linux/tools/perf/examples/bpf
Arnaldo Carvalho de Melo 79ef68c7e1 perf augmented_syscalls: Start collecting pathnames in the BPF program
This is the start of having the raw_syscalls:sys_enter BPF handler
collecting pointer arguments, namely pathnames, and with two syscalls
that have that pointer in different arguments, "open" as it as its first
argument, "openat" as the second.

With this in place the existing beautifiers in 'perf trace' works, those
args are shown instead of just the pointer that comes with the syscalls
tracepoints.

This also serves to show and document pitfalls in the process of using
just that place in the kernel (raw_syscalls:sys_enter) plus tables
provided by userspace to collect syscall pointer arguments.

One is the need to use a barrier, as suggested by Edward, to avoid clang
optimizations that make the kernel BPF verifier to refuse loading our
pointer contents collector.

The end result should be a generic eBPF program that works in all
architectures, with the differences amongst archs resolved by the
userspace component, 'perf trace', that should get all its tables
created automatically from the kernel components where they are defined,
via string table constructors for things not expressed in BTF/DWARF
(enums, structs, etc), and otherwise using those observability files
(BTF).

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Edward Cree <ecree@solarflare.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-37dz54pmotgpnwg9tb6zuk9j@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-05 12:41:10 -03:00
..
5sec.c perf bpf: Add probe() helper to reduce kprobes boilerplate 2018-05-15 14:31:24 -03:00
augmented_raw_syscalls.c perf augmented_syscalls: Start collecting pathnames in the BPF program 2018-11-05 12:41:10 -03:00
augmented_syscalls.c perf augmented_syscalls: Avoid optimization to pass older BPF validators 2018-09-03 15:29:53 -03:00
empty.c perf bpf: Add license(NAME) helper 2018-05-15 14:31:24 -03:00
etcsnoop.c perf trace: Add a etcsnoop.c augmented syscalls eBPF utility 2018-08-30 15:52:19 -03:00
hello.c perf bpf: Add bpf/stdio.h wrapper to bpf_perf_event_output function 2018-08-08 15:55:55 -03:00
sys_enter_openat.c perf bpf: Add 'syscall_enter' probe helper for syscall enter tracepoints 2018-08-08 15:55:44 -03:00