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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>
300 lines
8.6 KiB
C
300 lines
8.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* Module internals
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*
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/elf.h>
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#include <linux/compiler.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/rculist.h>
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#include <linux/rcupdate.h>
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#include <linux/mm.h>
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#ifndef ARCH_SHF_SMALL
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#define ARCH_SHF_SMALL 0
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#endif
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/*
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* Use highest 4 bits of sh_entsize to store the mod_mem_type of this
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* section. This leaves 28 bits for offset on 32-bit systems, which is
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* about 256 MiB (WARN_ON_ONCE if we exceed that).
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*/
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#define SH_ENTSIZE_TYPE_BITS 4
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#define SH_ENTSIZE_TYPE_SHIFT (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)
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#define SH_ENTSIZE_TYPE_MASK ((1UL << SH_ENTSIZE_TYPE_BITS) - 1)
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#define SH_ENTSIZE_OFFSET_MASK ((1UL << (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)) - 1)
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/* Maximum number of characters written by module_flags() */
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#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
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extern struct mutex module_mutex;
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extern struct list_head modules;
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extern struct module_attribute *modinfo_attrs[];
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extern size_t modinfo_attrs_count;
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/* Provided by the linker */
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extern const struct kernel_symbol __start___ksymtab[];
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extern const struct kernel_symbol __stop___ksymtab[];
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extern const struct kernel_symbol __start___ksymtab_gpl[];
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extern const struct kernel_symbol __stop___ksymtab_gpl[];
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extern const s32 __start___kcrctab[];
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extern const s32 __start___kcrctab_gpl[];
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#include <linux/dynamic_debug.h>
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struct load_info {
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const char *name;
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/* pointer to module in temporary copy, freed at end of load_module() */
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struct module *mod;
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Elf_Ehdr *hdr;
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unsigned long len;
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Elf_Shdr *sechdrs;
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char *secstrings, *strtab;
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unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
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struct _ddebug_info dyndbg;
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bool sig_ok;
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#ifdef CONFIG_KALLSYMS
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unsigned long mod_kallsyms_init_off;
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#endif
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#ifdef CONFIG_MODULE_DECOMPRESS
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struct page **pages;
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unsigned int max_pages;
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unsigned int used_pages;
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#endif
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struct {
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unsigned int sym, str, mod, vers, info, pcpu;
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} index;
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};
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enum mod_license {
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NOT_GPL_ONLY,
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GPL_ONLY,
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};
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struct find_symbol_arg {
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/* Input */
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const char *name;
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bool gplok;
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bool warn;
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/* Output */
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struct module *owner;
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const s32 *crc;
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const struct kernel_symbol *sym;
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enum mod_license license;
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};
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int mod_verify_sig(const void *mod, struct load_info *info);
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int try_to_force_load(struct module *mod, const char *reason);
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bool find_symbol(struct find_symbol_arg *fsa);
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struct module *find_module_all(const char *name, size_t len, bool even_unformed);
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int cmp_name(const void *name, const void *sym);
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long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
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Elf_Shdr *sechdr, unsigned int section);
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char *module_flags(struct module *mod, char *buf, bool show_state);
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size_t module_flags_taint(unsigned long taints, char *buf);
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static inline void module_assert_mutex_or_preempt(void)
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{
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#ifdef CONFIG_LOCKDEP
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if (unlikely(!debug_locks))
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return;
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WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
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!lockdep_is_held(&module_mutex));
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#endif
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}
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static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
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{
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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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return (unsigned long)offset_to_ptr(&sym->value_offset);
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#else
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return sym->value;
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#endif
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}
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#ifdef CONFIG_LIVEPATCH
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int copy_module_elf(struct module *mod, struct load_info *info);
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void free_module_elf(struct module *mod);
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#else /* !CONFIG_LIVEPATCH */
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static inline int copy_module_elf(struct module *mod, struct load_info *info)
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{
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return 0;
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}
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static inline void free_module_elf(struct module *mod) { }
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#endif /* CONFIG_LIVEPATCH */
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static inline bool set_livepatch_module(struct module *mod)
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{
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#ifdef CONFIG_LIVEPATCH
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mod->klp = true;
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return true;
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#else
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return false;
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#endif
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}
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#ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
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struct mod_unload_taint {
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struct list_head list;
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char name[MODULE_NAME_LEN];
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unsigned long taints;
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u64 count;
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};
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int try_add_tainted_module(struct module *mod);
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void print_unloaded_tainted_modules(void);
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#else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
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static inline int try_add_tainted_module(struct module *mod)
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{
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return 0;
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}
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static inline void print_unloaded_tainted_modules(void)
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{
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}
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#endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
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#ifdef CONFIG_MODULE_DECOMPRESS
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int module_decompress(struct load_info *info, const void *buf, size_t size);
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void module_decompress_cleanup(struct load_info *info);
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#else
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static inline int module_decompress(struct load_info *info,
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const void *buf, size_t size)
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{
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return -EOPNOTSUPP;
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}
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static inline void module_decompress_cleanup(struct load_info *info)
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{
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}
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#endif
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struct mod_tree_root {
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#ifdef CONFIG_MODULES_TREE_LOOKUP
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struct latch_tree_root root;
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#endif
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unsigned long addr_min;
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unsigned long addr_max;
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#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
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unsigned long data_addr_min;
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unsigned long data_addr_max;
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#endif
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};
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extern struct mod_tree_root mod_tree;
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#ifdef CONFIG_MODULES_TREE_LOOKUP
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void mod_tree_insert(struct module *mod);
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void mod_tree_remove_init(struct module *mod);
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void mod_tree_remove(struct module *mod);
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struct module *mod_find(unsigned long addr, struct mod_tree_root *tree);
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#else /* !CONFIG_MODULES_TREE_LOOKUP */
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static inline void mod_tree_insert(struct module *mod) { }
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static inline void mod_tree_remove_init(struct module *mod) { }
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static inline void mod_tree_remove(struct module *mod) { }
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static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
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{
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struct module *mod;
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list_for_each_entry_rcu(mod, &modules, list,
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lockdep_is_held(&module_mutex)) {
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if (within_module(addr, mod))
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return mod;
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}
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return NULL;
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}
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#endif /* CONFIG_MODULES_TREE_LOOKUP */
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void module_enable_ro(const struct module *mod, bool after_init);
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void module_enable_nx(const struct module *mod);
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void module_enable_x(const struct module *mod);
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int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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char *secstrings, struct module *mod);
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#ifdef CONFIG_MODULE_SIG
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int module_sig_check(struct load_info *info, int flags);
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#else /* !CONFIG_MODULE_SIG */
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static inline int module_sig_check(struct load_info *info, int flags)
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{
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return 0;
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}
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#endif /* !CONFIG_MODULE_SIG */
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#ifdef CONFIG_DEBUG_KMEMLEAK
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void kmemleak_load_module(const struct module *mod, const struct load_info *info);
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#else /* !CONFIG_DEBUG_KMEMLEAK */
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static inline void kmemleak_load_module(const struct module *mod,
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const struct load_info *info) { }
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#endif /* CONFIG_DEBUG_KMEMLEAK */
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#ifdef CONFIG_KALLSYMS
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void init_build_id(struct module *mod, const struct load_info *info);
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void layout_symtab(struct module *mod, struct load_info *info);
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void add_kallsyms(struct module *mod, const struct load_info *info);
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unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name);
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static inline bool sect_empty(const Elf_Shdr *sect)
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{
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return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
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}
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#else /* !CONFIG_KALLSYMS */
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static inline void init_build_id(struct module *mod, const struct load_info *info) { }
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static inline void layout_symtab(struct module *mod, struct load_info *info) { }
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static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }
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#endif /* CONFIG_KALLSYMS */
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#ifdef CONFIG_SYSFS
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int mod_sysfs_setup(struct module *mod, const struct load_info *info,
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struct kernel_param *kparam, unsigned int num_params);
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void mod_sysfs_teardown(struct module *mod);
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void init_param_lock(struct module *mod);
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#else /* !CONFIG_SYSFS */
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static inline int mod_sysfs_setup(struct module *mod,
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const struct load_info *info,
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struct kernel_param *kparam,
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unsigned int num_params)
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{
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return 0;
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}
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static inline void mod_sysfs_teardown(struct module *mod) { }
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static inline void init_param_lock(struct module *mod) { }
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#endif /* CONFIG_SYSFS */
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#ifdef CONFIG_MODVERSIONS
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int check_version(const struct load_info *info,
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const char *symname, struct module *mod, const s32 *crc);
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void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp,
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struct kernel_symbol *ks, struct tracepoint * const *tp);
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int check_modstruct_version(const struct load_info *info, struct module *mod);
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int same_magic(const char *amagic, const char *bmagic, bool has_crcs);
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#else /* !CONFIG_MODVERSIONS */
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static inline int check_version(const struct load_info *info,
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const char *symname,
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struct module *mod,
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const s32 *crc)
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{
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return 1;
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}
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static inline int check_modstruct_version(const struct load_info *info,
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struct module *mod)
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{
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return 1;
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}
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static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs)
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{
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return strcmp(amagic, bmagic) == 0;
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}
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#endif /* CONFIG_MODVERSIONS */
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