On Sat, Nov 24, 2018 at 11:20:43PM -0800, Yonghong Song wrote:
> Commit 838e96904ff3 ("bpf: Introduce bpf_func_info")
> added bpf func info support. The userspace is able
> to get better ksym's for bpf programs with jit, and
> is able to print out func prototypes.
>
> For a program containing func-to-func calls, the existing
> implementation returns user specified number of function
> calls and BTF types if jit is enabled. If the jit is not
> enabled, it only returns the type for the main function.
>
> This is undesirable. Interpreter may still be used
> and we should keep feature identical regardless of
> whether jit is enabled or not.
> This patch fixed this discrepancy.
>
> The following example shows bpftool output for
> the bpf program in selftests test_btf_haskv.o when jit
> is disabled:
> $ bpftool prog dump xlated id 1490
> int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
> 0: (85) call pc+2#__bpf_prog_run_args32
> 1: (b7) r0 = 0
> 2: (95) exit
> int test_long_fname_1(struct dummy_tracepoint_args * arg):
> 3: (85) call pc+1#__bpf_prog_run_args32
> 4: (95) exit
> int test_long_fname_2(struct dummy_tracepoint_args * arg):
> 5: (b7) r2 = 0
> 6: (63) *(u32 *)(r10 -4) = r2
> 7: (79) r1 = *(u64 *)(r1 +8)
> 8: (15) if r1 == 0x0 goto pc+9
> 9: (bf) r2 = r10
> 10: (07) r2 += -4
> 11: (18) r1 = map[id:1173]
> 13: (85) call bpf_map_lookup_elem#77088
> 14: (15) if r0 == 0x0 goto pc+3
> 15: (61) r1 = *(u32 *)(r0 +4)
> 16: (07) r1 += 1
> 17: (63) *(u32 *)(r0 +4) = r1
> 18: (95) exit
> $ bpftool prog dump jited id 1490
> no instructions returned
Applied to bpf-next. Thanks
