From: Arnd Bergmann <arnd@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: "Arnd Bergmann" <arnd@arndb.de>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"Andrii Nakryiko" <andrii@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@chromium.org>,
"David Miller" <davem@davemloft.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Jakub Sitnicki" <jakub@cloudflare.com>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jiri Olsa" <jolsa@kernel.org>,
"Pankaj Bharadiya" <pankaj.laxminarayan.bharadiya@intel.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] bpf: suppress -Wcast-function-type warning
Date: Mon, 26 Oct 2020 22:03:20 +0100 [thread overview]
Message-ID: <20201026210332.3885166-1-arnd@kernel.org> (raw)
From: Arnd Bergmann <arnd@arndb.de>
Building with -Wextra shows lots of warnings in the bpf
code such as
kernel/bpf/verifier.c: In function ‘jit_subprogs’:
include/linux/filter.h:345:4: warning: cast between incompatible function types from ‘unsigned int (*)(const void *, const struct bpf_insn *)’ to ‘u64 (*)(u64, u64, u64, u64, u64)’ {aka ‘long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)’} [-Wcast-function-type]
345 | ((u64 (*)(u64, u64, u64, u64, u64))(x))
| ^
kernel/bpf/verifier.c:10706:16: note: in expansion of macro ‘BPF_CAST_CALL’
10706 | insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) -
| ^~~~~~~~~~~~~
This appears to be intentional, so change the cast in a way that
suppresses the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
include/linux/filter.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 1b62397bd124..20ba04583eaa 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -342,7 +342,7 @@ static inline bool insn_is_zext(const struct bpf_insn *insn)
/* Function call */
#define BPF_CAST_CALL(x) \
- ((u64 (*)(u64, u64, u64, u64, u64))(x))
+ ((u64 (*)(u64, u64, u64, u64, u64))(uintptr_t)(x))
#define BPF_EMIT_CALL(FUNC) \
((struct bpf_insn) { \
--
2.27.0
next reply other threads:[~2020-10-26 21:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 21:03 Arnd Bergmann [this message]
2020-10-26 22:20 ` [PATCH] bpf: suppress -Wcast-function-type warning David Laight
2020-10-26 22:26 ` Andrii Nakryiko
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