From nobody Wed Dec 17 11:23:50 2025 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 9B1FAC25B48 for ; Thu, 26 Oct 2023 16:02:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345565AbjJZQCW (ORCPT ); Thu, 26 Oct 2023 12:02:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235128AbjJZQCB (ORCPT ); Thu, 26 Oct 2023 12:02:01 -0400 Received: from mail-yw1-x112d.google.com (mail-yw1-x112d.google.com [IPv6:2607:f8b0:4864:20::112d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15CBDD64 for ; Thu, 26 Oct 2023 09:01:38 -0700 (PDT) Received: by mail-yw1-x112d.google.com with SMTP id 00721157ae682-5a7d9d357faso8561987b3.0 for ; Thu, 26 Oct 2023 09:01:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1698336097; x=1698940897; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=uEKMOhNXhzYoW+58HZlorWdy0xM6bOeFhfp+J2ei5Pk=; b=UF24kzL8KHCKobWjP+px9fmlmmQxH9yWGNpsLZbuLJY+xYs/MAhviGKf9djclpdWkZ 7NtSBxlMGtEfD+bxkn04jRCPp8/GIbsuUkxWsoAOFXPEa4z+fQKfNY6esNhEuMl4WmU+ h7N+mdnhhQ8NqFVBFCjwXyrQuRecJs5JLTble+wAE7BCV8kWgtQKZYcGlbVS/AekZFh2 MDhBy3ccESy2GCYidca014KIUJ0+yUhUJwO20OjTsnl/1GDuUZ5nRpabFHI1PaN3mVE0 exrOFfOIRrtuGX9D9ecwotwvKm4IxEol3JKg4lgYwzCNIovOHzSORTUyxKK3UMsUVWq0 ARSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698336097; x=1698940897; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=uEKMOhNXhzYoW+58HZlorWdy0xM6bOeFhfp+J2ei5Pk=; b=ETLwUhmjOzf3VLMHE3xwdx+s7bqYG3I81qj+vF95Bl48XxAibfI1ZiJubWZ5C5u2Kf 3ZJ0Qkpzp0ZU13bD/7FQEK6QWNL88wUYk7IOq6a77nLHB3OhJkZoSGCahkmnQZEJi+6g u/V/Z0qVvzfZxcdt8+b3+xUKGVqoKByWdEHFRyc4BkLHhNm+YBdR0/B83BPgr1s2K351 R17iXbOlRW80PX9OGyylt7wgrxw+dHeouv+F5j0VUxi4ce33wdFJ99/JlIS5g9HQNZKP 8mc7Wca9xiGYH9FMVHQOio/FocxIzU9vLM+SmvIRCH+HPabAI9C0S/JE2sNL3wa75zge 3nwg== X-Gm-Message-State: AOJu0Yz0XDL4wcm0kSzW9gfn6QCX07ijYYy6DkWzgQv5Pm/kIhY43RE8 LzHbbLaaoJLMH7gUie50tWKDSKXWEw== X-Google-Smtp-Source: AGHT+IGr6fmyHg0YYbGU6O+RzU4fXu9VOlULo8dgdRjCbkY4llapt4dmowe19QQmBMjmutwcbGI8Rw== X-Received: by 2002:a81:a050:0:b0:5a7:ba54:af02 with SMTP id x77-20020a81a050000000b005a7ba54af02mr20164519ywg.38.1698336096799; Thu, 26 Oct 2023 09:01:36 -0700 (PDT) Received: from citadel.lan ([2600:6c4a:4d3f:6d5c::1019]) by smtp.gmail.com with ESMTPSA id a71-20020a0dd84a000000b005a20ab8a184sm6130129ywe.31.2023.10.26.09.01.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Oct 2023 09:01:36 -0700 (PDT) From: Brian Gerst To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: Ingo Molnar , Thomas Gleixner , Borislav Petkov , "H . Peter Anvin" , Peter Zijlstra , Uros Bizjak , Brian Gerst Subject: [PATCH v2 11/11] kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU Date: Thu, 26 Oct 2023 12:01:00 -0400 Message-ID: <20231026160100.195099-12-brgerst@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231026160100.195099-1-brgerst@gmail.com> References: <20231026160100.195099-1-brgerst@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" x86-64 was the only user. Signed-off-by: Brian Gerst --- init/Kconfig | 11 +----- kernel/kallsyms.c | 12 ++----- scripts/kallsyms.c | 80 ++++++++--------------------------------- scripts/link-vmlinux.sh | 4 --- 4 files changed, 18 insertions(+), 89 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 1af31b23e376..4d91c5632aaf 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1715,11 +1715,6 @@ config KALLSYMS_ALL =20 Say N unless you really need all symbols, or kernel live patching. =20 -config KALLSYMS_ABSOLUTE_PERCPU - bool - depends on KALLSYMS - default n - config KALLSYMS_BASE_RELATIVE bool depends on KALLSYMS @@ -1727,11 +1722,7 @@ config KALLSYMS_BASE_RELATIVE help Instead of emitting them as absolute values in the native word size, emit the symbol references in the kallsyms table as 32-bit entries, - each containing a relative value in the range [base, base + U32_MAX] - or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either - an absolute value in the range [0, S32_MAX] or a relative value in the - range [base, base + S32_MAX], where base is the lowest relative symbol - address encountered in the image. + each containing a relative value in the range [base, base + U32_MAX]. =20 On 64-bit builds, this reduces the size of the address table by 50%, but more importantly, it results in entries whose values are build diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 18edd57b5fe8..f4e8e531052a 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -151,16 +151,8 @@ unsigned long kallsyms_sym_address(int idx) if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) return kallsyms_addresses[idx]; =20 - /* values are unsigned offsets if --absolute-percpu is not in effect */ - if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU)) - return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; - - /* ...otherwise, positive offsets are absolute values */ - if (kallsyms_offsets[idx] >=3D 0) - return kallsyms_offsets[idx]; - - /* ...and negative offsets are relative to kallsyms_relative_base - 1 */ - return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; + /* values are unsigned offsets */ + return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; } =20 static void cleanup_symbol_name(char *s) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 653b92f6d4c8..501f978abf4b 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -5,8 +5,8 @@ * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * - * Usage: kallsyms [--all-symbols] [--absolute-percpu] - * [--base-relative] [--lto-clang] in.map > out.S + * Usage: kallsyms [--all-symbols] [--base-relative] [--lto-clang] + * in.map > out.S * * Table compression uses all the unused char codes on the symbols and * maps these to the most used substrings (tokens). For instance, it might @@ -37,7 +37,6 @@ struct sym_entry { unsigned int len; unsigned int seq; unsigned int start_pos; - unsigned int percpu_absolute; unsigned char sym[]; }; =20 @@ -55,14 +54,9 @@ static struct addr_range text_ranges[] =3D { #define text_range_text (&text_ranges[0]) #define text_range_inittext (&text_ranges[1]) =20 -static struct addr_range percpu_range =3D { - "__per_cpu_start", "__per_cpu_end", -1ULL, 0 -}; - static struct sym_entry **table; static unsigned int table_size, table_cnt; static int all_symbols; -static int absolute_percpu; static int base_relative; static int lto_clang; =20 @@ -75,7 +69,7 @@ static unsigned char best_table_len[256]; =20 static void usage(void) { - fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] " + fprintf(stderr, "Usage: kallsyms [--all-symbols] " "[--base-relative] [--lto-clang] in.map > out.S\n"); exit(1); } @@ -167,7 +161,6 @@ static struct sym_entry *read_symbol(FILE *in, char **b= uf, size_t *buf_len) return NULL; =20 check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges)); - check_symbol_range(name, addr, &percpu_range, 1); =20 /* include the type field in the symbol name, so that it gets * compressed together */ @@ -183,7 +176,6 @@ static struct sym_entry *read_symbol(FILE *in, char **b= uf, size_t *buf_len) sym->len =3D len; sym->sym[0] =3D type; strcpy(sym_name(sym), name); - sym->percpu_absolute =3D 0; =20 return sym; } @@ -334,11 +326,6 @@ static int expand_symbol(const unsigned char *data, in= t len, char *result) return total; } =20 -static int symbol_absolute(const struct sym_entry *s) -{ - return s->percpu_absolute; -} - static void cleanup_symbol_name(char *s) { char *p; @@ -499,30 +486,17 @@ static void write_src(void) */ =20 long long offset; - int overflow; - - if (!absolute_percpu) { - offset =3D table[i]->addr - relative_base; - overflow =3D (offset < 0 || offset > UINT_MAX); - } else if (symbol_absolute(table[i])) { - offset =3D table[i]->addr; - overflow =3D (offset < 0 || offset > INT_MAX); - } else { - offset =3D relative_base - table[i]->addr - 1; - overflow =3D (offset < INT_MIN || offset >=3D 0); - } - if (overflow) { + + offset =3D table[i]->addr - relative_base; + if (offset < 0 || offset > UINT_MAX) { fprintf(stderr, "kallsyms failure: " - "%s symbol value %#llx out of range in relative mode\n", - symbol_absolute(table[i]) ? "absolute" : "relative", + "symbol value %#llx out of range in relative mode\n", table[i]->addr); exit(EXIT_FAILURE); } printf("\t.long\t%#x /* %s */\n", (int)offset, table[i]->sym); - } else if (!symbol_absolute(table[i])) { - output_address(table[i]->addr); } else { - printf("\tPTR\t%#llx\n", table[i]->addr); + output_address(table[i]->addr); } } printf("\n"); @@ -775,36 +749,15 @@ static void sort_symbols(void) qsort(table, table_cnt, sizeof(table[0]), compare_symbols); } =20 -static void make_percpus_absolute(void) -{ - unsigned int i; - - for (i =3D 0; i < table_cnt; i++) - if (symbol_in_range(table[i], &percpu_range, 1)) { - /* - * Keep the 'A' override for percpu symbols to - * ensure consistent behavior compared to older - * versions of this tool. - */ - table[i]->sym[0] =3D 'A'; - table[i]->percpu_absolute =3D 1; - } -} - -/* find the minimum non-absolute symbol address */ +/* find the minimum symbol address */ static void record_relative_base(void) { - unsigned int i; - - for (i =3D 0; i < table_cnt; i++) - if (!symbol_absolute(table[i])) { - /* - * The table is sorted by address. - * Take the first non-absolute symbol value. - */ - relative_base =3D table[i]->addr; - return; - } + /* + * The table is sorted by address. + * Take the first symbol value. + */ + if (table_cnt) + relative_base =3D table[0]->addr; } =20 int main(int argc, char **argv) @@ -812,7 +765,6 @@ int main(int argc, char **argv) while (1) { static const struct option long_options[] =3D { {"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, <o_clang, 1}, {}, @@ -831,8 +783,6 @@ int main(int argc, char **argv) =20 read_map(argv[optind]); shrink_table(); - if (absolute_percpu) - make_percpus_absolute(); sort_symbols(); if (base_relative) record_relative_base(); diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index a432b171be82..d25b6d5de45e 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -148,10 +148,6 @@ kallsyms() kallsymopt=3D"${kallsymopt} --all-symbols" fi =20 - if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then - kallsymopt=3D"${kallsymopt} --absolute-percpu" - fi - if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then kallsymopt=3D"${kallsymopt} --base-relative" fi --=20 2.41.0