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

include/linux/kallsyms.h

@@ -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

@@ -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

@@ -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

@@ -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

@@ -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)

kernel/kallsyms_internal.h

@@ -26,5 +26,6 @@ extern const char kallsyms_token_table[] __weak;
 extern const u16 kallsyms_token_index[] __weak;
 
 extern const unsigned int kallsyms_markers[] __weak;
+extern const u8 kallsyms_seqs_of_names[] __weak;
 
 #endif // LINUX_KALLSYMS_INTERNAL_H_

kernel/kallsyms_selftest.h

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef LINUX_KALLSYMS_SELFTEST_H_
+#define LINUX_KALLSYMS_SELFTEST_H_
+
+#include <linux/types.h>
+
+extern int kallsyms_test_var_bss;
+extern int kallsyms_test_var_data;
+
+extern int kallsyms_test_func(void);
+extern int kallsyms_test_func_weak(void);
+
+#endif // LINUX_KALLSYMS_SELFTEST_H_

kernel/livepatch/core.c

@@ -125,20 +125,10 @@ struct klp_find_arg {
 	unsigned long pos;
 };
 
-static int klp_find_callback(void *data, const char *name,
-			     struct module *mod, unsigned long addr)
+static int klp_match_callback(void *data, unsigned long addr)
 {
 	struct klp_find_arg *args = data;
 
-	if ((mod && !args->objname) || (!mod && args->objname))
-		return 0;
-
-	if (strcmp(args->name, name))
-		return 0;
-
-	if (args->objname && strcmp(args->objname, mod->name))
-		return 0;
-
 	args->addr = addr;
 	args->count++;
 
@@ -153,6 +143,23 @@ static int klp_find_callback(void *data, const char *name,
 	return 0;
 }
 
+static int klp_find_callback(void *data, const char *name,
+			     struct module *mod, unsigned long addr)
+{
+	struct klp_find_arg *args = data;
+
+	if ((mod && !args->objname) || (!mod && args->objname))
+		return 0;
+
+	if (strcmp(args->name, name))
+		return 0;
+
+	if (args->objname && strcmp(args->objname, mod->name))
+		return 0;
+
+	return klp_match_callback(data, addr);
+}
+
 static int klp_find_object_symbol(const char *objname, const char *name,
 				  unsigned long sympos, unsigned long *addr)
 {
@@ -167,7 +174,7 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
-		kallsyms_on_each_symbol(klp_find_callback, &args);
+		kallsyms_on_each_match_symbol(klp_match_callback, name, &args);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;

kernel/module/Kconfig

@@ -221,9 +221,10 @@ endchoice
 
 config MODULE_DECOMPRESS
 	bool "Support in-kernel module decompression"
-	depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ
+	depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ || MODULE_COMPRESS_ZSTD
 	select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
 	select XZ_DEC if MODULE_COMPRESS_XZ
+	select ZSTD_DECOMPRESS if MODULE_COMPRESS_ZSTD
 	help
 
 	  Support for decompressing kernel modules by the kernel itself

kernel/module/decompress.c

@@ -50,7 +50,7 @@ static struct page *module_get_next_page(struct load_info *info)
 	return page;
 }
 
-#ifdef CONFIG_MODULE_COMPRESS_GZIP
+#if defined(CONFIG_MODULE_COMPRESS_GZIP)
 #include <linux/zlib.h>
 #define MODULE_COMPRESSION	gzip
 #define MODULE_DECOMPRESS_FN	module_gzip_decompress
@@ -114,8 +114,8 @@ static ssize_t module_gzip_decompress(struct load_info *info,
 	do {
 		struct page *page = module_get_next_page(info);
 
-		if (!page) {
-			retval = -ENOMEM;
+		if (IS_ERR(page)) {
+			retval = PTR_ERR(page);
 			goto out_inflate_end;
 		}
 
@@ -141,7 +141,7 @@ static ssize_t module_gzip_decompress(struct load_info *info,
 	kfree(s.workspace);
 	return retval;
 }
-#elif CONFIG_MODULE_COMPRESS_XZ
+#elif defined(CONFIG_MODULE_COMPRESS_XZ)
 #include <linux/xz.h>
 #define MODULE_COMPRESSION	xz
 #define MODULE_DECOMPRESS_FN	module_xz_decompress
@@ -173,8 +173,8 @@ static ssize_t module_xz_decompress(struct load_info *info,
 	do {
 		struct page *page = module_get_next_page(info);
 
-		if (!page) {
-			retval = -ENOMEM;
+		if (IS_ERR(page)) {
+			retval = PTR_ERR(page);
 			goto out;
 		}
 
@@ -199,6 +199,94 @@ static ssize_t module_xz_decompress(struct load_info *info,
 	xz_dec_end(xz_dec);
 	return retval;
 }
+#elif defined(CONFIG_MODULE_COMPRESS_ZSTD)
+#include <linux/zstd.h>
+#define MODULE_COMPRESSION	zstd
+#define MODULE_DECOMPRESS_FN	module_zstd_decompress
+
+static ssize_t module_zstd_decompress(struct load_info *info,
+				    const void *buf, size_t size)
+{
+	static const u8 signature[] = { 0x28, 0xb5, 0x2f, 0xfd };
+	ZSTD_outBuffer zstd_dec;
+	ZSTD_inBuffer zstd_buf;
+	zstd_frame_header header;
+	size_t wksp_size;
+	void *wksp = NULL;
+	ZSTD_DStream *dstream;
+	size_t ret;
+	size_t new_size = 0;
+	int retval;
+
+	if (size < sizeof(signature) ||
+	    memcmp(buf, signature, sizeof(signature))) {
+		pr_err("not a zstd compressed module\n");
+		return -EINVAL;
+	}
+
+	zstd_buf.src = buf;
+	zstd_buf.pos = 0;
+	zstd_buf.size = size;
+
+	ret = zstd_get_frame_header(&header, zstd_buf.src, zstd_buf.size);
+	if (ret != 0) {
+		pr_err("ZSTD-compressed data has an incomplete frame header\n");
+		retval = -EINVAL;
+		goto out;
+	}
+	if (header.windowSize > (1 << ZSTD_WINDOWLOG_MAX)) {
+		pr_err("ZSTD-compressed data has too large a window size\n");
+		retval = -EINVAL;
+		goto out;
+	}
+
+	wksp_size = zstd_dstream_workspace_bound(header.windowSize);
+	wksp = kmalloc(wksp_size, GFP_KERNEL);
+	if (!wksp) {
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	dstream = zstd_init_dstream(header.windowSize, wksp, wksp_size);
+	if (!dstream) {
+		pr_err("Can't initialize ZSTD stream\n");
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	do {
+		struct page *page = module_get_next_page(info);
+
+		if (!IS_ERR(page)) {
+			retval = PTR_ERR(page);
+			goto out;
+		}
+
+		zstd_dec.dst = kmap_local_page(page);
+		zstd_dec.pos = 0;
+		zstd_dec.size = PAGE_SIZE;
+
+		ret = zstd_decompress_stream(dstream, &zstd_dec, &zstd_buf);
+		kunmap(page);
+		retval = zstd_get_error_code(ret);
+		if (retval)
+			break;
+
+		new_size += zstd_dec.pos;
+	} while (zstd_dec.pos == PAGE_SIZE && ret != 0);
+
+	if (retval) {
+		pr_err("ZSTD-decompression failed with status %d\n", retval);
+		retval = -EINVAL;
+		goto out;
+	}
+
+	retval = new_size;
+
+ out:
+	kfree(wksp);
+	return retval;
+}
 #else
 #error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS"
 #endif

kernel/module/main.c

@@ -85,9 +85,6 @@ struct mod_tree_root mod_data_tree __cacheline_aligned = {
 };
 #endif
 
-#define module_addr_min mod_tree.addr_min
-#define module_addr_max mod_tree.addr_max
-
 struct symsearch {
 	const struct kernel_symbol *start, *stop;
 	const s32 *crcs;

kernel/module/sysfs.c

@@ -340,7 +340,7 @@ static int mod_sysfs_init(struct module *mod)
 	int err;
 	struct kobject *kobj;
 
-	if (!module_sysfs_initialized) {
+	if (!module_kset) {
 		pr_err("%s: module sysfs not initialized\n", mod->name);
 		err = -EINVAL;
 		goto out;

kernel/params.c

@@ -940,7 +940,6 @@ static const struct kset_uevent_ops module_uevent_ops = {
 };
 
 struct kset *module_kset;
-int module_sysfs_initialized;
 
 static void module_kobj_release(struct kobject *kobj)
 {
@@ -954,7 +953,11 @@ struct kobj_type module_ktype = {
 };
 
 /*
- * param_sysfs_init - wrapper for built-in params support
+ * param_sysfs_init - create "module" kset
+ *
+ * This must be done before the initramfs is unpacked and
+ * request_module() thus becomes possible, because otherwise the
+ * module load would fail in mod_sysfs_init.
  */
 static int __init param_sysfs_init(void)
 {
@@ -964,13 +967,25 @@ static int __init param_sysfs_init(void)
 			__FILE__, __LINE__);
 		return -ENOMEM;
 	}
-	module_sysfs_initialized = 1;
+
+	return 0;
+}
+subsys_initcall(param_sysfs_init);
+
+/*
+ * param_sysfs_builtin_init - add sysfs version and parameter
+ * attributes for built-in modules
+ */
+static int __init param_sysfs_builtin_init(void)
+{
+	if (!module_kset)
+		return -ENOMEM;
 
 	version_sysfs_builtin();
 	param_sysfs_builtin();
 
 	return 0;
 }
-subsys_initcall(param_sysfs_init);
+late_initcall(param_sysfs_builtin_init);
 
 #endif /* CONFIG_SYSFS */

scripts/kallsyms.c

@@ -49,6 +49,7 @@ _Static_assert(
 struct sym_entry {
 	unsigned long long addr;
 	unsigned int len;
+	unsigned int seq;
 	unsigned int start_pos;
 	unsigned int percpu_absolute;
 	unsigned char sym[];
@@ -77,6 +78,7 @@ static unsigned int table_size, table_cnt;
 static int all_symbols;
 static int absolute_percpu;
 static int base_relative;
+static int lto_clang;
 
 static int token_profit[0x10000];
 
@@ -88,7 +90,7 @@ static unsigned char best_table_len[256];
 static void usage(void)
 {
 	fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] "
-			"[--base-relative] in.map > out.S\n");
+			"[--base-relative] [--lto-clang] in.map > out.S\n");
 	exit(1);
 }
 
@@ -410,6 +412,65 @@ static int symbol_absolute(const struct sym_entry *s)
 	return s->percpu_absolute;
 }
 
+static char * s_name(char *buf)
+{
+	/* Skip the symbol type */
+	return buf + 1;
+}
+
+static void cleanup_symbol_name(char *s)
+{
+	char *p;
+
+	if (!lto_clang)
+		return;
+
+	/*
+	 * ASCII[.]   = 2e
+	 * ASCII[0-9] = 30,39
+	 * ASCII[A-Z] = 41,5a
+	 * ASCII[_]   = 5f
+	 * ASCII[a-z] = 61,7a
+	 *
+	 * As above, replacing '.' with '\0' does not affect the main sorting,
+	 * but it helps us with subsorting.
+	 */
+	p = strchr(s, '.');
+	if (p)
+		*p = '\0';
+}
+
+static int compare_names(const void *a, const void *b)
+{
+	int ret;
+	char sa_namebuf[KSYM_NAME_LEN];
+	char sb_namebuf[KSYM_NAME_LEN];
+	const struct sym_entry *sa = *(const struct sym_entry **)a;
+	const struct sym_entry *sb = *(const struct sym_entry **)b;
+
+	expand_symbol(sa->sym, sa->len, sa_namebuf);
+	expand_symbol(sb->sym, sb->len, sb_namebuf);
+	cleanup_symbol_name(s_name(sa_namebuf));
+	cleanup_symbol_name(s_name(sb_namebuf));
+	ret = strcmp(s_name(sa_namebuf), s_name(sb_namebuf));
+	if (!ret) {
+		if (sa->addr > sb->addr)
+			return 1;
+		else if (sa->addr < sb->addr)
+			return -1;
+
+		/* keep old order */
+		return (int)(sa->seq - sb->seq);
+	}
+
+	return ret;
+}
+
+static void sort_symbols_by_name(void)
+{
+	qsort(table, table_cnt, sizeof(table[0]), compare_names);
+}
+
 static void write_src(void)
 {
 	unsigned int i, k, off;
@@ -495,6 +556,7 @@ static void write_src(void)
 	for (i = 0; i < table_cnt; i++) {
 		if ((i & 0xFF) == 0)
 			markers[i >> 8] = off;
+		table[i]->seq = i;
 
 		/* There cannot be any symbol of length zero. */
 		if (table[i]->len == 0) {
@@ -535,6 +597,15 @@ static void write_src(void)
 
 	free(markers);
 
+	sort_symbols_by_name();
+	output_label("kallsyms_seqs_of_names");
+	for (i = 0; i < table_cnt; i++)
+		printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n",
+			(unsigned char)(table[i]->seq >> 16),
+			(unsigned char)(table[i]->seq >> 8),
+			(unsigned char)(table[i]->seq >> 0));
+	printf("\n");
+
 	output_label("kallsyms_token_table");
 	off = 0;
 	for (i = 0; i < 256; i++) {
@@ -573,7 +644,7 @@ static void forget_symbol(const unsigned char *symbol, int len)
 }
 
 /* do the initial token count */
-static void build_initial_tok_table(void)
+static void build_initial_token_table(void)
 {
 	unsigned int i;
 
@@ -698,7 +769,7 @@ static void insert_real_symbols_in_table(void)
 
 static void optimize_token_table(void)
 {
-	build_initial_tok_table();
+	build_initial_token_table();
 
 	insert_real_symbols_in_table();
 
@@ -818,6 +889,7 @@ int main(int argc, char **argv)
 			{"all-symbols",     no_argument, &all_symbols,     1},
 			{"absolute-percpu", no_argument, &absolute_percpu, 1},
 			{"base-relative",   no_argument, &base_relative,   1},
+			{"lto-clang",       no_argument, &lto_clang,       1},
 			{},
 		};
 

scripts/link-vmlinux.sh

@@ -156,6 +156,10 @@ kallsyms()
 		kallsymopt="${kallsymopt} --base-relative"
 	fi
 
+	if is_enabled CONFIG_LTO_CLANG; then
+		kallsymopt="${kallsymopt} --lto-clang"
+	fi
+
 	info KSYMS ${2}
 	scripts/kallsyms ${kallsymopt} ${1} > ${2}
 }