Previously we'd been relying on getting the machine-specific <endian.h>
instead of the top-level <endian.h>, and <sys/endian.h> was basically broken.
Now, with this patch and the previous patch we should have <endian.h>
and <sys/endian.h> behaving the same. This is basically how NetBSD's endian.h
works, and was probably how ours was originally intended to work.
Bug: http://code.google.com/p/android/issues/detail?id=39824
Change-Id: I71de5a507e633de166013a658b5764df9e1aa09c
The near duplicates upset fussier compilers that insist that
typedefs be exactly the same, but the fix isn't to make all
copies identical...
Change-Id: Icfdace41726f36ec33c9ae919dbb5a54d3529cc9
We'd manually hacked _BYTE_ORDER into the arm and mips "_types.h" headers,
but not into the x86 one. Judging by upstream, _BYTE_ORDER should be in
the "endian.h" headers instead, so let's uniformly do that.
I've also ironed out some of the other differences between the different
architectures' header files too.
Bug: http://code.google.com/p/android/issues/detail?id=39824
Change-Id: I19d3af7ffd74e1c02b1b6886aec0f0d11f44ab8d
Adds new code to function memset, optimized for Cortex A9.
Copyright (C) ST-Ericsson SA 2010
Added neon implementation
Author: Henrik Smiding henrik.smiding@stericsson.com for ST-Ericsson.
Change-Id: Id3c87767953439269040e15bd30a27aba709aef6
Signed-off-by: Christian Bejram <christian.bejram@stericsson.com>
Adds new code to memcpy function, optimized for Cortex A9.
Adds new ARM-only loop, for operations where source and
destination are aligned.
Copyright (C) ST-Ericsson SA 2010
Modified neon implementation to fit Cortex A9 cache line size,
for those running 32 bytes L2 cache line size.
Also split the implementation in aligned and unaligned access,
for those that allows unaligned memory access with Neon.
For totally aligned operations, arm-only code is used.
Change-Id: I95ebf6164cd6486b12a7e3e98e369db21e7e18d2
Author: Henrik Smiding henrik.smiding@stericsson.com for ST-Ericsson.
Signed-off-by: Christian Bejram <christian.bejram@stericsson.com>
This patch updates the C library headers to provide ucontext_t
definitions for three architectures.
+ Fix <signal.h> to always define 'struct sigcontext'.
The new declarations are announced with new macros defined in
<sys/cdefs.h> in order to make it easier to adapt client code
that already defines its own, incompatible, versions of the
structures seen here.
http://code.google.com/p/android/issues/detail?id=34784
Change-Id: Ie78c48690a4ce61c50593f6c39639be7fead3596
Add getsid() system call to bionic for
all architectures. This is needed for various tools
(e.g. perf).
Adding the getsid system call was done in 3 steps:
() add getsid system call (function name and syscall
number) to libc/SYSCALLS.TXT
() generate all necessary headers by calling
libc/tools/gensyscalls.py. This patch is adding
the generated files since the build system
does not call gensyscalls.py.
() add the system call signature to libc/include/unistd.h
Change-Id: Id69a257e13ec02e1a44085a6b217a3f19ab025b1
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Legacy ARM shared libraries use this generic version of atexit(),
which queues exit functions for invocation at program exit, at
which time the library may have been dlclose()'d, causing the
program to crash.
Change-Id: I41ae153c23268daa65ede7fb8966fc3e9caec369
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
To properly support legacy ARM shared libraries, libc.so needs
to export the symbols __dso_handle and atexit, even though
these are now supplied by the crt startup code.
This patch reshuffles the existing CRT_LEGACY_WORKAROUND
conditionally compiled code slightly so it works as the
original author likely intended.
Change-Id: Id6c0e94dc65b7928324a5f0bad7eba6eb2f464b9
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
The runtime linker parses the ELF section headers to
discover the size of the init_array and fini_array, so
there is no point in putting NULL terminators at the end.
Change-Id: I3246cd585efce9314155600277dd829e9f37d04f
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
None of the supported ARCHs actually populate these sections,
so there is no point in keeping them in the binaries.
Change-Id: I21a364f510118ac1114e1b49c53ec8c895c6bc6b
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
Useful if you're trying to defeat ASLR, otherwise not
so much ...
Change-Id: I17ebb50bb490a3967db9c3038f049adafe2b8ea7
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@gmail.com>
This header is used on bionic build and should be propagated into
sysroot on toolchain rebuild. Discussion re. this header is here:
http://gcc.gnu.org/ml/gcc-patches/2012-08/msg00936.html
It is available already in mips NDK platforms:
development/ndk/platforms/android-9/arch-mips/include/link.h
Change-Id: I39ff467cdac9f448e31c11ee3e14a6200e82ab57
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
Add a GNU_STACK marker to crtend* files. This tells the linker
that these files do not require an executable stack.
When linking, a missing GNU_STACK marker in any .o file can prevent
the compiler from automatically marking the final executable as NX
safe (executable stack not required). In Android, we normally work
around this by adding -Wa,--noexecstack / -Wl,-z,noexecstack.
For files like crtend.S / crtend_so.S, which are included in every
executable / shared library, it's better to add the GNU_STACK note
directly to the assembly file. This allows the compiler to
automatically mark the final executable as NX safe without any
special command line options.
References: http://www.gentoo.org/proj/en/hardened/gnu-stack.xml
Change-Id: I07bd058f9f60ddd8b146e0fb36ba26ff84c0357d
Move the stackpointer so a captured signal does not corrupt
stack variables needed for __thread_entry.
Change-Id: I3e1e7b94a6d7cd3a07081f849043262743aa8064
Rewrite
crtbegin.S -> crtbegin.c
crtbegin_so.S -> crtbegin_so.c
This change allows us to generate PIC code without relying
on text relocations.
As a consequence of this rewrite, also rewrite
__dso_handle.S -> __dso_handle.c
__dso_handle_so.S -> __dso_handle_so.c
atexit.S -> atexit.c
In crtbegin.c _start, place the __PREINIT_ARRAY__, __INIT_ARRAY__,
__FINI_ARRAY__, and __CTOR_LIST__ variables onto the stack, instead of
passing a pointer to the text section of the binary.
This change appears sorta wonky, as I attempted to preserve,
as much as possible, the structure of the original assembly.
As a result, you have C files including other C files, and other
programming uglyness.
Result: This change reduces the number of files with text-relocations
from 315 to 19 on my Android build.
Before:
$ scanelf -aR $OUT/system | grep TEXTREL | wc -l
315
After:
$ scanelf -aR $OUT/system | grep TEXTREL | wc -l
19
Change-Id: Ib9f98107c0eeabcb606e1ddc7ed7fc4eba01c9c4
crtbegin_dynamic and crtbegin_static are essentially identical,
minus a few trivial differences (comments and whitespace).
Eliminate duplicates.
Change-Id: Ic9fae6bc9695004974493b53bfc07cd3bb904480
Adds new code to function memcmp, optimized for Cortex A9.
Copyright (C) ST-Ericsson SA 2010
Added neon optimization
Change-Id: I8864d277042db40778b33232feddd90a02a27fb0
Author: Henrik Smiding henrik.smiding@stericsson.com for ST-Ericsson.
Signed-off-by: Christian Bejram <christian.bejram@stericsson.com>
Modify the dynamic linker so that executables can be loaded
at locations other than 0x00000000.
Modify crtbegin* so that non-PIC compilant "thumb interwork
veneers" are not created by the linker.
Bug: 5323301
Change-Id: Iece0272e2b708c79034f302c20160e1fe9029588
Some SoCs that support NEON nevertheless perform better with a non-NEON than a
NEON memcpy(). This patch adds build variable ARCH_ARM_USE_NON_NEON_MEMCPY,
which can be set in BoardConfig.mk. When ARCH_ARM_USE_NON_NEON_MEMCPY is
defined, we compile in the non-NEON optimized memcpy() even if the SoC supports
NEON.
Change-Id: Ia0e5bee6bad5880ffc5ff8f34a1382d567546cf9
So that we can always get the full stack trace regardless of gcc's handling
of the "noreturn" attribute associated with abort().
(Cherry pick of Id264a5167e7cabbf11515fbc48f5469c527e34d4.)
Bug: 6455193
Conflicts:
libc/Android.mk
Change-Id: I568fc5303fd1d747075ca933355f914122f94dac
So that we can always get the full stack trace regardless of gcc's handling
of the "noreturn" attribute associated with abort().
[cherry-picked from master]
BUG:6455193
Change-Id: I0102355f5bf20e636d3feab9d1424495f38e39e2
ARM Cortex A8 use 64 bytes and ARM Cortex A9 use 32 bytes cache line
size.
The following patch:
Adds code to adjust memcpy cache line size to match A9 cache line
size.
Adds a flag to select between 32 bytes and 64 bytes cache line
size.
Copyright (C) ST-Ericsson SA 2010
Modified neon implementation to fit Cortex A9 cache line size
Author: Henrik Smiding henrik.smiding@stericsson.com for
ST-Ericsson.
Change-Id: I8a55946bfb074e6ec0a14805ed65f73fcd0984a3
Signed-off-by: Christian Bejram <christian.bejram@stericsson.com>
The END macro was put too far down which made the linker complain about
it. Move up to the end of the code.
Change-Id: Ica71a9c6083b437d2213c7cefe34b0083c78f16b
Marking segments read-only was pushing the alignment of __on_dlclose by
2 bytes making it unaligned. This change makes sure the ARM code is
aligned to the 4 byte boundary.
Bug: 6313309
Change-Id: Ic2bf475e120dd61225ec19e5d8a9a8b1d0b7f081
This change fixes a segmentation fault in the libc unwinder when it goes
past __libc_init.
Unwind instructions for __libc_init direct it to grab the return address from
the stack frame. Without this change, the unwinder gets a wild address and
looks up further unwind instructions for the routine at that address. If it's
unlucky enough to hit an existing function, it will try to unwind it. Bad
things happen then.
With this change, the return address always points to the _start function,
which does not have unwind instructions associated with it. This stop the
unwind process.
__libc_init never returns, so this does not affect program execution, other
than adding 4 bytes on the main thread stack.
Change-Id: Id58612172e8825c8729cccd081541a13bff96bd0
Use the same pattern in atexit.S to reference __dso_handle in a way that
doesn't require a TEXTREL flag to be set.
Change-Id: Id69d20863ee203d2b2f7ef0db230f9b548657741
Some platform libraries built for ICS do not work with master
because of some refactoring in frameworks/base.
Make sure that these libgcc symbols are always present in our libc
Change-Id: Ib8d345878be0ba711f051082a778f5cc1f1b3a19
Signed-off-by: Dima Zavin <dima@android.com>
This patch defines a few new macros that can be used to control the
visibility of symbols exported by the C library:
- ENTRY_PRIVATE() can be used in assembly sources to indicate
that an assembler function should have "hidden" visibility, i.e.
will never be exported by the C library's shared library.
This is the equivalent of using __LIBC_HIDDEN__ for a C function,
but ENTRY_PRIVATE() works like ENTRY(), and must be used with
END() to tag the end of the function.
- __LIBC_ABI_PUBLIC__ can be used to tag a C functions as being
part of the C library's public ABI. This is important for a
few functions that must be exposed by the NDK to maintain
binary compatibility.
Once a symbol has been tagged with this macro, it shall
*never* be removed from the library, even if it becomes
directly unused due to implementation changes
(e.g. __is_threaded).
- __LIBC_ABI_PRIVATE__ can be used for C functions that should
always be exported by the C library because they are used by
other libraries in the platform, but should not be exposed
by the NDK. It is possible to remove such symbols from the
implementation if all callers are also modified.
+ Add missing END() assembly macro for x86
Change-Id: Ia96236ea0dbec41d57bea634b39d246b30e5e234
The xattr system calls are required for the SE Android userspace in
order to get and set file security contexts. In particular, libselinux
requires these calls.
Change-Id: I78f5eb3d8f3384aed0a5e7c6a6f001781d982017
Add bionic libc to support readahead system call.
This is needed to enable sreadahead to work.
Change-Id: I3856e1a3833db82e6cf42fd34af7631bd40cc723
Author: Winson Yung <winson.w.yung@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
The function must be named __atomic_cmpxchg, not __android_cmpxchg.
This typo broke existing prebuilt binaries (they couldn't be loaded
at runtime anymore).
Change-Id: I25ca7d18329817f0056e616a0409113269ad7b1f
Use tgkill instead of tkill to implement pthread_kill.
This is safer in the event that the thread has already terminated
and its id has been reused by a different process.
Change-Id: Ied715e11d7eadeceead79f33db5e2b5722954ac9
__atomic_cmpxchg and other related atomic operations did not
provide memory barriers, which can be a problem for non-platform
code that links against them when it runs on multi-core devices.
This patch does two things to fix this:
- It modifies the existing implementation of the functions
that are exported by the C library to always provide
full memory barriers. We need to keep them exported by
the C library to prevent breaking existing application
machine code.
- It also modifies <sys/atomics.h> to only export
always-inlined versions of the functions, to ensure that
any application code compiled against the new header will
not rely on the platform version of the functions.
This ensure that said machine code will run properly on
all multi-core devices.
This is based on the GCC built-in sync primitives.
The end result should be only slightly slower than the
previous implementation.
Note that the platform code does not use these functions
at all. A previous patch completely removed their usage in
the pthread and libstdc++ code.
+ rename arch-arm/bionic/atomics_arm.S to futex_arm.S
+ rename arch-x86/bionic/atomics_x86.S to futex_x86.S
+ remove arch-x86/include/sys/atomics.h which already
provided inlined functions to the x86 platform.
Change-Id: I752a594475090cf37fa926bb38209c2175dda539
Modify the dynamic linker so that executables can be loaded
at locations other than 0x00000000.
Modify crtbegin* so that non-PIC compilant "thumb interwork
veneers" are not created by the linker.
Bug: 5323301
Change-Id: Iece0272e2b708c79034f302c20160e1fe9029588
Without this change strcmp size is zero (not set), and it gets
ignored by Valgrind. Changes to memcpy and atexit don't affect the
generated binary in any way.
Change-Id: I05818cb5951f75901dc8c0eef02807a2e83a9231
This patch ensure that __aeabi_f2uiz is embedded in our C library.
This is needed to avoid breaking certain applications when they are
loaded in ICS. It is likely that the issue is due to mis-linked
binaries generated with the stand-alone toolchain (the problem
should not exist if you use ndk-build), but this fix is easier
than asking all app developers to fix their custom build system.
If you want more technical details, read the comments inside
libgcc_compat.c
Change-Id: I59ac1fc781ecb70b90b5573c5a3c67560ca8f270
Unfortunately, legacy .so files for ARM don't have a correct crtbegin file.
Consequently, we have to grandfather the old __dso_handle behaviour.
Add some ifdefs for ARM to allow it to use the old code until we can work
out a transition.
Change-Id: I6a28f368267d792c94e1d985d8344023bc632f6f
Author: H.J. Lu <hongjiu.lu@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Reference results of the experiments on TI OMAP3430 at 600 MHz
$ bench_strcmp -N "strcmp_1k" -s 1k -I 200
[original C code]
prc thr usecs/call samples errors cnt/samp size
strcmp_1k 1 1 10.38000 102 0 15000 1024
[ARM optimized code]
prc thr usecs/call samples errors cnt/samp size
strcmp_1k 1 1 3.08840 88 0 15000 1024
The work was derived from ARM Ltd, contributed to newlib, and reworked
for Android by Linaro.
Change-Id: Ib0d5755e1eb9adb07d80ef0252f57a5c4c57a425
Signed-off-by: Jim Huang <jserv@0xlab.org>
The kernel has supported this syscall for quite some time now,
but bionic did not. Now that there is a need for it, let's
add it to bionic.
Change-Id: Ifcef3e46f1438d79435b600c4e6063857ab16903
Used the new gensyscalls.py script to update the ARM syscalls with the
BEGIN(x) and END(x) macros to give size information for the code of the
syscall. Useful for valgrind.
Change-Id: I8c481c8928401ac110fd19b087f7d67e4db39326
Add a macro to annotate function end and start using both ENTRY and END
for each function. This allows valgrind (and presumably other debugging
tools) to use the debug symbols to trace the functions.
Change-Id: I5f09cef8e22fb356eb6f5cee952b031e567599b6
This patch improves the handling of 64-bit parameters in syscalls on ARM.
The ARM EABI mandates that 64-bit quantities be passed in even/odd register
pairs, which requires special treatment.
This allows us to simplify our implementations of pread() and pwrite()
and remove the C stubs for pread64() and pwrite64().
Also add ftruncate64() to <unistd.h>
Change-Id: I407e2fd223ba0093dd2d0b04c6152fadfc9ce3ef
Bug 3107933
This adds the cpu_set_t type definition and related functions
and macros used to handle CPU thread affinity.
sched_getcpu()
sched_setaffinity()
sched_getaffinity()
Change-Id: If382ecafde8926341a88478062b275553645065b
This elimates the makefile warning at the beginning of each build:
libc_common_intermediates/arch-arm/syscalls/eventfd.o' given more than once in the same rule.
Change-Id: I25cc0c373d55b5036dd17811a595c097fd6ca69a
The change explicitly isolates the assembly-only macros in header
<machine/cpu-features.h> in order to prevent mis-inclusion in C/C++
source files.
Change-Id: I0258e87c5ac3fd24944fb227290ac3b9cac4bfba
Merge commit 'bd8d987b3c3aa6d9d00cede2cb091f00bdb42204' into gingerbread-plus-aosp
* commit 'bd8d987b3c3aa6d9d00cede2cb091f00bdb42204':
libc: remove C++ comments from public headers.
Merge commit '3cf53d1a7814e1520df09d24b009c16f4f27db0d' into gingerbread-plus-aosp
* commit '3cf53d1a7814e1520df09d24b009c16f4f27db0d':
Fixes for the ARM-specific bswap_16, bswap_32, and bswap_64.
1. Make the feature test work by excluding known-deficient processors, so
we don't have to maintain a complete list of all the processors that support
REV and REV16.
2. Don't abuse 'register' to get an effect similar to GCC's +l constraint,
but which was unnecessarily restrictive.
3. Fix __swap64md so _x isn't clobbered, breaking 64-bit swaps.
4. Make <byteswap.h> (which declars bswap_16 and friends) use <endian.h>
rather than <sys/endian.h>, so we get the machine-dependent implementations.
Change-Id: I6a38fad7a9fbe394aff141489617eb3883e1e944
Merge commit '312be567a03aaf851707a268807ee666b12f8c74' into gingerbread-plus-aosp
* commit '312be567a03aaf851707a268807ee666b12f8c74':
Use ARMv6 instruction for handling byte order
Merge commit '3a1bbee36b773862e88c6f1895b607c0cd81b499' into gingerbread-plus-aosp
* commit '3a1bbee36b773862e88c6f1895b607c0cd81b499':
Add eventfd system call support
ARMv6 ISA has several instructions to handle data in different byte order.
For endian conversion (byte swapping) of single data words, it might be a
good idea to use the REV/REV16 instruction simply.
Change-Id: Ic4a5ed6254e082763e54aa70d428f59a0088636e
With this patch _and_ an upcoming build/ patch, the destruction
of static C++ objects contained in shared libraries will happen
properly when dlclose() is called.
Note that this change introduces crtbegin_so.S and crtend_so.S which
are currently ignored by the build system.
+ move definition of __dso_handle to the right place
(before that, all shared libraries used the __dso_handle
global variable from the C library).
Note that we keep a 'weak' __dso_handle in aeabi.c to avoid
breaking the build until the next patch to build/core/combo/
appears. We will be able to remove that later.
+ move bionic/aeabi.c to arch-arm/bionic/ (its proper location)
NOTE: The NDK will need to be modified to enable this feature in
the shared libraries that are generated through it.
Change-Id: I99cd801375bbaef0581175893d1aa0943211b9bc
With this patch, _and_ an upcoming build/ patch, the destruction
of static C++ objects contained in shared libraries will happen
properly when dlclose() is called.
Note that this change introduces crtbegin_so.S and crtend_so.S which
are currently ignored by the build system.
+ move definition of __dso_handle to the right place
(before that, all shared libraries used the __dso_handle
global variable from the C library).
Note that we keep a 'weak' __dso_handle in aeabi.c to avoid
breaking the build until the next patch to build/core/combo/
appears. We will be able to remove that later.
+ move bionic/aeabi.c to arch-arm/bionic/ (its proper location)
Change-Id: Ie771aa204e3acbdf02fd30ebd4150373a1398f39
NOTE: The NDK will need to be modified to enable this feature in
the shared libraries that are generated through it.
Update ARM atomic ops to use LDREX/STREX. Stripped out #if 0 chunk.
Insert explicit memory barriers in pthread and semaphore code.
For bug 2721865.
Change-Id: I0f153b797753a655702d8be41679273d1d5d6ae7
Added an underscore to _ARM_HAVE_LDREX_STREX to make it match the others.
Added __ARM_HAVE_DMB and __ARM_HAVE_LDREXD when appropriate.
Fixed some typos.
Change-Id: I2f55febcff4aeb7de572a514fb2cd2f820dca27c
GDB looks for specific opcode sequences when trying to recognize a stack
frame as a signal trampoline. The sequences it looks for happen to be those
created when SA_RESTORER is set, since glibc always sets a restorer. This
patch does the same here, so that the trampolines can be correctly identified.
Change-Id: I0ac574a68818cb24d939c3527f3aaeb04b853d04
This does not change the implementation of conditional variables
since we're waiting for other system components to properly use
pthread_condattr_init/setpshared before that.
Also remove an obsolete x86 source file.
Change-Id: Ia3e3fbac35b87a534fb04d4381c3c66b975bc8f7
Private futexes are a recent kernel addition: faster futexes that cannot be
shared between processes. This patch uses them by default, unless the PROCESS_SHARED
attribute flag is used when creating a mutex and/or conditional variable.
Also introduces pthread_condattr_init/destroy/setpshared/getpshared.
Change-Id: I3a0e2116f467072b046524cb5babc00e41057a53
Any of the setuid functions now updates /acct/uid/ with its own tid
before changing users. This is so we can properly account for cpu time
per uid.
Change-Id: I34186cf4d5228cac8439e582a9e26c01ef3011e4
Signed-off-by: Mike Chan <mike@android.com>
Only provide an implementation for ARM at the moment, since
it requires specific assembly fragments (the standard syscall
stubs cannot be used because the child returns in a different
stack).
Merge commit '76ef331cd6967ca8f5af779d25c8b634f8cdd2b6' into eclair-mr2-plus-aosp
* commit '76ef331cd6967ca8f5af779d25c8b634f8cdd2b6':
use local symbols in memset so it doesn't screw up profiling
Merge commit '7e7d6c48a064af82f0ec39f47b9eb803a6e1df4c' into eclair-plus-aosp
* commit '7e7d6c48a064af82f0ec39f47b9eb803a6e1df4c':
use local symbols in memset so it doesn't screw up profiling
Do not submit this patch before the one that modifies the Android emulator to
work-around a weird ARMv7 emulation issue. This is done to temporarily re-allow
the -user builds needed for QA.
This is required to work-around some corny bugs in ARMv7 emulation.
The emulation itself is required to run the dex pre-optimization pass
for -user builds.
Merge commit '7a9e06fa7e4e533074cde314f25dff3024f34a5d' into eclair-plus-aosp
* commit '7a9e06fa7e4e533074cde314f25dff3024f34a5d':
Fix ABI breakage in libc.so and libm.so between 1.6 and Eclair.
372 MB/s for large transfers, 440 MB/s for smaller ones down to 1KB. 130 MB/s for very small transfers ( < 32 bytes )
Performance is similar with non-congruent buffers.
For performance reasons, we don't call the kernel helper. Instead, we directly
access the TLS register on ARMv6 and higher. For ARMv5TE, keep using the hard-coded
address populated by the kernel on each task switch.
NOTE: Since we don't call the kernel helper, this must precisely match your
kernel configuration. This is controlled by setting the ARCH_ARM_HAVE_TLS_REGISTER
variable to 'true' in your board configuration file.
ARMv6 onwards. These architectures provide the load-linked, store-conditional pair of ldrex/strex whose use
is recommended in place of 'swp'. Also, the description of the 'swp' instruction in the ARMv6 reference
manual states that the swap operation does not include any memory barrier guarantees.This fix attempts to
address these issues by providing an atomic swap implementation using ldrex/strex under _ARM_HAVE_LDREX_STREX
macro. This Fix is verified on ST Ericsson's U8500 platform and Submitted on behalf of a third-party:
Surinder-pal SINGH from STMicroelectronics.
The problem was due to the fact that, in the case of dynamic executables,
the dynamic linker calls the DT_PREINIT_ARRAY, DT_INIT and DT_INIT_ARRAY
constructors when loading shared libraries and dynamic executables,
*before* calling the executable's entry point (i.e. arch-$ARCH/bionic/crtbegin_dynamic.c)
which in turns call __libc_init() in libc.so, as defined by bionic/libc_init_dynamic.c
The latter did call these constructors array again, mistakenly.
The patch also updates the documentation of many related functions.
Also adds a new section to linker/README.TXT explaining restrictions on
C library usage.
The patch has been tested on a Dream for stability issues with
proprietary blobs:
- H264 decoding works
- Camera + Video recording works
- GPS works
- Sensors work
The tests in system/extra/tests/bionic/libc/common/test_static_cpp_mutex.cpp has been
run and shows the static C++ constructor being called only once.
