From: Nathan Chancellor <nathan@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>,
Xu Kuohai <xukuohai@huawei.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>,
bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
patches@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH] bpf, arm64: Mark dummy_tramp as global
Date: Wed, 13 Jul 2022 10:35:03 -0700 [thread overview]
Message-ID: <20220713173503.3889486-1-nathan@kernel.org> (raw)
When building with clang + CONFIG_CFI_CLANG=y, the following error
occurs at link time:
ld.lld: error: undefined symbol: dummy_tramp
dummy_tramp is declared globally in C but its definition in inline
assembly does not use .global, which prevents clang from properly
resolving the references to it when creating the CFI jump tables.
Mark dummy_tramp as global so that the reference can be properly
resolved.
Fixes: b2ad54e1533e ("bpf, arm64: Implement bpf_arch_text_poke() for arm64")
Link: https://github.com/ClangBuiltLinux/linux/issues/1661
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/arm64/net/bpf_jit_comp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index fd1cb0d2aaa6..dcc572b7d4da 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -604,6 +604,7 @@ void dummy_tramp(void);
asm (
" .pushsection .text, \"ax\", @progbits\n"
+" .global dummy_tramp\n"
" .type dummy_tramp, %function\n"
"dummy_tramp:"
#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
base-commit: ace2bee839e08df324cb320763258dfd72e6120e
--
2.37.1
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>,
Xu Kuohai <xukuohai@huawei.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>,
bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
patches@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH] bpf, arm64: Mark dummy_tramp as global
Date: Wed, 13 Jul 2022 10:35:03 -0700 [thread overview]
Message-ID: <20220713173503.3889486-1-nathan@kernel.org> (raw)
When building with clang + CONFIG_CFI_CLANG=y, the following error
occurs at link time:
ld.lld: error: undefined symbol: dummy_tramp
dummy_tramp is declared globally in C but its definition in inline
assembly does not use .global, which prevents clang from properly
resolving the references to it when creating the CFI jump tables.
Mark dummy_tramp as global so that the reference can be properly
resolved.
Fixes: b2ad54e1533e ("bpf, arm64: Implement bpf_arch_text_poke() for arm64")
Link: https://github.com/ClangBuiltLinux/linux/issues/1661
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/arm64/net/bpf_jit_comp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index fd1cb0d2aaa6..dcc572b7d4da 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -604,6 +604,7 @@ void dummy_tramp(void);
asm (
" .pushsection .text, \"ax\", @progbits\n"
+" .global dummy_tramp\n"
" .type dummy_tramp, %function\n"
"dummy_tramp:"
#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
base-commit: ace2bee839e08df324cb320763258dfd72e6120e
--
2.37.1
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next reply other threads:[~2022-07-13 17:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 17:35 Nathan Chancellor [this message]
2022-07-13 17:35 ` [PATCH] bpf, arm64: Mark dummy_tramp as global Nathan Chancellor
2022-07-13 19:11 ` Stanislav Fomichev
2022-07-13 19:11 ` Stanislav Fomichev
2022-07-14 15:00 ` patchwork-bot+netdevbpf
2022-07-14 15:00 ` patchwork-bot+netdevbpf
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