• Martin KaFai Lau's avatar
    bpf: Add bpf_line_info support · c454a46b
    Martin KaFai Lau authored
    This patch adds bpf_line_info support.
    
    It accepts an array of bpf_line_info objects during BPF_PROG_LOAD.
    The "line_info", "line_info_cnt" and "line_info_rec_size" are added
    to the "union bpf_attr".  The "line_info_rec_size" makes
    bpf_line_info extensible in the future.
    
    The new "check_btf_line()" ensures the userspace line_info is valid
    for the kernel to use.
    
    When the verifier is translating/patching the bpf_prog (through
    "bpf_patch_insn_single()"), the line_infos' insn_off is also
    adjusted by the newly added "bpf_adj_linfo()".
    
    If the bpf_prog is jited, this patch also provides the jited addrs (in
    aux->jited_linfo) for the corresponding line_info.insn_off.
    "bpf_prog_fill_jited_linfo()" is added to fill the aux->jited_linfo.
    It is currently called by the x86 jit.  Other jits can also use
    "bpf_prog_fill_jited_linfo()" and it will be done in the followup patches.
    In the future, if it deemed necessary, a particular jit could also provide
    its own "bpf_prog_fill_jited_linfo()" implementation.
    
    A few "*line_info*" fields are added to the bpf_prog_info such
    that the user can get the xlated line_info back (i.e. the line_info
    with its insn_off reflecting the translated prog).  The jited_line_info
    is available if the prog is jited.  It is an array of __u64.
    If the prog is not jited, jited_line_info_cnt is 0.
    
    The verifier's verbose log with line_info will be done in
    a follow up patch.
    Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
    Acked-by: default avatarYonghong Song <yhs@fb.com>
    Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
    c454a46b
bpf.h 113 KB