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Subject[PATCH] Cleanup 1/2: Remove exported symbol list
Date
Now that the symbol lists and module lists are finally static to
kernel/module.c, we can get rid of the extable list (and just traverse
the modules), without effecting anyone else.

Name: Symbol list removal
Author: Rusty Russell
Status: Tested on 2.5.56

D: This removes the symbol list, and the concept of kernel symbol groups,
D: in favour of just iterating through the modules. Now all iteration is
D: within kernel/module.c, this is a fairly trivial cleanup.

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .5517-linux-2.5-bk/include/linux/module.h .5517-linux-2.5-bk.updated/include/linux/module.h
--- .5517-linux-2.5-bk/include/linux/module.h 2003-01-13 11:17:32.000000000 +1100
+++ .5517-linux-2.5-bk.updated/include/linux/module.h 2003-01-13 15:52:03.000000000 +1100
@@ -106,21 +106,6 @@ extern const struct gtype##_id __mod_##g
#define MODULE_DEVICE_TABLE(type,name) \
MODULE_GENERIC_TABLE(type##_device,name)

-struct kernel_symbol_group
-{
- /* Links us into the global symbol list */
- struct list_head list;
-
- /* Module which owns it (if any) */
- struct module *owner;
-
- /* Are we internal use only? */
- int gplonly;
-
- unsigned int num_syms;
- const struct kernel_symbol *syms;
-};
-
/* Given an address, look for it in the exception tables */
const struct exception_table_entry *search_exception_tables(unsigned long add);

@@ -175,10 +160,12 @@ struct module
char name[MODULE_NAME_LEN];

/* Exported symbols */
- struct kernel_symbol_group symbols;
+ const struct kernel_symbol *syms;
+ unsigned int num_ksyms;

/* GPL-only exported symbols. */
- struct kernel_symbol_group gpl_symbols;
+ const struct kernel_symbol *gpl_syms;
+ unsigned int num_gpl_syms;

/* Exception tables */
struct exception_table extable;
@@ -239,7 +226,7 @@ static inline int module_is_live(struct
}

/* Is this address in a module? */
-int module_text_address(unsigned long addr);
+struct module *module_text_address(unsigned long addr);

#ifdef CONFIG_MODULE_UNLOAD

@@ -332,9 +319,9 @@ search_module_extables(unsigned long add
}

/* Is this address in a module? */
-static inline int module_text_address(unsigned long addr)
+static inline struct module *module_text_address(unsigned long addr)
{
- return 0;
+ return NULL;
}

/* Get/put a kernel symbol (calls should be symmetric) */
@@ -359,8 +352,6 @@ extern struct module __this_module;
struct module __this_module
__attribute__((section(".gnu.linkonce.this_module"))) = {
.name = __stringify(KBUILD_MODNAME),
- .symbols = { .owner = &__this_module },
- .gpl_symbols = { .owner = &__this_module, .gplonly = 1 },
.init = init_module,
#ifdef CONFIG_MODULE_UNLOAD
.exit = cleanup_module,
@@ -436,14 +423,6 @@ extern int module_dummy_usage;
#define MOD_IN_USE 0
#define __MODULE_STRING(x) __stringify(x)

-/*
- * The exception and symbol tables, and the lock
- * to protect them.
- */
-extern spinlock_t modlist_lock;
-extern struct list_head extables;
-extern struct list_head symbols;
-
/* Use symbol_get and symbol_put instead. You'll thank me. */
#define HAVE_INTER_MODULE
extern void inter_module_register(const char *, struct module *, const void *);
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .13250-2.5-bk-extable-list.pre/include/linux/moduleloader.h .13250-2.5-bk-extable-list/include/linux/moduleloader.h
--- .13250-2.5-bk-extable-list.pre/include/linux/moduleloader.h 2003-01-10 10:55:43.000000000 +1100
+++ .13250-2.5-bk-extable-list/include/linux/moduleloader.h 2003-01-13 16:34:24.000000000 +1100
@@ -11,7 +11,7 @@ unsigned long find_symbol_internal(Elf_S
const char *strtab,
const char *name,
struct module *mod,
- struct kernel_symbol_group **group);
+ struct module **owner);

/* These must be implemented by the specific architecture */

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .5517-linux-2.5-bk/kernel/extable.c .5517-linux-2.5-bk.updated/kernel/extable.c
--- .5517-linux-2.5-bk/kernel/extable.c 2003-01-10 10:55:43.000000000 +1100
+++ .5517-linux-2.5-bk.updated/kernel/extable.c 2003-01-13 15:52:03.000000000 +1100
@@ -38,5 +38,5 @@ int kernel_text_address(unsigned long ad
addr <= (unsigned long)_etext)
return 1;

- return module_text_address(addr);
+ return module_text_address(addr) != NULL;
}
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .5517-linux-2.5-bk/kernel/module.c .5517-linux-2.5-bk.updated/kernel/module.c
--- .5517-linux-2.5-bk/kernel/module.c 2003-01-10 10:55:43.000000000 +1100
+++ .5517-linux-2.5-bk.updated/kernel/module.c 2003-01-13 15:53:14.000000000 +1100
@@ -57,7 +57,6 @@ static spinlock_t modlist_lock = SPIN_LO
/* List of modules, protected by module_mutex AND modlist_lock */
static DECLARE_MUTEX(module_mutex);
static LIST_HEAD(modules);
-static LIST_HEAD(symbols);
static LIST_HEAD(extables);

/* We require a truly strong try_module_get() */
@@ -75,23 +74,41 @@ int init_module(void)
}
EXPORT_SYMBOL(init_module);

-/* Find a symbol, return value and the symbol group */
+/* Provided by the linker */
+extern const struct kernel_symbol __start___ksymtab[];
+extern const struct kernel_symbol __stop___ksymtab[];
+extern const struct kernel_symbol __start___gpl_ksymtab[];
+extern const struct kernel_symbol __stop___gpl_ksymtab[];
+
+/* Find a symbol, return value and module which owns it */
static unsigned long __find_symbol(const char *name,
- struct kernel_symbol_group **group,
+ struct module **owner,
int gplok)
{
- struct kernel_symbol_group *ks;
+ struct module *mod;
+ unsigned int i;

- list_for_each_entry(ks, &symbols, list) {
- unsigned int i;
+ *owner = NULL;
+ for (i = 0; __start___ksymtab+i < __stop___ksymtab; i++)
+ if (strcmp(__start___ksymtab[i].name, name) == 0)
+ return __start___ksymtab[i].value;

- if (ks->gplonly && !gplok)
- continue;
- for (i = 0; i < ks->num_syms; i++) {
- if (strcmp(ks->syms[i].name, name) == 0) {
- *group = ks;
- return ks->syms[i].value;
- }
+ if (gplok) {
+ for (i = 0; __start___gpl_ksymtab+i<__stop___gpl_ksymtab; i++)
+ if (strcmp(__start___gpl_ksymtab[i].name, name) == 0)
+ return __start___gpl_ksymtab[i].value;
+ }
+
+ list_for_each_entry(mod, &modules, list) {
+ *owner = mod;
+ for (i = 0; i < mod->num_ksyms; i++)
+ if (strcmp(mod->syms[i].name, name) == 0)
+ return mod->syms[i].value;
+
+ if (gplok) {
+ for (i = 0; i < mod->num_gpl_syms; i++)
+ if (strcmp(mod->gpl_syms[i].name, name) == 0)
+ return mod->gpl_syms[i].value;
}
}
DEBUGP("Failed to find symbol %s\n", name);
@@ -516,36 +533,27 @@ static void print_unload_info(struct seq

void __symbol_put(const char *symbol)
{
- struct kernel_symbol_group *ksg;
+ struct module *mod;
unsigned long flags;

spin_lock_irqsave(&modlist_lock, flags);
- if (!__find_symbol(symbol, &ksg, 1))
+ if (!__find_symbol(symbol, &mod, 1))
BUG();
- module_put(ksg->owner);
+ module_put(mod);
spin_unlock_irqrestore(&modlist_lock, flags);
}
EXPORT_SYMBOL(__symbol_put);

void symbol_put_addr(void *addr)
{
- struct kernel_symbol_group *ks;
unsigned long flags;

- spin_lock_irqsave(&modlist_lock, flags);
- list_for_each_entry(ks, &symbols, list) {
- unsigned int i;
+ if (!kernel_text_address((unsigned long)addr))
+ BUG();

- for (i = 0; i < ks->num_syms; i++) {
- if (ks->syms[i].value == (unsigned long)addr) {
- module_put(ks->owner);
- spin_unlock_irqrestore(&modlist_lock, flags);
- return;
- }
- }
- }
+ spin_lock_irqsave(&modlist_lock, flags);
+ module_put(module_text_address((unsigned long)addr));
spin_unlock_irqrestore(&modlist_lock, flags);
- BUG();
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

@@ -729,21 +737,21 @@ unsigned long find_symbol_internal(Elf_S
const char *strtab,
const char *name,
struct module *mod,
- struct kernel_symbol_group **ksg)
+ struct module **owner)
{
unsigned long ret;

ret = find_local_symbol(sechdrs, symindex, strtab, name);
if (ret) {
- *ksg = NULL;
+ *owner = NULL;
return ret;
}
/* Look in other modules... */
spin_lock_irq(&modlist_lock);
- ret = __find_symbol(name, ksg, mod->license_gplok);
+ ret = __find_symbol(name, owner, mod->license_gplok);
if (ret) {
/* This can fail due to OOM, or module unloading */
- if (!use_module(mod, (*ksg)->owner))
+ if (!use_module(mod, *owner))
ret = 0;
}
spin_unlock_irq(&modlist_lock);
@@ -756,8 +764,6 @@ static void free_module(struct module *m
/* Delete from various lists */
spin_lock_irq(&modlist_lock);
list_del(&mod->list);
- list_del(&mod->symbols.list);
- list_del(&mod->gpl_symbols.list);
list_del(&mod->extable.list);
spin_unlock_irq(&modlist_lock);

@@ -774,12 +780,12 @@ static void free_module(struct module *m

void *__symbol_get(const char *symbol)
{
- struct kernel_symbol_group *ksg;
+ struct module *module;
unsigned long value, flags;

spin_lock_irqsave(&modlist_lock, flags);
- value = __find_symbol(symbol, &ksg, 1);
- if (value && !strong_try_module_get(ksg->owner))
+ value = __find_symbol(symbol, &module, 1);
+ if (value && !strong_try_module_get(module))
value = 0;
spin_unlock_irqrestore(&modlist_lock, flags);

@@ -871,7 +877,7 @@ static int simplify_symbols(Elf_Shdr *se
i++) {
if (sym[i].st_shndx == SHN_UNDEF) {
/* Look for symbol */
- struct kernel_symbol_group *ksg = NULL;
+ struct module *owner;
const char *strtab
= (char *)sechdrs[strindex].sh_addr;

@@ -881,7 +887,7 @@ static int simplify_symbols(Elf_Shdr *se
strtab,
strtab + sym[i].st_name,
mod,
- &ksg);
+ &owner);
}
}

@@ -1179,12 +1185,10 @@ static struct module *load_module(void *
goto cleanup;

/* Set up EXPORTed & EXPORT_GPLed symbols (section 0 is 0 length) */
- mod->symbols.num_syms = (sechdrs[exportindex].sh_size
- / sizeof(*mod->symbols.syms));
- mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr;
- mod->gpl_symbols.num_syms = (sechdrs[gplindex].sh_size
- / sizeof(*mod->symbols.syms));
- mod->gpl_symbols.syms = (void *)sechdrs[gplindex].sh_addr;
+ mod->num_ksyms = (sechdrs[exportindex].sh_size/ sizeof(*mod->syms));
+ mod->syms = (void *)sechdrs[exportindex].sh_addr;
+ mod->num_gpl_syms = sechdrs[gplindex].sh_size / sizeof(*mod->gpl_syms);
+ mod->gpl_syms = (void *)sechdrs[gplindex].sh_addr;

/* Set up exception table */
if (exindex) {
@@ -1288,8 +1292,6 @@ sys_init_module(void *umod,
strong_try_module_get() will fail. */
spin_lock_irq(&modlist_lock);
list_add(&mod->extable.list, &extables);
- list_add_tail(&mod->symbols.list, &symbols);
- list_add_tail(&mod->gpl_symbols.list, &symbols);
list_add(&mod->list, &modules);
spin_unlock_irq(&modlist_lock);

@@ -1462,7 +1464,7 @@ const struct exception_table_entry *sear
}

/* Is this a valid kernel address? We don't grab the lock: we are oopsing. */
-int module_text_address(unsigned long addr)
+struct module *module_text_address(unsigned long addr)
{
struct module *mod;

@@ -1473,32 +1475,6 @@ int module_text_address(unsigned long ad
return 0;
}

-/* Provided by the linker */
-extern const struct kernel_symbol __start___ksymtab[];
-extern const struct kernel_symbol __stop___ksymtab[];
-extern const struct kernel_symbol __start___gpl_ksymtab[];
-extern const struct kernel_symbol __stop___gpl_ksymtab[];
-
-static struct kernel_symbol_group kernel_symbols, kernel_gpl_symbols;
-
-static int __init symbols_init(void)
-{
- /* Add kernel symbols to symbol table */
- kernel_symbols.num_syms = (__stop___ksymtab - __start___ksymtab);
- kernel_symbols.syms = __start___ksymtab;
- kernel_symbols.gplonly = 0;
- list_add(&kernel_symbols.list, &symbols);
- kernel_gpl_symbols.num_syms = (__stop___gpl_ksymtab
- - __start___gpl_ksymtab);
- kernel_gpl_symbols.syms = __start___gpl_ksymtab;
- kernel_gpl_symbols.gplonly = 1;
- list_add(&kernel_gpl_symbols.list, &symbols);
-
- return 0;
-}
-
-__initcall(symbols_init);
-
/* Obsolete lvalue for broken code which asks about usage */
int module_dummy_usage = 1;
EXPORT_SYMBOL(module_dummy_usage);


--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
-
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