[PATCH] Consolidate code to get hwcap_mask into GET_HWCAP_MASK macro

[PATCH] Consolidate code to get hwcap_mask into GET_HWCAP_MASK macro

[Siddhesh Poyarekar]

Consolidate the preprocessor conditionals to get the HWCAP_MASK with
or without tunables into a single macro defined in a new header file
dl-hwcaps.h.

	* elf/dl-hwcaps.h: New file.
	* elf/dl-hwcaps.c: Include dl-hwcaps.h.
	(_dl_important_hwcaps) Use new GET_HWCAP_MASK macro.
	* sysdeps/sparc/sparc32/dl-machine.h: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/cpu-features.c: Likewise.
---
 elf/dl-hwcaps.c                                |  7 ++-----
 elf/dl-hwcaps.h                                | 25 +++++++++++++++++++++++++
 sysdeps/sparc/sparc32/dl-machine.h             |  9 ++-------
 sysdeps/unix/sysv/linux/aarch64/cpu-features.c |  9 ++-------
 4 files changed, 31 insertions(+), 19 deletions(-)
 create mode 100644 elf/dl-hwcaps.h

diff --git a/elf/dl-hwcaps.c b/elf/dl-hwcaps.c
index 2b9f7f1..a37a3ff 100644
--- a/elf/dl-hwcaps.c
+++ b/elf/dl-hwcaps.c
@@ -25,6 +25,7 @@
 
 #include <dl-procinfo.h>
 #include <dl-tunables.h>
+#include <dl-hwcaps.h>
 
 #ifdef _DL_FIRST_PLATFORM
 # define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT)
@@ -38,11 +39,7 @@ internal_function
 _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
 		      size_t *max_capstrlen)
 {
-#if HAVE_TUNABLES
-  uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
-#else
-  uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
-#endif
+  uint64_t hwcap_mask = GET_HWCAP_MASK();
   /* Determine how many important bits are set.  */
   uint64_t masked = GLRO(dl_hwcap) & hwcap_mask;
   size_t cnt = platform != NULL;
diff --git a/elf/dl-hwcaps.h b/elf/dl-hwcaps.h
new file mode 100644
index 0000000..0fd05ac
--- /dev/null
+++ b/elf/dl-hwcaps.h
@@ -0,0 +1,25 @@
+/* Hardware capability support for run-time dynamic loader.
+   Copyright (C) 2017 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 <elf/dl-tunables.h>
+
+#if HAVE_TUNABLES
+# define GET_HWCAP_MASK() TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t)
+#else
+# define GET_HWCAP_MASK() GLRO(dl_hwcap_mask)
+#endif
diff --git a/sysdeps/sparc/sparc32/dl-machine.h b/sysdeps/sparc/sparc32/dl-machine.h
index f5e8078..620cd2e 100644
--- a/sysdeps/sparc/sparc32/dl-machine.h
+++ b/sysdeps/sparc/sparc32/dl-machine.h
@@ -27,7 +27,7 @@
 #include <sysdep.h>
 #include <tls.h>
 #include <dl-plt.h>
-#include <elf/dl-tunables.h>
+#include <elf/dl-hwcaps.h>
 
 /* Return nonzero iff ELF header is compatible with the running host.  */
 static inline int
@@ -39,12 +39,7 @@ elf_machine_matches_host (const Elf32_Ehdr *ehdr)
     {
       /* XXX The following is wrong!  Dave Miller rejected to implement it
 	 correctly.  If this causes problems shoot *him*!  */
-#ifdef SHARED
-# if HAVE_TUNABLES
-      uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
-# else
-      uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
-# endif
+      uint64_t hwcap_mask = GET_HWCAP_MASK();
       return GLRO(dl_hwcap) & hwcap_mask & HWCAP_SPARC_V9;
 #else
       return GLRO(dl_hwcap) & HWCAP_SPARC_V9;
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
index 0478fcc..ef6eecd 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -18,17 +18,12 @@
 
 #include <cpu-features.h>
 #include <sys/auxv.h>
-#include <elf/dl-tunables.h>
+#include <elf/dl-hwcaps.h>
 
 static inline void
 init_cpu_features (struct cpu_features *cpu_features)
 {
-#if HAVE_TUNABLES
-  uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
-#else
-  uint64_t hwcap_mask = GLRO (dl_hwcap_mask);
-#endif
-
+  uint64_t hwcap_mask = GET_HWCAP_MASK();
   uint64_t hwcap = GLRO (dl_hwcap) & hwcap_mask;
 
   if (hwcap & HWCAP_CPUID)
-- 
2.7.4

Re: [PATCH] Consolidate code to get hwcap_mask into GET_HWCAP_MASK macro

[Siddhesh Poyarekar]

On Friday 19 May 2017 02:12 AM, Siddhesh Poyarekar wrote:
>        /* XXX The following is wrong!  Dave Miller rejected to implement it
>  	 correctly.  If this causes problems shoot *him*!  */
> -#ifdef SHARED
> -# if HAVE_TUNABLES
> -      uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
> -# else
> -      uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
> -# endif
> +      uint64_t hwcap_mask = GET_HWCAP_MASK();

Ugh, this is so wrong, good thing I noticed before I would have got shot :)

I'll fix this up.

Siddhesh