linux-kernel - [PATCH 03/16] scripts/kallsyms: set relative

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Date:   Sat, 23 Nov 2019 22:27:14 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-kbuild@...r.kernel.org
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 03/16] scripts/kallsyms: set relative_base more effectively

Currently, record_relative_base() iterates over the entire table to
find the minimum address, but it is not efficient because we sort
the table anyway.

After sort_symbol(), the table is sorted by address. (kallsyms parses
the 'nm -n' output, so the data is already sorted by address, but this
commit does not rely on it.)

Move record_relative_base() after sort_symbols(), and take the first
non-absolute symbol value.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 scripts/kallsyms.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 79641874d860..0959e1de381c 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -731,11 +731,15 @@ static void record_relative_base(void)
 {
 	unsigned int i;
 
-	relative_base = -1ULL;
 	for (i = 0; i < table_cnt; i++)
-		if (!symbol_absolute(&table[i]) &&
-		    table[i].addr < relative_base)
+		if (!symbol_absolute(&table[i])) {
+			/*
+			 * The table is sorted by address.
+			 * Take the first non-absolute symbol value.
+			 */
 			relative_base = table[i].addr;
+			return;
+		}
 }
 
 int main(int argc, char **argv)
@@ -758,9 +762,9 @@ int main(int argc, char **argv)
 	read_map(stdin);
 	if (absolute_percpu)
 		make_percpus_absolute();
+	sort_symbols();
 	if (base_relative)
 		record_relative_base();
-	sort_symbols();
 	optimize_token_table();
 	write_src();
 
-- 
2.17.1