----- On Jan 30, 2019, at 4:10 PM, Joseph Myers joseph@xxxxxxxxxxxxxxxx wrote: > On Wed, 30 Jan 2019, Mathieu Desnoyers wrote: > >> #if defined (__NR_rseq) && !defined (RSEQ_SIG) >> # error "UAPI headers support rseq system call, but glibc does not define >> RSEQ_SIG." >> #endif >> >> Would that take care of your concerns ? > > That would of course need appropriate conditionals based on the most > recent kernel version for which a given glibc version has been updated, so > that using new kernel headers with an existing glibc release does not make > the build fail (cf. the test of syscall-names.list). The test I hint at above would not be for the glibc build per se. It would be for a check that glibc implements support for all the system calls available in the kernel headers (if such a test target currently exists). > And being able to > write such a test only solves one half of the problem - it needs to be > easy to determine what value to put in that header in glibc for an > architecture that's newly gained support in the kernel, *without* needing > any architecture expertise. I'm afraid this requirement is incompatible with the nature of the RSEQ signature. This signature may be required to be a specific trap instruction by the architecture, so deciding on its value without architecture expertise is not possible. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
