On 15/10/15 12:18, Mikko Rapeli wrote: > On Thu, Oct 15, 2015 at 11:29:12AM +0100, David Vrabel wrote: >> On 15/10/15 06:56, Mikko Rapeli wrote: >>> xen/interface/xen.h is not exported from kernel headers so remove the >>> dependency and provide needed defines for domid_t and xen_pfn_t if they >>> are not already defined by some other e.g. Xen specific headers. >>> >>> Suggested by Andrew Cooper <andrew.coop...@citrix.com> on lkml message >>> <5569f9c9.8000...@citrix.com>. >>> >>> The ifdef for ARM is ugly but did not find better solutions for it. >>> >>> Fixes userspace compilation error: >>> >>> xen/privcmd.h:38:31: fatal error: xen/interface/xen.h: No such file or >>> directory >> [...] >>> --- a/include/uapi/xen/privcmd.h >>> +++ b/include/uapi/xen/privcmd.h >>> @@ -35,7 +35,19 @@ >>> >>> #include <linux/types.h> >>> #include <linux/compiler.h> >>> -#include <xen/interface/xen.h> >>> + >>> +/* Might be defined by Xen specific headers, but if not */ >>> +#ifndef domid_t >>> +typedef __u16 domid_t; >>> +#endif /* domid_t */ >> >> As the kbuild bot points out, this does not work since the existence of >> a typedef cannot be checked with #ifdef. > > Yeah, this hack doesn't cut it. Sorry. Tried to implement these changes: > http://www.spinics.net/lists/linux-api/msg11048.html > >> I'm not really sure what problem you're trying to solve. A user space >> program making use of this interface gets the domid_t and xen_pfn_t etc >> typedefs from the headers provided as part of the libxenctrl library. > > I'm trying to make sure that kernel headers in userspace compile with minimal > dependencies which are gcc and libc. > > For me it is clear by now that many Linux API's and ABI's like Xen parts do > not live in the uapi header files and instead there's a separate userspace > library with needed headers and defines which have embedded copies of > the needed API and ABI definitions, like header files. > > So how could this file be changed so that it compiles in userspace without > definitions from libxenctrl?
I don't think anything needs to be changed. Instead I would make your compilation check of this header dependent on the existence of the xen/interface/xen.h header. Or you may exclude the check of this header entirely. > I guess I could copy the needed definitions for domid_t and xen_pfn_t from > xen/interface/xen.h of libxenctrl. That I should have done to begin with > instead of trying to hack something on my own. I do not want definitions duplicated/copied from the hypervisor ABI headers. This causes problems when support for new architectures is added (for example). David -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
