[PATCH 2/2] Enable 'make CONFIG_FOO=y oldconfig'

[David Woodhouse <dwmw2@infradead.org>]

This allows you to set (and clear) config options on the make command
line, for all config targets. For example:

   make CONFIG_64BIT=n randconfig
   make CONFIG_64BIT=n allmodconfig
   make CONFIG_64BIT=y CONFIG_SATA_MV=y oldconfig

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
 scripts/kconfig/conf.c     |    7 ++++++-
 scripts/kconfig/confdata.c |   26 ++++++++++++++++++++++++++
 scripts/kconfig/lkc.h      |    1 +
 3 files changed, 33 insertions(+), 1 deletions(-)

diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 006ad81..2b91e3b 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -456,7 +456,7 @@ static struct option long_opts[] = {
 	{NULL, 0, NULL, 0}
 };
 
-int main(int ac, char **av)
+int main(int ac, char **av, char **ep)
 {
 	int opt;
 	const char *name;
@@ -563,6 +563,11 @@ int main(int ac, char **av)
 		break;
 	}
 
+	for ( ; *ep;  ep++) {
+		if (!strncmp(*ep, CONFIG_, strlen(CONFIG_)))
+			conf_set_symbol_from_env(*ep);
+	}
+
 	if (sync_kconfig) {
 		if (conf_get_changed()) {
 			name = getenv("KCONFIG_NOSILENTUPDATE");
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index a518ab3..c64eb33 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -342,6 +342,32 @@ setsym:
 	return 0;
 }
 
+void conf_set_symbol_from_env(char *str)
+{
+	char *p = strchr(str, '=');
+	struct symbol *sym;
+	int def = S_DEF_USER;
+	int def_flags = SYMBOL_DEF << def;
+
+	if (!p)
+		return;
+
+	*p = 0;
+	sym = sym_find(str + strlen(CONFIG_));
+	*p++ = '=';
+
+	if (!sym)
+		return;
+
+	sym_calc_value(sym);
+	if (!sym_set_string_value(sym, p))
+		return;
+
+	conf_message(CONFIG_ "%s set to %s from environment", sym->name, p);
+	if (sym_is_choice_value(sym))
+		conf_validate_choice_val(sym, def, def_flags);
+}
+
 int conf_read(const char *name)
 {
 	struct symbol *sym, *choice_sym;
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index f34a0a9..fc2f3ad 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -89,6 +89,7 @@ char *conf_get_default_confname(void);
 void sym_set_change_count(int count);
 void sym_add_change_count(int count);
 void conf_set_all_new_symbols(enum conf_def_mode mode);
+void conf_set_symbol_from_env(char *);
 
 /* confdata.c and expr.c */
 static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
-- 
1.7.6