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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Performance event support - PPC 8xx
   4  *
   5  * Copyright 2016 Christophe Leroy, CS Systemes d'Information
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/perf_event.h>
  11 #include <linux/percpu.h>
  12 #include <linux/hardirq.h>
  13 #include <asm/pmc.h>
  14 #include <asm/machdep.h>
  15 #include <asm/firmware.h>
  16 #include <asm/ptrace.h>
  17 #include <asm/code-patching.h>
  18 #include <asm/inst.h>
  19
  20 #define PERF_8xx_ID_CPU_CYCLES          1
  21 #define PERF_8xx_ID_HW_INSTRUCTIONS     2
  22 #define PERF_8xx_ID_ITLB_LOAD_MISS      3
  23 #define PERF_8xx_ID_DTLB_LOAD_MISS      4
  24
  25 #define C(x)    PERF_COUNT_HW_CACHE_##x
  26 #define DTLB_LOAD_MISS  (C(DTLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  27 #define ITLB_LOAD_MISS  (C(ITLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  28
  29 extern unsigned long itlb_miss_counter, dtlb_miss_counter;
  30 extern atomic_t instruction_counter;
  31
  32 static atomic_t insn_ctr_ref;
  33 static atomic_t itlb_miss_ref;
  34 static atomic_t dtlb_miss_ref;
  35
  36 static s64 get_insn_ctr(void)
  37 {
  38         int ctr;
  39         unsigned long counta;
  40
  41         do {
  42                 ctr = atomic_read(&instruction_counter);
  43                 counta = mfspr(SPRN_COUNTA);
  44         } while (ctr != atomic_read(&instruction_counter));
  45
  46         return ((s64)ctr << 16) | (counta >> 16);
  47 }
  48
  49 static int event_type(struct perf_event *event)
  50 {
  51         switch (event->attr.type) {
  52         case PERF_TYPE_HARDWARE:
  53                 if (event->attr.config == PERF_COUNT_HW_CPU_CYCLES)
  54                         return PERF_8xx_ID_CPU_CYCLES;
  55                 if (event->attr.config == PERF_COUNT_HW_INSTRUCTIONS)
  56                         return PERF_8xx_ID_HW_INSTRUCTIONS;
  57                 break;
  58         case PERF_TYPE_HW_CACHE:
  59                 if (event->attr.config == ITLB_LOAD_MISS)
  60                         return PERF_8xx_ID_ITLB_LOAD_MISS;
  61                 if (event->attr.config == DTLB_LOAD_MISS)
  62                         return PERF_8xx_ID_DTLB_LOAD_MISS;
  63                 break;
  64         case PERF_TYPE_RAW:
  65                 break;
  66         default:
  67                 return -ENOENT;
  68         }
  69         return -EOPNOTSUPP;
  70 }
  71
  72 static int mpc8xx_pmu_event_init(struct perf_event *event)
  73 {
  74         int type = event_type(event);
  75
  76         if (type < 0)
  77                 return type;
  78         return 0;
  79 }
  80
  81 static int mpc8xx_pmu_add(struct perf_event *event, int flags)
  82 {
  83         int type = event_type(event);
  84         s64 val = 0;
  85
  86         if (type < 0)
  87                 return type;
  88
  89         switch (type) {
  90         case PERF_8xx_ID_CPU_CYCLES:
  91                 val = get_tb();
  92                 break;
  93         case PERF_8xx_ID_HW_INSTRUCTIONS:
  94                 if (atomic_inc_return(&insn_ctr_ref) == 1)
  95                         mtspr(SPRN_ICTRL, 0xc0080007);
  96                 val = get_insn_ctr();
  97                 break;
  98         case PERF_8xx_ID_ITLB_LOAD_MISS:
  99                 if (atomic_inc_return(&itlb_miss_ref) == 1) {
 100                         unsigned long target = patch_site_addr(&patch__itlbmiss_perf);
 101
 102                         patch_branch_site(&patch__itlbmiss_exit_1, target, 0);
 103                 }
 104                 val = itlb_miss_counter;
 105                 break;
 106         case PERF_8xx_ID_DTLB_LOAD_MISS:
 107                 if (atomic_inc_return(&dtlb_miss_ref) == 1) {
 108                         unsigned long target = patch_site_addr(&patch__dtlbmiss_perf);
 109
 110                         patch_branch_site(&patch__dtlbmiss_exit_1, target, 0);
 111                 }
 112                 val = dtlb_miss_counter;
 113                 break;
 114         }
 115         local64_set(&event->hw.prev_count, val);
 116         return 0;
 117 }
 118
 119 static void mpc8xx_pmu_read(struct perf_event *event)
 120 {
 121         int type = event_type(event);
 122         s64 prev, val = 0, delta = 0;
 123
 124         if (type < 0)
 125                 return;
 126
 127         do {
 128                 prev = local64_read(&event->hw.prev_count);
 129                 switch (type) {
 130                 case PERF_8xx_ID_CPU_CYCLES:
 131                         val = get_tb();
 132                         delta = 16 * (val - prev);
 133                         break;
 134                 case PERF_8xx_ID_HW_INSTRUCTIONS:
 135                         val = get_insn_ctr();
 136                         delta = prev - val;
 137                         if (delta < 0)
 138                                 delta += 0x1000000000000LL;
 139                         break;
 140                 case PERF_8xx_ID_ITLB_LOAD_MISS:
 141                         val = itlb_miss_counter;
 142                         delta = (s64)((s32)val - (s32)prev);
 143                         break;
 144                 case PERF_8xx_ID_DTLB_LOAD_MISS:
 145                         val = dtlb_miss_counter;
 146                         delta = (s64)((s32)val - (s32)prev);
 147                         break;
 148                 }
 149         } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
 150
 151         local64_add(delta, &event->count);
 152 }
 153
 154 static void mpc8xx_pmu_del(struct perf_event *event, int flags)
 155 {
 156         ppc_inst_t insn = ppc_inst(PPC_RAW_MFSPR(10, SPRN_SPRG_SCRATCH2));
 157
 158         mpc8xx_pmu_read(event);
 159
 160         /* If it was the last user, stop counting to avoid useless overhead */
 161         switch (event_type(event)) {
 162         case PERF_8xx_ID_CPU_CYCLES:
 163                 break;
 164         case PERF_8xx_ID_HW_INSTRUCTIONS:
 165                 if (atomic_dec_return(&insn_ctr_ref) == 0)
 166                         mtspr(SPRN_ICTRL, 7);
 167                 break;
 168         case PERF_8xx_ID_ITLB_LOAD_MISS:
 169                 if (atomic_dec_return(&itlb_miss_ref) == 0)
 170                         patch_instruction_site(&patch__itlbmiss_exit_1, insn);
 171                 break;
 172         case PERF_8xx_ID_DTLB_LOAD_MISS:
 173                 if (atomic_dec_return(&dtlb_miss_ref) == 0)
 174                         patch_instruction_site(&patch__dtlbmiss_exit_1, insn);
 175                 break;
 176         }
 177 }
 178
 179 static struct pmu mpc8xx_pmu = {
 180         .event_init     = mpc8xx_pmu_event_init,
 181         .add            = mpc8xx_pmu_add,
 182         .del            = mpc8xx_pmu_del,
 183         .read           = mpc8xx_pmu_read,
 184         .capabilities   = PERF_PMU_CAP_NO_INTERRUPT |
 185                           PERF_PMU_CAP_NO_NMI,
 186 };
 187
 188 static int init_mpc8xx_pmu(void)
 189 {
 190         mtspr(SPRN_ICTRL, 7);
 191         mtspr(SPRN_CMPA, 0);
 192         mtspr(SPRN_COUNTA, 0xffff);
 193
 194         return perf_pmu_register(&mpc8xx_pmu, "cpu", PERF_TYPE_RAW);
 195 }
 196
 197 early_initcall(init_mpc8xx_pmu);