8xx_pmu_add(struct perf_event *event, int flags)
  85 {
  86         int type = event_type(event);
  87         s64 val = 0;
  88
  89         if (type < 0)
  90                 return type;
  91
  92         switch (type) {
  93         case PERF_8xx_ID_CPU_CYCLES:
  94                 val = get_tb();
  95                 break;
  96         case PERF_8xx_ID_HW_INSTRUCTIONS:
  97                 if (atomic_inc_return(&insn_ctr_ref) == 1)
  98                         mtspr(SPRN_ICTRL, 0xc0080007);
  99                 val = get_insn_ctr();
 100                 break;
 101         case PERF_8xx_ID_ITLB_LOAD_MISS:
 102                 if (atomic_inc_return(&itlb_miss_ref) == 1) {
 103                         unsigned long target = patch_site_addr(&patch__itlbmiss_perf);
 104
 105                         patch_branch_site(&patch__itlbmiss_exit_1, target, 0);
 106 #ifndef CONFIG_PIN_TLB_TEXT
 107                         patch_branch_site(&patch__itlbmiss_exit_2, target, 0);
 108 #endif
 109                 }
 110                 val = itlb_miss_counter;
 111                 break;
 112         case PERF_8xx_ID_DTLB_LOAD_MISS:
 113                 if (atomic_inc_return(&dtlb_miss_ref) == 1) {
 114                         unsigned long target = patch_site_addr(&patch__dtlbmiss_perf);
 115
 116                         patch_branch_site(&patch__dtlbmiss_exit_1, target, 0);
 117                         patch_branch_site(&patch__dtlbmiss_exit_2, target, 0);
 118                         patch_branch_site(&patch__dtlbmiss_exit_3, target, 0);
 119                 }
 120                 val = dtlb_miss_counter;
 121                 break;
 122         }
 123         local64_set(&event->hw.prev_count, val);
 124         return 0;
 125 }
 126
 127 static void mpc8xx_pmu_read(struct perf_event *event)
 128 {
 129         int type = event_type(event);
 130         s64 prev, val = 0, delta = 0;
 131
 132         if (type < 0)
 133                 return;
 134
 135         do {
 136                 prev = local64_read(&event->hw.prev_count);
 137                 switch (type) {
 138                 case PERF_8xx_ID_CPU_CYCLES:
 139                         val = get_tb();
 140                         delta = 16 * (val - prev);
 141                         break;
 142                 case PERF_8xx_ID_HW_INSTRUCTIONS:
 143                         val = get_insn_ctr();
 144                         delta = prev - val;
 145                         if (delta < 0)
 146                                 delta += 0x1000000000000LL;
 147                         break;
 148                 case PERF_8xx_ID_ITLB_LOAD_MISS:
 149                         val = itlb_miss_counter;
 150                         delta = (s64)((s32)val - (s32)prev);
 151                         break;
 152                 case PERF_8xx_ID_DTLB_LOAD_MISS:
 153                         val = dtlb_miss_counter;
 154                         delta = (s64)((s32)val - (s32)prev);
 155                         break;
 156                 }
 157         } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
 158
 159         local64_add(delta, &event->count);
 160 }
 161
 162 static void mpc8xx_pmu_del(struct perf_event *event, int flags)
 163 {
 164         /* mfspr r10, SPRN_SPRG_SCRATCH0 */
 165         unsigned int insn = PPC_INST_MFSPR | __PPC_RS(R10) |
 166                             __PPC_SPR(SPRN_SPRG_SCRATCH0);
 167
 168         mpc8xx_pmu_read(event);
 169
 170         /* If it was the last user, stop counting to avoid useles overhead */
 171         switch (event_type(event)) {
 172         case PERF_8xx_ID_CPU_CYCLES:
 173                 break;
 174         case PERF_8xx_ID_HW_INSTRUCTIONS:
 175                 if (atomic_dec_return(&insn_ctr_ref) == 0)
 176                         mtspr(SPRN_ICTRL, 7);
 177                 break;
 178         case PERF_8xx_ID_ITLB_LOAD_MISS:
 179                 if (atomic_dec_return(&itlb_miss_ref) == 0) {
 180                         patch_instruction_site(&patch__itlbmiss_exit_1, insn);
 181 #ifndef CONFIG_PIN_TLB_TEXT
 182                         patch_instruction_site(&patch__itlbmiss_exit_2, insn);
 183 #endif
 184                 }
 185                 break;
 186         case PERF_8xx_ID_DTLB_LOAD_MISS:
 187                 if (atomic_dec_return(&dtlb_miss_ref) == 0) {
 188                         patch_instruction_site(&patch__dtlbmiss_exit_1, insn);
 189                         patch_instruction_site(&patch__dtlbmiss_exit_2, insn);
 190                         patch_instruction_site(&patch__dtlbmiss_exit_3, insn);
 191                 }
 192                 break;
 193         }
 194 }
 195
 196 static struct pmu mpc8xx_pmu = {
 197         .event_init     = mpc8xx_pmu_event_init,
 198         .add            = mpc8xx_pmu_add,
 199         .del            = mpc8xx_pmu_del,
 200         .read           = mpc8xx_pmu_read,
 201         .capabilities   = PERF_PMU_CAP_NO_INTERRUPT |
 202                           PERF_PMU_CAP_NO_NMI,
 203 };
 204
 205 static int init_mpc8xx_pmu(void)
 206 {
 207         mtspr(SPRN_ICTRL, 7);
 208         mtspr(SPRN_CMPA, 0);
 209         mtspr(SPRN_COUNTA, 0xffff);
 210
 211         return perf_pmu_register(&mpc8xx_pmu, "cpu", PERF_TYPE_RAW);
 212 }
 213
 214 early_initcall(init_mpc8xx_pmu);