From: Roman Gushchin <guro@fb.com>
To: <netdev@vger.kernel.org>
CC: <linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
        Roman Gushchin <guro@fb.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH v2 bpf-next 2/2] tools/bpftool: fix bpftool build with bintutils >= 2.8
Date: Fri, 22 Dec 2017 16:11:52 +0000
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Bpftool build is broken with binutils version 2.28 and later.
The cause is commit 003ca0fd2286 ("Refactor disassembler selection")
in the binutils repo, which changed the disassembler() function
signature.

Fix this by adding a new "feature" to the tools/build/features
infrastructure and make it responsible for decision which
disassembler() function signature to use.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/bpf/Makefile                                | 29 +++++++++++++++++++++++
 tools/bpf/bpf_jit_disasm.c                        |  7 ++++++
 tools/bpf/bpftool/Makefile                        | 24 +++++++++++++++++++
 tools/bpf/bpftool/jit_disasm.c                    |  7 ++++++
 tools/build/feature/Makefile                      |  4 ++++
 tools/build/feature/test-disassembler-four-args.c | 15 ++++++++++++
 6 files changed, 86 insertions(+)
 create mode 100644 tools/build/feature/test-disassembler-four-args.c

diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
index 07a6697466ef..c8ec0ae16bf0 100644
--- a/tools/bpf/Makefile
+++ b/tools/bpf/Makefile
@@ -9,6 +9,35 @@ MAKE = make
 CFLAGS += -Wall -O2
 CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
 
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+FEATURE_USER = .bpf
+FEATURE_TESTS = libbfd disassembler-four-args
+FEATURE_DISPLAY = libbfd disassembler-four-args
+
+check_feat := 1
+NON_CHECK_FEAT_TARGETS := clean bpftool_clean
+ifdef MAKECMDGOALS
+ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
+  check_feat := 0
+endif
+endif
+
+ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
+include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
+endif
+
+ifeq ($(feature-disassembler-four-args), 1)
+CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
+endif
+
 %.yacc.c: %.y
 	$(YACC) -o $@ -d $<
 
diff --git a/tools/bpf/bpf_jit_disasm.c b/tools/bpf/bpf_jit_disasm.c
index 75bf526a0168..30044bc4f389 100644
--- a/tools/bpf/bpf_jit_disasm.c
+++ b/tools/bpf/bpf_jit_disasm.c
@@ -72,7 +72,14 @@ static void get_asm_insns(uint8_t *image, size_t len, int opcodes)
 
 	disassemble_init_for_target(&info);
 
+#ifdef DISASM_FOUR_ARGS_SIGNATURE
+	disassemble = disassembler(info.arch,
+				   bfd_big_endian(bfdf),
+				   info.mach,
+				   bfdf);
+#else
 	disassemble = disassembler(bfdf);
+#endif
 	assert(disassemble);
 
 	do {
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index f8f31a8d9269..2237bc43f71c 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -46,6 +46,30 @@ LIBS = -lelf -lbfd -lopcodes $(LIBBPF)
 INSTALL ?= install
 RM ?= rm -f
 
+FEATURE_USER = .bpftool
+FEATURE_TESTS = libbfd disassembler-four-args
+FEATURE_DISPLAY = libbfd disassembler-four-args
+
+check_feat := 1
+NON_CHECK_FEAT_TARGETS := clean uninstall doc doc-clean doc-install doc-uninstall
+ifdef MAKECMDGOALS
+ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
+  check_feat := 0
+endif
+endif
+
+ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
+include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
+endif
+
+ifeq ($(feature-disassembler-four-args), 1)
+CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
+endif
+
 include $(wildcard *.d)
 
 all: $(OUTPUT)bpftool
diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index 1551d3918d4c..57d32e8a1391 100644
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -107,7 +107,14 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes)
 
 	disassemble_init_for_target(&info);
 
+#ifdef DISASM_FOUR_ARGS_SIGNATURE
+	disassemble = disassembler(info.arch,
+				   bfd_big_endian(bfdf),
+				   info.mach,
+				   bfdf);
+#else
 	disassemble = disassembler(bfdf);
+#endif
 	assert(disassemble);
 
 	if (json_output)
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 96982640fbf8..17f2c73fff8b 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -13,6 +13,7 @@ FILES=                                          \
          test-hello.bin                         \
          test-libaudit.bin                      \
          test-libbfd.bin                        \
+         test-disassembler-four-args.bin        \
          test-liberty.bin                       \
          test-liberty-z.bin                     \
          test-cplus-demangle.bin                \
@@ -188,6 +189,9 @@ $(OUTPUT)test-libpython-version.bin:
 $(OUTPUT)test-libbfd.bin:
 	$(BUILD) -DPACKAGE='"perf"' -lbfd -lz -liberty -ldl
 
+$(OUTPUT)test-disassembler-four-args.bin:
+	$(BUILD) -lbfd -lopcodes
+
 $(OUTPUT)test-liberty.bin:
 	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
 
diff --git a/tools/build/feature/test-disassembler-four-args.c b/tools/build/feature/test-disassembler-four-args.c
new file mode 100644
index 000000000000..45ce65cfddf0
--- /dev/null
+++ b/tools/build/feature/test-disassembler-four-args.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <bfd.h>
+#include <dis-asm.h>
+
+int main(void)
+{
+	bfd *abfd = bfd_openr(NULL, NULL);
+
+	disassembler(bfd_get_arch(abfd),
+		     bfd_big_endian(abfd),
+		     bfd_get_mach(abfd),
+		     abfd);
+
+	return 0;
+}
-- 
2.14.3