From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailbox.box.xen0n.name (mail.xen0n.name [115.28.160.31]) by sourceware.org (Postfix) with ESMTPS id 20144385840C for ; Sun, 25 Sep 2022 08:28:17 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 20144385840C Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=xen0n.name Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=xen0n.name DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xen0n.name; s=mail; t=1664094491; bh=CH9RGIFvyqthrbVeZONhlUuQhin5G561XtLlU0T3N2c=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nhWQ7rxLILMN9Rr3E5hhfJpPenDJyhdssdtse1+TryjSiby6KA7B52II5zq6oN7Wm rbHsCDR2ENfilK7OENMThSMUspRj+GdTK2U8cxK7ZQ2YoQkoNXCzntanUhwHpU8Ztb QPIOHdMe6E1NeWt4q2v7KCUKC0q2trkYTUrQ6cUA= Received: from [192.168.71.110] (unknown [116.236.142.206]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mailbox.box.xen0n.name (Postfix) with ESMTPSA id 9EA776006F; Sun, 25 Sep 2022 16:28:10 +0800 (CST) Message-ID: <83e9a5ac-c509-066b-07f6-cb3ec4583e48@xen0n.name> Date: Sun, 25 Sep 2022 16:28:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:107.0) Gecko/20100101 Thunderbird/107.0a1 Subject: Re: [PATCH v2] LoongArch: Set e_flags to 0x40 of ELF while using new relocations. To: liuzhensong , binutils@sourceware.org Cc: i.swmail@xen0n.name, xry111@xry111.site, maskray@google.com, mengqinggang@loongson.cn References: <20220921011756.451005-1-liuzhensong@loongson.cn> Content-Language: en-US From: WANG Xuerui In-Reply-To: <20220921011756.451005-1-liuzhensong@loongson.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-14.7 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hi, Overall this is going in the right direction (finally!) and implementing the correct behavior, but a few small nits remain. Also, @xry111 WDYT? On 2022/9/21 09:17, liuzhensong wrote: > As the docs[1] describes, update the e_flags of ELF. > 1. 32 or 64 bit is represented by EI_CLASS. > 2. The bits of e_flags > Base ABI [2:0]: > soft float -- 0x1 > single float -- 0x2 > double float -- 0x3 > > ABI version [7:6]: > obj-v0 -- 0x0 > obj-v1 -- 0x1 > 3. Discussions [2]. > > docs: > [1] https://github.com/loongson/LoongArch-Documentation/blob/ > main/docs/LoongArch-ELF-ABI-EN.adoc#e_flags-identifies-abi-type-and-version > [2] https://github.com/loongson/LoongArch-Documentation/pull/61 Rewritten into (somewhat more) proper English for you, also we have another significant discussion thread that you hadn't mentioned: ``` Subject: LoongArch: Update ELF e_flags handling according to specification. Update handling of e_flags according to the documentation update [1] (discussions [2][3]). Object file bitness is now represented in the EI_CLASS byte. The e_flags field is now interpreted as follows: e_flags[2:0]: Base ABI modifier - 0x1: soft-float - 0x2: single-precision hard-float - 0x3: double-precision hard-float e_flags[7:6]: ELF object ABI version - 0x0: v0 - 0x1: v1 [1]: https://github.com/loongson/LoongArch-Documentation/blob/main/docs/LoongArch-ELF-ABI-EN.adoc#e_flags-identifies-abi-type-and-version [2]: https://github.com/loongson/LoongArch-Documentation/pull/61 [3]: https://github.com/loongson/LoongArch-Documentation/pull/47 ``` (Tip: next time when writing commit messages (or in fact anything) in English, please bear in mind that Chinese is a "topic-prominent" language [99] unlike English, meaning the idiomatic sentence pattern is usually different. In general people can still grasp the meaning but will probably have a headache in trying to do so...) [99]: https://en.wikipedia.org/wiki/Topic-prominent_language > --- > bfd/elfnn-loongarch.c | 21 ++++++++++++++++--- > binutils/readelf.c | 10 ++++----- > gas/config/tc-loongarch.c | 20 +++++++++--------- > include/elf/loongarch.h | 44 +++++++++++++++++++-------------------- > 4 files changed, 54 insertions(+), 41 deletions(-) > > diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c > index 33c85e5207c..5b4b83eb07a 100644 > --- a/bfd/elfnn-loongarch.c > +++ b/bfd/elfnn-loongarch.c > @@ -416,8 +416,22 @@ elfNN_loongarch_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info) > elf_elfheader (obfd)->e_flags = in_flags; > return true; > } > + else if (out_flags != in_flags) > + { > + if ((EF_LOONGARCH_IS_OBJ_V0 (out_flags) > + && EF_LOONGARCH_IS_OBJ_V1 (in_flags)) > + || (EF_LOONGARCH_IS_OBJ_V0 (in_flags) > + && EF_LOONGARCH_IS_OBJ_V1 (out_flags))) > + { > + elf_elfheader (obfd)->e_flags |= EF_LOONGARCH_ABI_OBJ_V1; > + out_flags = elf_elfheader (obfd)->e_flags; > + in_flags = out_flags; > + } > + } > > /* Disallow linking different ABIs. */ > + /* Only check relocation version. > + The obj_v0 is compatible with obj_v1 in this "release cycle". */ We know this cycle is 2.40 so directly mention that? > if (EF_LOONGARCH_ABI(out_flags ^ in_flags) & EF_LOONGARCH_ABI_MASK) > { > _bfd_error_handler (_("%pB: can't link different ABI object."), ibfd); > @@ -1579,15 +1593,16 @@ loongarch_elf_size_dynamic_sections (bfd *output_bfd, > if (bfd_link_executable (info) && !info->nointerp) > { > const char *interpreter; > - flagword flags = elf_elfheader (output_bfd)->e_flags; > s = bfd_get_linker_section (dynobj, ".interp"); > BFD_ASSERT (s != NULL); > - if (EF_LOONGARCH_IS_ILP32 (flags)) > + > + if (elf_elfheader (output_bfd)->e_ident[EI_CLASS] == ELFCLASS32) > interpreter = "/lib32/ld.so.1"; > - else if (EF_LOONGARCH_IS_LP64 (flags)) > + else if (elf_elfheader (output_bfd)->e_ident[EI_CLASS] == ELFCLASS64) > interpreter = "/lib64/ld.so.1"; > else > interpreter = "/lib/ld.so.1"; > + Wait what, are we still carrying the old-world defaults for the interpreter path here? I know it's harmless because in fact it gets overridden by gcc and glibc, but I'd suggest fixing it in a separate patch later for consistency. > s->contents = (unsigned char *) interpreter; > s->size = strlen (interpreter) + 1; > } > diff --git a/binutils/readelf.c b/binutils/readelf.c > index cafba9a4f56..6926cf16140 100644 > --- a/binutils/readelf.c > +++ b/binutils/readelf.c > @@ -4340,11 +4340,6 @@ get_machine_flags (Filedata * filedata, unsigned e_flags, unsigned e_machine) > } > break; > case EM_LOONGARCH: > - if (EF_LOONGARCH_IS_LP64 (e_flags)) > - strcat (buf, ", LP64"); > - else if (EF_LOONGARCH_IS_ILP32 (e_flags)) > - strcat (buf, ", ILP32"); > - > if (EF_LOONGARCH_IS_SOFT_FLOAT (e_flags)) > strcat (buf, ", SOFT-FLOAT"); > else if (EF_LOONGARCH_IS_SINGLE_FLOAT (e_flags)) > @@ -4352,6 +4347,11 @@ get_machine_flags (Filedata * filedata, unsigned e_flags, unsigned e_machine) > else if (EF_LOONGARCH_IS_DOUBLE_FLOAT (e_flags)) > strcat (buf, ", DOUBLE-FLOAT"); > > + if (EF_LOONGARCH_IS_OBJ_V0 (e_flags)) > + strcat (buf, ", OBJ-v0"); > + else if (EF_LOONGARCH_IS_OBJ_V1 (e_flags)) > + strcat (buf, ", OBJ-v1"); > + > break; > } > } > diff --git a/gas/config/tc-loongarch.c b/gas/config/tc-loongarch.c > index 5bb8d317c5a..3e9204a5fa4 100644 > --- a/gas/config/tc-loongarch.c > +++ b/gas/config/tc-loongarch.c > @@ -143,13 +143,13 @@ md_parse_option (int c, const char *arg) > char ilp32[256] = ""; > unsigned char *suf = (unsigned char *)arg; > > - lp64['s'] = lp64['S'] = EF_LOONGARCH_ABI_LP64_SOFT_FLOAT; > - lp64['f'] = lp64['F'] = EF_LOONGARCH_ABI_LP64_SINGLE_FLOAT; > - lp64['d'] = lp64['D'] = EF_LOONGARCH_ABI_LP64_DOUBLE_FLOAT; > + lp64['s'] = lp64['S'] = EF_LOONGARCH_ABI_SOFT_FLOAT; > + lp64['f'] = lp64['F'] = EF_LOONGARCH_ABI_SINGLE_FLOAT; > + lp64['d'] = lp64['D'] = EF_LOONGARCH_ABI_DOUBLE_FLOAT; > > - ilp32['s'] = ilp32['S'] = EF_LOONGARCH_ABI_ILP32_SOFT_FLOAT; > - ilp32['f'] = ilp32['F'] = EF_LOONGARCH_ABI_ILP32_SINGLE_FLOAT; > - ilp32['d'] = ilp32['D'] = EF_LOONGARCH_ABI_ILP32_DOUBLE_FLOAT; > + ilp32['s'] = ilp32['S'] = EF_LOONGARCH_ABI_SOFT_FLOAT; > + ilp32['f'] = ilp32['F'] = EF_LOONGARCH_ABI_SINGLE_FLOAT; > + ilp32['d'] = ilp32['D'] = EF_LOONGARCH_ABI_DOUBLE_FLOAT; > > switch (c) > { > @@ -216,24 +216,24 @@ void > loongarch_after_parse_args () > { > /* Set default ABI/ISA LP64D. */ > - if (!EF_LOONGARCH_IS_LP64(LARCH_opts.ase_abi) > - && !EF_LOONGARCH_IS_ILP32(LARCH_opts.ase_abi)) > + if (!LARCH_opts.ase_ilp32) > { > if (strcmp (default_arch, "loongarch64") == 0) > { > - LARCH_opts.ase_abi = EF_LOONGARCH_ABI_LP64_DOUBLE_FLOAT; > + LARCH_opts.ase_abi = EF_LOONGARCH_ABI_DOUBLE_FLOAT; > LARCH_opts.ase_ilp32 = 1; > LARCH_opts.ase_lp64 = 1; > } > else if (strcmp (default_arch, "loongarch32") == 0) > { > - LARCH_opts.ase_abi = EF_LOONGARCH_ABI_ILP32_DOUBLE_FLOAT; > + LARCH_opts.ase_abi = EF_LOONGARCH_ABI_DOUBLE_FLOAT; > LARCH_opts.ase_ilp32 = 1; > } > else > as_bad ("unknown default architecture `%s'", default_arch); > } > > + LARCH_opts.ase_abi |= EF_LOONGARCH_ABI_OBJ_V1; > /* Set default ISA double-float. */ > if (!LARCH_opts.ase_nf > && !LARCH_opts.ase_sf > diff --git a/include/elf/loongarch.h b/include/elf/loongarch.h > index 74757b82ca8..cceaa8cccc4 100644 > --- a/include/elf/loongarch.h > +++ b/include/elf/loongarch.h > @@ -232,36 +232,34 @@ RELOC_NUMBER (R_LARCH_RELAX, 100) > END_RELOC_NUMBERS (R_LARCH_count) > > /* Processor specific flags for the ELF header e_flags field. */ > -/*The flag lp64s/lp64f/lp64d/ilp32s/ilp32f/ilp32d 3bits. */ > -#define EF_LOONGARCH_ABI_LP64_SOFT_FLOAT 0x1 > -#define EF_LOONGARCH_ABI_LP64_SINGLE_FLOAT 0x2 > -#define EF_LOONGARCH_ABI_LP64_DOUBLE_FLOAT 0x3 > +/* ase ABI modifier, 3bits. */ Oh please no more MIPS "ASE"s. It's "Base ABI modifier" in the docs... > +#define EF_LOONGARCH_ABI_SOFT_FLOAT 0x1 > +#define EF_LOONGARCH_ABI_SINGLE_FLOAT 0x2 > +#define EF_LOONGARCH_ABI_DOUBLE_FLOAT 0x3 > +#define EF_LOONGARCH_ABI_MODIFIER_MASK 0x7 > > -#define EF_LOONGARCH_ABI_ILP32_SOFT_FLOAT 0x5 > -#define EF_LOONGARCH_ABI_ILP32_SINGLE_FLOAT 0x6 > -#define EF_LOONGARCH_ABI_ILP32_DOUBLE_FLOAT 0x7 > +#define EF_LOONGARCH_ABI_OBJ_V1 0x40 > +#define EF_LOONGARCH_ABI_OBJ_MASK 0xC0 I'd bikeshed a little and suggest "EF_LOONGARCH_OBJABI_foo" because it's actually "ELF object file ABI v1" and not "ELF ABI object v1". > > -#define EF_LOONGARCH_ABI_MASK 0x7 > -#define EF_LOONGARCH_ABI_ILP32_MASK 0x4 > -#define EF_LOONGARCH_ABI_FLOAT_MASK 0x3 > -#define EF_LOONGARCH_ABI_SOFT_FLOAT_MASK 0x1 > -#define EF_LOONGARCH_ABI_SINGLE_FLOAT_MASK 0x2 > -#define EF_LOONGARCH_ABI_DOUBLE_FLOAT_MASK 0x3 > +#define EF_LOONGARCH_ABI_MASK \ > + (EF_LOONGARCH_ABI_OBJ_MASK | EF_LOONGARCH_ABI_MODIFIER_MASK) > > -#define EF_LOONGARCH_ABI(abi) (EF_LOONGARCH_ABI_MASK & (abi)) > +#define EF_LOONGARCH_ABI_MODIFIER(abi) \ > + (EF_LOONGARCH_ABI_MODIFIER_MASK & (abi)) > +#define EF_LOONGARCH_ABI_OBJ(abi) \ > + (EF_LOONGARCH_ABI_OBJ_MASK & (abi)) > > -#define EF_LOONGARCH_IS_LP64(abi) \ > - (EF_LOONGARCH_ABI(abi) && (!(EF_LOONGARCH_ABI(abi) & EF_LOONGARCH_ABI_ILP32_MASK))) > -#define EF_LOONGARCH_IS_ILP32(abi) \ > - (EF_LOONGARCH_ABI(abi) && (EF_LOONGARCH_ABI(abi) & EF_LOONGARCH_ABI_ILP32_MASK)) > +#define EF_LOONGARCH_ABI(abi) ((abi) & EF_LOONGARCH_ABI_MASK) > > #define EF_LOONGARCH_IS_SOFT_FLOAT(abi) \ > - (!((EF_LOONGARCH_ABI(abi) & EF_LOONGARCH_ABI_FLOAT_MASK) ^ EF_LOONGARCH_ABI_SOFT_FLOAT_MASK)) > - > + (EF_LOONGARCH_ABI_MODIFIER (abi) == EF_LOONGARCH_ABI_SOFT_FLOAT) > #define EF_LOONGARCH_IS_SINGLE_FLOAT(abi) \ > - (!((EF_LOONGARCH_ABI(abi) & EF_LOONGARCH_ABI_FLOAT_MASK) ^ EF_LOONGARCH_ABI_SINGLE_FLOAT_MASK)) > - > + (EF_LOONGARCH_ABI_MODIFIER (abi) == EF_LOONGARCH_ABI_SINGLE_FLOAT) > #define EF_LOONGARCH_IS_DOUBLE_FLOAT(abi) \ > - (!((EF_LOONGARCH_ABI(abi) & EF_LOONGARCH_ABI_FLOAT_MASK) ^ EF_LOONGARCH_ABI_DOUBLE_FLOAT_MASK)) > + (EF_LOONGARCH_ABI_MODIFIER (abi) == EF_LOONGARCH_ABI_DOUBLE_FLOAT) > + > +#define EF_LOONGARCH_IS_OBJ_V0(abi) (!EF_LOONGARCH_ABI_OBJ(abi)) > +#define EF_LOONGARCH_IS_OBJ_V1(abi) \ > + (EF_LOONGARCH_ABI_OBJ (abi) == EF_LOONGARCH_ABI_OBJ_V1) > > #endif /* _ELF_LOONGARCH_H */