Updated ARM NPTL patch
Paul Brook
paul at codesourcery.com
Thu Dec 7 09:39:03 PST 2006
We've updated our ARM NPTL patch to apply relative to
r16195 of the public uClibc trunk. It also includes support for Thumb mode.
As before, it's a very large patch --- 3MB uncompressed. There are
changes throughout the uClibc tree. The patch is available at the
following URL:
http://www.codesourcery.com/public/uClibc-0.9.28-csl-nptl-7.patch.gz
The patch is relative to revision 16550 of the public uClibc trunk.
You can retrieve this base tree from the public uClibc repository with
the following command:
$ svn checkout -r 16550 svn://uclibc.org/trunk/uClibc
--
RECENT CHANGES
- uClibc-0.9.28-csl-nptl-9 --- vs. public uClibc trunk r16550
This release incorporates uClibc trunk changes, including Thumb ldso
fixes. It also incorporates Thumb NPTL support.
- uClibc-0.9.28-csl-nptl-8 --- vs. public uClibc trunk r16195
This release incorporates patches from Khem Raj to fix the handling
of the 'res_init' function by making it resemble the uClibc trunk
sources more closely.
- uClibc-0.9.28-csl-nptl-7 --- vs. public uClibc trunk r16195
A new release of our NPTL work, incorporating the public changes as
of Friday, 2006-9-22. There are two main regressions relative to
the -5 release:
- Due to a bug inherited from the public uClibc sources, when uClibc
is configured without thread support, user code cannot see errno
values set by functions in uClibc. For this reason, this release
is not useful in a non-threaded configuration.
The bug is described in more detail here:
http://uclibc.org/lists/uclibc/2006-September/016498.html
- When configured to use the NPTL pthread implementation, the call
'sysconf (_SC_THREAD_THREADS_MAX)' reports that the number of
threads is limited to roughly 16ki. This is incorrect; there is
no limit on the number of threads under NPTL.
- uClibc-0.9.28-csl-nptl-6 --- vs. public uClibc trunk r16105
This is an intermediate release. This merge introduced some test suite
regressions, but we felt it was worthwhile making the merged patch
available immediately. When the regressions have been addressed, we
will make a new release.
- uClibc-0.9.28-csl-nptl-5 --- vs. public uClibc trunk r15891
This release fixes a compilation problem in libc/inet/rpc/rpc_thread.c,
and avoids a duplicate definition of __USE_BX__ in libpthread/nptl/
sysdeps/arm/sysdep.h.
- uClibc-0.9.28-csl-nptl-4
This release is based on the public uClibc trunk, not the public
uClibc NPTL branch.
- uClibc-0.9.28-csl-nptl-3
This release is identical to the -2 release, except that it omits
patches to remove the 'CVS' directories present in the public
sources (r14664). Those directories are not included in the
complete source tree.
- uClibc-0.9.28-csl-nptl-2
The release uClibc-0.9.28-csl-nptl-1 omitted two changes:
- a fix for a space leak in dynamic linker related to thread-local
storage, and
- a fix to the test suite.
These changes are included in uClibc-0.9.28-csl-nptl-2.
- uClibc-0.9.28-csl-nptl-1
This is the initial release, based on revision 14664 of the public
uClibc NPTL branch, svn://uclibc.org/branches/uClibc-nptl
KNOWN LIMITATIONS
This release has some known limitations:
- The merge with public uClibc trunk revision r16105 introduced
some test suite regressions, as described above.
- When linking statically against uClibc, the dlopen function does not
work properly. The unmodified uClibc trunk has this problem as
well, so CodeSourcery does not believe that our NPTL patches are
responsible; in fact, we believe dlopen works better with our
patches than without.
However, many uClibc tests depend on dlopen, so this issue makes it
difficult to test static linking. It would be a good idea to
re-test if statically-linked dlopen is fixed in the future.
- The test tls/tst-tls6 fails in our tree, but passes under the GNU C
library. This test checks the allocation of TLS module ID numbers
to shared libraries; failure to do this correctly could result in
some dynamic linker data structures growing larger than necessary as
the program loads and unloads shared libraries. CodeSourcery will
investigate this failure.
TEST RESULTS
This release has no test suite regressions relative to the unmodified
public uClibc sources, and one regression relative to the GNU C
library (glibc) thread tests.
As a basis for comparison with uClibc, we use test results from the
unmodified public uClibc trunk, configured in two ways:
- with no thread support (called "none" in the chart below)
- with the old LinuxThreads thread library,
libpthread/linuxthreads.old (called "old")
We configured our uClibc with our changes in three ways:
- with no thread support ("none")
- with the old LinuxThreads thread library ("old")
- with the NPTL thread library ("nptl")
All tests pass in all configurations, except as follows:
unpatched trunk uClibc-0.9.28-csl-nptl-8
test none old none old nptl
============== ====== ====== ====== ====== ======
assert/assert (1) fail fail fail fail fail
inet/bug-if1(4) fail pass fail pass pass
malloc/tst-malloc(4) fail pass fail pass pass
malloc/tst-mcheck(4) fail pass fail pass pass
misc/bug-readdir1(4) fail pass fail pass pass
misc/opendir-tst1(4) fail pass fail pass pass
mmap/mmap (2) fail fail pass pass pass
pthread/ex1 N/A fail N/A pass pass
pthread/ex6 N/A fail N/A pass pass
pwd_grp/getgroups (3) fail fail fail fail fail
regex/testregexi hang hang pass pass pass
regex/tst-regex2 hang hang fail fail fail
signal/tst-sigsimple(4) fail pass fail pass pass
time/clocktest hang hang pass pass pass
unistd/errno(4) fail pass fail pass pass
"N/A" indicates that the test does not run in that configuration.
"hang" indicates that the test program runs indefinitely.
(1) The harness for this test is not designed for use with
cross-compilation.
(2) The mmap system call does not exist on ARM EABI Linux; it should
forward to mmap64.
(3) The test is not written portably.
(4) This test fails in non-threaded configurations of uClibc because
user code does not see errno values set by uClibc. This bug is
present in the public sources, and thus also present in our merged
sources.
The directories 'test/nptl' and 'test/tls' include tests copied from
the GNU C library 'nptl' and 'elf' directories. (Some GNU C library
tests are omitted; these tests are for features not implemented by
uClibc, like POSIX asynchronous I/O.) These tests run only when the
NPTL thread library is in use. All these tests pass with both the GNU
C library and our sources, except as follows:
test GNU C Library uClibc-0.9.28-csl-nptl-8
================ ============= ========================
nptl/tst-cancel7 fail fail
nptl/tst-cancelx7 fail fail
nptl/tst-exec4 fail fail
nptl/tst-sysconf pass fail (regression)
tls/tst-tls6 pass fail (regression)
BUILD TOOLS
This release has been built and tested using the SourceryG++ 4.1.1
arm-none-linux-gnueabi toolchain, modified to link against uClibc
instead of glibc. It should also work with other compilers, as long as
they have EABI+TLS support; however, this has not been tested.
In Thumb mode problems may be experienced with older linkers (eg. the
CodeSourcery 2006Q1 release). In particular there are known issues with
linking against Thumb symbols in shared libraries, and with calls that
require a PLT entry in Thumb mode. Binutils HEAD and CodeSourcery 2006Q3
have fixed for these issues.
KERNEL SOURCES
This release was built and tested using the headers from version
2.6.16 of the Linux kernel.
CONFIGURATION
uClibc uses a configuration system similar to that of the Linux
kernel: all Makefiles in the tree include a file in the top directory
named '.config', which sets variables affecting which portions of the
tree are built, and how.
To build uClibc for the ARM with the NPTL libpthread, make the
following selections in '.config':
- Target Architecture: arm (TARGET_arm=y; others unset)
- Use ARM EABI: yes (CONFIG_ARM_EABI=y)
- Target Processor Endianness: little (ARCH_LITTLE_ENDIAN=y)
- Linux kernel header location (KERNEL_SOURCE)
Set this to the path of the top of a Linux kernel source tree.
- POSIX Threading Support: yes (UCLIBC_HAS_THREADS=y)
- Build pthreads debugging support: yes (PTHREADS_DEBUG_SUPPORT=y)
- Native POSIX Threading (NPTL) Support: yes (UCLIBC_HAS_THREADS_NATIVE=y)
- Use the older (stable) version of (LINUXTHREADS_OLD unset)
linuxthreads: no
- Malloc Implementation: malloc-standard (MALLOC_STANDARD=y; others
unset)
This is necessary to run the NPTL tests in test/nptl; some depend on
features of the "standard" malloc implementation.
ACKNOWLEDGEMENTS
This work is based on Steve Hill's NPTL support for the MIPS
architecture, available from the public uClibc Subversion repository
on the branch mentioned above.
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