From nobody Thu Dec 18 10:21:19 2025 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CFA6B1FAC54 for ; Tue, 11 Feb 2025 11:50:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739274629; cv=none; b=WlbFSXM9JSro5duOEYm/Bw7qIgmRAGREuy+TQ7GThrk6vtffioVSNQvhq9NcO/oSJASly7yv/VJyWhhZ/9nLYbTSCKDuG7nL95c2bb2CH8c02H1FsFUSsI9bkNJsWu7IFzaGDRqyvm9M9fnhpzwELrGUH2aKD94ghN8wJOulxY4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739274629; c=relaxed/simple; bh=m/+8q1wrcgoC6wUJG2XUe5g49NSQY+/e+7aNV/Lentw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fgHmMpr1sOkuWcEjzpW0jDh0m1bZZSXnaRRbZvo9jBdCAplm+f3dMDO1Oepju1nTVXRBtLIO0D/fJ5B3GNFhiSaYKJ4bOrpIfEnxDP8VALXVolqEmfAoaum2n4BdM0ee8FgH45tMAX4M2GkfXG7c3oRahl5xW2/xSVx9aKvWVOQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8DxvnN+OatnWiJyAA--.35205S3; Tue, 11 Feb 2025 19:50:22 +0800 (CST) Received: from linux.localdomain (unknown [113.200.148.30]) by front1 (Coremail) with SMTP id qMiowMBx3MR6OatnNPMLAA--.43600S5; Tue, 11 Feb 2025 19:50:21 +0800 (CST) From: Tiezhu Yang To: Josh Poimboeuf , Peter Zijlstra , Huacai Chen Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v7 3/7] objtool: Handle PC relative relocation type Date: Tue, 11 Feb 2025 19:50:12 +0800 Message-ID: <20250211115016.26913-4-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20250211115016.26913-1-yangtiezhu@loongson.cn> References: <20250211115016.26913-1-yangtiezhu@loongson.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qMiowMBx3MR6OatnNPMLAA--.43600S5 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoWxZr48Ww13Xw15uryfGFyrKrX_yoW7Jw45pF srC398Kr4Yqr1xWw42ya1kWrW5Gws7Wry2qryqqryrZrZFqw15tFWxAFZ8Ka1UXwsYgFWx ZFnYgw17AF4qv3gCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUvEb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1ln4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2 x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1q6rW5 McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr4 1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_Jrv_ JF1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17 CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0 I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I 8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73 UjIFyTuYvjxU4AhLUUUUU Content-Type: text/plain; charset="utf-8" For the most part, an absolute relocation type is used for rodata. In the case of STT_SECTION, reloc->sym->offset is always zero, for the other symbol types, reloc_addend(reloc) is always zero, thus it can use a simple statement "reloc->sym->offset + reloc_addend(reloc)" to obtain the symbol offset for various symbol types. When compiling on LoongArch, there exist PC relative relocation types for rodata, it needs to calculate the symbol offset with "S + A - PC" according to the spec of "ELF for the LoongArch Architecture". If there is only one jump table in the rodata, the "PC" is the entry address which is equal with the value of reloc_offset(reloc), at this time, reloc_offset(table) is 0. If there are many jump tables in the rodata, the "PC" is the offset of the jump table's base address which is equal with the value of reloc_offset(reloc) - reloc_offset(table). So for LoongArch, if the relocation type is PC relative, it can use a statement "reloc_offset(reloc) - reloc_offset(table)" to get the "PC" value when calculating the symbol offset with "S + A - PC" for one or many jump tables in the rodata. Add an arch-specific function arch_jump_table_sym_offset() to assign the symbol offset, for the most part that is an absolute relocation, the default value is "reloc->sym->offset + reloc_addend(reloc)" in the weak definition, it can be overridden by each architecture that has different requirements. Link: https://github.com/loongson/la-abi-specs/blob/release/laelf.adoc Signed-off-by: Tiezhu Yang --- tools/objtool/arch/loongarch/decode.c | 17 +++++++++++++---- tools/objtool/arch/loongarch/include/arch/elf.h | 7 +++++++ tools/objtool/check.c | 7 ++++++- tools/objtool/include/objtool/arch.h | 1 + 4 files changed, 27 insertions(+), 5 deletions(-) diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loo= ngarch/decode.c index b64205b89f6b..02e490555966 100644 --- a/tools/objtool/arch/loongarch/decode.c +++ b/tools/objtool/arch/loongarch/decode.c @@ -5,10 +5,7 @@ #include #include #include - -#ifndef EM_LOONGARCH -#define EM_LOONGARCH 258 -#endif +#include =20 int arch_ftrace_match(char *name) { @@ -374,3 +371,15 @@ unsigned int arch_reloc_size(struct reloc *reloc) return 8; } } + +unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc= *table) +{ + switch (reloc_type(reloc)) { + case R_LARCH_32_PCREL: + case R_LARCH_64_PCREL: + return reloc->sym->offset + reloc_addend(reloc) - + (reloc_offset(reloc) - reloc_offset(table)); + default: + return reloc->sym->offset + reloc_addend(reloc); + } +} diff --git a/tools/objtool/arch/loongarch/include/arch/elf.h b/tools/objtoo= l/arch/loongarch/include/arch/elf.h index 9623d663220e..ec79062c9554 100644 --- a/tools/objtool/arch/loongarch/include/arch/elf.h +++ b/tools/objtool/arch/loongarch/include/arch/elf.h @@ -18,6 +18,13 @@ #ifndef R_LARCH_32_PCREL #define R_LARCH_32_PCREL 99 #endif +#ifndef R_LARCH_64_PCREL +#define R_LARCH_64_PCREL 109 +#endif + +#ifndef EM_LOONGARCH +#define EM_LOONGARCH 258 +#endif =20 #define R_NONE R_LARCH_NONE #define R_ABS32 R_LARCH_32 diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 85c1988014dc..7174dcb7496e 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1943,6 +1943,11 @@ static int add_special_section_alts(struct objtool_f= ile *file) return ret; } =20 +__weak unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struc= t reloc *table) +{ + return reloc->sym->offset + reloc_addend(reloc); +} + static int add_jump_table(struct objtool_file *file, struct instruction *i= nsn, struct reloc *next_table) { @@ -1971,7 +1976,7 @@ static int add_jump_table(struct objtool_file *file, = struct instruction *insn, if (prev_offset && reloc_offset(reloc) !=3D prev_offset + arch_reloc_siz= e(reloc)) break; =20 - sym_offset =3D reloc->sym->offset + reloc_addend(reloc); + sym_offset =3D arch_jump_table_sym_offset(reloc, table); =20 /* Detect function pointers from contiguous objects: */ if (reloc->sym->sec =3D=3D pfunc->sec && sym_offset =3D=3D pfunc->offset) diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/o= bjtool/arch.h index 396f7c6c81c0..089a1acc48a8 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -98,5 +98,6 @@ int arch_rewrite_retpolines(struct objtool_file *file); bool arch_pc_relative_reloc(struct reloc *reloc); =20 unsigned int arch_reloc_size(struct reloc *reloc); +unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc= *table); =20 #endif /* _ARCH_H */ --=20 2.42.0