The patch titled
Subject: kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
has been removed from the -mm tree. Its filename was
kconfigh-allow-to-use-is_enablereachable-in-macro-expansion.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Subject: kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
The typical usage of IS_ENABLED() is
if (IS_ENABLED(CONFIG_FOO)) {
...
}
or
#if IS_ENABLED(CONFIG_FOO)
...
#endif
The current implementation of IS_ENABLED() includes "||" operator,
which works well in those expressions like above.
However, there is a case where we want to evaluate a config option
beyond those use cases.
For example, the OF_TABLE() in include/asm-generic/vmlinux.lds.h
needs to evaluate a config option in macro expansion:
#define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name)
#define __OF_TABLE(cfg, name) ___OF_TABLE(cfg, name)
#define OF_TABLE(cfg, name) __OF_TABLE(config_enabled(cfg), name)
#define _OF_TABLE_0(name)
#define _OF_TABLE_1(name) ...
Here, we can not use IS_ENABLED() because of the "||" operator in
its define. It is true config_enabled() works well, but it is a bit
ambiguous to be used against config options.
This commit makes IS_ENABLED() available in more generic context by
calculating "or" with macro expansion only.
Do likewise for IS_REACHABLE().
Link: http://lkml.kernel.org/r/1465883938-25194-4-git-send-email-yamada.masahiro@xxxxxxxxxxxxx
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Michal Simek <michal.simek@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Michal Marek <mmarek@xxxxxxx>
Cc: Nicolas Pitre <nicolas.pitre@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kconfig.h | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff -puN include/linux/kconfig.h~kconfigh-allow-to-use-is_enablereachable-in-macro-expansion include/linux/kconfig.h
--- a/include/linux/kconfig.h~kconfigh-allow-to-use-is_enablereachable-in-macro-expansion
+++ a/include/linux/kconfig.h
@@ -3,6 +3,21 @@
#include <generated/autoconf.h>
+#define __ARG_PLACEHOLDER_1 0,
+#define __take_second_arg(__ignored, val, ...) val
+
+/*
+ * The use of "&&" / "||" is limited in certain expressions.
+ * The followings enable to calculate "and" / "or" with macro expansion only.
+ */
+#define __and(x, y) ___and(x, y)
+#define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y)
+#define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0)
+
+#define __or(x, y) ___or(x, y)
+#define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y)
+#define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y)
+
/*
* Helper macros to use CONFIG_ options in C/CPP expressions. Note that
* these only work with boolean and tristate options.
@@ -16,12 +31,10 @@
* When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
* the last step cherry picks the 2nd arg, we get a zero.
*/
-#define __ARG_PLACEHOLDER_1 0,
#define config_enabled(cfg) ___is_defined(cfg)
#define __is_defined(x) ___is_defined(x)
#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val)
#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
-#define __take_second_arg(__ignored, val, ...) val
/*
* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
@@ -42,14 +55,13 @@
* This is similar to IS_ENABLED(), but returns false when invoked from
* built-in code when CONFIG_FOO is set to 'm'.
*/
-#define IS_REACHABLE(option) (IS_BUILTIN(option) || \
- (IS_MODULE(option) && __is_defined(MODULE)))
+#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
+ __and(IS_MODULE(option), __is_defined(MODULE)))
/*
* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
* 0 otherwise.
*/
-#define IS_ENABLED(option) \
- (IS_BUILTIN(option) || IS_MODULE(option))
+#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
#endif /* __LINUX_KCONFIG_H */
_
Patches currently in -mm which might be from yamada.masahiro@xxxxxxxxxxxxx are
tree-wide-replace-config_enabled-with-is_enabled.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
