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
  19 #define PERF_8xx_ID_CPU_CYCLES          1
  20 #define PERF_8xx_ID_HW_INSTRUCTIONS     2
  21 #define PERF_8xx_ID_ITLB_LOAD_MISS      3
  22 #define PERF_8xx_ID_DTLB_LOAD_MISS      4
  23
  24 #define C(x)    PERF_COUNT_HW_CACHE_##x
  25 #define DTLB_LOAD_MISS  (C(DTLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  26 #define ITLB_LOAD_MISS  (C(ITLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
  27
  28 extern unsigned long itlb_miss_counter, dtlb_miss_counter;
  29 extern atomic_t instruction_counter;
  30
  31 static atomic_t insn_ctr_ref;
  32 static atomic_t itlb_miss_ref;
  33 static atomic_t dtlb_miss_ref;
  34
  35 static s64 get_insn_ctr(void)
  36 {
  37         int ctr;
  38         unsigned long counta;
  39
  40         do {
  41                 ctr = atomic_read(&instruction_counter);
  42                 counta = mfspr(SPRN_COUNTA);
  43         } while (ctr != atomic_read(&instruction_counter));
  44
  45         return ((s64)ctr << 16) | (counta >> 16);
  46 }
  47
  48 static int event_type(struct perf_event *event)
  49 {
  50         switch (event->attr.type) {
  51         case PERF_TYPE_HARDWARE:
  52                 if (event->attr.config == PERF_COUNT_HW_CPU_CYCLES)
  53                         return PERF_8xx_ID_CPU_CYCLES;
  54                 if (event->attr.config == PERF_COUNT_HW_INSTRUCTIONS)
  55                         return PERF_8xx_ID_HW_INSTRUCTIONS;
  56                 break;
  57         case PERF_TYPE_HW_CACHE:
  58                 if (event->attr.config == ITLB_LOAD_MISS)
  59                         return PERF_8xx_ID_ITLB_LOAD_MISS;
  60                 if (event->attr.config == DTLB_LOAD_MISS)
  61                         return PERF_8xx_ID_DTLB_LOAD_MISS;
  62                 break;
  63         case PERF_TYPE_RAW:
  64                 break;
  65         default:
  66                 return -ENOENT;
  67         }
  68         return -EOPNOTSUPP;
  69 }
  70
  71 static int mpc8xx_pmu_event_init(struct perf_event *event)
  72 {
  73         int type = event_type(event);
  74
  75         if (type < 0)
  76                 return type;
  77         return 0;
  78 }
  79
  80 static int mpc8xx_pmu_add(struct perf_event *event, int flags)
  81 {
  82         int type = event_type(event);
  83         s64 val = 0;
  84
  85         if (type < 0)
  86                 return type;
  87
  88         switch (type) {
  89         case PERF_8xx_ID_CPU_CYCLES:
  90                 val = get_tb();
  91                 break;
  92         case PERF_8xx_ID_HW_INSTRUCTIONS:
  93                 if (atomic_inc_return(&insn_ctr_ref) == 1)
  94                         mtspr(SPRN_ICTRL, 0xc0080007);
  95                 val = get_insn_ctr();
  96                 break;
  97         case PERF_8xx_ID_ITLB_LOAD_MISS:
  98                 if (atomic_inc_return(&itlb_miss_ref) == 1) {
  99                         unsigned long target = patch_site_addr(&patch__itlbmiss_perf);
 100
 101                         patch_branch_site(&patch__itlbmiss_exit_1, target, 0);
 102 #ifndef CONFIG_PIN_TLB_TEXT
 103                         patch_branch_site(&patch__itlbmiss_exit_2, target, 0);
 104 #endif
 105                 }
 106                 val = itlb_miss_counter;
 107                 break;
 108         case PERF_8xx_ID_DTLB_LOAD_MISS:
 109                 if (atomic_inc_return(&dtlb_miss_ref) == 1) {
 110                         unsigned long target = patch_site_addr(&patch__dtlbmiss_perf);
 111
 112                         patch_branch_site(&patch__dtlbmiss_exit_1, target, 0);
 113                         patch_branch_site(&patch__dtlbmiss_exit_2, target, 0);
 114                         patch_branch_site(&patch__dtlbmiss_exit_3, target, 0);
 115                 }
 116                 val = dtlb_miss_counter;
 117                 break;
 118         }
 119         local64_set(&event->hw.prev_count, val);
 120         return 0;
 121 }
 122
 123 static void mpc8xx_pmu_read(struct perf_event *event)
 124 {
 125         int type = event_type(event);
 126         s64 prev, val = 0, delta = 0;
 127
 128         if (type < 0)
 129                 return;
 130
 131         do {
 132                 prev = local64_read(&event->hw.prev_count);
 133                 switch (type) {
 134                 case PERF_8xx_ID_CPU_CYCLES:
 135                         val = get_tb();
 136                         delta = 16 * (val - prev);
 137                         break;
 138                 case PERF_8xx_ID_HW_INSTRUCTIONS:
 139                         val = get_insn_ctr();
 140                         delta = prev - val;
 141                         if (delta < 0)
 142                                 delta += 0x1000000000000LL;
 143                         break;
 144                 case PERF_8xx_ID_ITLB_LOAD_MISS:
 145                         val = itlb_miss_counter;
 146                         delta = (s64)((s32)val - (s32)prev);
 147                         break;
 148                 case PERF_8xx_ID_DTLB_LOAD_MISS:
 149                         val = dtlb_miss_counter;
 150                         delta = (s64)((s32)val - (s32)prev);
 151                         break;
 152                 }
 153         } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
 154
 155         local64_add(delta, &event->count);
 156 }
 157
 158 static void mpc8xx_pmu_del(struct perf_event *event, int flags)
 159 {
 160         mpc8xx_pmu_read(event);
 161
 162         /* If it was the last user, stop counting to avoid useles overhead */
 163         switch (event_type(event)) {
 164         case PERF_8xx_ID_CPU_CYCLES:
 165                 break;
 166         case PERF_8xx_ID_HW_INSTRUCTIONS:
 167                 if (atomic_dec_return(&insn_ctr_ref) == 0)
 168                         mtspr(SPRN_ICTRL, 7);
 169                 break;
 170         case PERF_8xx_ID_ITLB_LOAD_MISS:
 171                 if (atomic_dec_return(&itlb_miss_ref) == 0) {
 172                         /* mfspr r10, SPRN_SPRG_SCRATCH0 */
 173                         unsigned int insn = PPC_INST_MFSPR | __PPC_RS(R10) |
 174                                             __PPC_SPR(SPRN_SPRG_SCRATCH0);
 175
 176                         patch_instruction_site(&patch__itlbmiss_exit_1, insn);
 177 #ifndef CONFIG_PIN_TLB_TEXT
 178                         patch_instruction_site(&patch__itlbmiss_exit_2, insn);
 179 #endif
 180                 }
 181                 break;
 182         case PERF_8xx_ID_DTLB_LOAD_MISS:
 183                 if (atomic_dec_return(&dtlb_miss_ref) == 0) {
 184                         /* mfspr r10, SPRN_DAR */
 185                         unsigned int insn = PPC_INST_MFSPR | __PPC_RS(R10) |
 186                                             __PPC_SPR(SPRN_DAR);
 187
 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);