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Re: [PATCH] x86-64: Implement memmove family IFUNC selectors in C
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Wed, 14 Jun 2017 15:38:24 -0300
- Subject: Re: [PATCH] x86-64: Implement memmove family IFUNC selectors in C
- Authentication-results: sourceware.org; auth=none
- References: <20170612160930.GA25262@gmail.com>
On 12/06/2017 13:09, H.J. Lu wrote:
> Implement memmove family IFUNC selectors in C.
> All internal calls within libc.so can use IFUNC on x86-64 since unlike
> x86, x86-64 supports PC-relative addressing to access the GOT entry so
> that it can call via PLT without using an extra register. For libc.a,
> we can't use IFUNC for functions which are called before IFUNC has been
> initialized. Use IFUNC internally reduces the icache footprint since
> libc.so and other codes in the process use the same implementations.
> This patch uses IFUNC for memmove family functions within libc.
> Any comments?>
> 2017-06-07 H.J. Lu <email@example.com>
> Erich Elsen <firstname.lastname@example.org>
> Adhemerval Zanella <email@example.com>
> * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
> memmove-sse2-unaligned-erms, memcpy_chk-nonshared,
> mempcpy_chk-nonshared and memmove_chk-nonshared.
> * sysdeps/x86_64/multiarch/ifunc-impl-list.c
> (__libc_ifunc_impl_list): Add tests for __memmove_chk_erms,
> __memcpy_chk_erms and __mempcpy_chk_erms. Update comments.
> * sysdeps/x86_64/multiarch/ifunc-memmove.h: New file.
> * sysdeps/x86_64/multiarch/memcpy.c: Likewise.
> * sysdeps/x86_64/multiarch/memcpy_chk-nonshared.S: Likewise.
> * sysdeps/x86_64/multiarch/memcpy_chk.c: Likewise.
> * sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S: Likewise.
> * sysdeps/x86_64/multiarch/memmove.c: Likewise.
> * sysdeps/x86_64/multiarch/memmove_chk-nonshared.S: Likewise.
> * sysdeps/x86_64/multiarch/memmove_chk.c: Likewise.
> * sysdeps/x86_64/multiarch/mempcpy.c: Likewise.
> * sysdeps/x86_64/multiarch/mempcpy_chk-nonshared.S: Likewise.
> * sysdeps/x86_64/multiarch/mempcpy_chk.c: Likewise.
> * sysdeps/x86_64/multiarch/memcpy.S: Removed.
> * sysdeps/x86_64/multiarch/memcpy_chk.S: Likewise.
> * sysdeps/x86_64/multiarch/memmove.S: Likewise.
> * sysdeps/x86_64/multiarch/memmove_chk.S: Likewise.
> * sysdeps/x86_64/multiarch/mempcpy.S: Likewise.
> * sysdeps/x86_64/multiarch/mempcpy_chk.S: Likewise.
> * sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> (__mempcpy_chk_erms): New function.
> (__memmove_chk_erms): Likewise.
> (__memcpy_chk_erms): New alias.