Commit 67385a01d2 added a new feature for
powerpc, where we store HWCAP/Platform bits in the TCB. In the dynamic
linking case, we use the versioned symbol
'__parse_hwcap_and_convert_at_platform' to verify if this feature is
available. However, the same symbol was not exported to libc.a, making
it not possible for GCC to check for it prior to link time.
This patch adds a new feature for powerpc. In order to get faster access to
the HWCAP/HWCAP2 bits and platform number (i.e. for implementing
__builtin_cpu_is () / __builtin_cpu_supports () in GCC) without the overhead of
reading from the auxiliary vector, we now reserve space for them in the TCB.
This is an ABI change for GLIBC 2.23.
A new versioned symbol '__parse_hwcap_and_convert_at_platform' is available to
get the data from the auxiliary vector and parse it, and store it for later use
in the TLS initialization code. This function is called very early
(in _dl_sysdep_start () via DL_PLATFORM_INFO for the dynamic linking case, and
in __libc_start_main () for the static linking case) to make sure the data is
available at the time of TLS initialization.
* sysdeps/powerpc/Makefile (sysdep-dl-routines): Add hwcapinfo.
(sysdep_routines): Likewise.
(sysdep-rtld-routines): Likewise.
[$(subdir) = nptl](tests): Add test-get_hwcap and test-get_hwcap-static
[$(subdir) = nptl](tests-static): test-get_hwcap-static
* sysdeps/powerpc/Versions: Added new
__parse_hwcap_and_convert_at_platform symbol to GLIBC-2.23.
* sysdeps/powerpc/hwcapinfo.c: New file.
(__tcb_parse_hwcap_and_convert_at_platform): New function to initialize
and parse hwcap, hwcap2 and platform number information.
* sysdeps/powerpc/hwcapinfo.h: New file. Creates global variables
to store HWCAP+HWCAP2 and platform number.
* sysdeps/powerpc/nptl/tcb-offsets.sym: Added new offsets
for HWCAP+HWCAP2 and platform number in the TCB.
* sysdeps/powerpc/nptl/tls.h: New functionality. Stores
the HWCAP, HWCAP2 and platform number in the TCB.
(dtv): Added new fields for HWCAP+HWCAP2 and platform number.
(TLS_INIT_TP): Included calls to add the hwcap and
at_platform values in the TCB in TP initialization.
(TLS_DEFINE_INIT_TP): Likewise.
(THREAD_GET_HWCAP): New macro.
(THREAD_SET_HWCAP): Likewise.
(THREAD_GET_AT_PLATFORM): Likewise.
(THREAD_SET_AT_PLATFORM): Likewise.
* sysdeps/powerpc/powerpc32/dl-machine.h:
(dl_platform_init): New function that calls
__parse_hwcap_and_convert_at_platform for the dymanic linking case for
powerpc32.
* sysdeps/powerpc/powerpc64/dl-machine.h: Likewise, for powerpc64.
* sysdeps/powerpc/test-get_hwcap-static.c: New file. Testcase for
this functionality, static linking case.
* sysdeps/powerpc/test-get_hwcap.c: New file. Likewise, dynamic
linking case.
* sysdeps/unix/sysv/linux/powerpc/libc-start.c: Added call to
__parse_hwcap_and_convert_at_platform for the static linking case.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist:
Included the new __parse_hwcap_and_convert_at_platform symbol in the
ABI list for GLIBC 2.23.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist:
Likewise.
