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b89c2998d9
Yonghong Song says:
====================
Commit 838e96904f ("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
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.