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Sandipan Das f7f62c7134 tools: bpftool: add delimiters to multi-function JITed dumps 
This splits up the contiguous JITed dump obtained via the bpf
system call into more relatable chunks for each function in
the program. If the kernel symbols corresponding to these are
known, they are printed in the header for each JIT image dump
otherwise the masked start address is printed.

Before applying this patch:

  # bpftool prog dump jited id 1

     0:	push   %rbp
     1:	mov    %rsp,%rbp
  ...
    70:	leaveq
    71:	retq
    72:	push   %rbp
    73:	mov    %rsp,%rbp
  ...
    dd:	leaveq
    de:	retq

  # bpftool -p prog dump jited id 1

  [{
          "pc": "0x0",
          "operation": "push",
          "operands": ["%rbp"
          ]
      },{
  ...
      },{
          "pc": "0x71",
          "operation": "retq",
          "operands": [null
          ]
      },{
          "pc": "0x72",
          "operation": "push",
          "operands": ["%rbp"
          ]
      },{
  ...
      },{
          "pc": "0xde",
          "operation": "retq",
          "operands": [null
          ]
      }
  ]

After applying this patch:

  # echo 0 > /proc/sys/net/core/bpf_jit_kallsyms
  # bpftool prog dump jited id 1

  0xffffffffc02c7000:
     0:	push   %rbp
     1:	mov    %rsp,%rbp
  ...
    70:	leaveq
    71:	retq

  0xffffffffc02cf000:
     0:	push   %rbp
     1:	mov    %rsp,%rbp
  ...
    6b:	leaveq
    6c:	retq

  # bpftool -p prog dump jited id 1

  [{
          "name": "0xffffffffc02c7000",
          "insns": [{
                  "pc": "0x0",
                  "operation": "push",
                  "operands": ["%rbp"
                  ]
              },{
  ...
              },{
                  "pc": "0x71",
                  "operation": "retq",
                  "operands": [null
                  ]
              }
          ]
      },{
          "name": "0xffffffffc02cf000",
          "insns": [{
                  "pc": "0x0",
                  "operation": "push",
                  "operands": ["%rbp"
                  ]
              },{
  ...
              },{
                  "pc": "0x6c",
                  "operation": "retq",
                  "operands": [null
                  ]
              }
          ]
      }
  ]

  # echo 1 > /proc/sys/net/core/bpf_jit_kallsyms
  # bpftool prog dump jited id 1

  bpf_prog_b811aab41a39ad3d_foo:
     0:	push   %rbp
     1:	mov    %rsp,%rbp
  ...
    70:	leaveq
    71:	retq

  bpf_prog_cf418ac8b67bebd9_F:
     0:	push   %rbp
     1:	mov    %rsp,%rbp
  ...
    6b:	leaveq
    6c:	retq

  # bpftool -p prog dump jited id 1

  [{
          "name": "bpf_prog_b811aab41a39ad3d_foo",
          "insns": [{
                  "pc": "0x0",
                  "operation": "push",
                  "operands": ["%rbp"
                  ]
              },{
  ...
              },{
                  "pc": "0x71",
                  "operation": "retq",
                  "operands": [null
                  ]
              }
          ]
      },{
          "name": "bpf_prog_cf418ac8b67bebd9_F",
          "insns": [{
                  "pc": "0x0",
                  "operation": "push",
                  "operands": ["%rbp"
                  ]
              },{
  ...
              },{
                  "pc": "0x6c",
                  "operation": "retq",
                  "operands": [null
                  ]
              }
          ]
      }
  ]

Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-24 09:20:50 +02:00
..
bpftool tools: bpftool: add delimiters to multi-function JITed dumps 2018-05-24 09:20:50 +02:00
bpf_asm.c tools: rename tools/net directory to tools/bpf 2017-10-04 21:45:05 -07:00
bpf_dbg.c bpf: fix uninitialized variable in bpf tools 2018-04-26 22:23:02 +02:00
bpf_exp.l tools: rename tools/net directory to tools/bpf 2017-10-04 21:45:05 -07:00
bpf_exp.y tools: rename tools/net directory to tools/bpf 2017-10-04 21:45:05 -07:00
bpf_jit_disasm.c tools/bpf_jit_disasm: silence a static checker warning 2018-01-18 22:15:37 +01:00
Makefile bpf: fix for lex/yacc build error with gcc-5 2018-04-25 23:27:46 +02:00