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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 14:05:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 14:05:39 -0800
commit3ba2c3ff98ea8bfb219288dbacf2a23a902c751b (patch)
tree90165b304a5b0cf50bc88883ca7a61f1cec65b8c /scripts
parent0015edd6f66172f93aa720192020138ca13ba0a6 (diff)
parent4f1354d5c6a3264c91238962d1597eef40c40419 (diff)
downloadlwn-3ba2c3ff98ea8bfb219288dbacf2a23a902c751b.tar.gz
lwn-3ba2c3ff98ea8bfb219288dbacf2a23a902c751b.zip
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
Diffstat (limited to 'scripts')
-rw-r--r--scripts/kallsyms.c78
-rwxr-xr-xscripts/link-vmlinux.sh4
2 files changed, 79 insertions, 3 deletions
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 03fa07ad45d9..04e04fbd9625 100644
--- a/scripts/kallsyms.c
+++ b/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},
{},
};
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 918470d768e9..32e573943cf0 100755
--- a/scripts/link-vmlinux.sh
+++ b/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}
}