kbuild: import more build scripts from Linux v3.13 tag

This commit imports build scripts from Linux Kernel v3.13
as they are.

I know they include some trailing spaces
but I am intentionally keeping them untouched.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

3 files changed, 478 insertions, 0 deletions

diff --git a/scripts/basic/.gitignore b/scripts/basic/.gitignore
new file mode 100644
index 0000000..a776371
--- /dev/null
+++ b/scripts/basic/.gitignore
@@ -0,0 +1 @@
+fixdep
diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile
new file mode 100644
index 0000000..4fcef87
--- /dev/null
+++ b/scripts/basic/Makefile
@@ -0,0 +1,15 @@
+###
+# Makefile.basic lists the most basic programs used during the build process.
+# The programs listed herein are what are needed to do the basic stuff,
+# such as fix file dependencies.
+# This initial step is needed to avoid files to be recompiled
+# when kernel configuration changes (which is what happens when
+# .config is included by main Makefile.
+# ---------------------------------------------------------------------------
+# fixdep: 	 Used to generate dependency information during build process
+
+hostprogs-y	:= fixdep
+always		:= $(hostprogs-y)
+
+# fixdep is needed to compile other host programs
+$(addprefix $(obj)/,$(filter-out fixdep,$(always))): $(obj)/fixdep
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
new file mode 100644
index 0000000..078fe1d
--- /dev/null
+++ b/scripts/basic/fixdep.c
@@ -0,0 +1,462 @@
+/*
+ * "Optimize" a list of dependencies as spit out by gcc -MD
+ * for the kernel build
+ * ===========================================================================
+ *
+ * Author       Kai Germaschewski
+ * Copyright    2002 by Kai Germaschewski  <kai.germaschewski@gmx.de>
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ *
+ *
+ * Introduction:
+ *
+ * gcc produces a very nice and correct list of dependencies which
+ * tells make when to remake a file.
+ *
+ * To use this list as-is however has the drawback that virtually
+ * every file in the kernel includes autoconf.h.
+ *
+ * If the user re-runs make *config, autoconf.h will be
+ * regenerated.  make notices that and will rebuild every file which
+ * includes autoconf.h, i.e. basically all files. This is extremely
+ * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
+ *
+ * So we play the same trick that "mkdep" played before. We replace
+ * the dependency on autoconf.h by a dependency on every config
+ * option which is mentioned in any of the listed prequisites.
+ *
+ * kconfig populates a tree in include/config/ with an empty file
+ * for each config symbol and when the configuration is updated
+ * the files representing changed config options are touched
+ * which then let make pick up the changes and the files that use
+ * the config symbols are rebuilt.
+ *
+ * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
+ * which depend on "include/linux/config/his/driver.h" will be rebuilt,
+ * so most likely only his driver ;-)
+ *
+ * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
+ *
+ * So to get dependencies right, there are two issues:
+ * o if any of the files the compiler read changed, we need to rebuild
+ * o if the command line given to the compile the file changed, we
+ *   better rebuild as well.
+ *
+ * The former is handled by using the -MD output, the later by saving
+ * the command line used to compile the old object and comparing it
+ * to the one we would now use.
+ *
+ * Again, also this idea is pretty old and has been discussed on
+ * kbuild-devel a long time ago. I don't have a sensibly working
+ * internet connection right now, so I rather don't mention names
+ * without double checking.
+ *
+ * This code here has been based partially based on mkdep.c, which
+ * says the following about its history:
+ *
+ *   Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
+ *   This is a C version of syncdep.pl by Werner Almesberger.
+ *
+ *
+ * It is invoked as
+ *
+ *   fixdep <depfile> <target> <cmdline>
+ *
+ * and will read the dependency file <depfile>
+ *
+ * The transformed dependency snipped is written to stdout.
+ *
+ * It first generates a line
+ *
+ *   cmd_<target> = <cmdline>
+ *
+ * and then basically copies the .<target>.d file to stdout, in the
+ * process filtering out the dependency on autoconf.h and adding
+ * dependencies on include/config/my/option.h for every
+ * CONFIG_MY_OPTION encountered in any of the prequisites.
+ *
+ * It will also filter out all the dependencies on *.ver. We need
+ * to make sure that the generated version checksum are globally up
+ * to date before even starting the recursive build, so it's too late
+ * at this point anyway.
+ *
+ * The algorithm to grep for "CONFIG_..." is bit unusual, but should
+ * be fast ;-) We don't even try to really parse the header files, but
+ * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
+ * be picked up as well. It's not a problem with respect to
+ * correctness, since that can only give too many dependencies, thus
+ * we cannot miss a rebuild. Since people tend to not mention totally
+ * unrelated CONFIG_ options all over the place, it's not an
+ * efficiency problem either.
+ *
+ * (Note: it'd be easy to port over the complete mkdep state machine,
+ *  but I don't think the added complexity is worth it)
+ */
+/*
+ * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
+ * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
+ * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
+ * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
+ * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
+ * those files will have correct dependencies.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <limits.h>
+#include <ctype.h>
+#include <arpa/inet.h>
+
+#define INT_CONF ntohl(0x434f4e46)
+#define INT_ONFI ntohl(0x4f4e4649)
+#define INT_NFIG ntohl(0x4e464947)
+#define INT_FIG_ ntohl(0x4649475f)
+
+char *target;
+char *depfile;
+char *cmdline;
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
+	exit(1);
+}
+
+/*
+ * Print out the commandline prefixed with cmd_<target filename> :=
+ */
+static void print_cmdline(void)
+{
+	printf("cmd_%s := %s\n\n", target, cmdline);
+}
+
+struct item {
+	struct item	*next;
+	unsigned int	len;
+	unsigned int	hash;
+	char		name[0];
+};
+
+#define HASHSZ 256
+static struct item *hashtab[HASHSZ];
+
+static unsigned int strhash(const char *str, unsigned int sz)
+{
+	/* fnv32 hash */
+	unsigned int i, hash = 2166136261U;
+
+	for (i = 0; i < sz; i++)
+		hash = (hash ^ str[i]) * 0x01000193;
+	return hash;
+}
+
+/*
+ * Lookup a value in the configuration string.
+ */
+static int is_defined_config(const char *name, int len, unsigned int hash)
+{
+	struct item *aux;
+
+	for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
+		if (aux->hash == hash && aux->len == len &&
+		    memcmp(aux->name, name, len) == 0)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Add a new value to the configuration string.
+ */
+static void define_config(const char *name, int len, unsigned int hash)
+{
+	struct item *aux = malloc(sizeof(*aux) + len);
+
+	if (!aux) {
+		perror("fixdep:malloc");
+		exit(1);
+	}
+	memcpy(aux->name, name, len);
+	aux->len = len;
+	aux->hash = hash;
+	aux->next = hashtab[hash % HASHSZ];
+	hashtab[hash % HASHSZ] = aux;
+}
+
+/*
+ * Clear the set of configuration strings.
+ */
+static void clear_config(void)
+{
+	struct item *aux, *next;
+	unsigned int i;
+
+	for (i = 0; i < HASHSZ; i++) {
+		for (aux = hashtab[i]; aux; aux = next) {
+			next = aux->next;
+			free(aux);
+		}
+		hashtab[i] = NULL;
+	}
+}
+
+/*
+ * Record the use of a CONFIG_* word.
+ */
+static void use_config(const char *m, int slen)
+{
+	unsigned int hash = strhash(m, slen);
+	int c, i;
+
+	if (is_defined_config(m, slen, hash))
+	    return;
+
+	define_config(m, slen, hash);
+
+	printf("    $(wildcard include/config/");
+	for (i = 0; i < slen; i++) {
+		c = m[i];
+		if (c == '_')
+			c = '/';
+		else
+			c = tolower(c);
+		putchar(c);
+	}
+	printf(".h) \\\n");
+}
+
+static void parse_config_file(const char *map, size_t len)
+{
+	const int *end = (const int *) (map + len);
+	/* start at +1, so that p can never be < map */
+	const int *m   = (const int *) map + 1;
+	const char *p, *q;
+
+	for (; m < end; m++) {
+		if (*m == INT_CONF) { p = (char *) m  ; goto conf; }
+		if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
+		if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
+		if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
+		continue;
+	conf:
+		if (p > map + len - 7)
+			continue;
+		if (memcmp(p, "CONFIG_", 7))
+			continue;
+		for (q = p + 7; q < map + len; q++) {
+			if (!(isalnum(*q) || *q == '_'))
+				goto found;
+		}
+		continue;
+
+	found:
+		if (!memcmp(q - 7, "_MODULE", 7))
+			q -= 7;
+		if( (q-p-7) < 0 )
+			continue;
+		use_config(p+7, q-p-7);
+	}
+}
+
+/* test is s ends in sub */
+static int strrcmp(char *s, char *sub)
+{
+	int slen = strlen(s);
+	int sublen = strlen(sub);
+
+	if (sublen > slen)
+		return 1;
+
+	return memcmp(s + slen - sublen, sub, sublen);
+}
+
+static void do_config_file(const char *filename)
+{
+	struct stat st;
+	int fd;
+	void *map;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "fixdep: error opening config file: ");
+		perror(filename);
+		exit(2);
+	}
+	fstat(fd, &st);
+	if (st.st_size == 0) {
+		close(fd);
+		return;
+	}
+	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	if ((long) map == -1) {
+		perror("fixdep: mmap");
+		close(fd);
+		return;
+	}
+
+	parse_config_file(map, st.st_size);
+
+	munmap(map, st.st_size);
+
+	close(fd);
+}
+
+/*
+ * Important: The below generated source_foo.o and deps_foo.o variable
+ * assignments are parsed not only by make, but also by the rather simple
+ * parser in scripts/mod/sumversion.c.
+ */
+static void parse_dep_file(void *map, size_t len)
+{
+	char *m = map;
+	char *end = m + len;
+	char *p;
+	char s[PATH_MAX];
+	int is_target;
+	int saw_any_target = 0;
+	int is_first_dep = 0;
+
+	clear_config();
+
+	while (m < end) {
+		/* Skip any "white space" */
+		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
+			m++;
+		/* Find next "white space" */
+		p = m;
+		while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
+			p++;
+		/* Is the token we found a target name? */
+		is_target = (*(p-1) == ':');
+		/* Don't write any target names into the dependency file */
+		if (is_target) {
+			/* The /next/ file is the first dependency */
+			is_first_dep = 1;
+		} else {
+			/* Save this token/filename */
+			memcpy(s, m, p-m);
+			s[p - m] = 0;
+
+			/* Ignore certain dependencies */
+			if (strrcmp(s, "include/generated/autoconf.h") &&
+			    strrcmp(s, "arch/um/include/uml-config.h") &&
+			    strrcmp(s, "include/linux/kconfig.h") &&
+			    strrcmp(s, ".ver")) {
+				/*
+				 * Do not list the source file as dependency,
+				 * so that kbuild is not confused if a .c file
+				 * is rewritten into .S or vice versa. Storing
+				 * it in source_* is needed for modpost to
+				 * compute srcversions.
+				 */
+				if (is_first_dep) {
+					/*
+					 * If processing the concatenation of
+					 * multiple dependency files, only
+					 * process the first target name, which
+					 * will be the original source name,
+					 * and ignore any other target names,
+					 * which will be intermediate temporary
+					 * files.
+					 */
+					if (!saw_any_target) {
+						saw_any_target = 1;
+						printf("source_%s := %s\n\n",
+							target, s);
+						printf("deps_%s := \\\n",
+							target);
+					}
+					is_first_dep = 0;
+				} else
+					printf("  %s \\\n", s);
+				do_config_file(s);
+			}
+		}
+		/*
+		 * Start searching for next token immediately after the first
+		 * "whitespace" character that follows this token.
+		 */
+		m = p + 1;
+	}
+
+	if (!saw_any_target) {
+		fprintf(stderr, "fixdep: parse error; no targets found\n");
+		exit(1);
+	}
+
+	printf("\n%s: $(deps_%s)\n\n", target, target);
+	printf("$(deps_%s):\n", target);
+}
+
+static void print_deps(void)
+{
+	struct stat st;
+	int fd;
+	void *map;
+
+	fd = open(depfile, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "fixdep: error opening depfile: ");
+		perror(depfile);
+		exit(2);
+	}
+	if (fstat(fd, &st) < 0) {
+                fprintf(stderr, "fixdep: error fstat'ing depfile: ");
+                perror(depfile);
+                exit(2);
+        }
+	if (st.st_size == 0) {
+		fprintf(stderr,"fixdep: %s is empty\n",depfile);
+		close(fd);
+		return;
+	}
+	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	if ((long) map == -1) {
+		perror("fixdep: mmap");
+		close(fd);
+		return;
+	}
+
+	parse_dep_file(map, st.st_size);
+
+	munmap(map, st.st_size);
+
+	close(fd);
+}
+
+static void traps(void)
+{
+	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
+	int *p = (int *)test;
+
+	if (*p != INT_CONF) {
+		fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n",
+			*p);
+		exit(2);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	traps();
+
+	if (argc != 4)
+		usage();
+
+	depfile = argv[1];
+	target = argv[2];
+	cmdline = argv[3];
+
+	print_cmdline();
+	print_deps();
+
+	return 0;
+}