0fec6b9d88
__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 |
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| bionic | ||
| include | ||
| syscalls | ||
| syscalls.mk | ||