This is the mail archive of the
mailing list for the glibc project.
Re: [PATCH] x86-64: Implement memset family IFUNC selectors in C
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Thu, 15 Jun 2017 12:27:09 -0300
- Subject: Re: [PATCH] x86-64: Implement memset family IFUNC selectors in C
- Authentication-results: sourceware.org; auth=none
- References: <20170612160956.GB25262@gmail.com>
On 12/06/2017 13:09, H.J. Lu wrote:
> Implement memset 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 memset functions within libc.
> Any comments?
> 2017-06-07 H.J. Lu <firstname.lastname@example.org>
> Erich Elsen <email@example.com>
> * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
> memset-sse2-unaligned-erms, and memset_chk-nonshared.
> * sysdeps/x86_64/multiarch/ifunc-impl-list.c
> (__libc_ifunc_impl_list): Add test for __memset_chk_erms.
> Update comments.
> * sysdeps/x86_64/multiarch/ifunc-memset.h: New file.
> * sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S: Likewise.
> * sysdeps/x86_64/multiarch/memset.c: Likewise.
> * sysdeps/x86_64/multiarch/memset_chk-nonshared.S: Likewise.
> * sysdeps/x86_64/multiarch/memset_chk.c: Likewise.
> * sysdeps/x86_64/multiarch/memset.S: Removed.
> * sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
> * sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
> (__memset_chk_erms): New function.