From patchwork Wed Sep 25 15:01:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 13812155 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B68E18B484 for ; Wed, 25 Sep 2024 15:02:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276533; cv=none; b=RvB3lFeKBTtz8nrGPvdv5Seuzh7rojSjGbGwB/SKVRfcFf15Wg9HycvV2SHJwq0R0QtltnEXrKHcq6Xp1wwFZWlZoUGIqCXLSjL9xrGtLbDcB/iu+vyPtAXMG5IsqBbAk/iDynyLsL/j05/60UJlY+5Sg0qmf70ypJEmldZvgs8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276533; c=relaxed/simple; bh=uNZCRc4hsOOw5KhJ4tKlrDfm3UOmHFTj64isJZp8vsM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EEQ1FmR9Rkbp+dT4nriXl/QUkz+e5CYMJXjWkrtcNiIEkYX8609gS1j4aH5EZK8K35qKeUWvHZFuYA1WPrH59mOWoCH7EgQzQJ7+2ePL1ogX3f8yh65gxjT2PqNmmcPOqY5Ubzhd4Vi+IqNOtvDw5wQk5uYQ49uDHLRj+tb4vqA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=MW6uUn+Z; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="MW6uUn+Z" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-6e20e22243dso33201637b3.1 for ; Wed, 25 Sep 2024 08:02:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727276530; x=1727881330; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=lvBkJLcu5Sh3tnaE09NAZ6RZ9jqQeWc/oMvpiTXt3OQ=; b=MW6uUn+ZkZmLYEiLpaElXr/beisIKf4BBTfjJogoXH37rHomkt2A4B7qCm+Kiwfe8i FAqZas4anHYnFdXfVuHp2PvwmUi7ACiKyFFllm2+Z7yRRdclrUYTvUA4tQUPeMShD8LY ZlqhyR7ImxJxRIV9h0l72S+BLqNBA/NpY5xzPQfn4O4hKt/jCRIr3jBlqfjocnzMcaHJ Bpv1ps4IrEFACOyXPoBaXnoQAOR4VLwaJSCtUt+qWWFLIgC2NW6G0QTsvGprB9LCOqBx gmh8TYa5MGBI5H44V6/wqzoDLuiCSDzoe5P5loSjctWpvVH/Z+rmtLwou5SmGz/KPBHe knIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727276530; x=1727881330; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=lvBkJLcu5Sh3tnaE09NAZ6RZ9jqQeWc/oMvpiTXt3OQ=; b=snHhZ4wfmn/mu1hliv6eTLfxt13WhAvrIIu7JD6H/fXljNcQ55L818un2jj+57dclx TdAunPTM9h6D99lRMMhNkHr6tcsNiFaCAKWT9ZDTeWlqcOzCmFN58X2lhZN1FHBNBDNR /I/n63q+saCGxygbWHQChXxpbbF8yfzj4DrI0NMnacLrgega24XAD9PXGR2d1CTbHJnT wKkrYimNUORodrjTeKZLXEleUOxDgBCdfteVMwu/VDEa7eQ1Ld51o+1rHrrQFf/IFdaN 5XXasTGoX3242WmXXtLwSGQmLvBu+/f25kcokaL3EJmYdbqMPucB+4NEt3qLafj1GKgE zhpQ== X-Forwarded-Encrypted: i=1; AJvYcCXpk5tth9FUUwTIumGZlz9UNL/5nPBDImiXBWqgEwWPcqMfPuIdS7OEgUA5pP51fmiFeZE7nQD8vRme+Dw=@vger.kernel.org X-Gm-Message-State: AOJu0YxGfrubCTWEAUnIomB+6a/Hll/vsRr/5l7eoHvxAYlM1Y2NTkbz KTwytdbNFOCxo+GZbHVelbCrK08dpKujqxzJlQ2EFDVTRMPBDemgHU0q6p/mx3uTIA/g3A== X-Google-Smtp-Source: AGHT+IENPFDDE4RBTdISjbf4G4pk2mGOjzo8FmXYzCFJ7WDt9ZFnIbiw80yVnuCNeltTBlMkQAqf4tvt X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a05:690c:c9c:b0:6b0:d571:3540 with SMTP id 00721157ae682-6e21da796e6mr255067b3.6.1727276529787; Wed, 25 Sep 2024 08:02:09 -0700 (PDT) Date: Wed, 25 Sep 2024 17:01:08 +0200 In-Reply-To: <20240925150059.3955569-30-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240925150059.3955569-30-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=6334; i=ardb@kernel.org; h=from:subject; bh=rOkV7b1W8gqAvLsLoQ2i9zRn35wAefNGZsd9tIotAWg=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIe2L6vYGW5mupTcMu0+/lmvg/R+5wEt4Wbk5z8ydQtZqX U8bN7/vKGVhEONgkBVTZBGY/ffdztMTpWqdZ8nCzGFlAhnCwMUpABO5Lc3wP3L7HcnzmyvvZR1M rS85onToQ4R+5Y7wJefSbJaqGNxXYmVkaHXklA3NNHruJrHYtjJMvdzeSUx0wZXnutnTlvEcNXD iBAA= X-Mailer: git-send-email 2.46.0.792.g87dc391469-goog Message-ID: <20240925150059.3955569-38-ardb+git@google.com> Subject: [RFC PATCH 08/28] scripts/kallsyms: Remove support for absolute per-CPU variables From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , x86@kernel.org, "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Uros Bizjak , Dennis Zhou , Tejun Heo , Christoph Lameter , Mathieu Desnoyers , Paolo Bonzini , Vitaly Kuznetsov , Juergen Gross , Boris Ostrovsky , Greg Kroah-Hartman , Arnd Bergmann , Masahiro Yamada , Kees Cook , Nathan Chancellor , Keith Packard , Justin Stitt , Josh Poimboeuf , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-efi@vger.kernel.org, linux-arch@vger.kernel.org, linux-sparse@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-perf-users@vger.kernel.org, rust-for-linux@vger.kernel.org, llvm@lists.linux.dev From: Ard Biesheuvel SMP on x86_64 no longer needs absolute per-CPU variables, so this support can be dropped from kallsyms as well, as no other architectures rely on this functionality. Signed-off-by: Ard Biesheuvel --- init/Kconfig | 4 -- kernel/kallsyms.c | 12 +---- scripts/kallsyms.c | 51 +++----------------- scripts/link-vmlinux.sh | 4 -- 4 files changed, 9 insertions(+), 62 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index be8a9a786d3c..f6eeba81282d 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1835,10 +1835,6 @@ config KALLSYMS_ALL Say N unless you really need all symbols, or kernel live patching. -config KALLSYMS_ABSOLUTE_PERCPU - bool - depends on KALLSYMS - # end of the "standard kernel features (expert users)" menu config ARCH_HAS_MEMBARRIER_CALLBACKS diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index a9a0ca605d4a..4198f30aac3c 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -148,16 +148,8 @@ static unsigned int get_symbol_offset(unsigned long pos) unsigned long kallsyms_sym_address(int idx) { - /* 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] >= 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]; } static unsigned int get_symbol_seq(int index) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 09757d300a05..9c34b9397872 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -5,7 +5,7 @@ * 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] in.map > out.S + * Usage: kallsyms [--all-symbols] 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 long long addr; unsigned int len; unsigned int seq; - bool percpu_absolute; unsigned char sym[]; }; @@ -62,7 +61,6 @@ static struct addr_range percpu_range = { static struct sym_entry **table; static unsigned int table_size, table_cnt; static int all_symbols; -static int absolute_percpu; static int token_profit[0x10000]; @@ -73,7 +71,7 @@ static unsigned char best_table_len[256]; static void usage(void) { - fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] in.map > out.S\n"); + fprintf(stderr, "Usage: kallsyms [--all-symbols] in.map > out.S\n"); exit(1); } @@ -175,7 +173,6 @@ static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) sym->len = len; sym->sym[0] = type; strcpy(sym_name(sym), name); - sym->percpu_absolute = false; return sym; } @@ -319,11 +316,6 @@ static int expand_symbol(const unsigned char *data, int len, char *result) return total; } -static bool symbol_absolute(const struct sym_entry *s) -{ - return s->percpu_absolute; -} - static int compare_names(const void *a, const void *b) { int ret; @@ -457,20 +449,10 @@ static void write_src(void) long long offset; bool overflow; - if (!absolute_percpu) { - offset = table[i]->addr - relative_base; - overflow = offset < 0 || offset > UINT_MAX; - } else if (symbol_absolute(table[i])) { - offset = table[i]->addr; - overflow = offset < 0 || offset > INT_MAX; - } else { - offset = relative_base - table[i]->addr - 1; - overflow = offset < INT_MIN || offset >= 0; - } + offset = table[i]->addr - relative_base; + overflow = (offset < 0 || offset > UINT_MAX); if (overflow) { - fprintf(stderr, "kallsyms failure: " - "%s symbol value %#llx out of range in relative mode\n", - symbol_absolute(table[i]) ? "absolute" : "relative", + fprintf(stderr, "kallsyms failure: symbol value %#llx out of range\n", table[i]->addr); exit(EXIT_FAILURE); } @@ -725,32 +707,16 @@ static void sort_symbols(void) qsort(table, table_cnt, sizeof(table[0]), compare_symbols); } -static void make_percpus_absolute(void) -{ - unsigned int i; - - for (i = 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] = 'A'; - table[i]->percpu_absolute = true; - } -} - /* find the minimum non-absolute symbol address */ static void record_relative_base(void) { unsigned int i; for (i = 0; i < table_cnt; i++) - if (table[i]->addr && !symbol_absolute(table[i])) { + if (table[i]->addr) { /* * The table is sorted by address. - * Take the first non-absolute symbol value. + * Take the first non-zero symbol value. */ relative_base = table[i]->addr; return; @@ -762,7 +728,6 @@ int main(int argc, char **argv) while (1) { static const struct option long_options[] = { {"all-symbols", no_argument, &all_symbols, 1}, - {"absolute-percpu", no_argument, &absolute_percpu, 1}, {}, }; @@ -779,8 +744,6 @@ int main(int argc, char **argv) read_map(argv[optind]); shrink_table(); - if (absolute_percpu) - make_percpus_absolute(); sort_symbols(); record_relative_base(); optimize_token_table(); diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index a9b3f34a78d2..df5f3fbb46f3 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -140,10 +140,6 @@ kallsyms() kallsymopt="${kallsymopt} --all-symbols" fi - if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then - kallsymopt="${kallsymopt} --absolute-percpu" - fi - info KSYMS "${2}.S" scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"