| 1 | /* |
| 2 | * Copyright (C) 2019-2020 Paul Cercueil <paul@crapouillou.net> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; either |
| 7 | * version 2.1 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * This library is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | */ |
| 14 | |
| 15 | #include "debug.h" |
| 16 | #include "interpreter.h" |
| 17 | #include "lightrec-private.h" |
| 18 | #include "memmanager.h" |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <stdatomic.h> |
| 22 | #include <stdbool.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <pthread.h> |
| 25 | |
| 26 | struct block_rec { |
| 27 | struct block *block; |
| 28 | struct block_rec *next; |
| 29 | }; |
| 30 | |
| 31 | struct recompiler { |
| 32 | struct lightrec_state *state; |
| 33 | pthread_t thd; |
| 34 | pthread_cond_t cond; |
| 35 | pthread_mutex_t mutex; |
| 36 | bool stop; |
| 37 | struct block *current_block; |
| 38 | struct block_rec *list; |
| 39 | }; |
| 40 | |
| 41 | static void slist_remove(struct recompiler *rec, struct block_rec *elm) |
| 42 | { |
| 43 | struct block_rec *prev; |
| 44 | |
| 45 | if (rec->list == elm) { |
| 46 | rec->list = elm->next; |
| 47 | } else { |
| 48 | for (prev = rec->list; prev && prev->next != elm; ) |
| 49 | prev = prev->next; |
| 50 | if (prev) |
| 51 | prev->next = elm->next; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | static void lightrec_compile_list(struct recompiler *rec) |
| 56 | { |
| 57 | struct block_rec *next; |
| 58 | struct block *block; |
| 59 | int ret; |
| 60 | |
| 61 | while (!!(next = rec->list)) { |
| 62 | block = next->block; |
| 63 | rec->current_block = block; |
| 64 | |
| 65 | pthread_mutex_unlock(&rec->mutex); |
| 66 | |
| 67 | ret = lightrec_compile_block(block); |
| 68 | if (ret) { |
| 69 | pr_err("Unable to compile block at PC 0x%x: %d\n", |
| 70 | block->pc, ret); |
| 71 | } |
| 72 | |
| 73 | pthread_mutex_lock(&rec->mutex); |
| 74 | |
| 75 | slist_remove(rec, next); |
| 76 | lightrec_free(rec->state, MEM_FOR_LIGHTREC, |
| 77 | sizeof(*next), next); |
| 78 | pthread_cond_signal(&rec->cond); |
| 79 | } |
| 80 | |
| 81 | rec->current_block = NULL; |
| 82 | } |
| 83 | |
| 84 | static void * lightrec_recompiler_thd(void *d) |
| 85 | { |
| 86 | struct recompiler *rec = d; |
| 87 | |
| 88 | pthread_mutex_lock(&rec->mutex); |
| 89 | |
| 90 | for (;;) { |
| 91 | do { |
| 92 | pthread_cond_wait(&rec->cond, &rec->mutex); |
| 93 | |
| 94 | if (rec->stop) { |
| 95 | pthread_mutex_unlock(&rec->mutex); |
| 96 | return NULL; |
| 97 | } |
| 98 | |
| 99 | } while (!rec->list); |
| 100 | |
| 101 | lightrec_compile_list(rec); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | struct recompiler *lightrec_recompiler_init(struct lightrec_state *state) |
| 106 | { |
| 107 | struct recompiler *rec; |
| 108 | int ret; |
| 109 | |
| 110 | rec = lightrec_malloc(state, MEM_FOR_LIGHTREC, sizeof(*rec)); |
| 111 | if (!rec) { |
| 112 | pr_err("Cannot create recompiler: Out of memory\n"); |
| 113 | return NULL; |
| 114 | } |
| 115 | |
| 116 | rec->state = state; |
| 117 | rec->stop = false; |
| 118 | rec->current_block = NULL; |
| 119 | rec->list = NULL; |
| 120 | |
| 121 | ret = pthread_cond_init(&rec->cond, NULL); |
| 122 | if (ret) { |
| 123 | pr_err("Cannot init cond variable: %d\n", ret); |
| 124 | goto err_free_rec; |
| 125 | } |
| 126 | |
| 127 | ret = pthread_mutex_init(&rec->mutex, NULL); |
| 128 | if (ret) { |
| 129 | pr_err("Cannot init mutex variable: %d\n", ret); |
| 130 | goto err_cnd_destroy; |
| 131 | } |
| 132 | |
| 133 | ret = pthread_create(&rec->thd, NULL, lightrec_recompiler_thd, rec); |
| 134 | if (ret) { |
| 135 | pr_err("Cannot create recompiler thread: %d\n", ret); |
| 136 | goto err_mtx_destroy; |
| 137 | } |
| 138 | |
| 139 | return rec; |
| 140 | |
| 141 | err_mtx_destroy: |
| 142 | pthread_mutex_destroy(&rec->mutex); |
| 143 | err_cnd_destroy: |
| 144 | pthread_cond_destroy(&rec->cond); |
| 145 | err_free_rec: |
| 146 | lightrec_free(state, MEM_FOR_LIGHTREC, sizeof(*rec), rec); |
| 147 | return NULL; |
| 148 | } |
| 149 | |
| 150 | void lightrec_free_recompiler(struct recompiler *rec) |
| 151 | { |
| 152 | rec->stop = true; |
| 153 | |
| 154 | /* Stop the thread */ |
| 155 | pthread_mutex_lock(&rec->mutex); |
| 156 | pthread_cond_signal(&rec->cond); |
| 157 | pthread_mutex_unlock(&rec->mutex); |
| 158 | pthread_join(rec->thd, NULL); |
| 159 | |
| 160 | pthread_mutex_destroy(&rec->mutex); |
| 161 | pthread_cond_destroy(&rec->cond); |
| 162 | lightrec_free(rec->state, MEM_FOR_LIGHTREC, sizeof(*rec), rec); |
| 163 | } |
| 164 | |
| 165 | int lightrec_recompiler_add(struct recompiler *rec, struct block *block) |
| 166 | { |
| 167 | struct block_rec *block_rec, *prev; |
| 168 | |
| 169 | pthread_mutex_lock(&rec->mutex); |
| 170 | |
| 171 | for (block_rec = rec->list, prev = NULL; block_rec; |
| 172 | prev = block_rec, block_rec = block_rec->next) { |
| 173 | if (block_rec->block == block) { |
| 174 | /* The block to compile is already in the queue - bump |
| 175 | * it to the top of the list */ |
| 176 | if (prev) { |
| 177 | prev->next = block_rec->next; |
| 178 | block_rec->next = rec->list; |
| 179 | rec->list = block_rec; |
| 180 | } |
| 181 | |
| 182 | pthread_mutex_unlock(&rec->mutex); |
| 183 | return 0; |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | /* By the time this function was called, the block has been recompiled |
| 188 | * and ins't in the wait list anymore. Just return here. */ |
| 189 | if (block->function) { |
| 190 | pthread_mutex_unlock(&rec->mutex); |
| 191 | return 0; |
| 192 | } |
| 193 | |
| 194 | block_rec = lightrec_malloc(rec->state, MEM_FOR_LIGHTREC, |
| 195 | sizeof(*block_rec)); |
| 196 | if (!block_rec) { |
| 197 | pthread_mutex_unlock(&rec->mutex); |
| 198 | return -ENOMEM; |
| 199 | } |
| 200 | |
| 201 | pr_debug("Adding block PC 0x%x to recompiler\n", block->pc); |
| 202 | |
| 203 | block_rec->block = block; |
| 204 | block_rec->next = rec->list; |
| 205 | rec->list = block_rec; |
| 206 | |
| 207 | /* Signal the thread */ |
| 208 | pthread_cond_signal(&rec->cond); |
| 209 | pthread_mutex_unlock(&rec->mutex); |
| 210 | |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | void lightrec_recompiler_remove(struct recompiler *rec, struct block *block) |
| 215 | { |
| 216 | struct block_rec *block_rec; |
| 217 | |
| 218 | pthread_mutex_lock(&rec->mutex); |
| 219 | |
| 220 | for (block_rec = rec->list; block_rec; block_rec = block_rec->next) { |
| 221 | if (block_rec->block == block) { |
| 222 | if (block == rec->current_block) { |
| 223 | /* Block is being recompiled - wait for |
| 224 | * completion */ |
| 225 | do { |
| 226 | pthread_cond_wait(&rec->cond, |
| 227 | &rec->mutex); |
| 228 | } while (block == rec->current_block); |
| 229 | } else { |
| 230 | /* Block is not yet being processed - remove it |
| 231 | * from the list */ |
| 232 | slist_remove(rec, block_rec); |
| 233 | lightrec_free(rec->state, MEM_FOR_LIGHTREC, |
| 234 | sizeof(*block_rec), block_rec); |
| 235 | } |
| 236 | |
| 237 | break; |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | pthread_mutex_unlock(&rec->mutex); |
| 242 | } |
| 243 | |
| 244 | void * lightrec_recompiler_run_first_pass(struct block *block, u32 *pc) |
| 245 | { |
| 246 | bool freed; |
| 247 | |
| 248 | if (likely(block->function)) { |
| 249 | if (block->flags & BLOCK_FULLY_TAGGED) { |
| 250 | freed = atomic_flag_test_and_set(&block->op_list_freed); |
| 251 | |
| 252 | if (!freed) { |
| 253 | pr_debug("Block PC 0x%08x is fully tagged" |
| 254 | " - free opcode list\n", block->pc); |
| 255 | |
| 256 | /* The block was already compiled but the opcode list |
| 257 | * didn't get freed yet - do it now */ |
| 258 | lightrec_free_opcode_list(block->state, |
| 259 | block->opcode_list); |
| 260 | block->opcode_list = NULL; |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | return block->function; |
| 265 | } |
| 266 | |
| 267 | /* Mark the opcode list as freed, so that the threaded compiler won't |
| 268 | * free it while we're using it in the interpreter. */ |
| 269 | freed = atomic_flag_test_and_set(&block->op_list_freed); |
| 270 | |
| 271 | /* Block wasn't compiled yet - run the interpreter */ |
| 272 | *pc = lightrec_emulate_block(block, *pc); |
| 273 | |
| 274 | if (!freed) |
| 275 | atomic_flag_clear(&block->op_list_freed); |
| 276 | |
| 277 | /* The block got compiled while the interpreter was running. |
| 278 | * We can free the opcode list now. */ |
| 279 | if (block->function && (block->flags & BLOCK_FULLY_TAGGED) && |
| 280 | !atomic_flag_test_and_set(&block->op_list_freed)) { |
| 281 | pr_debug("Block PC 0x%08x is fully tagged" |
| 282 | " - free opcode list\n", block->pc); |
| 283 | |
| 284 | lightrec_free_opcode_list(block->state, block->opcode_list); |
| 285 | block->opcode_list = NULL; |
| 286 | } |
| 287 | |
| 288 | return NULL; |
| 289 | } |