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Commit 0c6d18bf authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Auto detecting kernel include options 



To help user find correct kernel include options, this patch extracts
them from kbuild system by an embedded script kinc_fetch_script, which
creates a temporary directory, generates Makefile and an empty dummy.o
then use the Makefile to fetch $(NOSTDINC_FLAGS), $(LINUXINCLUDE) and
$(EXTRA_CFLAGS) options. The result is passed to compiler script using
'KERNEL_INC_OPTIONS' environment variable.

Because options from kbuild contains relative path like
'Iinclude/generated/uapi', the work directory must be changed. This is
done by previous patch.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1436445342-1402-16-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d325d788

tools/perf/util/llvm-utils.c

+55 −5
Original line number Diff line number Diff line
@@ -246,15 +246,42 @@ static int detect_kbuild_dir(char **kbuild_dir) 
	return -ENOENT;

}



static const char *kinc_fetch_script =

"#!/usr/bin/env sh\n"

"if ! test -d \"$KBUILD_DIR\"\n"

"then\n"

"	exit -1\n"

"fi\n"

"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"

"then\n"

"	exit -1\n"

"fi\n"

"TMPDIR=`mktemp -d`\n"

"if test -z \"$TMPDIR\"\n"

"then\n"

"    exit -1\n"

"fi\n"

"cat << EOF > $TMPDIR/Makefile\n"

"obj-y := dummy.o\n"

"\\$(obj)/%.o: \\$(src)/%.c\n"

"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"

"EOF\n"

"touch $TMPDIR/dummy.c\n"

"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"

"RET=$?\n"

"rm -rf $TMPDIR\n"

"exit $RET\n";



static inline void

get_kbuild_opts(char **kbuild_dir)

get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)

{

	int err;



	if (!kbuild_dir)

	if (!kbuild_dir || !kbuild_include_opts)

		return;



	*kbuild_dir = NULL;

	*kbuild_include_opts = NULL;



	if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {

		pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
@@ -271,6 +298,27 @@ get_kbuild_opts(char **kbuild_dir) 
"     \tdetection.\n\n");

		return;

	}



	pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);

	force_set_env("KBUILD_DIR", *kbuild_dir);

	force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);

	err = read_from_pipe(kinc_fetch_script,

			     (void **)kbuild_include_opts,

			     NULL);

	if (err) {

		pr_warning(

"WARNING:\tunable to get kernel include directories from '%s'\n"

"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"

"     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"

"     \toption in [llvm] to \"\" to suppress this detection.\n\n",

			*kbuild_dir);



		free(*kbuild_dir);

		*kbuild_dir = NULL;

		return;

	}



	pr_debug("include option is set to %s\n", *kbuild_include_opts);

}



int llvm__compile_bpf(const char *path, void **p_obj_buf,
@@ -280,7 +328,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
	char clang_path[PATH_MAX];

	const char *clang_opt = llvm_param.clang_opt;

	const char *template = llvm_param.clang_bpf_cmd_template;

	char *kbuild_dir = NULL;

	char *kbuild_dir = NULL, *kbuild_include_opts = NULL;

	void *obj_buf = NULL;

	size_t obj_buf_sz;
@@ -302,11 +350,11 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
	 * This is an optional work. Even it fail we can continue our

	 * work. Needn't to check error return.

	 */

	get_kbuild_opts(&kbuild_dir);

	get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);



	force_set_env("CLANG_EXEC", clang_path);

	force_set_env("CLANG_OPTIONS", clang_opt);

	force_set_env("KERNEL_INC_OPTIONS", NULL);

	force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);

	force_set_env("WORKING_DIR", kbuild_dir ? : ".");



	/*
@@ -330,6 +378,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
	}



	free(kbuild_dir);

	free(kbuild_include_opts);

	if (!p_obj_buf)

		free(obj_buf);

	else
@@ -340,6 +389,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
	return 0;

errout:

	free(kbuild_dir);

	free(kbuild_include_opts);

	free(obj_buf);

	if (p_obj_buf)

		*p_obj_buf = NULL;