aarch64: Add hwcap string routines

Add support for routines in dl-procinfo.h to show string versions of
HWCAP entries when a program is invoked with the LD_SHOW_AUXV
environment variable set and also to aid in path resolution for
ldconfig.

	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
	(_dl_aarch64_cap_flags): New array.
	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
	(_dl_hwcap_string, _dl_string_hwcap, _dl_procinfo): Implement
	functions.

ChangeLog

@@ -1,5 +1,11 @@
 2017-06-07  Siddhesh Poyarekar  <siddhesh@sourceware.org>
 
+	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
+	(_dl_aarch64_cap_flags): New array.
+	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
+	(_dl_hwcap_string, _dl_string_hwcap, _dl_procinfo): Implement
+	functions.
+
 	* elf/dl-hwcaps.h [HAVE_TUNABLES]: Always read hwcap_mask.
 	* sysdeps/sparc/sparc32/dl-machine.h [HAVE_TUNABLES]:
 	Likewise.

sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c

@@ -56,5 +56,20 @@ PROCINFO_CLASS struct cpu_features _dl_aarch64_cpu_features
 # endif
 #endif
 
+#if !defined PROCINFO_DECL && defined SHARED
+  ._dl_aarch64_cap_flags
+#else
+PROCINFO_CLASS const char _dl_aarch64_cap_flags[13][10]
+#endif
+#ifndef PROCINFO_DECL
+= { "fp", "asimd", "evtstrm", "aes", "pmull", "sha1", "sha2", "crc32",
+    "atomics", "fphp", "asimdhp", "cpuid", "asimdrdm"}
+#endif
+#if !defined SHARED || defined PROCINFO_DECL
+;
+#else
+,
+#endif
+
 #undef PROCINFO_DECL
 #undef PROCINFO_CLASS

sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h

@@ -20,25 +20,67 @@
 #define _DL_PROCINFO_H	1
 
 #include <sys/auxv.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <sysdep.h>
 
 /* We cannot provide a general printing function.  */
-#define _dl_procinfo(type, word) -1
+static inline int
+__attribute__ ((unused))
+_dl_procinfo (unsigned int type, unsigned long int word)
+{
+  /* This table should match the information from arch/arm64/kernel/cpuinfo.c
+     in the kernel sources.  */
+  int i;
 
-/* There are no hardware capabilities defined.  */
-#define _dl_hwcap_string(idx) ""
+  /* Fallback to unknown output mechanism.  */
+  if (type == AT_HWCAP2)
+    return -1;
+
+  _dl_printf ("AT_HWCAP:   ");
+
+  for (i = 0; i < 32; ++i)
+    if (word & (1 << i))
+      _dl_printf (" %s", GLRO(dl_aarch64_cap_flags)[i]);
+
+  _dl_printf ("\n");
+
+  return 0;
+}
+
+static inline const char *
+__attribute__ ((unused))
+_dl_hwcap_string (int idx)
+{
+  return GLRO(dl_aarch64_cap_flags)[idx];
+};
+
+
+/* 13 HWCAP bits set.  */
+#define _DL_HWCAP_COUNT 13
+
+/* Low 13 bits are allocated in HWCAP.  */
+#define _DL_HWCAP_LAST 12
 
 /* HWCAP_CPUID should be available by default to influence IFUNC as well as
    library search.  */
 #define HWCAP_IMPORTANT HWCAP_CPUID
 
+static inline int
+__attribute__ ((unused))
+_dl_string_hwcap (const char *str)
+{
+  for (int i = 0; i < _DL_HWCAP_COUNT; i++)
+    {
+      if (strcmp (str, _dl_hwcap_string (i)) == 0)
+	return i;
+    }
+  return -1;
+};
+
 /* There're no platforms to filter out.  */
 #define _DL_HWCAP_PLATFORM 0
 
-/* We don't have any hardware capabilities.  */
-#define _DL_HWCAP_COUNT 0
-
-#define _dl_string_hwcap(str) (-1)
-
 #define _dl_string_platform(str) (-1)
 
 #endif /* dl-procinfo.h */