[PATCHv3] powerpc: ABI change - add HWCAP/HWCAP2/platform info to TCB

Carlos Eduardo Seo cseo@linux.vnet.ibm.com
Wed Sep 23 21:03:00 GMT 2015


Hi

After O’Donell's and Steve's comments (thanks again for the review, btw), I made the following changes to address his concerns (see the original discussion here - https://sourceware.org/ml/libc-alpha/2015-08/msg01138.html):

* Changed the data initialization: the function that processes the data before it can be written into the TCB (init_hwcapinfo) is now called very early in program initialization. In the dynamic linking case, init_hwcapinfo() is called in _dl_sysdep_start() (via DL_PLATFORM_INIT). In the static linking case, it has to be called as early as in __libc_start_main(), since the TLS initialization happens shortly after that, so we use the powerpc-specific libc-start.c file for that. This new procedure eliminates the concurrency issues raised by O’Donell in v2 and it should conform with the design goals Steve mentioned.

* Added a testcase for the static linking case.

* Testcases now cover multithreads.

* Addressed manual issues. It should have only the necessary information now.

* The ‘init_hwcapinfo’ symbol is moved to the loader, since it is used mostly by ld code now. But I’d like to read your comments about where this is most appropriate.

Tested on ppc32, ppc64 and ppc64le, both dynamic and static cases.

Please review.

Thanks,

-- 
Carlos Eduardo Seo
Software Engineer - Linux on Power Toolchain
cseo@linux.vnet.ibm.com

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