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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andriin@fb.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH 1/2] bpf: Fix build for disabled CONFIG_DEBUG_INFO_BTF option
Date: Tue, 14 Jul 2020 12:25:33 +0200	[thread overview]
Message-ID: <20200714102534.299280-1-jolsa@kernel.org> (raw)

Stephen reported following linker warnings on powerpc build:

  ld: warning: orphan section `.BTF_ids' from `kernel/trace/bpf_trace.o' being placed in section `.BTF_ids'
  ld: warning: orphan section `.BTF_ids' from `kernel/bpf/btf.o' being placed in section `.BTF_ids'
  ld: warning: orphan section `.BTF_ids' from `kernel/bpf/stackmap.o' being placed in section `.BTF_ids'
  ld: warning: orphan section `.BTF_ids' from `net/core/filter.o' being placed in section `.BTF_ids'
  ld: warning: orphan section `.BTF_ids' from `kernel/trace/bpf_trace.o' being placed in section `.BTF_ids'

It's because we generated .BTF_ids section even when
CONFIG_DEBUG_INFO_BTF is not enabled. Fixing this by
generating empty btf_id arrays for this case.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/btf_ids.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index fe019774f8a7..b3c73db9587c 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -3,6 +3,8 @@
 #ifndef _LINUX_BTF_IDS_H
 #define _LINUX_BTF_IDS_H
 
+#ifdef CONFIG_DEBUG_INFO_BTF
+
 #include <linux/compiler.h> /* for __PASTE */
 
 /*
@@ -83,5 +85,12 @@ asm(							\
 ".zero 4                                       \n"	\
 ".popsection;                                  \n");
 
+#else
+
+#define BTF_ID_LIST(name) static u32 name[5];
+#define BTF_ID(prefix, name)
+#define BTF_ID_UNUSED
+
+#endif /* CONFIG_DEBUG_INFO_BTF */
 
 #endif
-- 
2.25.4


             reply	other threads:[~2020-07-14 10:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14 10:25 Jiri Olsa [this message]
2020-07-14 10:25 ` [PATCH 2/2] bpf: Fix cross build for CONFIG_DEBUG_INFO_BTF option Jiri Olsa
2020-07-14 17:26 ` [PATCH 1/2] bpf: Fix build for disabled " Alexei Starovoitov

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