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.

ChangeLog

@@ -1,3 +1,48 @@
+2015-12-03  Carlos Eduardo Seo  <cseo@linux.vnet.ibm.com>
+
+	* 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.
+
 2015-12-02  Ludovic Courtès  <ludo@gnu.org>
 
 	* configure.ac: Use 'pwd -P' instead of '/bin/pwd'.

sysdeps/powerpc/Makefile

@@ -4,10 +4,10 @@ endif
 
 ifeq ($(subdir),elf)
 # extra shared linker files to link into dl-allobjs.so and libc
-sysdep-dl-routines += dl-machine
-sysdep_routines += dl-machine
+sysdep-dl-routines += dl-machine hwcapinfo
+sysdep_routines += dl-machine hwcapinfo
 # extra shared linker files to link only into dl-allobjs.so
-sysdep-rtld-routines += dl-machine
+sysdep-rtld-routines += dl-machine hwcapinfo
 # Don't optimize GD tls sequence to LE.
 LDFLAGS-tst-tlsopt-powerpc += -Wl,--no-tls-optimize
 tests += tst-tlsopt-powerpc
@@ -26,6 +26,11 @@ gen-as-const-headers += rtld-global-offsets.sym
 gen-as-const-headers += locale-defines.sym
 endif
 
+ifeq ($(subdir),nptl)
+tests += test-get_hwcap test-get_hwcap-static
+tests-static += test-get_hwcap-static
+endif
+
 ifeq ($(subdir),misc)
 sysdep_headers += sys/platform/ppc.h
 tests += test-gettimebase

sysdeps/powerpc/Versions

@@ -20,4 +20,9 @@ ld {
   GLIBC_2.22 {
     __tls_get_addr_opt;
   }
+  GLIBC_2.23 {
+    # Symbol used to version control when the ABI started to specify that HWCAP
+    # and AT_PLATFORM data should be stored into the TCB.
+    __parse_hwcap_and_convert_at_platform;
+  }
 }

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

sysdeps/powerpc/hwcapinfo.h

@@ -0,0 +1,29 @@
+/* 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 <stdint.h>
+
+#ifndef HWCAPINFO_H
+# define HWCAPINFO_H
+
+extern uint64_t __tcb_hwcap  attribute_hidden;
+extern uint32_t __tcb_platform attribute_hidden;
+
+extern void __tcb_parse_hwcap_and_convert_at_platform (void);
+
+#endif

sysdeps/powerpc/nptl/tcb-offsets.sym

@@ -19,7 +19,15 @@ POINTER_GUARD			(offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (
 TAR_SAVE			(offsetof (tcbhead_t, tar_save) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 DSO_SLOT1			(offsetof (tcbhead_t, dso_slot1) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 DSO_SLOT2			(offsetof (tcbhead_t, dso_slot2) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
+#ifdef __powerpc64__
+TCB_AT_PLATFORM			(offsetof (tcbhead_t, at_platform) - TLS_TCB_OFFSET - sizeof(tcbhead_t))
+#endif
 TM_CAPABLE			(offsetof (tcbhead_t, tm_capable) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
+#ifndef __powerpc64__
+TCB_AT_PLATFORM			(offsetof (tcbhead_t, at_platform) - TLS_TCB_OFFSET - sizeof(tcbhead_t))
+PADDING				(offsetof (tcbhead_t, padding) - TLS_TCB_OFFSET - sizeof(tcbhead_t))
+#endif
+TCB_HWCAP			(offsetof (tcbhead_t, hwcap) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 #ifndef __ASSUME_PRIVATE_FUTEX
 PRIVATE_FUTEX_OFFSET		thread_offsetof (header.private_futex)
 #endif

sysdeps/powerpc/nptl/tls.h

@@ -44,6 +44,8 @@ typedef union dtv
 
 #ifndef __ASSEMBLER__
 
+# include <hwcapinfo.h>
+
 /* Get system call information.  */
 # include <sysdep.h>
 
@@ -63,8 +65,24 @@ typedef union dtv
    are private.  */
 typedef struct
 {
+  /* Reservation for HWCAP data.  To be accessed by GCC in
+     __builtin_cpu_supports(), so it is a part of public ABI.  */
+  uint64_t hwcap;
+  /* Reservation for AT_PLATFORM data.  To be accessed by GCC in
+     __builtin_cpu_is(), so it is a part of public ABI.  Since there
+     are different ABIs for 32 and 64 bit, we put this field in a
+     previously empty padding space for powerpc64.  */
+#ifndef __powerpc64__
+  /* Padding to maintain alignment.  */
+  uint32_t padding;
+  uint32_t at_platform;
+#endif
   /* Indicate if HTM capable (ISA 2.07).  */
-  int tm_capable;
+  uint32_t tm_capable;
+  /* Reservation for AT_PLATFORM data - powerpc64.  */
+#ifdef __powerpc64__
+  uint32_t at_platform;
+#endif
   /* Reservation for Dynamic System Optimizer ABI.  */
   uintptr_t dso_slot2;
   uintptr_t dso_slot1;
@@ -134,15 +152,21 @@ register void *__thread_register __asm__ ("r13");
 # define TLS_INIT_TP(tcbp) \
   ({ 									      \
     __thread_register = (void *) (tcbp) + TLS_TCB_OFFSET;		      \
-    THREAD_SET_TM_CAPABLE (GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_HTM ? 1 : 0);  \
+    THREAD_SET_TM_CAPABLE (__tcb_hwcap & PPC_FEATURE2_HAS_HTM ? 1 : 0);	      \
+    THREAD_SET_HWCAP (__tcb_hwcap);					      \
+    THREAD_SET_AT_PLATFORM (__tcb_platform);				      \
     NULL;								      \
   })
 
 /* Value passed to 'clone' for initialization of the thread register.  */
 # define TLS_DEFINE_INIT_TP(tp, pd) \
     void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE;	      \
     (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].tm_capable) =	      \
-      THREAD_GET_TM_CAPABLE ();
+      THREAD_GET_TM_CAPABLE ();						      \
+    (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].hwcap) =	      \
+      THREAD_GET_HWCAP ();						      \
+    (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].at_platform) =	      \
+      THREAD_GET_AT_PLATFORM ();
 
 /* Return the address of the dtv for the current thread.  */
 # define THREAD_DTV() \
@@ -203,6 +227,20 @@ register void *__thread_register __asm__ ("r13");
 # define THREAD_SET_TM_CAPABLE(value) \
     (THREAD_GET_TM_CAPABLE () = (value))
 
+/* hwcap field in TCB head.  */
+# define THREAD_GET_HWCAP() \
+    (((tcbhead_t *) ((char *) __thread_register				      \
+		     - TLS_TCB_OFFSET))[-1].hwcap)
+# define THREAD_SET_HWCAP(value) \
+    (THREAD_GET_HWCAP () = (value))
+
+/* at_platform field in TCB head.  */
+# define THREAD_GET_AT_PLATFORM() \
+    (((tcbhead_t *) ((char *) __thread_register				      \
+		     - TLS_TCB_OFFSET))[-1].at_platform)
+# define THREAD_SET_AT_PLATFORM(value) \
+    (THREAD_GET_AT_PLATFORM () = (value))
+
 /* l_tls_offset == 0 is perfectly valid on PPC, so we have to use some
    different value to mean unset l_tls_offset.  */
 # define NO_TLS_OFFSET		-1

sysdeps/powerpc/powerpc32/dl-machine.h

@@ -24,6 +24,7 @@
 #include <assert.h>
 #include <dl-tls.h>
 #include <dl-irel.h>
+#include <hwcapinfo.h>
 
 /* Translate a processor specific dynamic tag to the index
    in l_info array.  */
@@ -150,6 +151,19 @@ __elf_preferred_address(struct link_map *loader, size_t maplength,
 #define ELF_MACHINE_NO_REL 1
 #define ELF_MACHINE_NO_RELA 0
 
+/* We define an initialization function to initialize HWCAP/HWCAP2 and
+   platform data so it can be copied into the TCB later.  This is called
+   very early in _dl_sysdep_start for dynamically linked binaries.  */
+#ifdef SHARED
+# define DL_PLATFORM_INIT dl_platform_init ()
+
+static inline void __attribute__ ((unused))
+dl_platform_init (void)
+{
+  __tcb_parse_hwcap_and_convert_at_platform ();
+}
+#endif
+
 /* Set up the loaded object described by MAP so its unrelocated PLT
    entries will jump to the on-demand fixup code in dl-runtime.c.
    Also install a small trampoline to be used by entries that have

sysdeps/powerpc/powerpc64/dl-machine.h

@@ -26,6 +26,7 @@
 #include <sys/param.h>
 #include <dl-tls.h>
 #include <sysdep.h>
+#include <hwcapinfo.h>
 
 /* Translate a processor specific dynamic tag to the index
    in l_info array.  */
@@ -296,6 +297,19 @@ BODY_PREFIX "_dl_start_user:\n"						\
 #define ELF_MACHINE_NO_REL 1
 #define ELF_MACHINE_NO_RELA 0
 
+/* We define an initialization function to initialize HWCAP/HWCAP2 and
+   platform data so it can be copied into the TCB later.  This is called
+   very early in _dl_sysdep_start for dynamically linked binaries.  */
+#ifdef SHARED
+# define DL_PLATFORM_INIT dl_platform_init ()
+
+static inline void __attribute__ ((unused))
+dl_platform_init (void)
+{
+  __tcb_parse_hwcap_and_convert_at_platform ();
+}
+#endif
+
 /* Stuff for the PLT.  */
 #if _CALL_ELF != 2
 #define PLT_INITIAL_ENTRY_WORDS 3

sysdeps/powerpc/test-get_hwcap-static.c

@@ -0,0 +1,23 @@
+/* Check __ppc_get_hwcap() and __ppc_get_at_plaftorm() functionality.
+   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/>.  */
+
+/* Tests if the hwcap, hwcap2 and platform data are stored in the TCB.  */
+
+#define STATIC_TST_HWCAP 1
+
+#include "test-get_hwcap.c"