cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tree_lookup.c (2940B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Modules tree lookup
      4 *
      5 * Copyright (C) 2015 Peter Zijlstra
      6 * Copyright (C) 2015 Rusty Russell
      7 */
      8
      9#include <linux/module.h>
     10#include <linux/rbtree_latch.h>
     11#include "internal.h"
     12
     13/*
     14 * Use a latched RB-tree for __module_address(); this allows us to use
     15 * RCU-sched lookups of the address from any context.
     16 *
     17 * This is conditional on PERF_EVENTS || TRACING because those can really hit
     18 * __module_address() hard by doing a lot of stack unwinding; potentially from
     19 * NMI context.
     20 */
     21
     22static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
     23{
     24	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
     25
     26	return (unsigned long)layout->base;
     27}
     28
     29static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
     30{
     31	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
     32
     33	return (unsigned long)layout->size;
     34}
     35
     36static __always_inline bool
     37mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
     38{
     39	return __mod_tree_val(a) < __mod_tree_val(b);
     40}
     41
     42static __always_inline int
     43mod_tree_comp(void *key, struct latch_tree_node *n)
     44{
     45	unsigned long val = (unsigned long)key;
     46	unsigned long start, end;
     47
     48	start = __mod_tree_val(n);
     49	if (val < start)
     50		return -1;
     51
     52	end = start + __mod_tree_size(n);
     53	if (val >= end)
     54		return 1;
     55
     56	return 0;
     57}
     58
     59static const struct latch_tree_ops mod_tree_ops = {
     60	.less = mod_tree_less,
     61	.comp = mod_tree_comp,
     62};
     63
     64static noinline void __mod_tree_insert(struct mod_tree_node *node, struct mod_tree_root *tree)
     65{
     66	latch_tree_insert(&node->node, &tree->root, &mod_tree_ops);
     67}
     68
     69static void __mod_tree_remove(struct mod_tree_node *node, struct mod_tree_root *tree)
     70{
     71	latch_tree_erase(&node->node, &tree->root, &mod_tree_ops);
     72}
     73
     74/*
     75 * These modifications: insert, remove_init and remove; are serialized by the
     76 * module_mutex.
     77 */
     78void mod_tree_insert(struct module *mod)
     79{
     80	mod->core_layout.mtn.mod = mod;
     81	mod->init_layout.mtn.mod = mod;
     82
     83	__mod_tree_insert(&mod->core_layout.mtn, &mod_tree);
     84	if (mod->init_layout.size)
     85		__mod_tree_insert(&mod->init_layout.mtn, &mod_tree);
     86
     87#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
     88	mod->data_layout.mtn.mod = mod;
     89	__mod_tree_insert(&mod->data_layout.mtn, &mod_data_tree);
     90#endif
     91}
     92
     93void mod_tree_remove_init(struct module *mod)
     94{
     95	if (mod->init_layout.size)
     96		__mod_tree_remove(&mod->init_layout.mtn, &mod_tree);
     97}
     98
     99void mod_tree_remove(struct module *mod)
    100{
    101	__mod_tree_remove(&mod->core_layout.mtn, &mod_tree);
    102	mod_tree_remove_init(mod);
    103#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
    104	__mod_tree_remove(&mod->data_layout.mtn, &mod_data_tree);
    105#endif
    106}
    107
    108struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
    109{
    110	struct latch_tree_node *ltn;
    111
    112	ltn = latch_tree_find((void *)addr, &tree->root, &mod_tree_ops);
    113	if (!ltn)
    114		return NULL;
    115
    116	return container_of(ltn, struct mod_tree_node, node)->mod;
    117}