In <https://sourceware.org/ml/libc-alpha/2016-01/msg00885.html> I
proposed a minimum Linux kernel version of 3.2 for glibc 2.24, since
Linux 2.6.32 has reached EOL.
In the discussion in February, some concerns were expressed about
compatibility with OpenVZ containers. It's not clear that these are
real issues, given OpenVZ backporting kernel features and faking the
kernel version for guest software, as discussed in
<https://sourceware.org/ml/libc-alpha/2016-02/msg00278.html>. It's
also not clear that supporting running GNU/Linux distributions from
late 2016 (at the earliest) on a kernel series from 2009 is a sensible
expectation. However, as an interim step, this patch increases the
requirement everywhere except x86 / x86_64 (since the controversy was
only about those architectures); the special caveats and settings can
easily be removed later when we're ready to increase the requirements
on x86 / x86_64 (and if someone would like to raise the issue on LWN
as suggested in the previous discussion, that would be welcome). 3.2
kernel headers are required everywhere by this patch.
(x32 already requires 3.4 or later, so is unaffected by this patch.)
As usual for such a change, this patch only changes the configure
scripts and associated documentation. The intent is to follow up with
removal of dead __LINUX_KERNEL_VERSION conditionals. Each __ASSUME_*
or other macro that becomes dead can then be removed independently.
Tested for x86_64 and x86.
* sysdeps/unix/sysv/linux/configure.ac (LIBC_LINUX_VERSION):
Define to 3.2.0.
(arch_minimum_kernel): Likewise.
* sysdeps/unix/sysv/linux/configure: Regenerated.
* sysdeps/unix/sysv/linux/i386/configure.ac (arch_minimum_kernel):
Define to 2.6.32.
* sysdeps/unix/sysv/linux/i386/configure: Regenerated.
* sysdeps/unix/sysv/linux/x86_64/64/configure.ac
(arch_minimum_kernel): Define to 2.6.32.
* sysdeps/unix/sysv/linux/x86_64/64/configure: Regenerated.
* README: Document Linux 3.2 requirement.
* manual/install.texi (Linux): Document Linux 3.2 headers
requirement.
* INSTALL: Regenerated.
This patch continues removing architecture-specific cases from
non-architecture-specific files by moving the logic to use directories
such as /lib64 out of sysdeps/gnu/configure.ac.
A new macro LIBC_SLIBDIR_RTLDDIR is created that sysdeps configure
scripts can use to declare the library directories to be used; the
logic was previously duplicated in configure fragments for aarch64,
mips and x32 as well as in sysdeps/gnu/configure.ac. This macro is
used directly in sysdeps/gnu/configure.ac only to provide the /lib
default (the logic saying that with --prefix=/usr shared libraries go
in /lib not /usr/lib); the architecture cases formerly there are moved
into various new or existing configure.ac files. The new macro is
also used in the various architecture fragments that already had such
logic. In the x32 there was previously a configure fragment, but it
was a directly written one without a .ac file; now a .ac file is used
there instead to generate configure.
Tested x86_64 that the installed shared libraries, and the directory
structure of the installation, are unchanged by this patch.
There is an old bug report - bug 6441 - about library directories
changing after reconfiguring. If this is still applicable - and I
haven't attempted to confirm it or review the old patch pointed to in
that bug - then this patch should reduce the number of places needing
changing in any fix.
* aclocal.m4 (LIBC_SLIBDIR_RTLDDIR): New macro.
* sysdeps/gnu/configure.ac: Use LIBC_SLIBDIR_RTLDDIR. Remove
cases for individual architectures.
* sysdeps/gnu/configure: Regenerated.
* sysdeps/unix/sysv/linux/aarch64/configure.ac: Use
LIBC_SLIBDIR_RTLDDIR.
* sysdeps/unix/sysv/linux/aarch64/configure: Regenerated.
* sysdeps/unix/sysv/linux/mips/configure.ac: Use
LIBC_SLIBDIR_RTLDDIR.
* sysdeps/unix/sysv/linux/mips/configure: Regenerated.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac: Use
LIBC_SLIBDIR_RTLDDIR.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/configure:
Regenerated.
* sysdeps/unix/sysv/linux/s390/s390-64/configure.ac: New file.
* sysdeps/unix/sysv/linux/s390/s390-64/configure: New generated
file.
* sysdeps/unix/sysv/linux/sparc/sparc64/configure.ac: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/configure: New generated
file.
* sysdeps/unix/sysv/linux/x86_64/64/configure.ac: New file.
* sysdeps/unix/sysv/linux/x86_64/64/configure: New generated file.
* sysdeps/unix/sysv/linux/x86_64/x32/configure.ac: New file.
* sysdeps/unix/sysv/linux/x86_64/x32/configure: Generate.
