[bpf-next v2] bpf: drop deprecated bpf_jit_enable == 2

Christophe Leroy christophe.leroy at csgroup.eu
Tue Jan 17 06:55:53 PST 2023



Le 17/01/2023 à 15:41, Quentin Monnet a écrit :
> [Vous ne recevez pas souvent de courriers de quentin at isovalent.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
> 
> 2023-01-17 14:25 UTC+0000 ~ Christophe Leroy <christophe.leroy at csgroup.eu>
>>
>>
>> Le 17/01/2023 à 15:18, Tonghao Zhang a écrit :
>>>
>>>
>>>> On Jan 17, 2023, at 7:36 PM, Christophe Leroy <christophe.leroy at csgroup.eu> wrote:
>>>>
>>>>
>>>>
>>>> Le 17/01/2023 à 08:30, Christophe Leroy a écrit :
>>>>>
>>>>>
>>>>> Le 17/01/2023 à 06:30, Tonghao Zhang a écrit :
>>>>>>
>>>>>>
>>>>>>> On Jan 9, 2023, at 4:15 PM, Christophe Leroy
>>>>>>> <christophe.leroy at csgroup.eu> wrote:
> 
> [...]
> 
>>>>>>> Sure I will try to test bpftool again in the coming days.
>>>>>>>
>>>>>>> Previous discussion about that subject is here:
>>>>>>> https://patchwork.kernel.org/project/linux-riscv/patch/20210415093250.3391257-1-Jianlin.Lv@arm.com/#24176847=
> 
> Christophe, apologies from dropping the discussion the last time, it
> seems your last message on that thread didn't make it to my inbox at the
> time :/. Thanks a lot for looking into that again!
> 
>>>>>> Hi Christophe
>>>>>> Any progress? We discuss to deprecate the bpf_jit_enable == 2 in 2021,
>>>>>> but bpftool can not run on powerpc.
>>>>>> Now can we fix this issue?
>>>>>
>>>>> Hi Tong,
>>>>>
>>>>> I have started to look at it but I don't have any fruitfull feedback yet.
>>>>
>>>> Hi Again,
>>>>
>>>> I tested again, the problem is still the same as one year ago:
>>>>
>>>> root at vgoip:~# ./bpftool prog
>>>> libbpf: elf: endianness mismatch in pid_iter_bpf.
>>> It seem to be not right ehdr->e_ident[EI_DATA]. Do we can print the real value?
>>> /*
>>>    * e_ident[EI_DATA]
>>>    */
>>> #define ELFDATANONE     0
>>> #define ELFDATA2LSB     1
>>> #define ELFDATA2MSB     2
>>> #define ELFDATANUM      3
>>>
>>> bpf_object__elf_init:
>>> obj->efile.ehdr = ehdr = elf64_getehdr(elf);
>>>
>>>> libbpf: failed to initialize skeleton BPF object 'pid_iter_bpf': -4003
>>>> Error: failed to open PID iterator skeleton
>>>>
>>>> root at vgoip:~# uname -a
>>>> Linux vgoip 6.2.0-rc3-02596-g1c2c9c13e256 #242 PREEMPT Tue Jan 17
>>>> 09:36:08 CET 2023 ppc GNU/Linux
>>> On my pc, elf is little endian.
>>> # readelf -h tools/bpf/bpftool/pid_iter.bpf.o
>>> ELF Header:
>>>     Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
>>>     Class:                             ELF64
>>>     Data:                              2's complement, little endian # x86_64
>>>     Version:                           1 (current)
>>>     OS/ABI:                            UNIX - System V
>>>     ABI Version:                       0
>>>     Type:                              REL (Relocatable file)
>>>     Machine:                           Linux BPF
>>>     Version:                           0x1
>>>     Entry point address:               0x0
>>>     Start of program headers:          0 (bytes into file)
>>>     Start of section headers:          64832 (bytes into file)
>>>     Flags:                             0x0
>>>     Size of this header:               64 (bytes)
>>>     Size of program headers:           0 (bytes)
>>>     Number of program headers:         0
>>>     Size of section headers:           64 (bytes)
>>>     Number of section headers:         13
>>>     Section header string table index: 1
>>>
>>
>> Yes, must be something wrong with the build, I get same as you :
>>
>> $ LANG= readelf -h pid_iter.bpf.o
>> ELF Header:
>>     Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
>>     Class:                             ELF64
>>     Data:                              2's complement, little endian
>>     Version:                           1 (current)
>>     OS/ABI:                            UNIX - System V
>>     ABI Version:                       0
>>     Type:                              REL (Relocatable file)
>>     Machine:                           Linux BPF
>>     Version:                           0x1
>>     Entry point address:               0x0
>>     Start of program headers:          0 (bytes into file)
>>     Start of section headers:          34704 (bytes into file)
>>     Flags:                             0x0
>>     Size of this header:               64 (bytes)
>>     Size of program headers:           0 (bytes)
>>     Number of program headers:         0
>>     Size of section headers:           64 (bytes)
>>     Number of section headers:         13
>>     Section header string table index: 1
>>
>>
>> Whereas I expect the same as bpftool I suppose, which is :
>>
>> $ LANG= readelf -h bpftool
>> ELF Header:
>>     Magic:   7f 45 4c 46 01 02 01 00 00 00 00 00 00 00 00 00
>>     Class:                             ELF32
>>     Data:                              2's complement, big endian
>>     Version:                           1 (current)
>>     OS/ABI:                            UNIX - System V
>>     ABI Version:                       0
>>     Type:                              EXEC (Executable file)
>>     Machine:                           PowerPC
>>     Version:                           0x1
>>     Entry point address:               0x100027d0
>>     Start of program headers:          52 (bytes into file)
>>     Start of section headers:          1842896 (bytes into file)
>>     Flags:                             0x0
>>     Size of this header:               52 (bytes)
>>     Size of program headers:           32 (bytes)
>>     Number of program headers:         9
>>     Size of section headers:           40 (bytes)
>>     Number of section headers:         39
>>     Section header string table index: 38
>>
> 
> pid_iter.bpf.o should be generated from that command in bpftool's Makefile:
> 
>          $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h \
>                          $(LIBBPF_BOOTSTRAP)
>                  $(QUIET_CLANG)$(CLANG) \
>                          -I$(or $(OUTPUT),.) \
>                          -I$(srctree)/tools/include/uapi/ \
>                          -I$(LIBBPF_BOOTSTRAP_INCLUDE) \
>                          -g -O2 -Wall -fno-stack-protector \
>                          -target bpf -c $< -o $@
> 
> My understanding is that "-target bpf" is supposed to pick the
> endianness for the host (see "llc --version | grep bpf". If that's not
> the case, could you please try to turn that into '-target bpfeb' in the
> Makefile instead? I'd be curious to see if it helps.
> 

I guess it cannot work if it picks the endianness for the build host. It 
should pick the endianness for the target host.

That's worse it seems with bpfeb : it fails at build :

   LINK    /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/bpftool
   GEN     vmlinux.h
   CLANG   pid_iter.bpf.o
   GEN     pid_iter.skel.h
libbpf: elf: endianness mismatch in pid_iter_bpf.
Error: failed to open BPF object file: Endian mismatch
make: *** [Makefile:222: pid_iter.skel.h] Error 93


Complete build in case it helps:

$ LANG= make CROSS_COMPILE=ppc-linux- ARCH=powerpc

Auto-detecting system features:
...                         clang-bpf-co-re: [ on  ]
...                                    llvm: [ OFF ]
...                                  libcap: [ OFF ]
...                                  libbfd: [ OFF ]

   MKDIR   /home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/
make[1]: Entering directory '/home/chleroy/linux-powerpc/tools/lib/bpf'
   GEN 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/bpf_helper_defs.h
   MKDIR   /home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/libbpf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/bpf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/nlattr.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/btf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/libbpf_errno.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/str_error.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/netlink.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/bpf_prog_linfo.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/libbpf_probes.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/hashmap.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/btf_dump.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/ringbuf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/strset.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/linker.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/gen_loader.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/relo_core.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/usdt.o
   LD 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/staticobjs/libbpf-in.o
   LINK    /home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/libbpf.a
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/libbpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/btf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/libbpf_common.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/libbpf_legacy.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf_helpers.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf_tracing.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf_endian.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf_core_read.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/skel_internal.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/libbpf_version.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/usdt.bpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/bpf_helper_defs.h
   INSTALL libbpf_headers
make[1]: Leaving directory '/home/chleroy/linux-powerpc/tools/lib/bpf'
   MKDIR   /home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/hashmap.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/nlattr.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/relo_core.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/libbpf/include/bpf/libbpf_internal.h
   CC      btf.o
   CC      btf_dumper.o
   CC      cfg.o
   CC      cgroup.o
   CC      common.o
   CC      feature.o
   CC      gen.o
   CC      iter.o
   CC      json_writer.o
   CC      link.o
   CC      main.o
   CC      map.o
   CC      map_perf_ring.o
   CC      net.o
   CC      netlink_dumper.o
   CC      perf.o
   MKDIR 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/hashmap.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/relo_core.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/libbpf_internal.h
   MKDIR   /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/
   MKDIR   /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/
make[1]: Entering directory '/home/chleroy/linux-powerpc/tools/lib/bpf'
   GEN 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/bpf_helper_defs.h
   MKDIR 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/libbpf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/bpf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/nlattr.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/btf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/libbpf_errno.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/str_error.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/netlink.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/bpf_prog_linfo.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/libbpf_probes.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/hashmap.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/btf_dump.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/ringbuf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/strset.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/linker.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/gen_loader.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/relo_core.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/usdt.o
   LD 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/staticobjs/libbpf-in.o
   LINK 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/libbpf.a
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/libbpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/btf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/libbpf_common.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/libbpf_legacy.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_tracing.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_endian.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_core_read.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/skel_internal.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/libbpf_version.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/usdt.bpf.h
   INSTALL 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h
   INSTALL libbpf_headers
make[1]: Leaving directory '/home/chleroy/linux-powerpc/tools/lib/bpf'
   CC      /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/main.o
   CC      /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/common.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/json_writer.o
   CC      /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/gen.o
   CC      /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/btf.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/xlated_dumper.o
   CC 
/home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/btf_dumper.o
   CC      /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/disasm.o
   LINK    /home/chleroy/linux-powerpc/tools/bpf/bpftool/bootstrap/bpftool
   GEN     vmlinux.h
   CLANG   pid_iter.bpf.o
   GEN     pid_iter.skel.h
libbpf: elf: endianness mismatch in pid_iter_bpf.
Error: failed to open BPF object file: Endian mismatch
make: *** [Makefile:222: pid_iter.skel.h] Error 93


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