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a3820c4811
Establish SEC("?abc") naming convention (i.e., adding question mark in front of otherwise normal section name) that allows to set corresponding program's autoload property to false. This is effectively just a declarative way to do bpf_program__set_autoload(prog, false). Having a way to do this declaratively in BPF code itself is useful and convenient for various scenarios. E.g., for testing, when BPF object consists of multiple independent BPF programs that each needs to be tested separately. Opting out all of them by default and then setting autoload to true for just one of them at a time simplifies testing code (see next patch for few conversions in BPF selftests taking advantage of this new feature). Another real-world use case is in libbpf-tools for cases when different BPF programs have to be picked depending on particulars of the host kernel due to various incompatible changes (like kernel function renames or signature change, or to pick kprobe vs fentry depending on corresponding kernel support for the latter). Marking all the different BPF program candidates as non-autoloaded declaratively makes this more obvious in BPF source code and allows simpler code in user-space code. When BPF program marked as SEC("?abc") it is otherwise treated just like SEC("abc") and bpf_program__section_name() reported will be "abc". Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220419002452.632125-1-andrii@kernel.org |
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.. | ||
.gitignore | ||
bpf.c | ||
bpf.h | ||
bpf_core_read.h | ||
bpf_endian.h | ||
bpf_gen_internal.h | ||
bpf_helpers.h | ||
bpf_prog_linfo.c | ||
bpf_tracing.h | ||
btf.c | ||
btf.h | ||
btf_dump.c | ||
Build | ||
gen_loader.c | ||
hashmap.c | ||
hashmap.h | ||
libbpf.c | ||
libbpf.h | ||
libbpf.map | ||
libbpf.pc.template | ||
libbpf_common.h | ||
libbpf_errno.c | ||
libbpf_internal.h | ||
libbpf_legacy.h | ||
libbpf_probes.c | ||
libbpf_version.h | ||
linker.c | ||
Makefile | ||
netlink.c | ||
nlattr.c | ||
nlattr.h | ||
relo_core.c | ||
relo_core.h | ||
ringbuf.c | ||
skel_internal.h | ||
str_error.c | ||
str_error.h | ||
strset.c | ||
strset.h | ||
usdt.bpf.h | ||
usdt.c | ||
xsk.c | ||
xsk.h |