From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752930AbbC3Ltp (ORCPT ); Mon, 30 Mar 2015 07:49:45 -0400 Received: from mail-wg0-f49.google.com ([74.125.82.49]:35190 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752847AbbC3Ltk (ORCPT ); Mon, 30 Mar 2015 07:49:40 -0400 From: Ard Biesheuvel To: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arnd@arndb.de, mmarek@suse.cz, linux@arm.linux.org.uk Cc: Ard Biesheuvel Subject: [RFC PATCH 1/2] Kbuild: kallsyms: ignore veneers emitted by the ARM linker Date: Mon, 30 Mar 2015 13:49:26 +0200 Message-Id: <1427716167-25078-2-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1427716167-25078-1-git-send-email-ard.biesheuvel@linaro.org> References: <1427716167-25078-1-git-send-email-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When linking large kernels on ARM, the linker will insert veneers (i.e., PLT like stubs) when function symbols are out of reach for the ordinary relative branch/branch-and-link instructions. However, due to the fact that the kallsyms region sits in .rodata, which is between .text and .init.text, additional veneers may be emitted in the second pass due to the fact that the size of the kallsyms region itself has pushed the .init.text section further down, resulting in additional veneers to be emitted. So ignore the veneers when generating the symbol table. Veneers have no corresponding source code, and they will not turn up in backtraces anyway. Signed-off-by: Ard Biesheuvel --- scripts/kallsyms.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index c6d33bd15b04..6668c87d599f 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -212,6 +212,12 @@ static int symbol_valid(struct sym_entry *s) "_SDA_BASE_", /* ppc */ "_SDA2_BASE_", /* ppc */ NULL }; + + static char *special_suffixes[] = { + "_compiled.", /* gcc < 3.0: "gcc[0-9]_compiled." */ + "_veneer", /* arm */ + NULL }; + int i; int offset = 1; @@ -244,13 +250,18 @@ static int symbol_valid(struct sym_entry *s) } /* Exclude symbols which vary between passes. */ - if (strstr((char *)s->sym + offset, "_compiled.")) - return 0; - for (i = 0; special_symbols[i]; i++) if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 ) return 0; + for (i = 0; special_suffixes[i]; i++) { + char *sym_name = (char *)s->sym + offset; + int l = strlen(sym_name) - strlen(special_suffixes[i]); + + if (l >= 0 && strcmp(sym_name + l, special_suffixes[i]) == 0) + return 0; + } + return 1; } -- 1.8.3.2