powerpc: Add hwcap/hwcap2/platform data to TCB.

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.

1 files changed, 76 insertions, 0 deletions

diff --git a/sysdeps/powerpc/hwcapinfo.c b/sysdeps/powerpc/hwcapinfo.c
new file mode 100644
index 0000000000..a115ffccd9
--- /dev/null
+++ b/sysdeps/powerpc/hwcapinfo.c
@@ -0,0 +1,76 @@
+/* powerpc HWCAP/HWCAP2 and AT_PLATFORM data pre-processing.
+   Copyright (C) 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <unistd.h>
+#include <shlib-compat.h>
+#include <dl-procinfo.h>
+
+uint64_t __tcb_hwcap __attribute__ ((visibility ("hidden")));
+uint32_t __tcb_platform __attribute__ ((visibility ("hidden")));
+
+/* This function parses the HWCAP/HWCAP2 fields, adding the previous supported
+   ISA bits, as well as converting the AT_PLATFORM string to a number.  This
+   data is stored in two global variables that can be used later by the
+   powerpc-specific code to store it into the TCB.  */
+void
+__tcb_parse_hwcap_and_convert_at_platform (void)
+{
+
+  uint64_t h1, h2;
+
+  /* Read AT_PLATFORM string from auxv and convert it to a number.  */
+  __tcb_platform = _dl_string_platform (GLRO (dl_platform));
+
+  /* Read HWCAP and HWCAP2 from auxv.  */
+  h1 = GLRO (dl_hwcap);
+  h2 = GLRO (dl_hwcap2);
+
+  /* hwcap contains only the latest supported ISA, the code checks which is
+     and fills the previous supported ones.  */
+
+  if (h2 & PPC_FEATURE2_ARCH_2_07)
+    h1 |= PPC_FEATURE_ARCH_2_06
+       | PPC_FEATURE_ARCH_2_05
+       | PPC_FEATURE_POWER5_PLUS
+       | PPC_FEATURE_POWER5
+       | PPC_FEATURE_POWER4;
+  else if (h1 & PPC_FEATURE_ARCH_2_06)
+    h1 |= PPC_FEATURE_ARCH_2_05
+       | PPC_FEATURE_POWER5_PLUS
+       | PPC_FEATURE_POWER5
+       | PPC_FEATURE_POWER4;
+  else if (h1 & PPC_FEATURE_ARCH_2_05)
+    h1 |= PPC_FEATURE_POWER5_PLUS
+       | PPC_FEATURE_POWER5
+       | PPC_FEATURE_POWER4;
+  else if (h1 & PPC_FEATURE_POWER5_PLUS)
+    h1 |= PPC_FEATURE_POWER5
+       | PPC_FEATURE_POWER4;
+  else if (h1 & PPC_FEATURE_POWER5)
+    h1 |= PPC_FEATURE_POWER4;
+
+  /* Consolidate both HWCAP and HWCAP2 into a single doubleword so that
+     we can read both in a single load later.  */
+  __tcb_hwcap = h2;
+  __tcb_hwcap = (h1 << 32) | __tcb_hwcap;
+
+}
+#if IS_IN (rtld)
+versioned_symbol (ld, __tcb_parse_hwcap_and_convert_at_platform, \
+		  __parse_hwcap_and_convert_at_platform, GLIBC_2_23);
+#endif