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Commit d325d788 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Auto detecting kernel build directory 



This patch detects kernel build directory by checking the existence of
include/generated/autoconf.h.

clang working directory is changed to kbuild directory if it is found,
to help user use relative include path. Following patch will detect
kernel include directory, which contains relative include patch so this
workdir changing is needed.

Users are allowed to set 'kbuild-dir = ""' manually to disable this
checking.

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/n/tip-owyfwfbemrjn0tlj6tgk2nf5@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4cea3a9c

tools/perf/util/llvm-utils.c

+79 −1
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 */



#include <stdio.h>

#include <sys/utsname.h>

#include "util.h"

#include "debug.h"

#include "llvm-utils.h"
@@ -204,6 +205,74 @@ version_notice(void) 
);

}



static int detect_kbuild_dir(char **kbuild_dir)

{

	const char *test_dir = llvm_param.kbuild_dir;

	const char *prefix_dir = "";

	const char *suffix_dir = "";



	char *autoconf_path;

	struct utsname utsname;



	int err;



	if (!test_dir) {

		err = uname(&utsname);

		if (err) {

			pr_warning("uname failed: %s\n", strerror(errno));

			return -EINVAL;

		}



		test_dir = utsname.release;

		prefix_dir = "/lib/modules/";

		suffix_dir = "/build";

	}



	err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",

		       prefix_dir, test_dir, suffix_dir);

	if (err < 0)

		return -ENOMEM;



	if (access(autoconf_path, R_OK) == 0) {

		free(autoconf_path);



		err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,

			       suffix_dir);

		if (err < 0)

			return -ENOMEM;

		return 0;

	}

	free(autoconf_path);

	return -ENOENT;

}



static inline void

get_kbuild_opts(char **kbuild_dir)

{

	int err;



	if (!kbuild_dir)

		return;



	*kbuild_dir = NULL;



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

		pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");

		pr_debug("Skip kbuild options detection.\n");

		return;

	}



	err = detect_kbuild_dir(kbuild_dir);

	if (err) {

		pr_warning(

"WARNING:\tunable to get correct kernel building directory.\n"

"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"

"     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"

"     \tdetection.\n\n");

		return;

	}

}



int llvm__compile_bpf(const char *path, void **p_obj_buf,

		      size_t *p_obj_buf_sz)

{
@@ -211,6 +280,7 @@ 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;

	void *obj_buf = NULL;

	size_t obj_buf_sz;
@@ -228,10 +298,16 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
		return -ENOENT;

	}



	/*

	 * This is an optional work. Even it fail we can continue our

	 * work. Needn't to check error return.

	 */

	get_kbuild_opts(&kbuild_dir);



	force_set_env("CLANG_EXEC", clang_path);

	force_set_env("CLANG_OPTIONS", clang_opt);

	force_set_env("KERNEL_INC_OPTIONS", NULL);

	force_set_env("WORKING_DIR", ".");

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



	/*

	 * Since we may reset clang's working dir, path of source file
@@ -253,6 +329,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
		goto errout;

	}



	free(kbuild_dir);

	if (!p_obj_buf)

		free(obj_buf);

	else
@@ -262,6 +339,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, 
		*p_obj_buf_sz = obj_buf_sz;

	return 0;

errout:

	free(kbuild_dir);

	free(obj_buf);

	if (p_obj_buf)

		*p_obj_buf = NULL;