| 1 | |
| 2 | |
| 3 | * Modules tree lookup
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| 4 | *
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| 5 | * Copyright (C) 2015 Peter Zijlstra
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| 6 | * Copyright (C) 2015 Rusty Russell
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| 7 |
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| 8 |
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| 9 | #include <linux/module.h>
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| 10 | #include <linux/rbtree_latch.h>
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| 11 | #include "internal.h"
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| 12 |
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| 13 | |
| 14 | * Use a latched RB-tree for __module_address(); this allows us to use
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| 15 | * RCU lookups of the address from any context.
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| 16 | *
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| 17 | * This is conditional on PERF_EVENTS || TRACING || CFI because those can
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| 18 | * really hit __module_address() hard by doing a lot of stack unwinding;
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| 19 | * potentially from NMI context.
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| 20 |
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| 21 |
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| 22 | static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
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| 23 | {
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| 24 | struct module_memory *mod_mem = container_of(n, struct module_memory, mtn.node);
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| 25 |
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| 26 | return (unsigned long)mod_mem->base;
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| 27 | }
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| 28 |
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| 29 | static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
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| 30 | {
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| 31 | struct module_memory *mod_mem = container_of(n, struct module_memory, mtn.node);
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| 32 |
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| 33 | return (unsigned long)mod_mem->size;
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| 34 | }
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| 35 |
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| 36 | static __always_inline bool
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| 37 | mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
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| 38 | {
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| 39 | return __mod_tree_val(a) < __mod_tree_val(b);
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| 40 | }
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| 41 |
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| 42 | static __always_inline int
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| 43 | mod_tree_comp(void *key, struct latch_tree_node *n)
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| 44 | {
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| 45 | unsigned long val = (unsigned long)key;
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| 46 | unsigned long start, end;
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| 47 |
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| 48 | start = __mod_tree_val(n);
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| 49 | if (val < start)
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| 50 | return -1;
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| 51 |
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| 52 | end = start + __mod_tree_size(n);
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| 53 | if (val >= end)
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| 54 | return 1;
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| 55 |
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| 56 | return 0;
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| 57 | }
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| 58 |
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| 59 | static const struct latch_tree_ops mod_tree_ops = {
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| 60 | .less = mod_tree_less,
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| 61 | .comp = mod_tree_comp,
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| 62 | };
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| 63 |
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| 64 | static noinline void __mod_tree_insert(struct mod_tree_node *node, struct mod_tree_root *tree)
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| 65 | {
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| 66 | latch_tree_insert(&node->node, &tree->root, &mod_tree_ops);
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| 67 | }
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| 68 |
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| 69 | static void __mod_tree_remove(struct mod_tree_node *node, struct mod_tree_root *tree)
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| 70 | {
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| 71 | latch_tree_erase(&node->node, &tree->root, &mod_tree_ops);
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| 72 | }
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| 73 |
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| 74 | |
| 75 | * These modifications: insert, remove_init and remove; are serialized by the
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| 76 | * module_mutex.
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| 77 |
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| 78 | void mod_tree_insert(struct module *mod)
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| 79 | {
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| 80 | for_each_mod_mem_type(type) {
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| 81 | mod->mem[type].mtn.mod = mod;
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| 82 | if (mod->mem[type].size)
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| 83 | __mod_tree_insert(&mod->mem[type].mtn, &mod_tree);
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| 84 | }
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| 85 | }
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| 86 |
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| 87 | void mod_tree_remove_init(struct module *mod)
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| 88 | {
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| 89 | for_class_mod_mem_type(type, init) {
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| 90 | if (mod->mem[type].size)
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| 91 | __mod_tree_remove(&mod->mem[type].mtn, &mod_tree);
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| 92 | }
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| 93 | }
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| 94 |
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| 95 | void mod_tree_remove(struct module *mod)
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| 96 | {
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| 97 | for_each_mod_mem_type(type) {
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| 98 | if (mod->mem[type].size)
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| 99 | __mod_tree_remove(&mod->mem[type].mtn, &mod_tree);
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| 100 | }
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| 101 | }
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| 102 |
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| 103 | struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
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| 104 | {
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| 105 | struct latch_tree_node *ltn;
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| 106 |
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| 107 | ltn = latch_tree_find((void *)addr, &tree->root, &mod_tree_ops);
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| 108 | if (!ltn)
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| 109 | return NULL;
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| 110 |
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| 111 | return container_of(ltn, struct mod_tree_node, node)->mod;
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| 112 | }
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