kbuild: redo fake deps at include/config/*.h

Make include/config/foo/bar.h fake deps files generation simpler.

* delete .h suffix
	those aren't header files, shorten filenames,

* delete tolower()
	Linux filesystems can deal with both upper and lowercase
	filenames very well,

* put everything in 1 directory
	Presumably 'mkdir -p' split is from dark times when filesystems
	handled huge directories badly, disks were round adding to
	seek times.

	x86_64 allmodconfig lists 12364 files in include/config.

	../obj/include/config/
	├── 104_QUAD_8
	├── 60XX_WDT
	├── 64BIT
		...
	├── ZSWAP_DEFAULT_ON
	├── ZSWAP_ZPOOL_DEFAULT
	└── ZSWAP_ZPOOL_DEFAULT_ZBUD

	0 directories, 12364 files

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

3 files changed, 13 insertions, 49 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index e47c054d3db2..5e39b0517186 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -239,8 +239,8 @@ endif # CONFIG_STACK_VALIDATION
 
 # Rebuild all objects when objtool changes, or is enabled/disabled.
 objtool_dep = $(objtool_obj)					\
-	      $(wildcard include/config/orc/unwinder.h		\
-			 include/config/stack/validation.h)
+	      $(wildcard include/config/ORC_UNWINDER		\
+			 include/config/STACK_VALIDATION)
 
 ifdef CONFIG_TRIM_UNUSED_KSYMS
 cmd_gen_ksymdeps = \
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index d98540552941..44e887cff49b 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -34,7 +34,7 @@
  * 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.h" will be rebuilt,
+ * 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.
@@ -74,7 +74,7 @@
  *
  * 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
+ * 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
@@ -107,8 +107,8 @@ static void usage(void)
 
 /*
  * In the intended usage of this program, the stdout is redirected to .*.cmd
- * files. The return value of printf() and putchar() must be checked to catch
- * any error, e.g. "No space left on device".
+ * files. The return value of printf() must be checked to catch any error,
+ * e.g. "No space left on device".
  */
 static void xprintf(const char *format, ...)
 {
@@ -124,38 +124,6 @@ static void xprintf(const char *format, ...)
 	va_end(ap);
 }
 
-static void xputchar(int c)
-{
-	int ret;
-
-	ret = putchar(c);
-	if (ret == EOF) {
-		perror("fixdep");
-		exit(1);
-	}
-}
-
-/*
- * Print out a dependency path from a symbol name
- */
-static void print_dep(const char *m, int slen, const char *dir)
-{
-	int c, prev_c = '/', i;
-
-	xprintf("    $(wildcard %s/", dir);
-	for (i = 0; i < slen; i++) {
-		c = m[i];
-		if (c == '_')
-			c = '/';
-		else
-			c = tolower(c);
-		if (c != '/' || prev_c != '/')
-			xputchar(c);
-		prev_c = c;
-	}
-	xprintf(".h) \\\n");
-}
-
 struct item {
 	struct item	*next;
 	unsigned int	len;
@@ -220,7 +188,8 @@ static void use_config(const char *m, int slen)
 	    return;
 
 	define_config(m, slen, hash);
-	print_dep(m, slen, "include/config");
+	/* Print out a dependency path from a symbol name. */
+	xprintf("    $(wildcard include/config/%.*s) \\\n", slen, m);
 }
 
 /* test if s ends in sub */
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 2568dbe16ed6..c7b7e1c62a9c 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -130,19 +130,14 @@ static size_t depfile_prefix_len;
 static int conf_touch_dep(const char *name)
 {
 	int fd, ret;
-	const char *s;
-	char *d, c;
+	char *d;
 
-	/* check overflow: prefix + name + ".h" + '\0' must fit in buffer. */
-	if (depfile_prefix_len + strlen(name) + 3 > sizeof(depfile_path))
+	/* check overflow: prefix + name + '\0' must fit in buffer. */
+	if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
 		return -1;
 
 	d = depfile_path + depfile_prefix_len;
-	s = name;
-
-	while ((c = *s++))
-		*d++ = (c == '_') ? '/' : tolower(c);
-	strcpy(d, ".h");
+	strcpy(d, name);
 
 	/* Assume directory path already exists. */
 	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
@@ -465,7 +460,7 @@ load:
 					 * Reading from include/config/auto.conf
 					 * If CONFIG_FOO previously existed in
 					 * auto.conf but it is missing now,
-					 * include/config/foo.h must be touched.
+					 * include/config/FOO must be touched.
 					 */
 					conf_touch_dep(line + strlen(CONFIG_));
 				else