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| author | Alan Modra <amodra@gmail.com> | 2015-03-25 15:53:47 +1030 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2015-03-25 15:53:47 +1030 |
| commit | afcd9480feca651eef436d8438b783dde5c3bbb2 (patch) | |
| tree | 97bd1be08268c51e674154d3bf98af3a2256c6f8 /sysdeps/unix | |
| parent | da9f3334106ee0f98c499c54bdfe3c4fcbb348f4 (diff) | |
| download | glibc-afcd9480feca651eef436d8438b783dde5c3bbb2.zip glibc-afcd9480feca651eef436d8438b783dde5c3bbb2.tar.gz glibc-afcd9480feca651eef436d8438b783dde5c3bbb2.tar.bz2 | |
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.
Diffstat (limited to 'sysdeps/unix')
4 files changed, 11 insertions, 0 deletions
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 |