bpf: Add some description about BPF_JIT_ALWAYS_ON in Kconfig

When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
is permanently set to 1 and setting any other value than that will return
failure.

Add the above description in the help text of config BPF_JIT_ALWAYS_ON, and
then we can distinguish between BPF_JIT_ALWAYS_ON and BPF_JIT_DEFAULT_ON.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/1645523826-18149-2-git-send-email-yangtiezhu@loongson.cn

diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
index d24d518..c3cf0b8 100644 (file)
--- a/kernel/bpf/Kconfig
+++ b/kernel/bpf/Kconfig
@@ -58,6 +58,10 @@ config BPF_JIT_ALWAYS_ON
          Enables BPF JIT and removes BPF interpreter to avoid speculative
          execution of BPF instructions by the interpreter.
 
+         When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
+         is permanently set to 1 and setting any other value than that will
+         return failure.
+
 config BPF_JIT_DEFAULT_ON
        def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
        depends on HAVE_EBPF_JIT && BPF_JIT