Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 445 insertions, 0 deletions

diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
new file mode 100644
index 0000000000..84b6efa849
--- /dev/null
+++ b/scripts/basic/fixdep.c
@@ -0,0 +1,445 @@
+/*
+ * "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 prerequisites.
+ *
+ * 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/config/HIS_DRIVER" 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
+ *
+ *   savedcmd_<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 for every
+ * CONFIG_MY_OPTION encountered in any of the prerequisites.
+ *
+ * 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)
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
+	exit(1);
+}
+
+struct item {
+	struct item	*next;
+	unsigned int	len;
+	unsigned int	hash;
+	char		name[];
+};
+
+#define HASHSZ 256
+static struct item *config_hashtab[HASHSZ], *file_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;
+}
+
+/*
+ * Add a new value to the configuration string.
+ */
+static void add_to_hashtable(const char *name, int len, unsigned int hash,
+			     struct item *hashtab[])
+{
+	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;
+}
+
+/*
+ * Lookup a string in the hash table. If found, just return true.
+ * If not, add it to the hashtable and return false.
+ */
+static bool in_hashtable(const char *name, int len, struct item *hashtab[])
+{
+	struct item *aux;
+	unsigned int hash = strhash(name, len);
+
+	for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
+		if (aux->hash == hash && aux->len == len &&
+		    memcmp(aux->name, name, len) == 0)
+			return true;
+	}
+
+	add_to_hashtable(name, len, hash, hashtab);
+
+	return false;
+}
+
+/*
+ * Record the use of a CONFIG_* word.
+ */
+static void use_config(const char *m, int slen)
+{
+	if (in_hashtable(m, slen, config_hashtab))
+		return;
+
+	/* Print out a dependency path from a symbol name. */
+	printf("    $(wildcard include/config/%.*s) \\\n", slen, m);
+}
+
+/* test if s ends in sub */
+static int str_ends_with(const char *s, int slen, const char *sub)
+{
+	int sublen = strlen(sub);
+
+	if (sublen > slen)
+		return 0;
+
+	return !memcmp(s + slen - sublen, sub, sublen);
+}
+
+static void parse_config_file(const char *p)
+{
+	const char *q, *r;
+	const char *start = p;
+
+	while ((p = strstr(p, "CONFIG_"))) {
+		if (p > start && (isalnum(p[-1]) || p[-1] == '_')) {
+			p += 7;
+			continue;
+		}
+		p += 7;
+		q = p;
+		while (isalnum(*q) || *q == '_')
+			q++;
+		if (str_ends_with(p, q - p, "_MODULE"))
+			r = q - 7;
+		else
+			r = q;
+		if (r > p)
+			use_config(p, r - p);
+		p = q;
+	}
+}
+
+static void *read_file(const char *filename)
+{
+	struct stat st;
+	int fd;
+	char *buf;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "fixdep: error opening file: ");
+		perror(filename);
+		exit(2);
+	}
+	if (fstat(fd, &st) < 0) {
+		fprintf(stderr, "fixdep: error fstat'ing file: ");
+		perror(filename);
+		exit(2);
+	}
+	buf = malloc(st.st_size + 1);
+	if (!buf) {
+		perror("fixdep: malloc");
+		exit(2);
+	}
+	if (read(fd, buf, st.st_size) != st.st_size) {
+		perror("fixdep: read");
+		exit(2);
+	}
+	buf[st.st_size] = '\0';
+	close(fd);
+
+	return buf;
+}
+
+/* Ignore certain dependencies */
+static int is_ignored_file(const char *s, int len)
+{
+	return str_ends_with(s, len, "include/generated/autoconf.h");
+}
+
+/* Do not parse these files */
+static int is_no_parse_file(const char *s, int len)
+{
+	/* rustc may list binary files in dep-info */
+	return str_ends_with(s, len, ".rlib") ||
+	       str_ends_with(s, len, ".rmeta") ||
+	       str_ends_with(s, len, ".so");
+}
+
+/*
+ * 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(char *p, const char *target)
+{
+	bool saw_any_target = false;
+	bool is_target = true;
+	bool is_source = false;
+	bool need_parse;
+	char *q, saved_c;
+
+	while (*p) {
+		/* handle some special characters first. */
+		switch (*p) {
+		case '#':
+			/*
+			 * skip comments.
+			 * rustc may emit comments to dep-info.
+			 */
+			p++;
+			while (*p != '\0' && *p != '\n') {
+				/*
+				 * escaped newlines continue the comment across
+				 * multiple lines.
+				 */
+				if (*p == '\\')
+					p++;
+				p++;
+			}
+			continue;
+		case ' ':
+		case '\t':
+			/* skip whitespaces */
+			p++;
+			continue;
+		case '\\':
+			/*
+			 * backslash/newline combinations continue the
+			 * statement. Skip it just like a whitespace.
+			 */
+			if (*(p + 1) == '\n') {
+				p += 2;
+				continue;
+			}
+			break;
+		case '\n':
+			/*
+			 * Makefiles use a line-based syntax, where the newline
+			 * is the end of a statement. After seeing a newline,
+			 * we expect the next token is a target.
+			 */
+			p++;
+			is_target = true;
+			continue;
+		case ':':
+			/*
+			 * assume the first dependency after a colon as the
+			 * source file.
+			 */
+			p++;
+			is_target = false;
+			is_source = true;
+			continue;
+		}
+
+		/* find the end of the token */
+		q = p;
+		while (*q != ' ' && *q != '\t' && *q != '\n' && *q != '#' && *q != ':') {
+			if (*q == '\\') {
+				/*
+				 * backslash/newline combinations work like as
+				 * a whitespace, so this is the end of token.
+				 */
+				if (*(q + 1) == '\n')
+					break;
+
+				/* escaped special characters */
+				if (*(q + 1) == '#' || *(q + 1) == ':') {
+					memmove(p + 1, p, q - p);
+					p++;
+				}
+
+				q++;
+			}
+
+			if (*q == '\0')
+				break;
+			q++;
+		}
+
+		/* Just discard the target */
+		if (is_target) {
+			p = q;
+			continue;
+		}
+
+		saved_c = *q;
+		*q = '\0';
+		need_parse = false;
+
+		/*
+		 * 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_source) {
+			/*
+			 * The DT build rule concatenates multiple dep files.
+			 * When processing them, only process the first source
+			 * name, which will be the original one, and ignore any
+			 * other source names, which will be intermediate
+			 * temporary files.
+			 *
+			 * rustc emits the same dependency list for each
+			 * emission type. It is enough to list the source name
+			 * just once.
+			 */
+			if (!saw_any_target) {
+				saw_any_target = true;
+				printf("source_%s := %s\n\n", target, p);
+				printf("deps_%s := \\\n", target);
+				need_parse = true;
+			}
+		} else if (!is_ignored_file(p, q - p) &&
+			   !in_hashtable(p, q - p, file_hashtab)) {
+			printf("  %s \\\n", p);
+			need_parse = true;
+		}
+
+		if (need_parse && !is_no_parse_file(p, q - p)) {
+			void *buf;
+
+			buf = read_file(p);
+			parse_config_file(buf);
+			free(buf);
+		}
+
+		is_source = false;
+		*q = saved_c;
+		p = q;
+	}
+
+	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);
+}
+
+int main(int argc, char *argv[])
+{
+	const char *depfile, *target, *cmdline;
+	void *buf;
+
+	if (argc != 4)
+		usage();
+
+	depfile = argv[1];
+	target = argv[2];
+	cmdline = argv[3];
+
+	printf("savedcmd_%s := %s\n\n", target, cmdline);
+
+	buf = read_file(depfile);
+	parse_dep_file(buf, target);
+	free(buf);
+
+	fflush(stdout);
+
+	/*
+	 * In the intended usage, the stdout is redirected to .*.cmd files.
+	 * Call ferror() to catch errors such as "No space left on device".
+	 */
+	if (ferror(stdout)) {
+		fprintf(stderr, "fixdep: not all data was written to the output\n");
+		exit(1);
+	}
+
+	return 0;
+}