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![Song Liu](/assets/img/avatar_default.png)
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>
152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Module proc support
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*
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* Copyright (C) 2008 Alexey Dobriyan
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*/
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/mutex.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include "internal.h"
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#ifdef CONFIG_MODULE_UNLOAD
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static inline void print_unload_info(struct seq_file *m, struct module *mod)
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{
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struct module_use *use;
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int printed_something = 0;
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seq_printf(m, " %i ", module_refcount(mod));
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/*
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* Always include a trailing , so userspace can differentiate
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* between this and the old multi-field proc format.
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*/
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list_for_each_entry(use, &mod->source_list, source_list) {
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printed_something = 1;
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seq_printf(m, "%s,", use->source->name);
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}
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if (mod->init && !mod->exit) {
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printed_something = 1;
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seq_puts(m, "[permanent],");
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}
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if (!printed_something)
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seq_puts(m, "-");
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}
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#else /* !CONFIG_MODULE_UNLOAD */
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static inline void print_unload_info(struct seq_file *m, struct module *mod)
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{
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/* We don't know the usage count, or what modules are using. */
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seq_puts(m, " - -");
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}
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#endif /* CONFIG_MODULE_UNLOAD */
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/* Called by the /proc file system to return a list of modules. */
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static void *m_start(struct seq_file *m, loff_t *pos)
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{
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mutex_lock(&module_mutex);
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return seq_list_start(&modules, *pos);
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}
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static void *m_next(struct seq_file *m, void *p, loff_t *pos)
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{
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return seq_list_next(p, &modules, pos);
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}
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static void m_stop(struct seq_file *m, void *p)
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{
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mutex_unlock(&module_mutex);
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}
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static unsigned int module_total_size(struct module *mod)
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{
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int size = 0;
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for_each_mod_mem_type(type)
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size += mod->mem[type].size;
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return size;
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}
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static int m_show(struct seq_file *m, void *p)
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{
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struct module *mod = list_entry(p, struct module, list);
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char buf[MODULE_FLAGS_BUF_SIZE];
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void *value;
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unsigned int size;
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/* We always ignore unformed modules. */
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if (mod->state == MODULE_STATE_UNFORMED)
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return 0;
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size = module_total_size(mod);
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seq_printf(m, "%s %u", mod->name, size);
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print_unload_info(m, mod);
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/* Informative for users. */
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seq_printf(m, " %s",
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mod->state == MODULE_STATE_GOING ? "Unloading" :
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mod->state == MODULE_STATE_COMING ? "Loading" :
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"Live");
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/* Used by oprofile and other similar tools. */
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value = m->private ? NULL : mod->mem[MOD_TEXT].base;
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seq_printf(m, " 0x%px", value);
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/* Taints info */
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if (mod->taints)
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seq_printf(m, " %s", module_flags(mod, buf, true));
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seq_puts(m, "\n");
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return 0;
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}
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/*
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* Format: modulename size refcount deps address
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*
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* Where refcount is a number or -, and deps is a comma-separated list
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* of depends or -.
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*/
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static const struct seq_operations modules_op = {
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.start = m_start,
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.next = m_next,
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.stop = m_stop,
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.show = m_show
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};
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/*
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* This also sets the "private" pointer to non-NULL if the
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* kernel pointers should be hidden (so you can just test
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* "m->private" to see if you should keep the values private).
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*
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* We use the same logic as for /proc/kallsyms.
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*/
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static int modules_open(struct inode *inode, struct file *file)
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{
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int err = seq_open(file, &modules_op);
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if (!err) {
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struct seq_file *m = file->private_data;
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m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
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}
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return err;
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}
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static const struct proc_ops modules_proc_ops = {
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.proc_flags = PROC_ENTRY_PERMANENT,
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.proc_open = modules_open,
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.proc_read = seq_read,
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.proc_lseek = seq_lseek,
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.proc_release = seq_release,
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};
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static int __init proc_modules_init(void)
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{
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proc_create("modules", 0, NULL, &modules_proc_ops);
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return 0;
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}
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module_init(proc_modules_init);
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