From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Creekmore Subject: Re: [PATCH v5 1/8] Kconfig: import kconfig.h from Linux 4.3 Date: Sat, 23 Jan 2016 11:14:44 -0600 Message-ID: References: <1453536020-16196-1-git-send-email-zhaoshenglong@huawei.com> <1453536020-16196-2-git-send-email-zhaoshenglong@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <1453536020-16196-2-git-send-email-zhaoshenglong@huawei.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Shannon Zhao Cc: ian.campbell@citrix.com, Doug Goldstein , peter.huangpeng@huawei.com, xen-devel@lists.xen.org, julien.grall@citrix.com, stefano.stabellini@citrix.com, shannon.zhao@linaro.org List-Id: xen-devel@lists.xenproject.org Shannon Zhao writes: > From: Shannon Zhao > > To support using CONFIG_ options in C/CPP expressions, import kconfig.h > from the Linux v4.3 tag (commit id > 6a13feb9c82803e2b815eca72fa7a9f5561d7861). > > CC: Doug Goldstein > Signed-off-by: Shannon Zhao > --- > xen/include/xen/config.h | 2 +- > xen/include/xen/kconfig.h | 54 +++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 55 insertions(+), 1 deletion(-) > create mode 100644 xen/include/xen/kconfig.h > > diff --git a/xen/include/xen/config.h b/xen/include/xen/config.h > index 7595599..eeb49db 100644 > --- a/xen/include/xen/config.h > +++ b/xen/include/xen/config.h > @@ -7,7 +7,7 @@ > #ifndef __XEN_CONFIG_H__ > #define __XEN_CONFIG_H__ > > -#include > +#include > > #ifndef __ASSEMBLY__ > #include > diff --git a/xen/include/xen/kconfig.h b/xen/include/xen/kconfig.h > new file mode 100644 > index 0000000..d68a7ed > --- /dev/null > +++ b/xen/include/xen/kconfig.h > @@ -0,0 +1,54 @@ > +#ifndef __XEN_KCONFIG_H > +#define __XEN_KCONFIG_H > + > +#include > + > +/* > + * Helper macros to use CONFIG_ options in C/CPP expressions. Note that > + * these only work with boolean and tristate options. > + */ > + > +/* > + * Getting something that works in C and CPP for an arg that may or may > + * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1" > + * we match on the placeholder define, insert the "0," for arg1 and generate > + * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one). > + * 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) _config_enabled(cfg) > +#define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value) > +#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0) > +#define ___config_enabled(__ignored, val, ...) val > + > +/* > + * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0 > + * otherwise. For boolean options, this is equivalent to > + * IS_ENABLED(CONFIG_FOO). > + */ > +#define IS_BUILTIN(option) config_enabled(option) > + > +/* > + * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 > + * otherwise. > + */ > +#define IS_MODULE(option) config_enabled(option##_MODULE) > + > +/* > + * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled > + * code can call a function defined in code compiled based on CONFIG_FOO. > + * 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) (config_enabled(option) || \ > + (config_enabled(option##_MODULE) && config_enabled(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)) > + > +#endif /* __XEN_KCONFIG_H */ I am not sure that the complexity of this file is necessary since Xen does not support loadable modules. Essentially, IS_ENABLED(CONFIG_FOO) is as simple as #ifdef CONFIG_FOO.