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From:   Tiezhu Yang <yangtiezhu@loongson.cn>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>
Cc:     Xuefeng Li <lixuefeng@loongson.cn>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH bpf-next v3 1/2] bpf: Add some description about BPF_JIT_ALWAYS_ON in Kconfig
Date:   Tue, 22 Feb 2022 17:57:05 +0800
Message-Id: <1645523826-18149-2-git-send-email-yangtiezhu@loongson.cn>
In-Reply-To: <1645523826-18149-1-git-send-email-yangtiezhu@loongson.cn>
References: <1645523826-18149-1-git-send-email-yangtiezhu@loongson.cn>
Precedence: bulk

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>
Acked-by: Song Liu <songliubraving@fb.com>
---
 kernel/bpf/Kconfig | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
index d24d518..f3db15a 100644
--- 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
-- 
2.1.0