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

Tonghao Zhang tong at infragraf.org
Fri Jan 6 23:05:22 AEDT 2023



> On Jan 6, 2023, at 1:53 AM, Christophe Leroy <christophe.leroy at csgroup.eu> wrote:
> 
> 
> 
> Le 05/01/2023 à 04:06, tong at infragraf.org <mailto:tong at infragraf.org> a écrit :
>> From: Tonghao Zhang <tong at infragraf.org>
>> 
>> The x86_64 can't dump the valid insn in this way. A test BPF prog
>> which include subprog:
>> 
>> $ llvm-objdump -d subprog.o
>> Disassembly of section .text:
>> 0000000000000000 <subprog>:
>>        0:       18 01 00 00 73 75 62 70 00 00 00 00 72 6f 67 00 r1 = 29114459903653235 ll
>>        2:       7b 1a f8 ff 00 00 00 00 *(u64 *)(r10 - 8) = r1
>>        3:       bf a1 00 00 00 00 00 00 r1 = r10
>>        4:       07 01 00 00 f8 ff ff ff r1 += -8
>>        5:       b7 02 00 00 08 00 00 00 r2 = 8
>>        6:       85 00 00 00 06 00 00 00 call 6
>>        7:       95 00 00 00 00 00 00 00 exit
>> Disassembly of section raw_tp/sys_enter:
>> 0000000000000000 <entry>:
>>        0:       85 10 00 00 ff ff ff ff call -1
>>        1:       b7 00 00 00 00 00 00 00 r0 = 0
>>        2:       95 00 00 00 00 00 00 00 exit
>> 
>> kernel print message:
>> [  580.775387] flen=8 proglen=51 pass=3 image=ffffffffa000c20c from=kprobe-load pid=1643
>> [  580.777236] JIT code: 00000000: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
>> [  580.779037] JIT code: 00000010: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
>> [  580.780767] JIT code: 00000020: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
>> [  580.782568] JIT code: 00000030: cc cc cc
>> 
>> $ bpf_jit_disasm
>> 51 bytes emitted from JIT compiler (pass:3, flen:8)
>> ffffffffa000c20c + <x>:
>>    0:   int3
>>    1:   int3
>>    2:   int3
>>    3:   int3
>>    4:   int3
>>    5:   int3
>>    ...
>> 
>> Until bpf_jit_binary_pack_finalize is invoked, we copy rw_header to header
>> and then image/insn is valid. BTW, we can use the "bpftool prog dump" JITed instructions.
> 
> NACK.
> 
> Because the feature is buggy on x86_64, you remove it for all 
> architectures ?
> 
> On powerpc bpf_jit_enable == 2 works and is very usefull.
> 
> Last time I tried to use bpftool on powerpc/32 it didn't work. I don't 
> remember the details, I think it was an issue with endianess. Maybe it 
> is fixed now, but it needs to be verified.

I think bpftool may dump the jited insn too.
> So please, before removing a working and usefull feature, make sure 
> there is an alternative available to it for all architectures in all 
> configurations.
> 
> Also, I don't think bpftool is usable to dump kernel BPF selftests. 
Why bpftool does’t work for you ? I think this is a core function for bpf. If you can dump the jited insn using bpf_jit_enable == 2, you should
dump the inns tool, while in selftest case.

Alexei any thoughts?

> That's vital when a selftest fails if you want to have a chance to 
> understand why it fails.
> Thanks
> Christophe
> 
>> 
>> Signed-off-by: Tonghao Zhang <tong at infragraf.org>
>> Suggested-by: Alexei Starovoitov <ast at kernel.org>
>> Cc: Alexei Starovoitov <ast at kernel.org>
>> Cc: Daniel Borkmann <daniel at iogearbox.net>
>> Cc: Andrii Nakryiko <andrii at kernel.org>
>> Cc: Martin KaFai Lau <martin.lau at linux.dev>
>> Cc: Song Liu <song at kernel.org>
>> Cc: Yonghong Song <yhs at fb.com>
>> Cc: John Fastabend <john.fastabend at gmail.com>
>> Cc: KP Singh <kpsingh at kernel.org>
>> Cc: Stanislav Fomichev <sdf at google.com>
>> Cc: Hao Luo <haoluo at google.com>
>> Cc: Jiri Olsa <jolsa at kernel.org>
>> Cc: Hou Tao <houtao1 at huawei.com>
>> ---
>>  Documentation/admin-guide/sysctl/net.rst |   1 +
>>  Documentation/networking/filter.rst      |  98 +------
>>  arch/arm/net/bpf_jit_32.c                |   4 -
>>  arch/arm64/net/bpf_jit_comp.c            |   4 -
>>  arch/loongarch/net/bpf_jit.c             |   4 -
>>  arch/mips/net/bpf_jit_comp.c             |   3 -
>>  arch/powerpc/net/bpf_jit_comp.c          |  11 -
>>  arch/riscv/net/bpf_jit_core.c            |   3 -
>>  arch/s390/net/bpf_jit_comp.c             |   4 -
>>  arch/sparc/net/bpf_jit_comp_32.c         |   3 -
>>  arch/sparc/net/bpf_jit_comp_64.c         |  13 -
>>  arch/x86/net/bpf_jit_comp.c              |   3 -
>>  arch/x86/net/bpf_jit_comp32.c            |   3 -
>>  net/core/sysctl_net_core.c               |  12 +-
>>  tools/bpf/.gitignore                     |   1 -
>>  tools/bpf/Makefile                       |  10 +-
>>  tools/bpf/bpf_jit_disasm.c               | 332 -----------------------
>>  17 files changed, 9 insertions(+), 500 deletions(-)
>>  delete mode 100644 tools/bpf/bpf_jit_disasm.c
>> 
>> diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
>> index 6394f5dc2303..82ca05ca6ed0 100644
>> --- a/Documentation/admin-guide/sysctl/net.rst
>> +++ b/Documentation/admin-guide/sysctl/net.rst
>> @@ -88,6 +88,7 @@ Values:
>>         - 0 - disable the JIT (default value)
>>         - 1 - enable the JIT
>>         - 2 - enable the JIT and ask the compiler to emit traces on kernel log.
>> +              (deprecated since v6.3, use ``bpftool prog dump jited id <id>`` instead)
>> 
>>  bpf_jit_harden
>>  --------------
>> diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst
>> index f69da5074860..5f51c050e88f 100644
>> --- a/Documentation/networking/filter.rst
>> +++ b/Documentation/networking/filter.rst
>> @@ -520,102 +520,8 @@ been previously enabled by root::
>> 
>>    echo 1 > /proc/sys/net/core/bpf_jit_enable
>> 
>> -For JIT developers, doing audits etc, each compile run can output the generated
>> -opcode image into the kernel log via::
>> -
>> -  echo 2 > /proc/sys/net/core/bpf_jit_enable
>> -
>> -Example output from dmesg::
>> -
>> -    [ 3389.935842] flen=6 proglen=70 pass=3 image=ffffffffa0069c8f
>> -    [ 3389.935847] JIT code: 00000000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 68
>> -    [ 3389.935849] JIT code: 00000010: 44 2b 4f 6c 4c 8b 87 d8 00 00 00 be 0c 00 00 00
>> -    [ 3389.935850] JIT code: 00000020: e8 1d 94 ff e0 3d 00 08 00 00 75 16 be 17 00 00
>> -    [ 3389.935851] JIT code: 00000030: 00 e8 28 94 ff e0 83 f8 01 75 07 b8 ff ff 00 00
>> -    [ 3389.935852] JIT code: 00000040: eb 02 31 c0 c9 c3
>> -
>> -When CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1 and
>> -setting any other value than that will return in failure. This is even the case for
>> -setting bpf_jit_enable to 2, since dumping the final JIT image into the kernel log
>> -is discouraged and introspection through bpftool (under tools/bpf/bpftool/) is the
>> -generally recommended approach instead.
>> -
>> -In the kernel source tree under tools/bpf/, there's bpf_jit_disasm for
>> -generating disassembly out of the kernel log's hexdump::
>> -
>> -       # ./bpf_jit_disasm
>> -       70 bytes emitted from JIT compiler (pass:3, flen:6)
>> -       ffffffffa0069c8f + <x>:
>> -       0:      push   %rbp
>> -       1:      mov    %rsp,%rbp
>> -       4:      sub    $0x60,%rsp
>> -       8:      mov    %rbx,-0x8(%rbp)
>> -       c:      mov    0x68(%rdi),%r9d
>> -       10:     sub    0x6c(%rdi),%r9d
>> -       14:     mov    0xd8(%rdi),%r8
>> -       1b:     mov    $0xc,%esi
>> -       20:     callq  0xffffffffe0ff9442
>> -       25:     cmp    $0x800,%eax
>> -       2a:     jne    0x0000000000000042
>> -       2c:     mov    $0x17,%esi
>> -       31:     callq  0xffffffffe0ff945e
>> -       36:     cmp    $0x1,%eax
>> -       39:     jne    0x0000000000000042
>> -       3b:     mov    $0xffff,%eax
>> -       40:     jmp    0x0000000000000044
>> -       42:     xor    %eax,%eax
>> -       44:     leaveq
>> -       45:     retq
>> -
>> -       Issuing option `-o` will "annotate" opcodes to resulting assembler
>> -       instructions, which can be very useful for JIT developers:
>> -
>> -       # ./bpf_jit_disasm -o
>> -       70 bytes emitted from JIT compiler (pass:3, flen:6)
>> -       ffffffffa0069c8f + <x>:
>> -       0:      push   %rbp
>> -               55
>> -       1:      mov    %rsp,%rbp
>> -               48 89 e5
>> -       4:      sub    $0x60,%rsp
>> -               48 83 ec 60
>> -       8:      mov    %rbx,-0x8(%rbp)
>> -               48 89 5d f8
>> -       c:      mov    0x68(%rdi),%r9d
>> -               44 8b 4f 68
>> -       10:     sub    0x6c(%rdi),%r9d
>> -               44 2b 4f 6c
>> -       14:     mov    0xd8(%rdi),%r8
>> -               4c 8b 87 d8 00 00 00
>> -       1b:     mov    $0xc,%esi
>> -               be 0c 00 00 00
>> -       20:     callq  0xffffffffe0ff9442
>> -               e8 1d 94 ff e0
>> -       25:     cmp    $0x800,%eax
>> -               3d 00 08 00 00
>> -       2a:     jne    0x0000000000000042
>> -               75 16
>> -       2c:     mov    $0x17,%esi
>> -               be 17 00 00 00
>> -       31:     callq  0xffffffffe0ff945e
>> -               e8 28 94 ff e0
>> -       36:     cmp    $0x1,%eax
>> -               83 f8 01
>> -       39:     jne    0x0000000000000042
>> -               75 07
>> -       3b:     mov    $0xffff,%eax
>> -               b8 ff ff 00 00
>> -       40:     jmp    0x0000000000000044
>> -               eb 02
>> -       42:     xor    %eax,%eax
>> -               31 c0
>> -       44:     leaveq
>> -               c9
>> -       45:     retq
>> -               c3
>> -
>> -For BPF JIT developers, bpf_jit_disasm, bpf_asm and bpf_dbg provides a useful
>> -toolchain for developing and testing the kernel's JIT compiler.
>> +For JIT developers, doing audits etc, should use `bpftool prog dump` to
>> +veiw the JIT generated opcode image.
>> 
>>  BPF kernel internals
>>  --------------------
>> diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
>> index 6a1c9fca5260..39301d59b537 100644
>> --- a/arch/arm/net/bpf_jit_32.c
>> +++ b/arch/arm/net/bpf_jit_32.c
>> @@ -1999,10 +1999,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>         }
>>         flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
>> 
>> -       if (bpf_jit_enable > 1)
>> -               /* there are 2 passes here */
>> -               bpf_jit_dump(prog->len, image_size, 2, ctx.target);
>> -
>>         bpf_jit_binary_lock_ro(header);
>>         prog->bpf_func = (void *)ctx.target;
>>         prog->jited = 1;
>> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
>> index 62f805f427b7..59c35b4d77b7 100644
>> --- a/arch/arm64/net/bpf_jit_comp.c
>> +++ b/arch/arm64/net/bpf_jit_comp.c
>> @@ -1567,10 +1567,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 goto out_off;
>>         }
>> 
>> -       /* And we're done. */
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, prog_size, 2, ctx.image);
>> -
>>         bpf_flush_icache(header, ctx.image + ctx.idx);
>> 
>>         if (!prog->is_func || extra_pass) {
>> diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
>> index bdcd0c7719a9..ea37f52faa6e 100644
>> --- a/arch/loongarch/net/bpf_jit.c
>> +++ b/arch/loongarch/net/bpf_jit.c
>> @@ -1123,10 +1123,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 goto out_offset;
>>         }
>> 
>> -       /* And we're done */
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, image_size, 2, ctx.image);
>> -
>>         /* Update the icache */
>>         flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx));
>> 
>> diff --git a/arch/mips/net/bpf_jit_comp.c b/arch/mips/net/bpf_jit_comp.c
>> index b17130d510d4..ccbb7c231cb0 100644
>> --- a/arch/mips/net/bpf_jit_comp.c
>> +++ b/arch/mips/net/bpf_jit_comp.c
>> @@ -1012,9 +1012,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>         flush_icache_range((unsigned long)header,
>>                            (unsigned long)&ctx.target[ctx.jit_index]);
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, image_size, 2, ctx.target);
>> -
>>         prog->bpf_func = (void *)ctx.target;
>>         prog->jited = 1;
>>         prog->jited_len = image_size;
>> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
>> index 43e634126514..f0f7d8ff2022 100644
>> --- a/arch/powerpc/net/bpf_jit_comp.c
>> +++ b/arch/powerpc/net/bpf_jit_comp.c
>> @@ -262,20 +262,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
>>                         goto out_addrs;
>>                 }
>>                 bpf_jit_build_epilogue(code_base, &cgctx);
>> -
>> -               if (bpf_jit_enable > 1)
>> -                       pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass,
>> -                               proglen - (cgctx.idx * 4), cgctx.seen);
>>         }
>> 
>>  skip_codegen_passes:
>> -       if (bpf_jit_enable > 1)
>> -               /*
>> -                * Note that we output the base address of the code_base
>> -                * rather than image, since opcodes are in code_base.
>> -                */
>> -               bpf_jit_dump(flen, proglen, pass, code_base);
>> -
>>  #ifdef CONFIG_PPC64_ELF_ABI_V1
>>         /* Function descriptor nastiness: Address + TOC */
>>         ((u64 *)image)[0] = (u64)code_base;
>> diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
>> index 737baf8715da..ff168c50d46a 100644
>> --- a/arch/riscv/net/bpf_jit_core.c
>> +++ b/arch/riscv/net/bpf_jit_core.c
>> @@ -151,9 +151,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>         }
>>         bpf_jit_build_epilogue(ctx);
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, prog_size, pass, ctx->insns);
>> -
>>         prog->bpf_func = (void *)ctx->insns;
>>         prog->jited = 1;
>>         prog->jited_len = prog_size;
>> diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
>> index af35052d06ed..13d996e27602 100644
>> --- a/arch/s390/net/bpf_jit_comp.c
>> +++ b/arch/s390/net/bpf_jit_comp.c
>> @@ -1831,10 +1831,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
>>                 fp = orig_fp;
>>                 goto free_addrs;
>>         }
>> -       if (bpf_jit_enable > 1) {
>> -               bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
>> -               print_fn_code(jit.prg_buf, jit.size_prg);
>> -       }
>>         if (!fp->is_func || extra_pass) {
>>                 bpf_jit_binary_lock_ro(header);
>>         } else {
>> diff --git a/arch/sparc/net/bpf_jit_comp_32.c b/arch/sparc/net/bpf_jit_comp_32.c
>> index a74e5004c6c8..08de0ed84831 100644
>> --- a/arch/sparc/net/bpf_jit_comp_32.c
>> +++ b/arch/sparc/net/bpf_jit_comp_32.c
>> @@ -743,9 +743,6 @@ cond_branch:                        f_offset = addrs[i + filter[i].jf];
>>                 oldproglen = proglen;
>>         }
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(flen, proglen, pass + 1, image);
>> -
>>         if (image) {
>>                 fp->bpf_func = (void *)image;
>>                 fp->jited = 1;
>> diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
>> index fa0759bfe498..14c9e5ce4100 100644
>> --- a/arch/sparc/net/bpf_jit_comp_64.c
>> +++ b/arch/sparc/net/bpf_jit_comp_64.c
>> @@ -1549,16 +1549,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 }
>>                 build_epilogue(&ctx);
>> 
>> -               if (bpf_jit_enable > 1)
>> -                       pr_info("Pass %d: size = %u, seen = [%c%c%c%c%c%c]\n", pass,
>> -                               ctx.idx * 4,
>> -                               ctx.tmp_1_used ? '1' : ' ',
>> -                               ctx.tmp_2_used ? '2' : ' ',
>> -                               ctx.tmp_3_used ? '3' : ' ',
>> -                               ctx.saw_frame_pointer ? 'F' : ' ',
>> -                               ctx.saw_call ? 'C' : ' ',
>> -                               ctx.saw_tail_call ? 'T' : ' ');
>> -
>>                 if (ctx.idx * 4 == prev_image_size)
>>                         break;
>>                 prev_image_size = ctx.idx * 4;
>> @@ -1596,9 +1586,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 goto out_off;
>>         }
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, image_size, pass, ctx.image);
>> -
>>         bpf_flush_icache(header, (u8 *)header + header->size);
>> 
>>         if (!prog->is_func || extra_pass) {
>> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
>> index e3e2b57e4e13..197ff8651a56 100644
>> --- a/arch/x86/net/bpf_jit_comp.c
>> +++ b/arch/x86/net/bpf_jit_comp.c
>> @@ -2551,9 +2551,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 cond_resched();
>>         }
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, proglen, pass + 1, image);
>> -
>>         if (image) {
>>                 if (!prog->is_func || extra_pass) {
>>                         /*
>> diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
>> index 429a89c5468b..ca53f20aca73 100644
>> --- a/arch/x86/net/bpf_jit_comp32.c
>> +++ b/arch/x86/net/bpf_jit_comp32.c
>> @@ -2597,9 +2597,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                 cond_resched();
>>         }
>> 
>> -       if (bpf_jit_enable > 1)
>> -               bpf_jit_dump(prog->len, proglen, pass + 1, image);
>> -
>>         if (image) {
>>                 bpf_jit_binary_lock_ro(header);
>>                 prog->bpf_func = (void *)image;
>> diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
>> index 5b1ce656baa1..562ace48e1c9 100644
>> --- a/net/core/sysctl_net_core.c
>> +++ b/net/core/sysctl_net_core.c
>> @@ -276,14 +276,10 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
>>         tmp.data = &jit_enable;
>>         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
>>         if (write && !ret) {
>> -               if (jit_enable < 2 ||
>> -                   (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) {
>> -                       *(int *)table->data = jit_enable;
>> -                       if (jit_enable == 2)
>> -                               pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
>> -               } else {
>> -                       ret = -EPERM;
>> -               }
>> +               *(int *)table->data = jit_enable;
>> +
>> +               if (jit_enable == 2)
>> +                       pr_warn_once("bpf_jit_enable == 2 was deprecated! Use bpftool prog dump instead.\n");
>>         }
>> 
>>         if (write && ret && min == max)
>> diff --git a/tools/bpf/.gitignore b/tools/bpf/.gitignore
>> index cf53342175e7..5c70cfb9092e 100644
>> --- a/tools/bpf/.gitignore
>> +++ b/tools/bpf/.gitignore
>> @@ -4,4 +4,3 @@ feature
>>  bpf_asm
>>  bpf_dbg
>>  bpf_exp.yacc.*
>> -bpf_jit_disasm
>> diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
>> index 243b79f2b451..9264d7b0edf6 100644
>> --- a/tools/bpf/Makefile
>> +++ b/tools/bpf/Makefile
>> @@ -74,14 +74,10 @@ $(OUTPUT)%.yacc.o: $(OUTPUT)%.yacc.c
>>  $(OUTPUT)%.lex.o: $(OUTPUT)%.lex.c
>>         $(QUIET_CC)$(CC) $(CFLAGS) -c -o $@ $<
>> 
>> -PROGS = $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg $(OUTPUT)bpf_asm
>> +PROGS = $(OUTPUT)bpf_dbg $(OUTPUT)bpf_asm
>> 
>>  all: $(PROGS) bpftool runqslower
>> 
>> -$(OUTPUT)bpf_jit_disasm: CFLAGS += -DPACKAGE='bpf_jit_disasm'
>> -$(OUTPUT)bpf_jit_disasm: $(OUTPUT)bpf_jit_disasm.o
>> -       $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lopcodes -lbfd -ldl
>> -
>>  $(OUTPUT)bpf_dbg: $(OUTPUT)bpf_dbg.o
>>         $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lreadline
>> 
>> @@ -94,16 +90,14 @@ $(OUTPUT)bpf_exp.lex.o: $(OUTPUT)bpf_exp.lex.c
>> 
>>  clean: bpftool_clean runqslower_clean resolve_btfids_clean
>>         $(call QUIET_CLEAN, bpf-progs)
>> -       $(Q)$(RM) -r -- $(OUTPUT)*.o $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg \
>> +       $(Q)$(RM) -r -- $(OUTPUT)*.o $(OUTPUT)bpf_dbg \
>>                $(OUTPUT)bpf_asm $(OUTPUT)bpf_exp.yacc.* $(OUTPUT)bpf_exp.lex.*
>>         $(call QUIET_CLEAN, core-gen)
>>         $(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpf
>>         $(Q)$(RM) -r -- $(OUTPUT)feature
>> 
>>  install: $(PROGS) bpftool_install
>> -       $(call QUIET_INSTALL, bpf_jit_disasm)
>>         $(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(prefix)/bin
>> -       $(Q)$(INSTALL) $(OUTPUT)bpf_jit_disasm $(DESTDIR)$(prefix)/bin/bpf_jit_disasm
>>         $(call QUIET_INSTALL, bpf_dbg)
>>         $(Q)$(INSTALL) $(OUTPUT)bpf_dbg $(DESTDIR)$(prefix)/bin/bpf_dbg
>>         $(call QUIET_INSTALL, bpf_asm)
>> diff --git a/tools/bpf/bpf_jit_disasm.c b/tools/bpf/bpf_jit_disasm.c
>> deleted file mode 100644
>> index a90a5d110f92..000000000000
>> --- a/tools/bpf/bpf_jit_disasm.c
>> +++ /dev/null
>> @@ -1,332 +0,0 @@
>> -// SPDX-License-Identifier: GPL-2.0-only
>> -/*
>> - * Minimal BPF JIT image disassembler
>> - *
>> - * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for
>> - * debugging or verification purposes.
>> - *
>> - * To get the disassembly of the JIT code, do the following:
>> - *
>> - *  1) `echo 2 > /proc/sys/net/core/bpf_jit_enable`
>> - *  2) Load a BPF filter (e.g. `tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24`)
>> - *  3) Run e.g. `bpf_jit_disasm -o` to read out the last JIT code
>> - *
>> - * Copyright 2013 Daniel Borkmann <borkmann at redhat.com>
>> - */
>> -
>> -#include <stdint.h>
>> -#include <stdio.h>
>> -#include <stdlib.h>
>> -#include <assert.h>
>> -#include <unistd.h>
>> -#include <string.h>
>> -#include <bfd.h>
>> -#include <dis-asm.h>
>> -#include <regex.h>
>> -#include <fcntl.h>
>> -#include <sys/klog.h>
>> -#include <sys/types.h>
>> -#include <sys/stat.h>
>> -#include <limits.h>
>> -#include <tools/dis-asm-compat.h>
>> -
>> -#define CMD_ACTION_SIZE_BUFFER         10
>> -#define CMD_ACTION_READ_ALL            3
>> -
>> -static void get_exec_path(char *tpath, size_t size)
>> -{
>> -       char *path;
>> -       ssize_t len;
>> -
>> -       snprintf(tpath, size, "/proc/%d/exe", (int) getpid());
>> -       tpath[size - 1] = 0;
>> -
>> -       path = strdup(tpath);
>> -       assert(path);
>> -
>> -       len = readlink(path, tpath, size);
>> -       tpath[len] = 0;
>> -
>> -       free(path);
>> -}
>> -
>> -static void get_asm_insns(uint8_t *image, size_t len, int opcodes)
>> -{
>> -       int count, i, pc = 0;
>> -       char tpath[PATH_MAX];
>> -       struct disassemble_info info;
>> -       disassembler_ftype disassemble;
>> -       bfd *bfdf;
>> -
>> -       memset(tpath, 0, sizeof(tpath));
>> -       get_exec_path(tpath, sizeof(tpath));
>> -
>> -       bfdf = bfd_openr(tpath, NULL);
>> -       assert(bfdf);
>> -       assert(bfd_check_format(bfdf, bfd_object));
>> -
>> -       init_disassemble_info_compat(&info, stdout,
>> -                                    (fprintf_ftype) fprintf,
>> -                                    fprintf_styled);
>> -       info.arch = bfd_get_arch(bfdf);
>> -       info.mach = bfd_get_mach(bfdf);
>> -       info.buffer = image;
>> -       info.buffer_length = len;
>> -
>> -       disassemble_init_for_target(&info);
>> -
>> -#ifdef DISASM_FOUR_ARGS_SIGNATURE
>> -       disassemble = disassembler(info.arch,
>> -                                  bfd_big_endian(bfdf),
>> -                                  info.mach,
>> -                                  bfdf);
>> -#else
>> -       disassemble = disassembler(bfdf);
>> -#endif
>> -       assert(disassemble);
>> -
>> -       do {
>> -               printf("%4x:\t", pc);
>> -
>> -               count = disassemble(pc, &info);
>> -
>> -               if (opcodes) {
>> -                       printf("\n\t");
>> -                       for (i = 0; i < count; ++i)
>> -                               printf("%02x ", (uint8_t) image[pc + i]);
>> -               }
>> -               printf("\n");
>> -
>> -               pc += count;
>> -       } while(count > 0 && pc < len);
>> -
>> -       bfd_close(bfdf);
>> -}
>> -
>> -static char *get_klog_buff(unsigned int *klen)
>> -{
>> -       int ret, len;
>> -       char *buff;
>> -
>> -       len = klogctl(CMD_ACTION_SIZE_BUFFER, NULL, 0);
>> -       if (len < 0)
>> -               return NULL;
>> -
>> -       buff = malloc(len);
>> -       if (!buff)
>> -               return NULL;
>> -
>> -       ret = klogctl(CMD_ACTION_READ_ALL, buff, len);
>> -       if (ret < 0) {
>> -               free(buff);
>> -               return NULL;
>> -       }
>> -
>> -       *klen = ret;
>> -       return buff;
>> -}
>> -
>> -static char *get_flog_buff(const char *file, unsigned int *klen)
>> -{
>> -       int fd, ret, len;
>> -       struct stat fi;
>> -       char *buff;
>> -
>> -       fd = open(file, O_RDONLY);
>> -       if (fd < 0)
>> -               return NULL;
>> -
>> -       ret = fstat(fd, &fi);
>> -       if (ret < 0 || !S_ISREG(fi.st_mode))
>> -               goto out;
>> -
>> -       len = fi.st_size + 1;
>> -       buff = malloc(len);
>> -       if (!buff)
>> -               goto out;
>> -
>> -       memset(buff, 0, len);
>> -       ret = read(fd, buff, len - 1);
>> -       if (ret <= 0)
>> -               goto out_free;
>> -
>> -       close(fd);
>> -       *klen = ret;
>> -       return buff;
>> -out_free:
>> -       free(buff);
>> -out:
>> -       close(fd);
>> -       return NULL;
>> -}
>> -
>> -static char *get_log_buff(const char *file, unsigned int *klen)
>> -{
>> -       return file ? get_flog_buff(file, klen) : get_klog_buff(klen);
>> -}
>> -
>> -static void put_log_buff(char *buff)
>> -{
>> -       free(buff);
>> -}
>> -
>> -static uint8_t *get_last_jit_image(char *haystack, size_t hlen,
>> -                                  unsigned int *ilen)
>> -{
>> -       char *ptr, *pptr, *tmp;
>> -       off_t off = 0;
>> -       unsigned int proglen;
>> -       int ret, flen, pass, ulen = 0;
>> -       regmatch_t pmatch[1];
>> -       unsigned long base;
>> -       regex_t regex;
>> -       uint8_t *image;
>> -
>> -       if (hlen == 0)
>> -               return NULL;
>> -
>> -       ret = regcomp(&regex, "flen=[[:alnum:]]+ proglen=[[:digit:]]+ "
>> -                     "pass=[[:digit:]]+ image=[[:xdigit:]]+", REG_EXTENDED);
>> -       assert(ret == 0);
>> -
>> -       ptr = haystack;
>> -       memset(pmatch, 0, sizeof(pmatch));
>> -
>> -       while (1) {
>> -               ret = regexec(&regex, ptr, 1, pmatch, 0);
>> -               if (ret == 0) {
>> -                       ptr += pmatch[0].rm_eo;
>> -                       off += pmatch[0].rm_eo;
>> -                       assert(off < hlen);
>> -               } else
>> -                       break;
>> -       }
>> -
>> -       ptr = haystack + off - (pmatch[0].rm_eo - pmatch[0].rm_so);
>> -       ret = sscanf(ptr, "flen=%d proglen=%u pass=%d image=%lx",
>> -                    &flen, &proglen, &pass, &base);
>> -       if (ret != 4) {
>> -               regfree(&regex);
>> -               return NULL;
>> -       }
>> -       if (proglen > 1000000) {
>> -               printf("proglen of %d too big, stopping\n", proglen);
>> -               return NULL;
>> -       }
>> -
>> -       image = malloc(proglen);
>> -       if (!image) {
>> -               printf("Out of memory\n");
>> -               return NULL;
>> -       }
>> -       memset(image, 0, proglen);
>> -
>> -       tmp = ptr = haystack + off;
>> -       while ((ptr = strtok(tmp, "\n")) != NULL && ulen < proglen) {
>> -               tmp = NULL;
>> -               if (!strstr(ptr, "JIT code"))
>> -                       continue;
>> -               pptr = ptr;
>> -               while ((ptr = strstr(pptr, ":")))
>> -                       pptr = ptr + 1;
>> -               ptr = pptr;
>> -               do {
>> -                       image[ulen++] = (uint8_t) strtoul(pptr, &pptr, 16);
>> -                       if (ptr == pptr) {
>> -                               ulen--;
>> -                               break;
>> -                       }
>> -                       if (ulen >= proglen)
>> -                               break;
>> -                       ptr = pptr;
>> -               } while (1);
>> -       }
>> -
>> -       assert(ulen == proglen);
>> -       printf("%u bytes emitted from JIT compiler (pass:%d, flen:%d)\n",
>> -              proglen, pass, flen);
>> -       printf("%lx + <x>:\n", base);
>> -
>> -       regfree(&regex);
>> -       *ilen = ulen;
>> -       return image;
>> -}
>> -
>> -static void usage(void)
>> -{
>> -       printf("Usage: bpf_jit_disasm [...]\n");
>> -       printf("       -o          Also display related opcodes (default: off).\n");
>> -       printf("       -O <file>   Write binary image of code to file, don't disassemble to stdout.\n");
>> -       printf("       -f <file>   Read last image dump from file or stdin (default: klog).\n");
>> -       printf("       -h          Display this help.\n");
>> -}
>> -
>> -int main(int argc, char **argv)
>> -{
>> -       unsigned int len, klen, opt, opcodes = 0;
>> -       char *kbuff, *file = NULL;
>> -       char *ofile = NULL;
>> -       int ofd;
>> -       ssize_t nr;
>> -       uint8_t *pos;
>> -       uint8_t *image = NULL;
>> -
>> -       while ((opt = getopt(argc, argv, "of:O:")) != -1) {
>> -               switch (opt) {
>> -               case 'o':
>> -                       opcodes = 1;
>> -                       break;
>> -               case 'O':
>> -                       ofile = optarg;
>> -                       break;
>> -               case 'f':
>> -                       file = optarg;
>> -                       break;
>> -               default:
>> -                       usage();
>> -                       return -1;
>> -               }
>> -       }
>> -
>> -       bfd_init();
>> -
>> -       kbuff = get_log_buff(file, &klen);
>> -       if (!kbuff) {
>> -               fprintf(stderr, "Could not retrieve log buffer!\n");
>> -               return -1;
>> -       }
>> -
>> -       image = get_last_jit_image(kbuff, klen, &len);
>> -       if (!image) {
>> -               fprintf(stderr, "No JIT image found!\n");
>> -               goto done;
>> -       }
>> -       if (!ofile) {
>> -               get_asm_insns(image, len, opcodes);
>> -               goto done;
>> -       }
>> -
>> -       ofd = open(ofile, O_WRONLY | O_CREAT | O_TRUNC, DEFFILEMODE);
>> -       if (ofd < 0) {
>> -               fprintf(stderr, "Could not open file %s for writing: ", ofile);
>> -               perror(NULL);
>> -               goto done;
>> -       }
>> -       pos = image;
>> -       do {
>> -               nr = write(ofd, pos, len);
>> -               if (nr < 0) {
>> -                       fprintf(stderr, "Could not write data to %s: ", ofile);
>> -                       perror(NULL);
>> -                       goto done;
>> -               }
>> -               len -= nr;
>> -               pos += nr;
>> -       } while (len);
>> -       close(ofd);
>> -
>> -done:
>> -       put_log_buff(kbuff);
>> -       free(image);
>> -       return 0;
>> -}
>> --
>> 2.27.0

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20230106/bffd023d/attachment-0001.htm>


More information about the Linuxppc-dev mailing list