On 10/5/22 17:43, Arnaldo Carvalho de Melo wrote:
> Em Wed, Oct 05, 2022 at 11:37:13AM -0300, Arnaldo Carvalho de Melo
> escreveu:
>> Em Wed, Oct 05, 2022 at 09:23:32AM +0200, Martin Liška escreveu:
>>> On 10/4/22 23:44, Arnaldo Carvalho de Melo wrote:
>>>> I assume "binutils master" means:
>>>>
>>>> git://sourceware.org/git/binutils-gdb.git master?
>>>
>>> Yes.
>>
>> Taking notes:
>>
>> Using what is in opensuse:tumbleweed it works:
>
> So I built and installed from
> git://sourceware.org/git/binutils-gdb.git, it got on /usr/local/bin,
> taking precedence above /usr/bin/, and didn't get any
> DW_TAG_unspecified_type:
Hey.
Well, it's more trickier what gcc driver runs as a GAS even though you prefixed
/usr/local/bin.
$ echo '' | gcc -c -x c - --verbose 2>&1 | grep 'as\>'
/usr/lib64/gcc/x86_64-suse-linux/12/../../../../x86_64-suse-linux/bin/as -v --64 -o -.o /tmp/cclvchQd.s
Anyway, the easiest approach how to use a different gas is using -B gcc option, which
would search the location for 'as' binary:
$ pwd
/home/marxin/Programming/binutils/objdir/gas
$ ./as-new --version
GNU assembler (GNU Binutils) 2.39.50.20221004
...
$ ln -s as-new as
$ gcc -Wp,-MMD,arch/x86/entry/.entry.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -D__KERNEL__ -fmacro-prefix-map=./= -D__ASSEMBLY__ -fno-PIE -m64 -c -o arch/x86/entry/entry.o arch/x86/entry/entry.S -g -B/home/marxin/Programming/binutils/objdir/gas
(note I'm using make defconfig), and not I can see:
$ readelf -wi arch/x86/entry/entry.o
Contents of the .debug_info section:
Compilation Unit @ offset 0x0:
Length: 0x35 (32-bit)
Version: 5
Unit Type: DW_UT_compile (1)
Abbrev Offset: 0x0
Pointer Size: 8
<0><c>: Abbrev Number: 1 (DW_TAG_compile_unit)
<d> DW_AT_stmt_list : 0x0
<11> DW_AT_low_pc : 0x0
<19> DW_AT_high_pc : 19
<1a> DW_AT_name : (indirect string, offset: 0x0): arch/x86/entry/entry.S
<1e> DW_AT_comp_dir : (indirect string, offset: 0x17): /home/marxin/Programming/linux
<22> DW_AT_producer : (indirect string, offset: 0x36): GNU AS 2.39.50
<26> DW_AT_language : 32769 (MIPS assembler)
<1><28>: Abbrev Number: 2 (DW_TAG_subprogram)
<29> DW_AT_name : (indirect string, offset: 0x45): entry_ibpb
<2d> DW_AT_external : 1
<2d> DW_AT_type : <0x37>
<2e> DW_AT_low_pc : 0x0
<36> DW_AT_high_pc : 19
<1><37>: Abbrev Number: 3 (DW_TAG_unspecified_type)
<1><38>: Abbrev Number: 0
as seen, you get the DW_AT_producer tag that shows the AS version (2.39.50)
and the DW_TAG_unspecified_type tag.
Cheers,
Martin
>
> 15e20ce2324a:~/git/linux # type readelf readelf is hashed
> (/usr/local/bin/readelf) 15e20ce2324a:~/git/linux #
> /usr/local/bin/readelf -v GNU readelf (GNU Binutils)
> 2.39.50.20221005 Copyright (C) 2022 Free Software Foundation, Inc.
> This program is free software; you may redistribute it under the
> terms of the GNU General Public License version 3 or (at your option)
> any later version. This program has absolutely no warranty.
> 15e20ce2324a:~/git/linux # rpm -q binutils binutils-2.38-6.2.x86_64
> 15e20ce2324a:~/git/linux #
>
> 15e20ce2324a:~/git/linux # readelf -wi
> ../build/v6.0.0+binutils-latest/vmlinux|grep DW_TAG_unspecified_type
> 15e20ce2324a:~/git/linux #
>
> 15e20ce2324a:~/git/linux # egrep BTF\|DWARF\|PAHOLE
> ../build/v6.0.0+binutils-latest/.config CONFIG_PAHOLE_VERSION=122
> CONFIG_VIDEO_SONY_BTF_MPX=m
> CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y #
> CONFIG_DEBUG_INFO_DWARF4 is not set # CONFIG_DEBUG_INFO_DWARF5 is not
> set CONFIG_DEBUG_INFO_BTF=y CONFIG_PAHOLE_HAS_SPLIT_BTF=y
> CONFIG_DEBUG_INFO_BTF_MODULES=y # CONFIG_MODULE_ALLOW_BTF_MISMATCH is
> not set 15e20ce2324a:~/git/linux #
>
>
> Its CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y and it ends up being
> DWARF5 as its the toolchain default, at least from the
> /usr/local/bin/readelf -wi output below.
>
> Can you hand me your kernel .config file, please?
>
>
> <1><92163>: Abbrev Number: 0 Compilation Unit @ offset 0x92164:
> Length: 0x24 (32-bit) Version: 5 Unit Type:
> DW_UT_compile (1) Abbrev Offset: 0x5555 Pointer Size: 8 <0><92170>:
> Abbrev Number: 1 (DW_TAG_compile_unit) <92171> DW_AT_stmt_list :
> 0x7df2 <92175> DW_AT_low_pc : 0xffffffff81c62000 <9217d>
> DW_AT_high_pc : 19 <9217e> DW_AT_name : (indirect
> string, offset: 0x1878d): /root/git/linux/arch/x86/entry/entry.S
> <92182> DW_AT_comp_dir : (indirect string, offset: 0x2a):
> /root/git/build/v6.0.0+binutils-latest <92186> DW_AT_producer :
> (indirect string, offset: 0x51): GNU AS 2.38 <9218a> DW_AT_language
> : 32769 (MIPS assembler) Compilation Unit @ offset 0x9218c: Length:
> 0x1f (32-bit) Version: 5 Unit Type: DW_UT_compile (1)
> Abbrev Offset: 0x5569 Pointer Size: 8 <0><92198>: Abbrev Number: 1
> (DW_TAG_compile_unit) <92199> DW_AT_stmt_list : 0x7e43 <9219d>
> DW_AT_ranges : 0x12e3 <921a1> DW_AT_name : (indirect
> string, offset: 0x187b4): /root/git/linux/arch/x86/entry/entry_64.S
> <921a5> DW_AT_comp_dir : (indirect string, offset: 0x2a):
> /root/git/build/v6.0.0+binutils-latest <921a9> DW_AT_producer :
> (indirect string, offset: 0x51): GNU AS 2.38 <921ad> DW_AT_language
> : 32769 (MIPS assembler) Compilation Unit @ offset 0x921af: Length:
> 0x1e93 (32-bit) Version: 5 Unit Type: DW_UT_compile (1)
> Abbrev Offset: 0x557b Pointer Size: 8 <0><921bb>: Abbrev Number: 13
> (DW_TAG_compile_unit) <921bc> DW_AT_producer : (indirect string,
> offset: 0x6622): GNU C11 12.1.1 20220629 [revision
> 7811663964aa7e31c3939b859bbfa2e16919639f] -mno-sse -mno-mmx -mno-sse2
> -mno-3dnow -mno-avx -m64 -mno-80387 -mno-fp-ret-in-387
> -mpreferred-stack-boundary=3 -mskip-rax-setup -mtune=generic
> -mno-red-zone -mcmodel=kernel -mindirect-branch=thunk-extern
> -mindirect-branch-register -mindirect-branch-cs-prefix
> -mfunction-return=thunk-extern -mharden-sls=all -mrecord-mcount
> -mfentry -march=x86-64 -g -O2 -std=gnu11 -p -fno-strict-aliasing
> -fno-common -fshort-wchar -fno-PIE -fcf-protection=none
> -falign-jumps=1 -falign-loops=1 -fno-asynchronous-unwind-tables
> -fno-jump-tables -fno-delete-null-pointer-checks
> -fno-allow-store-data-races -fstack-protector-strong
> -fno-stack-clash-protection -fzero-call-used-regs=used-gpr
> -fno-strict-overflow -fstack-check=no -fconserve-stack <921c0>
> DW_AT_language : 29 (C11) <921c1> DW_AT_name :
> (indirect line string, offset: 0x14b6):
> /root/git/linux/arch/x86/entry/syscall_64.c <921c5> DW_AT_comp_dir
> : (indirect line string, offset: 0):
> /root/git/build/v6.0.0+binutils-latest <921c9> DW_AT_stmt_list :
> 0x8110 <1><921cd>: Abbrev Number: 6 (DW_TAG_base_type) <921ce>
> DW_AT_byte_size : 8 <921cf> DW_AT_encoding : 7 (unsigned)
> <921d0> DW_AT_name : (indirect string, offset: 0x4dc4): long
> unsigned int
>
