From afcd9480feca651eef436d8438b783dde5c3bbb2 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Wed, 25 Mar 2015 15:53:47 +1030 Subject: powerpc __tls_get_addr call optimization This patch is glibc support for a PowerPC TLS optimization, inspired by Alexandre Oliva's TLS optimization for other processors, http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt In essence, this optimization uses a zero module id in the tls_index GOT entry to indicate that a TLS variable is allocated space in the static TLS area. A special plt call linker stub for __tls_get_addr checks for such a tls_index and if found, returns the offset immediately. The linker communicates the fact that the special __tls_get_addr stub is used by setting a bit in the dynamic tag DT_PPC64_OPT/DT_PPC_OPT. glibc communicates to the linker that this optimization is available by the presence of __tls_get_addr_opt. tst-tlsmod2.so is built with -Wl,--no-tls-get-addr-optimize for tst-tls-dlinfo, which otherwise would fail since it tests that no static tls is allocated. The ld option --no-tls-get-addr-optimize has been available since binutils-2.20 so doesn't need a configure test. * NEWS: Advertise TLS optimization. * elf/elf.h (R_PPC_TLSGD, R_PPC_TLSLD, DT_PPC_OPT, PPC_OPT_TLS): Define. (DT_PPC_NUM): Increment. * elf/dynamic-link.h (HAVE_STATIC_TLS): Define. (CHECK_STATIC_TLS): Use here. * sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_rela): Optimize TLS descriptors. * sysdeps/powerpc/powerpc64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/powerpc/dl-tls.c: New file. * sysdeps/powerpc/Versions: Add __tls_get_addr_opt. * sysdeps/powerpc/tst-tlsopt-powerpc.c: New tls test. * sysdeps/unix/sysv/linux/powerpc/Makefile: Add new test. Build tst-tlsmod2.so with --no-tls-get-addr-optimize. * sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist: Update. * sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist: Likewise. --- sysdeps/powerpc/Makefile | 3 ++ sysdeps/powerpc/Versions | 6 +++ sysdeps/powerpc/dl-tls.c | 24 ++++++++++ sysdeps/powerpc/powerpc32/dl-machine.h | 48 ++++++++++++++++++++ sysdeps/powerpc/powerpc64/dl-machine.h | 48 ++++++++++++++++++++ sysdeps/powerpc/tst-tlsopt-powerpc.c | 52 ++++++++++++++++++++++ sysdeps/unix/sysv/linux/powerpc/Makefile | 2 + .../unix/sysv/linux/powerpc/powerpc32/ld.abilist | 3 ++ .../sysv/linux/powerpc/powerpc64/ld-le.abilist | 3 ++ .../unix/sysv/linux/powerpc/powerpc64/ld.abilist | 3 ++ 10 files changed, 192 insertions(+) create mode 100644 sysdeps/powerpc/dl-tls.c create mode 100644 sysdeps/powerpc/tst-tlsopt-powerpc.c (limited to 'sysdeps') diff --git a/sysdeps/powerpc/Makefile b/sysdeps/powerpc/Makefile index b11edd7..533d763 100644 --- a/sysdeps/powerpc/Makefile +++ b/sysdeps/powerpc/Makefile @@ -8,6 +8,9 @@ sysdep-dl-routines += dl-machine sysdep_routines += dl-machine # extra shared linker files to link only into dl-allobjs.so sysdep-rtld-routines += dl-machine +# Don't optimize GD tls sequence to LE. +LDFLAGS-tst-tlsopt-powerpc += -Wl,--no-tls-optimize +tests += tst-tlsopt-powerpc endif ifeq ($(subdir),setjmp) diff --git a/sysdeps/powerpc/Versions b/sysdeps/powerpc/Versions index 47c2c3e..2aebf7c 100644 --- a/sysdeps/powerpc/Versions +++ b/sysdeps/powerpc/Versions @@ -15,3 +15,9 @@ libc { __vmx__libc_longjmp; __vmx__libc_siglongjmp; } } + +ld { + GLIBC_2.22 { + __tls_get_addr_opt; + } +} diff --git a/sysdeps/powerpc/dl-tls.c b/sysdeps/powerpc/dl-tls.c new file mode 100644 index 0000000..a18b23e --- /dev/null +++ b/sysdeps/powerpc/dl-tls.c @@ -0,0 +1,24 @@ +/* Thread-local storage handling in the ELF dynamic linker. PowerPC version. + Copyright (C) 2009-2015 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include "elf/dl-tls.c" + +#ifdef SHARED +strong_alias(__tls_get_addr, __tls_get_addr_opt) +#endif diff --git a/sysdeps/powerpc/powerpc32/dl-machine.h b/sysdeps/powerpc/powerpc32/dl-machine.h index c94674f..8b0c067 100644 --- a/sysdeps/powerpc/powerpc32/dl-machine.h +++ b/sysdeps/powerpc/powerpc32/dl-machine.h @@ -333,6 +333,32 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, # endif case R_PPC_DTPMOD32: + if (map->l_info[DT_PPC(OPT)] + && (map->l_info[DT_PPC(OPT)]->d_un.d_val & PPC_OPT_TLS)) + { + if (!NOT_BOOTSTRAP) + { + reloc_addr[0] = 0; + reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET + + TLS_DTV_OFFSET); + break; + } + else if (sym_map != NULL) + { +# ifndef SHARED + CHECK_STATIC_TLS (map, sym_map); +# else + if (TRY_STATIC_TLS (map, sym_map)) +# endif + { + reloc_addr[0] = 0; + /* Set up for local dynamic. */ + reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET + + TLS_DTV_OFFSET); + break; + } + } + } if (!NOT_BOOTSTRAP) /* During startup the dynamic linker is always index 1. */ *reloc_addr = 1; @@ -342,6 +368,28 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, *reloc_addr = sym_map->l_tls_modid; break; case R_PPC_DTPREL32: + if (map->l_info[DT_PPC(OPT)] + && (map->l_info[DT_PPC(OPT)]->d_un.d_val & PPC_OPT_TLS)) + { + if (!NOT_BOOTSTRAP) + { + *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc); + break; + } + else if (sym_map != NULL) + { + /* This reloc is always preceded by R_PPC_DTPMOD32. */ +# ifndef SHARED + assert (HAVE_STATIC_TLS (map, sym_map)); +# else + if (HAVE_STATIC_TLS (map, sym_map)) +# endif + { + *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc); + break; + } + } + } /* During relocation all TLS symbols are defined and used. Therefore the offset is already correct. */ if (NOT_BOOTSTRAP && sym_map != NULL) diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h index 5cb0087..55ac736 100644 --- a/sysdeps/powerpc/powerpc64/dl-machine.h +++ b/sysdeps/powerpc/powerpc64/dl-machine.h @@ -701,6 +701,32 @@ elf_machine_rela (struct link_map *map, return; case R_PPC64_DTPMOD64: + if (map->l_info[DT_PPC64(OPT)] + && (map->l_info[DT_PPC64(OPT)]->d_un.d_val & PPC64_OPT_TLS)) + { +#ifdef RTLD_BOOTSTRAP + reloc_addr[0] = 0; + reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET + + TLS_DTV_OFFSET); + return; +#else + if (sym_map != NULL) + { +# ifndef SHARED + CHECK_STATIC_TLS (map, sym_map); +# else + if (TRY_STATIC_TLS (map, sym_map)) +# endif + { + reloc_addr[0] = 0; + /* Set up for local dynamic. */ + reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET + + TLS_DTV_OFFSET); + return; + } + } +#endif + } #ifdef RTLD_BOOTSTRAP /* During startup the dynamic linker is always index 1. */ *reloc_addr = 1; @@ -713,6 +739,28 @@ elf_machine_rela (struct link_map *map, return; case R_PPC64_DTPREL64: + if (map->l_info[DT_PPC64(OPT)] + && (map->l_info[DT_PPC64(OPT)]->d_un.d_val & PPC64_OPT_TLS)) + { +#ifdef RTLD_BOOTSTRAP + *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc); + return; +#else + if (sym_map != NULL) + { + /* This reloc is always preceded by R_PPC64_DTPMOD64. */ +# ifndef SHARED + assert (HAVE_STATIC_TLS (map, sym_map)); +# else + if (HAVE_STATIC_TLS (map, sym_map)) +# endif + { + *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc); + return; + } + } +#endif + } /* During relocation all TLS symbols are defined and used. Therefore the offset is already correct. */ #ifndef RTLD_BOOTSTRAP diff --git a/sysdeps/powerpc/tst-tlsopt-powerpc.c b/sysdeps/powerpc/tst-tlsopt-powerpc.c new file mode 100644 index 0000000..c9a14cb --- /dev/null +++ b/sysdeps/powerpc/tst-tlsopt-powerpc.c @@ -0,0 +1,52 @@ +/* glibc test for __tls_get_addr optimization. */ +#include + +#include "../../elf/tls-macros.h" +#include "dl-tls.h" + +/* common 'int' variable in TLS. */ +COMMON_INT_DEF(foo); + + +#define TEST_FUNCTION do_test () +static int +do_test (void) +{ + int result = 0; + + /* Get variable using general dynamic model. */ + int *ap = TLS_GD (foo); + if (*ap != 0) + { + printf ("foo = %d\n", *ap); + result = 1; + } + + tls_index *tls_arg; +#ifdef __powerpc64__ + register unsigned long thread_pointer __asm__ ("r13"); + asm ("addi %0,2,foo@got@tlsgd" : "=r" (tls_arg)); +#else + register unsigned long thread_pointer __asm__ ("r2"); + asm ("bcl 20,31,1f\n1:\t" + "mflr %0\n\t" + "addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n\t" + "addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n\t" + "addi %0,%0,foo@got@tlsgd" : "=b" (tls_arg)); +#endif + + if (tls_arg->ti_module != 0) + { + printf ("tls_index not optimized, binutils too old?\n"); + result = 1; + } + else if (tls_arg->ti_offset + thread_pointer != (unsigned long) ap) + { + printf ("tls_index->ti_offset wrong value\n"); + result = 1; + } + + return result; +} + +#include "../../test-skeleton.c" diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile index fcf3bb5..c89ed9e 100644 --- a/sysdeps/unix/sysv/linux/powerpc/Makefile +++ b/sysdeps/unix/sysv/linux/powerpc/Makefile @@ -20,6 +20,8 @@ ifeq ($(build-shared),yes) # This is needed for DSO loading from static binaries. sysdep-dl-routines += dl-static endif +# Otherwise tst-tls-dlinfo fails due to tst-tlsmod2.so using static tls. +LDFLAGS-tst-tlsmod2.so += -Wl,--no-tls-get-addr-optimize endif ifeq ($(subdir),misc) diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist index d71611f..7d24961 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist @@ -10,6 +10,9 @@ GLIBC_2.1 GLIBC_2.1 A __libc_stack_end D 0x4 _dl_mcount F +GLIBC_2.22 + GLIBC_2.22 A + __tls_get_addr_opt F GLIBC_2.3 GLIBC_2.3 A __tls_get_addr F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist index 3530fb4..3174e21 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist @@ -9,3 +9,6 @@ GLIBC_2.17 free F malloc F realloc F +GLIBC_2.22 + GLIBC_2.22 A + __tls_get_addr_opt F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist index 899360e..d8c4201 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist @@ -1,3 +1,6 @@ +GLIBC_2.22 + GLIBC_2.22 A + __tls_get_addr_opt F GLIBC_2.3 GLIBC_2.3 A __libc_memalign F -- cgit v1.1