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ac3b432839
module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:
1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
obvious how these data are used (are they RO, RX, or RW?)
Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:
MOD_TEXT,
MOD_DATA,
MOD_RODATA,
MOD_RO_AFTER_INIT,
MOD_INIT_TEXT,
MOD_INIT_DATA,
MOD_INIT_RODATA,
and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.
Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.
module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.
Signed-off-by: Song Liu <song@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
113 lines
2.6 KiB
C
113 lines
2.6 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_memory *mod_mem = container_of(n, struct module_memory, mtn.node);
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return (unsigned long)mod_mem->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_memory *mod_mem = container_of(n, struct module_memory, mtn.node);
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return (unsigned long)mod_mem->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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for_each_mod_mem_type(type) {
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mod->mem[type].mtn.mod = mod;
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if (mod->mem[type].size)
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__mod_tree_insert(&mod->mem[type].mtn, &mod_tree);
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}
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}
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void mod_tree_remove_init(struct module *mod)
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{
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for_class_mod_mem_type(type, init) {
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if (mod->mem[type].size)
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__mod_tree_remove(&mod->mem[type].mtn, &mod_tree);
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}
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}
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void mod_tree_remove(struct module *mod)
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{
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for_each_mod_mem_type(type) {
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if (mod->mem[type].size)
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__mod_tree_remove(&mod->mem[type].mtn, &mod_tree);
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}
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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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