From nobody Wed Apr 15 00:02:48 2026 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 6BC7DC00140 for ; Fri, 29 Jul 2022 02:08:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231401AbiG2CI0 (ORCPT ); Thu, 28 Jul 2022 22:08:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230081AbiG2CIY (ORCPT ); Thu, 28 Jul 2022 22:08:24 -0400 Received: from xry111.site (xry111.site [IPv6:2001:470:683e::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AB2232DA6 for ; Thu, 28 Jul 2022 19:08:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1659060500; bh=Pr7+lAk3BpHjZc9aaO+tL3K4NBHyUQwC5PAB5P1mSzc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=CwGAIYmSH009Ww9mOOslXQadpkJZ/k/rprbkrxALrQn5XhQEgStIXNqjCWA2t5xWX EjTYeFhz41oYgUe01lB0M7WC1n1ufwKZojxfKmM3aP5d9fxD7a/IUzRbUVKzY8P6Ty U170ZYRDR+33alhuewOIvc/4qXiRaIPkBYQYmOEw= Received: from localhost.localdomain (xry111.site [IPv6:2001:470:683e::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384)) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id 5E01665929; Thu, 28 Jul 2022 22:08:19 -0400 (EDT) Message-ID: <2ad1085b3789765bf04bd26d65efc06a79d4cfc0.camel@xry111.site> Subject: [PATCH v3 1/4] LoongArch: Add section of GOT for kernel module From: Xi Ruoyao To: loongarch@lists.linux.dev Cc: linux-kernel@vger.kernel.org, WANG Xuerui , Huacai Chen , Youling Tang , Jinyang He Date: Fri, 29 Jul 2022 10:08:18 +0800 In-Reply-To: References: Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The address of external symbols will locate more than 32-bit offset. We were using the `-Wa,-mla-global-with-abs` and `-Wa,-mla-local-with-abs` to prevent the compiler and assembler from generating GOT relocations, but these options are undocumented hacks and do not work anymore with GAS 2.40 and GCC 13. Let the module loader emit GOT entries for data symbols so we would be able to handle GOT relocations. The GOT entry is just the data symbol address. In module.lds, emit a stub .got section for a section header entry. The actual content of the entry will be filled at runtime by module_frob_arch_sections. A special symbol named "_GLOBAL_OFFSET_TABLE_" is used by stack-based relocations for the PC-relative offset of a GOT entry, like: R_LARCH_SOP_PUSH_PCREL _GLOBAL_OFFSET_TABLE_ R_LARCH_SOP_PUSH_GPREL foo R_LARCH_SOP_ADD Each kernel module has its own GOT (like a shared object), so we need to generate _GLOBAL_OFFSET_TABLE_ as a local symbol for each module. Signed-off-by: Xi Ruoyao --- arch/loongarch/include/asm/module.h | 23 +++++++++++++ arch/loongarch/include/asm/module.lds.h | 1 + arch/loongarch/kernel/module-sections.c | 43 ++++++++++++++++++++++--- 3 files changed, 63 insertions(+), 4 deletions(-) diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/a= sm/module.h index 9f6718df1854..76a98a0ab8a0 100644 --- a/arch/loongarch/include/asm/module.h +++ b/arch/loongarch/include/asm/module.h @@ -19,6 +19,7 @@ struct mod_section { struct mod_arch_specific { struct mod_section plt; struct mod_section plt_idx; + struct mod_section got; }; =20 struct plt_entry { @@ -28,11 +29,16 @@ struct plt_entry { u32 inst_jirl; }; =20 +struct got_entry { + Elf_Addr symbol_addr; +}; + struct plt_idx_entry { unsigned long symbol_addr; }; =20 Elf_Addr module_emit_plt_entry(struct module *mod, unsigned long val); +Elf_Addr module_emit_got_entry(struct module *mod, Elf_Addr val); =20 static inline struct plt_entry emit_plt_entry(unsigned long val) { @@ -51,6 +57,11 @@ static inline struct plt_idx_entry emit_plt_idx_entry(un= signed long val) return (struct plt_idx_entry) { val }; } =20 +static inline struct got_entry emit_got_entry(Elf_Addr val) +{ + return (struct got_entry) { val }; +} + static inline int get_plt_idx(unsigned long val, const struct mod_section = *sec) { int i; @@ -77,4 +88,16 @@ static inline struct plt_entry *get_plt_entry(unsigned l= ong val, return plt + plt_idx; } =20 +static inline struct got_entry *get_got_entry(Elf_Addr val, + const struct mod_section *sec) +{ + struct got_entry *got =3D (struct got_entry *)sec->shdr->sh_addr; + int i; + + for (i =3D 0; i < sec->num_entries; i++) + if (got[i].symbol_addr =3D=3D val) + return &got[i]; + return NULL; +} + #endif /* _ASM_MODULE_H */ diff --git a/arch/loongarch/include/asm/module.lds.h b/arch/loongarch/inclu= de/asm/module.lds.h index 31c1c0db11a3..42b7cca0b947 100644 --- a/arch/loongarch/include/asm/module.lds.h +++ b/arch/loongarch/include/asm/module.lds.h @@ -4,4 +4,5 @@ SECTIONS { . =3D ALIGN(4); .plt : { BYTE(0) } .plt.idx : { BYTE(0) } + .got : { HIDDEN(_GLOBAL_OFFSET_TABLE_ =3D .); BYTE(0) } } diff --git a/arch/loongarch/kernel/module-sections.c b/arch/loongarch/kerne= l/module-sections.c index 6d498288977d..36a77771d18c 100644 --- a/arch/loongarch/kernel/module-sections.c +++ b/arch/loongarch/kernel/module-sections.c @@ -33,6 +33,25 @@ Elf_Addr module_emit_plt_entry(struct module *mod, unsig= ned long val) return (Elf_Addr)&plt[nr]; } =20 +Elf_Addr module_emit_got_entry(struct module *mod, Elf_Addr val) +{ + struct mod_section *got_sec =3D &mod->arch.got; + int i =3D got_sec->num_entries; + struct got_entry *got =3D get_got_entry(val, got_sec); + + if (got) + return (Elf_Addr)got; + + /* There is no GOT entry existing for val yet. Create a new one. */ + got =3D (struct got_entry *)got_sec->shdr->sh_addr; + got[i] =3D emit_got_entry(val); + + got_sec->num_entries++; + BUG_ON(got_sec->num_entries > got_sec->max_entries); + + return (Elf_Addr)&got[i]; +} + static int is_rela_equal(const Elf_Rela *x, const Elf_Rela *y) { return x->r_info =3D=3D y->r_info && x->r_addend =3D=3D y->r_addend; @@ -50,7 +69,8 @@ static bool duplicate_rela(const Elf_Rela *rela, int idx) return false; } =20 -static void count_max_entries(Elf_Rela *relas, int num, unsigned int *plts) +static void count_max_entries(Elf_Rela *relas, int num, + unsigned int *plts, unsigned int *gots) { unsigned int i, type; =20 @@ -59,14 +79,16 @@ static void count_max_entries(Elf_Rela *relas, int num,= unsigned int *plts) if (type =3D=3D R_LARCH_SOP_PUSH_PLT_PCREL) { if (!duplicate_rela(relas, i)) (*plts)++; - } + } else if (type =3D=3D R_LARCH_SOP_PUSH_GPREL) + if (!duplicate_rela(relas, i)) + (*gots)++; } } =20 int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { - unsigned int i, num_plts =3D 0; + unsigned int i, num_plts =3D 0, num_gots =3D 0; =20 /* * Find the empty .plt sections. @@ -76,6 +98,8 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *s= echdrs, mod->arch.plt.shdr =3D sechdrs + i; else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx")) mod->arch.plt_idx.shdr =3D sechdrs + i; + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got")) + mod->arch.got.shdr =3D sechdrs + i; } =20 if (!mod->arch.plt.shdr) { @@ -86,6 +110,10 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr = *sechdrs, pr_err("%s: module PLT.IDX section(s) missing\n", mod->name); return -ENOEXEC; } + if (!mod->arch.got.shdr) { + pr_err("%s: module GOT section(s) missing\n", mod->name); + return -ENOEXEC; + } =20 /* Calculate the maxinum number of entries */ for (i =3D 0; i < ehdr->e_shnum; i++) { @@ -100,7 +128,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr = *sechdrs, if (!(dst_sec->sh_flags & SHF_EXECINSTR)) continue; =20 - count_max_entries(relas, num_rela, &num_plts); + count_max_entries(relas, num_rela, &num_plts, &num_gots); } =20 mod->arch.plt.shdr->sh_type =3D SHT_NOBITS; @@ -117,5 +145,12 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr= *sechdrs, mod->arch.plt_idx.num_entries =3D 0; mod->arch.plt_idx.max_entries =3D num_plts; =20 + mod->arch.got.shdr->sh_type =3D SHT_NOBITS; + mod->arch.got.shdr->sh_flags =3D SHF_ALLOC; + mod->arch.got.shdr->sh_addralign =3D L1_CACHE_BYTES; + mod->arch.got.shdr->sh_size =3D (num_gots + 1) * sizeof(struct got_entry); + mod->arch.got.num_entries =3D 0; + mod->arch.got.max_entries =3D num_gots; + return 0; } --=20 2.37.0 From nobody Wed Apr 15 00:02:48 2026 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 83293C00140 for ; Fri, 29 Jul 2022 02:09:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231826AbiG2CJA (ORCPT ); Thu, 28 Jul 2022 22:09:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230081AbiG2CIz (ORCPT ); Thu, 28 Jul 2022 22:08:55 -0400 Received: from xry111.site (xry111.site [89.208.246.23]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 072E532DA6 for ; Thu, 28 Jul 2022 19:08:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1659060534; bh=qVACV7bz4zGf1t3CnRp5Cj62T95tqtofD76Q2nBE43Y=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=gwlf0iYHJ0ResOx2sIfRr4pm6x2RVTj7g5i52O9KPRcns5ytqOhv520VajLerTvYa SXkvS7RXuADBnr9OUj/aPDmOvVWBir2z4e3cK7Wvl/N2aKyk12kvWaszY1Nw3PRNck K01+09VKFrLnKhh8wl4XiggS0USMd6QZMJokxnqk= Received: from localhost.localdomain (xry111.site [IPv6:2001:470:683e::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384) server-digest SHA384) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id 5D3DE65929; Thu, 28 Jul 2022 22:08:53 -0400 (EDT) Message-ID: Subject: [PATCH v3 2/4] LoongArch: Support R_LARCH_SOP_PUSH_GPREL relocation type in kernel module From: Xi Ruoyao To: loongarch@lists.linux.dev Cc: linux-kernel@vger.kernel.org, WANG Xuerui , Huacai Chen , Youling Tang , Jinyang He Date: Fri, 29 Jul 2022 10:08:51 +0800 In-Reply-To: References: Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This relocation type pushes the offset of the GOT entry for a symbol from the beginning of GOT into the relocation stack. Our linker script has initialized an empty GOT, so we need to create a new GOT entry if there is no exist one for a symbol. Signed-off-by: Xi Ruoyao --- arch/loongarch/kernel/module.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c index 638427ff0d51..3ac4fbb5f109 100644 --- a/arch/loongarch/kernel/module.c +++ b/arch/loongarch/kernel/module.c @@ -122,6 +122,16 @@ static int apply_r_larch_sop_push_plt_pcrel(struct mod= ule *mod, u32 *location, E return apply_r_larch_sop_push_pcrel(mod, location, v, rela_stack, rela_st= ack_top, type); } =20 +static int apply_r_larch_sop_push_gprel(struct module *mod, u32 *location, + Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, + unsigned int type) +{ + Elf_Addr got =3D module_emit_got_entry(mod, v); + ptrdiff_t offset =3D (void *)got - (void *)mod->arch.got.shdr->sh_addr; + + return rela_stack_push(offset, rela_stack, rela_stack_top); +} + static int apply_r_larch_sop(struct module *mod, u32 *location, Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, unsigned int type) { @@ -306,6 +316,7 @@ static reloc_rela_handler reloc_rela_handlers[] =3D { [R_LARCH_SOP_PUSH_PCREL] =3D apply_r_larch_sop_push_pcrel, [R_LARCH_SOP_PUSH_ABSOLUTE] =3D apply_r_larch_sop_push_absolute, [R_LARCH_SOP_PUSH_DUP] =3D apply_r_larch_sop_push_dup, + [R_LARCH_SOP_PUSH_GPREL] =3D apply_r_larch_sop_push_gprel, [R_LARCH_SOP_PUSH_PLT_PCREL] =3D apply_r_larch_sop_push_plt_pcrel, [R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE] =3D apply_r_larch_sop, [R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] =3D apply_r_larch_so= p_imm_field, --=20 2.37.0 From nobody Wed Apr 15 00:02:48 2026 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 7C210C00140 for ; Fri, 29 Jul 2022 02:10:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231945AbiG2CKB (ORCPT ); Thu, 28 Jul 2022 22:10:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbiG2CJ6 (ORCPT ); Thu, 28 Jul 2022 22:09:58 -0400 Received: from xry111.site (xry111.site [IPv6:2001:470:683e::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB30479EE4 for ; Thu, 28 Jul 2022 19:09:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1659060594; bh=eKojhGSrp5Nzdwbp8zmcNPFzO/9cxIKBEXrBgbRon5Q=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=INJrpYgHv2XlnNjM4pbSiZAbH0MW6V2t5UKFYKfWXk3q4ctNIAA15gp0axYAKqkI3 xszjq0BkKPashPapR2nhymh8LpfgQxTKrhXNxpY/NUyPF+bku/oNdq36ScE8oh9TjE uwp21KUPp1dmVQZ1I9jsSwPPZSEVrqL/ijk9Re8U= Received: from localhost.localdomain (xry111.site [IPv6:2001:470:683e::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384)) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id 2E83A65929; Thu, 28 Jul 2022 22:09:52 -0400 (EDT) Message-ID: <4da7ce6a6e5b6d609c37ebf6815caacc3b3b8297.camel@xry111.site> Subject: [PATCH v3 3/4] LoongArch: Remove -fplt and -Wa,-mla-* from CFLAGS From: Xi Ruoyao To: loongarch@lists.linux.dev Cc: linux-kernel@vger.kernel.org, WANG Xuerui , Huacai Chen , Youling Tang , Jinyang He Date: Fri, 29 Jul 2022 10:09:51 +0800 In-Reply-To: References: Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" -fplt is the default of all supported compilers (GCC, and maybe Clang in the future), so it needs not to be explicitly specified. -Wa,-mla-* options were used to prevent the assembler from generating GOT accesses for "la.local" and "la.global" macros. But GCC >=3D 13 will generate GOT access explicitly without use of these macros, so these options are ineffective for symbol addressing in C code with GCC >=3D 13. Now we can handle GOT and GOT-based relocations properly, so we can remove these options and use GOT access for both GCC 12 and 13 (or newer). GAS <=3D 2.39 does not support "la.got [reg], [sym] + [offset]" with a non-zero offset. So in the assembly code we explicitly use "la.pcrel" instead of "la" (now defaulted to "la.got") where a PC-relative addressing is suitable, in order to work around this limitation and keep the compatibility with old toolchains. Signed-off-by: Xi Ruoyao --- arch/loongarch/Makefile | 4 ---- arch/loongarch/kernel/head.S | 10 +++++----- 2 files changed, 5 insertions(+), 9 deletions(-) diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index 039dcc4fe1f3..800349ea9310 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -40,10 +40,6 @@ endif =20 cflags-y +=3D -G0 -pipe -msoft-float LDFLAGS_vmlinux +=3D -G0 -static -n -nostdlib -KBUILD_AFLAGS_KERNEL +=3D -Wa,-mla-global-with-pcrel -KBUILD_CFLAGS_KERNEL +=3D -Wa,-mla-global-with-pcrel -KBUILD_AFLAGS_MODULE +=3D -Wa,-mla-global-with-abs -KBUILD_CFLAGS_MODULE +=3D -fplt -Wa,-mla-global-with-abs,-mla-local-with-= abs =20 cflags-y +=3D -ffreestanding cflags-y +=3D $(call cc-option, -mno-check-zero-division) diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index 74ea7bf6c8d6..193329ed6e8c 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -60,17 +60,17 @@ SYM_CODE_START(kernel_entry) # kernel entry point la.abs t0, 0f jirl zero, t0, 0 0: - la t0, __bss_start # clear .bss + la.pcrel t0, __bss_start # clear .bss st.d zero, t0, 0 - la t1, __bss_stop - LONGSIZE + la.pcrel t1, __bss_stop - LONGSIZE 1: addi.d t0, t0, LONGSIZE st.d zero, t0, 0 bne t0, t1, 1b =20 - la t0, fw_arg0 + la.pcrel t0, fw_arg0 st.d a0, t0, 0 # firmware arguments - la t0, fw_arg1 + la.pcrel t0, fw_arg1 st.d a1, t0, 0 =20 /* KSave3 used for percpu base, initialized as 0 */ @@ -78,7 +78,7 @@ SYM_CODE_START(kernel_entry) # kernel entry point /* GPR21 used for percpu base (runtime), initialized as 0 */ or u0, zero, zero =20 - la tp, init_thread_union + la.pcrel tp, init_thread_union /* Set the SP after an empty pt_regs. */ PTR_LI sp, (_THREAD_SIZE - 32 - PT_SIZE) PTR_ADD sp, sp, tp --=20 2.37.0 From nobody Wed Apr 15 00:02:48 2026 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 88975C00140 for ; Fri, 29 Jul 2022 02:10:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232062AbiG2CKx (ORCPT ); Thu, 28 Jul 2022 22:10:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbiG2CKv (ORCPT ); Thu, 28 Jul 2022 22:10:51 -0400 Received: from xry111.site (xry111.site [IPv6:2001:470:683e::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A843B7968B for ; Thu, 28 Jul 2022 19:10:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1659060648; bh=rcLqsq6zGpUEl1DJZyTxmkc4RA2vFFdgR8IfyXZm0Dc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=GPsVCk1/p7ltOX+uH/HxodPxmQWkyIead67nGhczHUtcTfpmTFWZ3B2lPco12X2Of nD0qWxD9gO39ZElxd8Jye75tLV5GHz5z2dJTn9Grqf/ciikMdUkAYAizKmv7+IW3hx mhEi3Gv6Wo+WfditXfB4vQLadTRx+dpCqvWsHmto= Received: from localhost.localdomain (xry111.site [IPv6:2001:470:683e::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384) server-digest SHA384) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id EE85766939; Thu, 28 Jul 2022 22:10:46 -0400 (EDT) Message-ID: <5ecc0813d90990d6db7b401ddff57ec847874d14.camel@xry111.site> Subject: [PATCH v3 4/4] LoongArch: Support modules with new relocation types From: Xi Ruoyao To: loongarch@lists.linux.dev Cc: linux-kernel@vger.kernel.org, WANG Xuerui , Huacai Chen , Youling Tang , Jinyang He Date: Fri, 29 Jul 2022 10:10:44 +0800 In-Reply-To: References: Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If GAS 2.40 and/or GCC 13 is used to build the kernel, the modules will contain R_LARCH_B26, R_LARCH_PCALA_HI20, R_LARCH_PCALA_LO12, R_LARCH_GOT_PC_HI20, and R_LARCH_GOT_PC_LO12 relocations. Support them in the module loader to allow a kernel built with latest toolchain capable to load the modules. Signed-off-by: Xi Ruoyao --- arch/loongarch/include/asm/elf.h | 37 +++++++++++ arch/loongarch/kernel/module-sections.c | 12 +++- arch/loongarch/kernel/module.c | 85 +++++++++++++++++++++++++ 3 files changed, 132 insertions(+), 2 deletions(-) diff --git a/arch/loongarch/include/asm/elf.h b/arch/loongarch/include/asm/= elf.h index 5f3ff4781fda..7af0cebf28d7 100644 --- a/arch/loongarch/include/asm/elf.h +++ b/arch/loongarch/include/asm/elf.h @@ -74,6 +74,43 @@ #define R_LARCH_SUB64 56 #define R_LARCH_GNU_VTINHERIT 57 #define R_LARCH_GNU_VTENTRY 58 +#define R_LARCH_B16 64 +#define R_LARCH_B21 65 +#define R_LARCH_B26 66 +#define R_LARCH_ABS_HI20 67 +#define R_LARCH_ABS_LO12 68 +#define R_LARCH_ABS64_LO20 69 +#define R_LARCH_ABS64_HI12 70 +#define R_LARCH_PCALA_HI20 71 +#define R_LARCH_PCALA_LO12 72 +#define R_LARCH_PCALA64_LO20 73 +#define R_LARCH_PCALA64_HI12 74 +#define R_LARCH_GOT_PC_HI20 75 +#define R_LARCH_GOT_PC_LO12 76 +#define R_LARCH_GOT64_PC_LO20 77 +#define R_LARCH_GOT64_PC_HI12 78 +#define R_LARCH_GOT_HI20 79 +#define R_LARCH_GOT_LO12 80 +#define R_LARCH_GOT64_LO20 81 +#define R_LARCH_GOT64_HI12 82 +#define R_LARCH_TLS_LE_HI20 83 +#define R_LARCH_TLS_LE_LO12 84 +#define R_LARCH_TLS_LE64_LO20 85 +#define R_LARCH_TLS_LE64_HI12 86 +#define R_LARCH_TLS_IE_PC_HI20 87 +#define R_LARCH_TLS_IE_PC_LO12 88 +#define R_LARCH_TLS_IE64_PC_LO20 89 +#define R_LARCH_TLS_IE64_PC_HI12 90 +#define R_LARCH_TLS_IE_HI20 91 +#define R_LARCH_TLS_IE_LO12 92 +#define R_LARCH_TLS_IE64_LO20 93 +#define R_LARCH_TLS_IE64_HI12 94 +#define R_LARCH_TLS_LD_PC_HI20 95 +#define R_LARCH_TLS_LD_HI20 96 +#define R_LARCH_TLS_GD_PC_HI20 97 +#define R_LARCH_TLS_GD_HI20 98 +#define R_LARCH_32_PCREL 99 +#define R_LARCH_RELAX 100 =20 #ifndef ELF_ARCH =20 diff --git a/arch/loongarch/kernel/module-sections.c b/arch/loongarch/kerne= l/module-sections.c index 36a77771d18c..8c0e4ad048cc 100644 --- a/arch/loongarch/kernel/module-sections.c +++ b/arch/loongarch/kernel/module-sections.c @@ -76,12 +76,20 @@ static void count_max_entries(Elf_Rela *relas, int num, =20 for (i =3D 0; i < num; i++) { type =3D ELF_R_TYPE(relas[i].r_info); - if (type =3D=3D R_LARCH_SOP_PUSH_PLT_PCREL) { + switch (type) { + case R_LARCH_SOP_PUSH_PLT_PCREL: + case R_LARCH_B26: if (!duplicate_rela(relas, i)) (*plts)++; - } else if (type =3D=3D R_LARCH_SOP_PUSH_GPREL) + break; + case R_LARCH_SOP_PUSH_GPREL: + case R_LARCH_GOT_PC_HI20: if (!duplicate_rela(relas, i)) (*gots)++; + break; + default: + /* Do nothing. */ + } } } =20 diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c index 3ac4fbb5f109..c7b40150e1f0 100644 --- a/arch/loongarch/kernel/module.c +++ b/arch/loongarch/kernel/module.c @@ -291,6 +291,86 @@ static int apply_r_larch_add_sub(struct module *mod, u= 32 *location, Elf_Addr v, } } =20 +static int apply_r_larch_b26(struct module *mod, u32 *location, Elf_Addr v, + s64 *rela_stack, size_t *rela_stack_top, unsigned int type) +{ + ptrdiff_t offset =3D (void *)v - (void *)location; + union loongarch_instruction *insn =3D (union loongarch_instruction *)loca= tion; + + if (offset >=3D SZ_128M) + v =3D module_emit_plt_entry(mod, v); + + if (offset < -SZ_128M) + v =3D module_emit_plt_entry(mod, v); + + offset =3D (void *)v - (void *)location; + + if (offset & 3) { + pr_err("module %s: jump offset =3D 0x%llx unaligned! dangerous R_LARCH_B= 26 (%u) relocation\n", + mod->name, (long long)offset, type); + return -ENOEXEC; + } + + if (!signed_imm_check(offset, 28)) { + pr_err("module %s: jump offset =3D 0x%llx overflow! dangerous R_LARCH_B2= 6 (%u) relocation\n", + mod->name, (long long)offset, type); + return -ENOEXEC; + } + + offset >>=3D 2; + insn->reg0i26_format.immediate_l =3D offset & 0xffff; + insn->reg0i26_format.immediate_h =3D (offset >> 16) & 0x3ff; + return 0; +} + +static int apply_r_larch_pcala_hi20(struct module *mod, u32 *location, + Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, + unsigned int type) +{ + ptrdiff_t offset =3D (void *)((v + 0x800) & ~0xfff) - + (void *)((Elf_Addr)location & ~0xfff); + union loongarch_instruction *insn =3D (union loongarch_instruction *)loca= tion; + + if (!signed_imm_check(offset, 32)) { + pr_err("module %s: PCALA offset =3D 0x%llx does not fit in 32-bit signed= and is unsupported by kernel! dangerous %s (%u) relocation\n", + mod->name, (long long)offset, __func__, type); + return -ENOEXEC; + } + + insn->reg1i20_format.immediate =3D (offset >> 12) & 0xfffff; + return 0; +} + +static int apply_r_larch_got_pc_hi20(struct module *mod, u32 *location, + Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, + unsigned int type) +{ + Elf_Addr got =3D module_emit_got_entry(mod, v); + + return apply_r_larch_pcala_hi20(mod, location, got, rela_stack, + rela_stack_top, type); +} + +static int apply_r_larch_pcala_lo12(struct module *mod, u32 *location, + Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, + unsigned int type) +{ + union loongarch_instruction *insn =3D (union loongarch_instruction *)loca= tion; + + insn->reg2i12_format.immediate =3D v & 0xfff; + return 0; +} + +static int apply_r_larch_got_pc_lo12(struct module *mod, u32 *location, + Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top, + unsigned int type) +{ + Elf_Addr got =3D module_emit_got_entry(mod, v); + + return apply_r_larch_pcala_lo12(mod, location, got, rela_stack, + rela_stack_top, type); +} + /* * reloc_handlers_rela() - Apply a particular relocation to a module * @mod: the module to apply the reloc to @@ -321,6 +401,11 @@ static reloc_rela_handler reloc_rela_handlers[] =3D { [R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE] =3D apply_r_larch_sop, [R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] =3D apply_r_larch_so= p_imm_field, [R_LARCH_ADD32 ... R_LARCH_SUB64] =3D apply_r_larch_add_sub, + [R_LARCH_B26] =3D apply_r_larch_b26, + [R_LARCH_PCALA_HI20] =3D apply_r_larch_pcala_hi20, + [R_LARCH_PCALA_LO12] =3D apply_r_larch_pcala_lo12, + [R_LARCH_GOT_PC_HI20] =3D apply_r_larch_got_pc_hi20, + [R_LARCH_GOT_PC_LO12] =3D apply_r_larch_got_pc_lo12, }; =20 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, --=20 2.37.0