Jesper wanted to see offsets at callq sites when doing some performance
investigation related to retpolines, so save him some time by providing
a 'O' hotkey to allow showing offsets from function start at call
instructions or in all instructions, just go on pressing 'O' till the
offsets you need appear.

Example:

Starts with:

Samples: 64  of event 'cycles:ppp', 100000 Hz, Event count (approx.): 318963
ixgbe_read_reg  /proc/kcore
Percent│    ↑ je     2a
       │   ┌──cmp    $0xffffffff,%r13d
       │   ├──je     d0
       │   │  mov    $0x53e3,%edi
       │   │→ callq  __const_udelay
       │   │  sub    $0x1,%r15d
       │   │↑ jne    83
       │   │  mov    0x8(%rbp),%rax
       │   │  testb  $0x20,0x1799(%rax)
       │   │↑ je     2a
       │   │  mov    0x200(%rax),%rdi
       │   │  mov    %r13d,%edx
       │   │  mov    $0xffffffffc02595d8,%rsi
       │   │→ callq  netdev_warn
       │   │↑ jmpq   2a
       │d0:└─→mov    0x8(%rbp),%rsi
       │      mov    %rbp,%rdi
       │      mov    %eax,0x4(%rsp)
       │    → callq  ixgbe_remove_adapter.isra.77
       │      mov    0x4(%rsp),%eax
Press 'h' for help on key bindings
============================================================================

Pess 'O':

Samples: 64  of event 'cycles:ppp', 100000 Hz, Event count (approx.): 318963
ixgbe_read_reg  /proc/kcore
Percent│    ↑ je     2a
       │   ┌──cmp    $0xffffffff,%r13d
       │   ├──je     d0
       │   │  mov    $0x53e3,%edi
       │99:│→ callq  __const_udelay
       │   │  sub    $0x1,%r15d
       │   │↑ jne    83
       │   │  mov    0x8(%rbp),%rax
       │   │  testb  $0x20,0x1799(%rax)
       │   │↑ je     2a
       │   │  mov    0x200(%rax),%rdi
       │   │  mov    %r13d,%edx
       │   │  mov    $0xffffffffc02595d8,%rsi
       │c6:│→ callq  netdev_warn
       │   │↑ jmpq   2a
       │d0:└─→mov    0x8(%rbp),%rsi
       │      mov    %rbp,%rdi
       │      mov    %eax,0x4(%rsp)
       │db: → callq  ixgbe_remove_adapter.isra.77
       │      mov    0x4(%rsp),%eax
Press 'h' for help on key bindings
============================================================================

Press 'O' again:

Samples: 64  of event 'cycles:ppp', 100000 Hz, Event count (approx.): 318963
ixgbe_read_reg  /proc/kcore
Percent│8c: ↑ je     2a
       │8e:┌──cmp    $0xffffffff,%r13d
       │92:├──je     d0
       │94:│  mov    $0x53e3,%edi
       │99:│→ callq  __const_udelay
       │9e:│  sub    $0x1,%r15d
       │a2:│↑ jne    83
       │a4:│  mov    0x8(%rbp),%rax
       │a8:│  testb  $0x20,0x1799(%rax)
       │af:│↑ je     2a
       │b5:│  mov    0x200(%rax),%rdi
       │bc:│  mov    %r13d,%edx
       │bf:│  mov    $0xffffffffc02595d8,%rsi
       │c6:│→ callq  netdev_warn
       │cb:│↑ jmpq   2a
       │d0:└─→mov    0x8(%rbp),%rsi
       │d4:   mov    %rbp,%rdi
       │d7:   mov    %eax,0x4(%rsp)
       │db: → callq  ixgbe_remove_adapter.isra.77
       │e0:   mov    0x4(%rsp),%eax
Press 'h' for help on key bindings
============================================================================

Press 'O' again and it will show just jump target offsets.
Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Liška <mliska@suse.cz>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-upp6pfdetwlsx18ec2uf1od4@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>