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5 Commits

Author SHA1 Message Date
Florian Weimer
2fe2af88ab i386: Remove broken CAN_USE_REGISTER_ASM_EBP (bug 28771) 
The configure check for CAN_USE_REGISTER_ASM_EBP tried to compile a
simple function that uses %ebp as an inline assembly operand.  If
compilation failed, CAN_USE_REGISTER_ASM_EBP was set 0, which
eventually had these consequences:

(1) %ebx was avoided as an inline assembly operand, with an
    assembler macro hack to avoid unnecessary register moves.
(2) %ebp was avoided as an inline assembly operand, using an
    out-of-line syscall function for 6-argument system calls.

(1) is no longer needed for any GCC version that is supported for
building glibc.  %ebx can be used directly as a register operand.
Therefore, this commit removes the %ebx avoidance completely.  This
avoids the assembler macro hack, which turns out to be incompatible
with the current Systemtap probe macros (which switch to .altmacro
unconditionally).

(2) is still needed in many build configurations.  The existing
configure check cannot really capture that because the simple function
succeeds to compile, while the full glibc build still fails.
Therefore, this commit removes the check, the CAN_USE_REGISTER_ASM_EBP
macro, and uses the out-of-line syscall function for 6-argument system
calls unconditionally.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit a78e6a10d0)
 2022-01-13 15:21:32 +01:00
Joseph Myers
139ace9575 Require Linux kernel 3.2 or later on x86 / x86_64. 
As per the recent discussion, this patch implements a requirement for
Linux 3.2 or later for x86 and x86_64.  This is only the initial
change to increase the configured minimum; it's expected that followup
patches would deal with associated removal of conditionals that are no
longer needed.  If we remove the start-up test on the kernel version,
of course the NEWS and README text should then be revised (to reflect
that this version is just one such that glibc does not intend to
include compatibility code for any older kernel version, rather than
older kernels necessarily failing to work or glibc necessarily having
compatibility code for newer interfaces).

The followups would be able to assume presence of getcpu (x86_64),
recvmmsg (not always through its own syscall, sometimes only through
socketcall), sendmmsg (likewise), /proc/$pid/task/$tid/comm, f_flags
from statfs, prlimit64.

Tested for x86_64 and x86.

	* sysdeps/unix/sysv/linux/i386/configure.ac (arch_minimum_kernel):
	Remove.
	* sysdeps/unix/sysv/linux/i386/configure: Regenerated.
	* sysdeps/unix/sysv/linux/x86_64/64/configure.ac
	(arch_minimum_kernel): Remove.
	* sysdeps/unix/sysv/linux/x86_64/64/configure: Regenerated.
	* README: Update statement about Linux kernel requirements.
 2017-05-08 10:45:20 +00:00
Adhemerval Zanella
3b33d6ed60 Rework -fno-omit-frame-pointer support on i386 
Commit 6b1df8b27f fixed the -OS build issue on i386 (BZ#20729) by
expliciting disabling frame pointer (-fomit-frame-pointer) on the
faulty objects.  Although it does fix the issue, it is a subpar
workaround that adds complexity in build process (a rule for each
object to add the required compiler option and pontentially more
rules for objects that call {INLINE,INTERNAL}_SYSCALL) and does not
allow the implementations to get all the possible debug/calltrack
information possible (used mainly in debuggers and performance
measurement tools).

This patch fixes it by adding an explicit configure check to see
if -fno-omit-frame-pointer is set and to act accordingly (set or
not OPTIMIZE_FOR_GCC_5).  The make rules is simplified and only
one is required: to add libc-do-syscall on loader due mmap
(which will be empty anyway for default build with
-fomit-frame-pointer).

Checked on i386-linux-gnu with GCC 6.2.1 with CFLAGS sets as
'-Os', '-O2 -fno-omit-frame-pointer', and '-O2 -fomit-frame-pointer'.
For '-Os' the testsuite issues described by BZ#19463 and BZ#15105
still applied.

It fixes BZ #21029, although it is marked as duplicated of #20729
(I reopened to track this cleanup).

	[BZ #21029]
	* config.h.in [CAN_USE_REGISTER_ASM_EBP]: New define.
	* sysdeps/unix/sysv/linux/i386/Makefile
	[$(subdir) = elf] (sysdep-dl-routines): Add libc-do-syscall.
	(uses-6-syscall-arguments): Remove.
	[$(subdir) = misc] (CFLAGS-epoll_pwait.o): Likewise.
	[$(subdir) = misc] (CFLAGS-epoll_pwait.os): Likewise.
	[$(subdir) = misc] (CFLAGS-mmap.o): Likewise.
	[$(subdir) = misc] (CFLAGS-mmap.os): Likewise.
	[$(subdir) = misc] (CFLAGS-mmap64.o): Likewise.
	[$(subdir) = misc] (CFLAGS-mmap64.os): Likewise.
	[$(subdir) = misc] (CFLAGS-pselect.o): Likewise.
	[$(subdir) = misc] (cflags-pselect.o): Likewise.
	[$(subdir) = misc] (cflags-pselect.os): Likewise.
	[$(subdir) = misc] (cflags-rtld-mmap.os): Likewise.
	[$(subdir) = sysvipc] (cflags-semtimedop.o): Likewise.
	[$(subdir) = sysvipc] (cflags-semtimedop.os): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fadvise64.o): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fadvise64.os): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fallocate.o): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fallocate.os): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fallocate64.o): Likewise.
	[$(subdir) = io] (CFLAGS-posix_fallocate64.os): Likewise.
	[$(subdir) = io] (CFLAGS-sync_file_range.o): Likewise.
	[$(subdir) = io] (CFLAGS-sync_file_range.os): Likewise.
	[$(subdir) = io] (CFLAGS-fallocate.o): Likewise.
	[$(subdir) = io] (CFLAGS-fallocate.os): Likewise.
	[$(subdir) = io] (CFLAGS-fallocate64.o): Likewise.
	[$(subdir) = io] (CFLAGS-fallocate64.os): Likewise.
	[$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.o):
	Likewise.
	[$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.os):
	Likewise.
	[$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.o):
	Likewise.
	[$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.os):
	Likewise.
	[$(subdir) = nptl] (CFLAGS-sem_wait.o): Likewise.
	[$(subdir) = nptl] (CFLAGS-sem_wait.os): Likewise.
	[$(subdir) = nptl] (CFLAGS-sem_timedwait.o): Likewise.
	[$(subdir) = nptl] (CFLAGS-sem_timedwait.os): Likewise.
	* sysdeps/unix/sysv/linux/i386/configure.ac: Add check if compiler allows
	ebp on inline assembly.
	* sysdeps/unix/sysv/linux/i386/configure: Regenerate.
	* sysdeps/unix/sysv/linux/i386/sysdep.h (OPTIMIZE_FOR_GCC_5):
	Set if CAN_USE_REGISTER_ASM_EBP is set.
	(check_consistency): Likewise.
 2017-02-17 18:06:29 -02:00
Joseph Myers
5b4ecd3f95 Require Linux 3.2 except on x86 / x86_64, 3.2 headers everywhere. 
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.
 2016-02-24 17:15:12 +00:00
Joseph Myers
0ea5d373c7 Move architecture cases out of sysdeps/unix/sysv/linux/configure.ac. 
Continuing the process of making non-ex-ports architectures follow the
preferred sysdeps practices followed by ex-ports architectures - that
is, putting things in architecture-specific sysdeps files rather than
having architecture-specific cases in architecture-independent files -
this patch moves architecture cases out of
sysdeps/unix/sysv/linux/configure.ac into (new or existing) configure
fragments for each architecture.  (In the case of the
arch_minimum_kernel setting for x32,
sysdeps/unix/sysv/linux/x86_64/x32/configure already has such a
setting so the setting in sysdeps/unix/sysv/linux/configure.ac was a
duplicate that could just be removed - though I haven't tested for
x32.)

Tested for x86_64 and x86 that the patch causes no changes to the
installed shared libraries or ldd (or any part of the installation
except for the parts that always change because the files contain
timestamps - nscd and static libraries).

	* sysdeps/unix/sysv/linux/configure.ac: Remove cases for
	individual architectures.
	* sysdeps/unix/sysv/linux/configure: Regenerated.
	* sysdeps/unix/sysv/linux/i386/configure.ac: New file.
	* sysdeps/unix/sysv/linux/i386/configure: New generated file.
	* sysdeps/unix/sysv/linux/powerpc/configure.ac
	(ldd_rewrite_script): Define variable.
	* sysdeps/unix/sysv/linux/powerpc/configure: Regenerated.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure.ac: New
	file.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure: New
	generated file.
	* sysdeps/unix/sysv/linux/s390/configure.ac: New file.
	* sysdeps/unix/sysv/linux/s390/configure: New generated file.
	* sysdeps/unix/sysv/linux/sh/configure.ac: New file.
	* sysdeps/unix/sysv/linux/sh/configure: New generated file.
	* sysdeps/unix/sysv/linux/sparc/configure.ac: New file.
	* sysdeps/unix/sysv/linux/sparc/configure: New generated file.
	* sysdeps/unix/sysv/linux/x86_64/configure.ac: New file.
	* sysdeps/unix/sysv/linux/x86_64/configure: New generated file.
 2014-06-24 20:53:03 +00:00