Commit 3ba2c3ff authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'modules-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux 

Pull modules updates from Luis Chamberlain:
 "Tux gets for xmas an improvement to the average lookup performance of
  kallsyms_lookup_name() by 715x thanks to the work by Zhen Lei, which
  upgraded our old implementation from being O(n) to O(log(n)), while
  also retaining the old implementation support on /proc/kallsyms.

  The only penalty was increasing the memory footprint by 3 *
  kallsyms_num_syms. Folks who want to improve this further now also
  have a dedicated selftest facility through KALLSYMS_SELFTEST.

  Stephen Boyd added zstd in-kernel decompression support, but the only
  users of this would be folks using the load-pin LSM because otherwise
  we do module decompression in userspace.

  The only other thing with mentioning is a minor boot time optimization
  by Rasmus Villemoes which deferes param_sysfs_init() to late init. The
  rest is cleanups and minor fixes"

* tag 'modules-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  livepatch: Call klp_match_callback() in klp_find_callback() to avoid code duplication
  module/decompress: Support zstd in-kernel decompression
  kallsyms: Remove unneeded semicolon
  kallsyms: Add self-test facility
  livepatch: Use kallsyms_on_each_match_symbol() to improve performance
  kallsyms: Add helper kallsyms_on_each_match_symbol()
  kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[]
  kallsyms: Correctly sequence symbols when CONFIG_LTO_CLANG=y
  kallsyms: Improve the performance of kallsyms_lookup_name()
  scripts/kallsyms: rename build_initial_tok_table()
  module: Fix NULL vs IS_ERR checking for module_get_next_page
  kernel/params.c: defer most of param_sysfs_init() to late_initcall time
  module: Remove unused macros module_addr_min/max
  module: remove redundant module_sysfs_initialized variable
parents 0015edd6 4f1354d5

include/linux/kallsyms.h

+9 −0
Original line number Diff line number Diff line
@@ -66,9 +66,12 @@ static inline void *dereference_symbol_descriptor(void *ptr) 
}



#ifdef CONFIG_KALLSYMS

unsigned long kallsyms_sym_address(int idx);

int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,

				      unsigned long),

			    void *data);

int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),

				  const char *name, void *data);



/* Lookup the address for a symbol. Returns 0 if not found. */

unsigned long kallsyms_lookup_name(const char *name);
@@ -168,6 +171,12 @@ static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct 
{

	return -EOPNOTSUPP;

}



static inline int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),

						const char *name, void *data)

{

	return -EOPNOTSUPP;

}

#endif /*CONFIG_KALLSYMS*/



static inline void print_ip_sym(const char *loglvl, unsigned long ip)

include/linux/module.h

+0 −1
Original line number Diff line number Diff line
@@ -827,7 +827,6 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr) 
#ifdef CONFIG_SYSFS

extern struct kset *module_kset;

extern struct kobj_type module_ktype;

extern int module_sysfs_initialized;

#endif /* CONFIG_SYSFS */



#define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)

init/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -1723,6 +1723,19 @@ config KALLSYMS 
	  symbolic stack backtraces. This increases the size of the kernel

	  somewhat, as all symbols have to be loaded into the kernel image.



config KALLSYMS_SELFTEST

	bool "Test the basic functions and performance of kallsyms"

	depends on KALLSYMS

	default n

	help

	  Test the basic functions and performance of some interfaces, such as

	  kallsyms_lookup_name. It also calculates the compression rate of the

	  kallsyms compression algorithm for the current symbol set.



	  Start self-test automatically after system startup. Suggest executing

	  "dmesg | grep kallsyms_selftest" to collect test results. "finish" is

	  displayed in the last line, indicating that the test is complete.



config KALLSYMS_ALL

	bool "Include all symbols in kallsyms"

	depends on DEBUG_KERNEL && KALLSYMS

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ endif 
obj-$(CONFIG_UID16) += uid16.o

obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o

obj-$(CONFIG_KALLSYMS) += kallsyms.o

obj-$(CONFIG_KALLSYMS_SELFTEST) += kallsyms_selftest.o

obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o

obj-$(CONFIG_CRASH_CORE) += crash_core.o

obj-$(CONFIG_KEXEC_CORE) += kexec_core.o

kernel/kallsyms.c

+104 −12
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ static unsigned int get_symbol_offset(unsigned long pos) 
	return name - kallsyms_names;

}



static unsigned long kallsyms_sym_address(int idx)

unsigned long kallsyms_sym_address(int idx)

{

	if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))

		return kallsyms_addresses[idx];
@@ -187,26 +187,100 @@ static bool cleanup_symbol_name(char *s) 
	return false;

}



static int compare_symbol_name(const char *name, char *namebuf)

{

	int ret;



	ret = strcmp(name, namebuf);

	if (!ret)

		return ret;



	if (cleanup_symbol_name(namebuf) && !strcmp(name, namebuf))

		return 0;



	return ret;

}



static unsigned int get_symbol_seq(int index)

{

	unsigned int i, seq = 0;



	for (i = 0; i < 3; i++)

		seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];



	return seq;

}



static int kallsyms_lookup_names(const char *name,

				 unsigned int *start,

				 unsigned int *end)

{

	int ret;

	int low, mid, high;

	unsigned int seq, off;

	char namebuf[KSYM_NAME_LEN];



	low = 0;

	high = kallsyms_num_syms - 1;



	while (low <= high) {

		mid = low + (high - low) / 2;

		seq = get_symbol_seq(mid);

		off = get_symbol_offset(seq);

		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));

		ret = compare_symbol_name(name, namebuf);

		if (ret > 0)

			low = mid + 1;

		else if (ret < 0)

			high = mid - 1;

		else

			break;

	}



	if (low > high)

		return -ESRCH;



	low = mid;

	while (low) {

		seq = get_symbol_seq(low - 1);

		off = get_symbol_offset(seq);

		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));

		if (compare_symbol_name(name, namebuf))

			break;

		low--;

	}

	*start = low;



	if (end) {

		high = mid;

		while (high < kallsyms_num_syms - 1) {

			seq = get_symbol_seq(high + 1);

			off = get_symbol_offset(seq);

			kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));

			if (compare_symbol_name(name, namebuf))

				break;

			high++;

		}

		*end = high;

	}



	return 0;

}



/* Lookup the address for this symbol. Returns 0 if not found. */

unsigned long kallsyms_lookup_name(const char *name)

{

	char namebuf[KSYM_NAME_LEN];

	unsigned long i;

	unsigned int off;

	int ret;

	unsigned int i;



	/* Skip the search for empty string. */

	if (!*name)

		return 0;



	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {

		off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));



		if (strcmp(namebuf, name) == 0)

			return kallsyms_sym_address(i);

	ret = kallsyms_lookup_names(name, &i, NULL);

	if (!ret)

		return kallsyms_sym_address(get_symbol_seq(i));



		if (cleanup_symbol_name(namebuf) && strcmp(namebuf, name) == 0)

			return kallsyms_sym_address(i);

	}

	return module_kallsyms_lookup_name(name);

}
@@ -233,6 +307,24 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, 
	return 0;

}



int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),

				  const char *name, void *data)

{

	int ret;

	unsigned int i, start, end;



	ret = kallsyms_lookup_names(name, &start, &end);

	if (ret)

		return 0;



	for (i = start; !ret && i <= end; i++) {

		ret = fn(data, kallsyms_sym_address(get_symbol_seq(i)));

		cond_resched();

	}



	return ret;

}



static unsigned long get_symbol_pos(unsigned long addr,

				    unsigned long *symbolsize,

				    unsigned long *offset)