linux/tools/include
Jiri Olsa f92c1e1836 bpf: Add get_func_[arg|ret|arg_cnt] helpers
Adding following helpers for tracing programs:

Get n-th argument of the traced function:
  long bpf_get_func_arg(void *ctx, u32 n, u64 *value)

Get return value of the traced function:
  long bpf_get_func_ret(void *ctx, u64 *value)

Get arguments count of the traced function:
  long bpf_get_func_arg_cnt(void *ctx)

The trampoline now stores number of arguments on ctx-8
address, so it's easy to verify argument index and find
return value argument's position.

Moving function ip address on the trampoline stack behind
the number of functions arguments, so it's now stored on
ctx-16 address if it's needed.

All helpers above are inlined by verifier.

Also bit unrelated small change - using newly added function
bpf_prog_has_trampoline in check_get_func_ip.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211208193245.172141-5-jolsa@kernel.org
2021-12-13 09:25:59 -08:00
..
asm tools arch: Update arch/x86/lib/mem{cpy,set}_64.S copies used in 'perf bench mem memcpy' 2021-05-10 09:01:00 -03:00
asm-generic x86/insn: Use get_unaligned() instead of memcpy() 2021-10-06 11:56:37 +02:00
linux tools/lib/lockdep: drop leftover liblockdep headers 2021-12-09 09:37:49 -08:00
nolibc tools/nolibc: Implement msleep() 2021-07-20 13:42:26 -07:00
tools tools: bpf: fix license for a compat header file 2018-09-19 23:49:58 +02:00
trace/events tools/lib/lockdep: Remove private kernel headers 2017-06-05 09:28:14 +02:00
uapi bpf: Add get_func_[arg|ret|arg_cnt] helpers 2021-12-13 09:25:59 -08:00
vdso tools headers: Synchronize linux/bits.h with the kernel sources 2020-04-14 11:40:05 -03:00