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module: Move latched RB-tree support to a separate file

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No functional change.

This patch migrates module latched RB-tree support
(e.g. see __module_address()) from core module code
into kernel/module/tree_lookup.c.

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
Aaron Tomlin 2022-03-22 14:03:35 +00:00 committed by Luis Chamberlain
parent 1be9473e31
commit 58d208de3e
4 changed files with 147 additions and 126 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
kernel/module/Makefile
View File

@ -11,3 +11,4 @@ obj-y += main.o
obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
obj-$(CONFIG_MODULE_SIG) += signing.o
obj-$(CONFIG_LIVEPATCH) += livepatch.o
obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o

33
kernel/module/internal.h
View File

@ -9,6 +9,7 @@
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
@ -93,3 +94,35 @@ static inline void module_decompress_cleanup(struct load_info *info)
{
}
#endif
#ifdef CONFIG_MODULES_TREE_LOOKUP
struct mod_tree_root {
struct latch_tree_root root;
unsigned long addr_min;
unsigned long addr_max;
};
extern struct mod_tree_root mod_tree;
void mod_tree_insert(struct module *mod);
void mod_tree_remove_init(struct module *mod);
void mod_tree_remove(struct module *mod);
struct module *mod_find(unsigned long addr);
#else /* !CONFIG_MODULES_TREE_LOOKUP */
static inline void mod_tree_insert(struct module *mod) { }
static inline void mod_tree_remove_init(struct module *mod) { }
static inline void mod_tree_remove(struct module *mod) { }
static inline struct module *mod_find(unsigned long addr)
{
struct module *mod;
list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
if (within_module(addr, mod))
return mod;
}
return NULL;
}
#endif /* CONFIG_MODULES_TREE_LOOKUP */

130
kernel/module/main.c
View File

@ -90,138 +90,16 @@ static DECLARE_WORK(init_free_wq, do_free_init);
static LLIST_HEAD(init_free_list);
#ifdef CONFIG_MODULES_TREE_LOOKUP
/*
* Use a latched RB-tree for __module_address(); this allows us to use
* RCU-sched lookups of the address from any context.
*
* This is conditional on PERF_EVENTS || TRACING because those can really hit
* __module_address() hard by doing a lot of stack unwinding; potentially from
* NMI context.
*/
static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
{
struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
return (unsigned long)layout->base;
}
static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
{
struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
return (unsigned long)layout->size;
}
static __always_inline bool
mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
{
return __mod_tree_val(a) < __mod_tree_val(b);
}
static __always_inline int
mod_tree_comp(void *key, struct latch_tree_node *n)
{
unsigned long val = (unsigned long)key;
unsigned long start, end;
start = __mod_tree_val(n);
if (val < start)
return -1;
end = start + __mod_tree_size(n);
if (val >= end)
return 1;
return 0;
}
static const struct latch_tree_ops mod_tree_ops = {
.less = mod_tree_less,
.comp = mod_tree_comp,
};
static struct mod_tree_root {
struct latch_tree_root root;
unsigned long addr_min;
unsigned long addr_max;
} mod_tree __cacheline_aligned = {
struct mod_tree_root mod_tree __cacheline_aligned = {
.addr_min = -1UL,
};
#define module_addr_min mod_tree.addr_min
#define module_addr_max mod_tree.addr_max
static noinline void __mod_tree_insert(struct mod_tree_node *node)
{
latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
}
static void __mod_tree_remove(struct mod_tree_node *node)
{
latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops);
}
/*
* These modifications: insert, remove_init and remove; are serialized by the
* module_mutex.
*/
static void mod_tree_insert(struct module *mod)
{
mod->core_layout.mtn.mod = mod;
mod->init_layout.mtn.mod = mod;
__mod_tree_insert(&mod->core_layout.mtn);
if (mod->init_layout.size)
__mod_tree_insert(&mod->init_layout.mtn);
}
static void mod_tree_remove_init(struct module *mod)
{
if (mod->init_layout.size)
__mod_tree_remove(&mod->init_layout.mtn);
}
static void mod_tree_remove(struct module *mod)
{
__mod_tree_remove(&mod->core_layout.mtn);
mod_tree_remove_init(mod);
}
static struct module *mod_find(unsigned long addr)
{
struct latch_tree_node *ltn;
ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops);
if (!ltn)
return NULL;
return container_of(ltn, struct mod_tree_node, node)->mod;
}
#else /* MODULES_TREE_LOOKUP */
static unsigned long module_addr_min = -1UL, module_addr_max = 0;
static void mod_tree_insert(struct module *mod) { }
static void mod_tree_remove_init(struct module *mod) { }
static void mod_tree_remove(struct module *mod) { }
static struct module *mod_find(unsigned long addr)
{
struct module *mod;
list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
if (within_module(addr, mod))
return mod;
}
return NULL;
}
#endif /* MODULES_TREE_LOOKUP */
#else /* !CONFIG_MODULES_TREE_LOOKUP */
static unsigned long module_addr_min = -1UL, module_addr_max;
#endif /* CONFIG_MODULES_TREE_LOOKUP */
/*
* Bounds of module text, for speeding up __module_address.

109
kernel/module/tree_lookup.c Normal file
View File

@ -0,0 +1,109 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Modules tree lookup
*
* Copyright (C) 2015 Peter Zijlstra
* Copyright (C) 2015 Rusty Russell
*/
#include <linux/module.h>
#include <linux/rbtree_latch.h>
#include "internal.h"
/*
* Use a latched RB-tree for __module_address(); this allows us to use
* RCU-sched lookups of the address from any context.
*
* This is conditional on PERF_EVENTS || TRACING because those can really hit
* __module_address() hard by doing a lot of stack unwinding; potentially from
* NMI context.
*/
static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
{
struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
return (unsigned long)layout->base;
}
static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
{
struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
return (unsigned long)layout->size;
}
static __always_inline bool
mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
{
return __mod_tree_val(a) < __mod_tree_val(b);
}
static __always_inline int
mod_tree_comp(void *key, struct latch_tree_node *n)
{
unsigned long val = (unsigned long)key;
unsigned long start, end;
start = __mod_tree_val(n);
if (val < start)
return -1;
end = start + __mod_tree_size(n);
if (val >= end)
return 1;
return 0;
}
static const struct latch_tree_ops mod_tree_ops = {
.less = mod_tree_less,
.comp = mod_tree_comp,
};
static noinline void __mod_tree_insert(struct mod_tree_node *node)
{
latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
}
static void __mod_tree_remove(struct mod_tree_node *node)
{
latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops);
}
/*
* These modifications: insert, remove_init and remove; are serialized by the
* module_mutex.
*/
void mod_tree_insert(struct module *mod)
{
mod->core_layout.mtn.mod = mod;
mod->init_layout.mtn.mod = mod;
__mod_tree_insert(&mod->core_layout.mtn);
if (mod->init_layout.size)
__mod_tree_insert(&mod->init_layout.mtn);
}
void mod_tree_remove_init(struct module *mod)
{
if (mod->init_layout.size)
__mod_tree_remove(&mod->init_layout.mtn);
}
void mod_tree_remove(struct module *mod)
{
__mod_tree_remove(&mod->core_layout.mtn);
mod_tree_remove_init(mod);
}
struct module *mod_find(unsigned long addr)
{
struct latch_tree_node *ltn;
ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops);
if (!ltn)
return NULL;
return container_of(ltn, struct mod_tree_node, node)->mod;
}