Re: [PATCH] <bits/syscall.h>: Use an arch-independent system call list on Linux

[Florian Weimer <fweimer at redhat dot com>]

On 04/06/2017 02:29 PM, Andreas Schwab wrote:
> On Apr 06 2017, Florian Weimer <fweimer@redhat.com> wrote:
>
> > As a result, current glibc has this elaborate dance at built where it runs
> > “gcc -E -dM” (with varying additional parameters to get the
> > lib/libx32/lib64 variants).  I want to get rid of that because it means
> > that if you upgrade the kernel headers after building glibc, the SYS_* and
> > __NR_* macros drift apart.
>
> You have to rebuild glibc anyway if new syscalls come along, so there
> isn't much difference.

Yes, but if glibc carries an explicit list, we can schedule the glibc 
rebuild before the kernel build.  If we do that with a recent enough 
upstream kernel, we do not even need to know at that point which system 
calls will actually backported.  The required SYS_* macros will simply 
appear if the kernel headers add the __NR_* macro.

Thanks,
Florian