From patchwork Wed May 17 12:56:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 13244854 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6F4979C0 for ; Wed, 17 May 2023 12:56:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61242C433EF; Wed, 17 May 2023 12:56:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684328194; bh=N5w8zSa8G+0c9DkpbjE5wIaKBUm//T9/7Q6k5MttMfE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uchGo/0hNRi3WLSo7De+RlxONVgD8OJPqYVjxWuzaj2A9/g+DTrC/u2XF3QdKsCqp xiODetgRLJ0K1RrqEUwzh77ytfS219TLPWyOQoinx4clc4O0qkeZ93kIuk2KeuRzw/ ry2g0IvnbkmEgNL8KBD9F+JTdQAO99ZI1TnWacdtPnq/jG5cqG26On1N0cQruzK2dh i6gX9tgaDXTR1mXBu3e9V1k/hqB5Bck/7b/lQvZpcuhrj3spgl8Tmis4wlSxneZmND eXF+r1mtAWkZE5DLxiSdfSe4Z8x1YjoQtOHm/+RHhzX5MO9c8A0Bth6m7q6dbdhgyI Qcv54fzjRhIwQ== From: Arnd Bergmann To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Arnd Bergmann , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , "Jason A. Donenfeld" , Kumar Kartikeya Dwivedi , Delyan Kratunov , Ilya Leoshkevich , Menglong Dong , Yafang Shao , bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] bpf: add bpf_probe_read_kernel declaration Date: Wed, 17 May 2023 14:56:09 +0200 Message-Id: <20230517125617.931437-2-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230517125617.931437-1-arnd@kernel.org> References: <20230517125617.931437-1-arnd@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Arnd Bergmann bpf_probe_read_kernel() has a __weak definition in core.c and another definition with an incompatible prototype in kernel/trace/bpf_trace.c, when CONFIG_BPF_EVENTS is enabled. Since the two are incompatible, there cannot be a shared declaration in a header file, but the lack of a prototype causes a W=1 warning: kernel/bpf/core.c:1638:12: error: no previous prototype for 'bpf_probe_read_kernel' [-Werror=missing-prototypes] Add a prototype directly in front of the function instead to shut up the warning. Also, to avoid having an incompatible function override the __weak definition, use an #ifdef to ensure that only one of the two is ever defined. I'm not sure what can be done to make the two prototypes match. Signed-off-by: Arnd Bergmann --- kernel/bpf/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6f5ede31e471..38762a784b86 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1635,11 +1635,14 @@ bool bpf_opcode_in_insntable(u8 code) } #ifndef CONFIG_BPF_JIT_ALWAYS_ON -u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) +u64 bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr); +#ifndef CONFIG_BPF_EVENTS +u64 bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) { memset(dst, 0, size); return -EFAULT; } +#endif /** * ___bpf_prog_run - run eBPF program on a given context