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01dc0386ef
Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC to allow architectures to request having modules data in vmalloc area instead of module area. This is required on powerpc book3s/32 in order to set data non executable, because it is not possible to set executability on page basis, this is done per 256 Mbytes segments. The module area has exec right, vmalloc area has noexec. This can also be useful on other powerpc/32 in order to maximize the chance of code being close enough to kernel core to avoid branch trampolines. Cc: Jason Wessel <jason.wessel@windriver.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Douglas Anderson <dianders@chromium.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> [mcgrof: rebased in light of kernel/module/kdb.c move] Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Modules tree lookup
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*
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* Copyright (C) 2015 Peter Zijlstra
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* Copyright (C) 2015 Rusty Russell
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*/
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#include <linux/module.h>
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#include <linux/rbtree_latch.h>
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#include "internal.h"
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/*
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* Use a latched RB-tree for __module_address(); this allows us to use
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* RCU-sched lookups of the address from any context.
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*
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* This is conditional on PERF_EVENTS || TRACING because those can really hit
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* __module_address() hard by doing a lot of stack unwinding; potentially from
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* NMI context.
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*/
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static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
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{
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struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
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return (unsigned long)layout->base;
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}
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static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
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{
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struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
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return (unsigned long)layout->size;
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}
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static __always_inline bool
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mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
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{
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return __mod_tree_val(a) < __mod_tree_val(b);
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}
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static __always_inline int
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mod_tree_comp(void *key, struct latch_tree_node *n)
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{
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unsigned long val = (unsigned long)key;
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unsigned long start, end;
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start = __mod_tree_val(n);
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if (val < start)
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return -1;
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end = start + __mod_tree_size(n);
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if (val >= end)
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return 1;
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return 0;
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}
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static const struct latch_tree_ops mod_tree_ops = {
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.less = mod_tree_less,
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.comp = mod_tree_comp,
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};
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static noinline void __mod_tree_insert(struct mod_tree_node *node, struct mod_tree_root *tree)
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{
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latch_tree_insert(&node->node, &tree->root, &mod_tree_ops);
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}
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static void __mod_tree_remove(struct mod_tree_node *node, struct mod_tree_root *tree)
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{
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latch_tree_erase(&node->node, &tree->root, &mod_tree_ops);
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}
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/*
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* These modifications: insert, remove_init and remove; are serialized by the
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* module_mutex.
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*/
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void mod_tree_insert(struct module *mod)
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{
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mod->core_layout.mtn.mod = mod;
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mod->init_layout.mtn.mod = mod;
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__mod_tree_insert(&mod->core_layout.mtn, &mod_tree);
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if (mod->init_layout.size)
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__mod_tree_insert(&mod->init_layout.mtn, &mod_tree);
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#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
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mod->data_layout.mtn.mod = mod;
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__mod_tree_insert(&mod->data_layout.mtn, &mod_data_tree);
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#endif
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}
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void mod_tree_remove_init(struct module *mod)
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{
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if (mod->init_layout.size)
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__mod_tree_remove(&mod->init_layout.mtn, &mod_tree);
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}
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void mod_tree_remove(struct module *mod)
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{
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__mod_tree_remove(&mod->core_layout.mtn, &mod_tree);
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mod_tree_remove_init(mod);
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#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
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__mod_tree_remove(&mod->data_layout.mtn, &mod_data_tree);
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#endif
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}
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struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
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{
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struct latch_tree_node *ltn;
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ltn = latch_tree_find((void *)addr, &tree->root, &mod_tree_ops);
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if (!ltn)
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return NULL;
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return container_of(ltn, struct mod_tree_node, node)->mod;
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}
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