| 1 | /* |
| 2 | * Copyright (C) 2015-2020 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 "blockcache.h" |
| 16 | #include "debug.h" |
| 17 | #include "lightrec-private.h" |
| 18 | #include "memmanager.h" |
| 19 | |
| 20 | #include <stdbool.h> |
| 21 | #include <stdlib.h> |
| 22 | |
| 23 | /* Must be power of two */ |
| 24 | #define LUT_SIZE 0x4000 |
| 25 | |
| 26 | struct blockcache { |
| 27 | struct lightrec_state *state; |
| 28 | struct block * lut[LUT_SIZE]; |
| 29 | }; |
| 30 | |
| 31 | struct block * lightrec_find_block(struct blockcache *cache, u32 pc) |
| 32 | { |
| 33 | struct block *block; |
| 34 | |
| 35 | pc = kunseg(pc); |
| 36 | |
| 37 | for (block = cache->lut[(pc >> 2) & (LUT_SIZE - 1)]; |
| 38 | block; block = block->next) |
| 39 | if (kunseg(block->pc) == pc) |
| 40 | return block; |
| 41 | |
| 42 | return NULL; |
| 43 | } |
| 44 | |
| 45 | void remove_from_code_lut(struct blockcache *cache, struct block *block) |
| 46 | { |
| 47 | struct lightrec_state *state = block->state; |
| 48 | const struct opcode *op; |
| 49 | u32 offset = lut_offset(block->pc); |
| 50 | |
| 51 | /* Use state->get_next_block in the code LUT, which basically |
| 52 | * calls back get_next_block_func(), until the compiler |
| 53 | * overrides this. This is required, as a NULL value in the code |
| 54 | * LUT means an outdated block. */ |
| 55 | state->code_lut[offset] = state->get_next_block; |
| 56 | |
| 57 | for (op = block->opcode_list; op; op = op->next) |
| 58 | if (op->c.i.op == OP_META_SYNC) |
| 59 | state->code_lut[offset + op->offset] = NULL; |
| 60 | |
| 61 | } |
| 62 | |
| 63 | void lightrec_register_block(struct blockcache *cache, struct block *block) |
| 64 | { |
| 65 | u32 pc = kunseg(block->pc); |
| 66 | struct block *old; |
| 67 | |
| 68 | old = cache->lut[(pc >> 2) & (LUT_SIZE - 1)]; |
| 69 | if (old) |
| 70 | block->next = old; |
| 71 | |
| 72 | cache->lut[(pc >> 2) & (LUT_SIZE - 1)] = block; |
| 73 | |
| 74 | remove_from_code_lut(cache, block); |
| 75 | } |
| 76 | |
| 77 | void lightrec_unregister_block(struct blockcache *cache, struct block *block) |
| 78 | { |
| 79 | u32 pc = kunseg(block->pc); |
| 80 | struct block *old = cache->lut[(pc >> 2) & (LUT_SIZE - 1)]; |
| 81 | |
| 82 | if (old == block) { |
| 83 | cache->lut[(pc >> 2) & (LUT_SIZE - 1)] = old->next; |
| 84 | return; |
| 85 | } |
| 86 | |
| 87 | for (; old; old = old->next) { |
| 88 | if (old->next == block) { |
| 89 | old->next = block->next; |
| 90 | return; |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | pr_err("Block at PC 0x%x is not in cache\n", block->pc); |
| 95 | } |
| 96 | |
| 97 | void lightrec_free_block_cache(struct blockcache *cache) |
| 98 | { |
| 99 | struct block *block, *next; |
| 100 | unsigned int i; |
| 101 | |
| 102 | for (i = 0; i < LUT_SIZE; i++) { |
| 103 | for (block = cache->lut[i]; block; block = next) { |
| 104 | next = block->next; |
| 105 | lightrec_free_block(block); |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | lightrec_free(cache->state, MEM_FOR_LIGHTREC, sizeof(*cache), cache); |
| 110 | } |
| 111 | |
| 112 | struct blockcache * lightrec_blockcache_init(struct lightrec_state *state) |
| 113 | { |
| 114 | struct blockcache *cache; |
| 115 | |
| 116 | cache = lightrec_calloc(state, MEM_FOR_LIGHTREC, sizeof(*cache)); |
| 117 | if (!cache) |
| 118 | return NULL; |
| 119 | |
| 120 | cache->state = state; |
| 121 | |
| 122 | return cache; |
| 123 | } |
| 124 | |
| 125 | u32 lightrec_calculate_block_hash(const struct block *block) |
| 126 | { |
| 127 | const struct lightrec_mem_map *map = block->map; |
| 128 | u32 pc, hash = 0xffffffff; |
| 129 | const u32 *code; |
| 130 | unsigned int i; |
| 131 | |
| 132 | pc = kunseg(block->pc) - map->pc; |
| 133 | |
| 134 | while (map->mirror_of) |
| 135 | map = map->mirror_of; |
| 136 | |
| 137 | code = map->address + pc; |
| 138 | |
| 139 | /* Jenkins one-at-a-time hash algorithm */ |
| 140 | for (i = 0; i < block->nb_ops; i++) { |
| 141 | hash += *code++; |
| 142 | hash += (hash << 10); |
| 143 | hash ^= (hash >> 6); |
| 144 | } |
| 145 | |
| 146 | hash += (hash << 3); |
| 147 | hash ^= (hash >> 11); |
| 148 | hash += (hash << 15); |
| 149 | |
| 150 | return hash; |
| 151 | } |
| 152 | |
| 153 | bool lightrec_block_is_outdated(struct block *block) |
| 154 | { |
| 155 | void **lut_entry = &block->state->code_lut[lut_offset(block->pc)]; |
| 156 | bool outdated; |
| 157 | |
| 158 | if (*lut_entry) |
| 159 | return false; |
| 160 | |
| 161 | outdated = block->hash != lightrec_calculate_block_hash(block); |
| 162 | if (likely(!outdated)) { |
| 163 | /* The block was marked as outdated, but the content is still |
| 164 | * the same */ |
| 165 | if (block->function) |
| 166 | *lut_entry = block->function; |
| 167 | else |
| 168 | *lut_entry = block->state->get_next_block; |
| 169 | } |
| 170 | |
| 171 | return outdated; |
| 172 | } |