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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 /NEWS | |
| 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 'NEWS')
| -rw-r--r-- | NEWS | 4 |
1 files changed, 4 insertions, 0 deletions
@@ -17,6 +17,10 @@ Version 2.22 18039, 18042, 18043, 18046, 18047, 18068, 18080, 18093, 18100, 18104, 18110, 18111, 18128, 18138. +* A powerpc and powerpc64 optimization for TLS, similar to TLS descriptors + for LD and GD on x86 and x86-64, has been implemented. You will need + binutils-2.24 or later to enable this optimization. + * Character encoding and ctype tables were updated to Unicode 7.0.0, using new generator scripts contributed by Pravin Satpute and Mike FABIAN (Red Hat). These updates cause user visible changes, such as the fix for bug |