From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DF0AC001E0 for ; Mon, 23 Oct 2023 11:27:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233975AbjJWL1y (ORCPT ); Mon, 23 Oct 2023 07:27:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233974AbjJWL1x (ORCPT ); Mon, 23 Oct 2023 07:27:53 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5155CDC for ; Mon, 23 Oct 2023 04:27:50 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AA2BC433C8; Mon, 23 Oct 2023 11:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698060469; bh=ANLp9EHGumIP9oIrUFxJjW7FxaJ7tKmmnrwnzPdJhOA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2hoL0iwMq+akAeV4lvjIS1TSkM+kigqjl7P7EbLK/VVa2Mgv71NxaqNRY6cpf7QTT dGoxVVd4efHeWyEAsNq2fw6dWZ0+GxI1wnu9oGu8ZTUXFjhx/GStLUJmKLN38me/wX mZtOipFDEpTNpzmk8LQivqx4A3DvDZh5TNMAbX6g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhen Lei , Luis Chamberlain , Sasha Levin Subject: [PATCH 6.1 183/196] kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[] Date: Mon, 23 Oct 2023 12:57:28 +0200 Message-ID: <20231023104833.563121736@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104828.488041585@linuxfoundation.org> References: <20231023104828.488041585@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhen Lei [ Upstream commit 19bd8981dc2ee35fdc81ab1b0104b607c917d470 ] kallsyms_seqs_of_names[] records the symbol index sorted by address, the maximum value in kallsyms_seqs_of_names[] is the number of symbols. And 2^24 = 16777216, which means that three bytes are enough to store the index. This can help us save (1 * kallsyms_num_syms) bytes of memory. Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain Stable-dep-of: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") Signed-off-by: Sasha Levin --- kernel/kallsyms.c | 18 ++++++++++++++---- kernel/kallsyms_internal.h | 2 +- scripts/kallsyms.c | 5 ++++- 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index ad3cccb0970f8..32cba13eee6c4 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -197,6 +197,16 @@ static int compare_symbol_name(const char *name, char *namebuf) return strcmp(name, namebuf); } +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) @@ -211,7 +221,7 @@ static int kallsyms_lookup_names(const char *name, while (low <= high) { mid = low + (high - low) / 2; - seq = kallsyms_seqs_of_names[mid]; + seq = get_symbol_seq(mid); off = get_symbol_offset(seq); kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); ret = compare_symbol_name(name, namebuf); @@ -228,7 +238,7 @@ static int kallsyms_lookup_names(const char *name, low = mid; while (low) { - seq = kallsyms_seqs_of_names[low - 1]; + 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)) @@ -240,7 +250,7 @@ static int kallsyms_lookup_names(const char *name, if (end) { high = mid; while (high < kallsyms_num_syms - 1) { - seq = kallsyms_seqs_of_names[high + 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)) @@ -265,7 +275,7 @@ unsigned long kallsyms_lookup_name(const char *name) ret = kallsyms_lookup_names(name, &i, NULL); if (!ret) - return kallsyms_sym_address(kallsyms_seqs_of_names[i]); + return kallsyms_sym_address(get_symbol_seq(i)); return module_kallsyms_lookup_name(name); } diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h index a04b7a5cb1e3e..27fabdcc40f57 100644 --- a/kernel/kallsyms_internal.h +++ b/kernel/kallsyms_internal.h @@ -26,6 +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 unsigned int kallsyms_seqs_of_names[] __weak; +extern const u8 kallsyms_seqs_of_names[] __weak; #endif // LINUX_KALLSYMS_INTERNAL_H_ diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 80aab2aa72246..ff8cce1757849 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -602,7 +602,10 @@ static void write_src(void) sort_symbols_by_name(); output_label("kallsyms_seqs_of_names"); for (i = 0; i < table_cnt; i++) - printf("\t.long\t%u\n", table[i]->seq); + 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"); -- 2.42.0