From: Dave Marchevsky <davemarchevsky@fb.com> mainline inclusion from mainline-v6.7-rc1 commit 15fb6f2b6c4c3c129adc2412ae12ec15e60a6adb category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- Not all uses of __diag_ignore_all(...) in BPF-related code in order to suppress warnings are wrapping kfunc definitions. Some "hook point" definitions - small functions meant to be used as attach points for fentry and similar BPF progs - need to suppress -Wmissing-declarations. We could use __bpf_kfunc_{start,end}_defs added in the previous patch in such cases, but this might be confusing to someone unfamiliar with BPF internals. Instead, this patch adds __bpf_hook_{start,end} macros, currently having the same effect as __bpf_kfunc_{start,end}_defs, then uses them to suppress warnings for two hook points in the kernel itself and some bpf_testmod hook points as well. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Cc: Yafang Shao <laoar.shao@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> Link: https://lore.kernel.org/r/20231031215625.2343848-2-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- include/linux/btf.h | 2 ++ kernel/cgroup/rstat.c | 9 +++------ net/socket.c | 8 ++------ tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 6 ++---- 4 files changed, 9 insertions(+), 16 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index dc5ce962f600..59d404e22814 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -92,6 +92,8 @@ "Global kfuncs as their definitions will be in BTF") #define __bpf_kfunc_end_defs() __diag_pop() +#define __bpf_hook_start() __bpf_kfunc_start_defs() +#define __bpf_hook_end() __bpf_kfunc_end_defs() /* * Return the name of the passed struct, if exists, or halt the build if for diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 329c10c084a2..c6d6bec9bcce 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -156,19 +156,16 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, * optimize away the callsite. Therefore, __weak is needed to ensure that the * call is still emitted, by telling the compiler that we don't know what the * function might eventually be. - * - * __diag_* below are needed to dismiss the missing prototype warning. */ -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "kfuncs which will be used in BPF programs"); + +__bpf_hook_start(); __weak noinline void bpf_rstat_flush(struct cgroup *cgrp, struct cgroup *parent, int cpu) { } -__diag_pop(); +__bpf_hook_end(); /* see cgroup_rstat_flush() */ static void cgroup_rstat_flush_locked(struct cgroup *cgrp) diff --git a/net/socket.c b/net/socket.c index 23c08b0d2899..15b696635e43 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1696,20 +1696,16 @@ struct file *__sys_socket_file(int family, int type, int protocol) * Therefore, __weak is needed to ensure that the call is still * emitted, by telling the compiler that we don't know what the * function might eventually be. - * - * __diag_* below are needed to dismiss the missing prototype warning. */ -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "A fmod_ret entry point for BPF programs"); +__bpf_hook_start(); __weak noinline int update_socket_protocol(int family, int type, int protocol) { return protocol; } -__diag_pop(); +__bpf_hook_end(); int __sys_socket(int family, int type, int protocol) { diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 2e8adf059fa3..1b8589143bd3 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -40,9 +40,7 @@ struct bpf_testmod_struct_arg_4 { int b; }; -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "Global functions as their definitions will be in bpf_testmod.ko BTF"); +__bpf_hook_start(); noinline int bpf_testmod_test_struct_arg_1(struct bpf_testmod_struct_arg_2 a, int b, int c) { @@ -332,7 +330,7 @@ noinline int bpf_fentry_shadow_test(int a) } EXPORT_SYMBOL_GPL(bpf_fentry_shadow_test); -__diag_pop(); +__bpf_hook_end(); static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = { .attr = { .name = "bpf_testmod", .mode = 0666, }, -- 2.34.1