S/390: Get cache information via sysconf

This patch adds support to query cache information on s390
via sysconf() function - e.g. with _SC_LEVEL1_ICACHE_SIZE.
The attributes size, linesize and assoc can be queried
for cache level 1 - 4 via "extract cpu attribute" instruction,
which was first available with z10.

* NEWS: Mention sysconf() cache information support for s390.
* sysdeps/unix/sysv/linux/s390/sysconf.c: New File.

3 files changed, 238 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 2c01eac57f..f5aeedeea6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-04-24  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* NEWS: Mention sysconf() cache information support for s390.
+	* sysdeps/unix/sysv/linux/s390/sysconf.c: New File.
+
 2015-04-22  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	* math/k_casinh.c (__kernel_casinh): Use __copysign.
diff --git a/NEWS b/NEWS
index ccc4d135b9..a628b5aef9 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,9 @@ Version 2.22
   18080, 18093, 18100, 18104, 18110, 18111, 18128, 18138, 18185, 18197,
   18206, 18210, 18211, 18247, 18287.
 
+* Cache information can be queried via sysconf() function on s390 e.g. with
+  _SC_LEVEL1_ICACHE_SIZE as argument.
+
 * A buffer overflow in gethostbyname_r and related functions performing DNS
   requests has been fixed.  If the NSS functions were called with a
   misaligned buffer, the buffer length change due to pointer alignment was
diff --git a/sysdeps/unix/sysv/linux/s390/sysconf.c b/sysdeps/unix/sysv/linux/s390/sysconf.c
new file mode 100644
index 0000000000..7d61c507e0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/s390/sysconf.c
@@ -0,0 +1,230 @@
+/* Get system parameters, e.g. cache information.  S390/S390x version.
+   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 <dl-procinfo.h>
+
+static long int linux_sysconf (int name);
+
+/* Possible arguments for get_cache_info.
+   The values are reflecting the level/attribute/type indications
+   of ecag-instruction (extract cpu attribue).  */
+#define CACHE_LEVEL_MAX        8
+#define CACHE_ATTR_LINESIZE    1
+#define CACHE_ATTR_SIZE        2
+#define CACHE_ATTR_ASSOC       3
+#define CACHE_TYPE_DATA        0
+#define CACHE_TYPE_INSTRUCTION 1
+
+static long
+get_cache_info (int level, int attr, int type)
+{
+  unsigned long int val;
+  unsigned int cmd;
+  unsigned long int arg;
+
+  /* Check arguments.  */
+  if (level < 1 || level > CACHE_LEVEL_MAX
+      || attr < CACHE_ATTR_LINESIZE || attr > CACHE_ATTR_ASSOC
+      || type < CACHE_TYPE_DATA || type > CACHE_TYPE_INSTRUCTION)
+    return 0L;
+
+  /* Check if ecag-instruction is available.
+     ecag - extract CPU attribute (only in zarch; arch >= z10; in as 2.24)  */
+  if (!(GLRO (dl_hwcap) & HWCAP_S390_STFLE)
+#if !defined __s390x__
+      || !(GLRO (dl_hwcap) & HWCAP_S390_ZARCH)
+      || !(GLRO (dl_hwcap) & HWCAP_S390_HIGH_GPRS)
+#endif /* !__s390x__ */
+      )
+    {
+      /* stfle (or zarch, high-gprs on s390-32) is not available.
+	 We are on an old machine. Return 256byte for LINESIZE for L1 d/i-cache,
+         otherwise 0.  */
+      if (level == 1 && attr == CACHE_ATTR_LINESIZE)
+	return 256L;
+      else
+	return 0L;
+    }
+
+  /* Store facility list and check for z10.
+     (see ifunc-resolver for details)  */
+  register unsigned long reg0 asm("0") = 0;
+#ifdef __s390x__
+  unsigned long stfle_bits;
+# define STFLE_Z10_MASK (1UL << (63 - 34))
+#else
+  unsigned long long stfle_bits;
+# define STFLE_Z10_MASK (1ULL << (63 - 34))
+#endif /* !__s390x__ */
+  asm volatile(".machine push"        "\n\t"
+	       ".machinemode \"zarch_nohighgprs\"\n\t"
+	       ".machine \"z9-109\""  "\n\t"
+	       "stfle %0"             "\n\t"
+	       ".machine pop"         "\n"
+	       : "=QS" (stfle_bits), "+d" (reg0)
+	       : : "cc");
+
+  if (!(stfle_bits & STFLE_Z10_MASK))
+    {
+      /* We are at least on a z9 machine.
+	 Return 256byte for LINESIZE for L1 d/i-cache,
+         otherwise 0.  */
+      if (level == 1 && attr == CACHE_ATTR_LINESIZE)
+	return 256L;
+      else
+	return 0L;
+    }
+
+  /* Check cache topology, if cache is available at this level.  */
+  arg = (CACHE_LEVEL_MAX - level) * 8;
+  asm volatile (".machine push\n\t"
+		".machine \"z10\"\n\t"
+		".machinemode \"zarch_nohighgprs\"\n\t"
+		"ecag %0,%%r0,0\n\t"   /* returns 64bit unsigned integer.  */
+		"srlg %0,%0,0(%1)\n\t" /* right align 8bit cache info field.  */
+		".machine pop"
+		: "=&d" (val)
+		: "a" (arg)
+		);
+  val &= 0xCUL; /* Extract cache scope information from cache topology summary.
+		   (bits 4-5 of 8bit-field; 00 means cache does not exist).  */
+  if (val == 0)
+    return 0L;
+
+  /* Get cache information for level, attribute and type.  */
+  cmd = (attr << 4) | ((level - 1) << 1) | type;
+  asm volatile (".machine push\n\t"
+		".machine \"z10\"\n\t"
+		".machinemode \"zarch_nohighgprs\"\n\t"
+		"ecag %0,%%r0,0(%1)\n\t"
+		".machine pop"
+		: "=d" (val)
+		: "a" (cmd)
+		);
+  return val;
+}
+
+long int
+__sysconf (int name)
+{
+  if (name >= _SC_LEVEL1_ICACHE_SIZE && name <= _SC_LEVEL4_CACHE_LINESIZE)
+    {
+      int level;
+      int attr;
+      int type;
+
+      switch (name)
+	{
+	case _SC_LEVEL1_ICACHE_SIZE:
+	  level = 1;
+	  attr = CACHE_ATTR_SIZE;
+	  type = CACHE_TYPE_INSTRUCTION;
+	  break;
+	case _SC_LEVEL1_ICACHE_ASSOC:
+	  level = 1;
+	  attr = CACHE_ATTR_ASSOC;
+	  type = CACHE_TYPE_INSTRUCTION;
+	  break;
+	case _SC_LEVEL1_ICACHE_LINESIZE:
+	  level = 1;
+	  attr = CACHE_ATTR_LINESIZE;
+	  type = CACHE_TYPE_INSTRUCTION;
+	  break;
+
+	case _SC_LEVEL1_DCACHE_SIZE:
+	  level = 1;
+	  attr = CACHE_ATTR_SIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL1_DCACHE_ASSOC:
+	  level = 1;
+	  attr = CACHE_ATTR_ASSOC;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL1_DCACHE_LINESIZE:
+	  level = 1;
+	  attr = CACHE_ATTR_LINESIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+
+	case _SC_LEVEL2_CACHE_SIZE:
+	  level = 2;
+	  attr = CACHE_ATTR_SIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL2_CACHE_ASSOC:
+	  level = 2;
+	  attr = CACHE_ATTR_ASSOC;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL2_CACHE_LINESIZE:
+	  level = 2;
+	  attr = CACHE_ATTR_LINESIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+
+	case _SC_LEVEL3_CACHE_SIZE:
+	  level = 3;
+	  attr = CACHE_ATTR_SIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL3_CACHE_ASSOC:
+	  level = 3;
+	  attr = CACHE_ATTR_ASSOC;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL3_CACHE_LINESIZE:
+	  level = 3;
+	  attr = CACHE_ATTR_LINESIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+
+	case _SC_LEVEL4_CACHE_SIZE:
+	  level = 4;
+	  attr = CACHE_ATTR_SIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL4_CACHE_ASSOC:
+	  level = 4;
+	  attr = CACHE_ATTR_ASSOC;
+	  type = CACHE_TYPE_DATA;
+	  break;
+	case _SC_LEVEL4_CACHE_LINESIZE:
+	  level = 4;
+	  attr = CACHE_ATTR_LINESIZE;
+	  type = CACHE_TYPE_DATA;
+	  break;
+
+	default:
+	  level = 0;
+	  attr = 0;
+	  type = 0;
+	  break;
+	}
+
+      return get_cache_info (level, attr, type);
+    }
+
+  return linux_sysconf (name);
+}
+
+/* Now the generic Linux version.  */
+#undef __sysconf
+#define __sysconf static linux_sysconf
+#include <sysdeps/unix/sysv/linux/sysconf.c>