hwf: add detection of s390x/zSeries hardware features

* configure.ac (gcry_cv_gcc_inline_asm_s390x)
(HAVE_CPU_ARCH_S390X): Add s390x detection support.
* mpi/config.links: Add setup for s390x links.
* src/Makefile.am: Add 'hwf-s390x.c'.
* src/g10lib.h (HWF_S390X_MSA, HWF_S390X_MSA_4, HWF_S390X_8): New.
* src/hwf_common.h (_gcry_hwf_detect_s390x): New.
* src/hwf-s390x.c: New.
* src/hwfeatures.c: Add "s390x-msa", "s390x-msa-4" and "s390x-msa-8".
--

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>

7 files changed, 299 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index fda74056..cf0d5e61 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2001,6 +2001,58 @@ if test "$gcry_cv_gcc_inline_asm_ppc_arch_3_00" = "yes" ; then
 fi
 
 
+#
+# Check whether GCC inline assembler supports zSeries instructions
+#
+AC_CACHE_CHECK([whether GCC inline assembler supports zSeries instructions],
+      [gcry_cv_gcc_inline_asm_s390x],
+      [if test "$mpi_cpu_arch" != "s390x" ||
+	  test "$try_asm_modules" != "yes" ; then
+	  gcry_cv_gcc_inline_asm_s390x="n/a"
+	else
+	  gcry_cv_gcc_inline_asm_s390x=no
+	  AC_COMPILE_IFELSE([AC_LANG_SOURCE(
+	  [[typedef unsigned int u128_t __attribute__ ((mode (TI)));
+	    unsigned int testfunc(unsigned int x, void *y, unsigned int z)
+	    {
+	      unsigned long fac[8];
+	      register unsigned long reg0 asm("0") = 0;
+	      register unsigned long reg1 asm("1") = x;
+	      u128_t r1 = ((u128_t)(unsigned long)y << 64) | (unsigned long)z;
+	      u128_t r2 = 0;
+	      u128_t r3 = 0;
+	      asm volatile (".insn rre,0xb92e << 16, %[r1], %[r2]\n\t"
+			    : [r1] "+a" (r1), [r2] "+a" (r2)
+			    : "r" (reg0), "r" (reg1)
+			    : "cc", "memory");
+	      asm volatile (".insn rrf,0xb929 << 16, %[r1], %[r2], %[r3], 0\n\t"
+			    : [r1] "+a" (r1), [r2] "+a" (r2), [r3] "+a" (r3)
+			    : "r" (reg0), "r" (reg1)
+			    : "cc", "memory");
+	      reg0 = 8 - 1;
+	      asm ("stfle %1\n\t"
+	           : "+d" (reg0), "=Q" (fac[0])
+	           :
+	           : "cc", "memory");
+	      asm volatile ("mvc 0(16, %0), 0(%1)\n\t"
+			    :
+			    : "a" (y), "a" (fac)
+			    : "memory");
+	      asm volatile ("xc 0(16, %0), 0(%0)\n\t"
+			    :
+			    : "a" (fac)
+			    : "memory");
+	      return (unsigned int)r1 ^ reg0;
+	    }
+	    ]])],
+	  [gcry_cv_gcc_inline_asm_s390x=yes])
+	fi])
+if test "$gcry_cv_gcc_inline_asm_s390x" = "yes" ; then
+   AC_DEFINE(HAVE_GCC_INLINE_ASM_S390X,1,
+     [Defined if inline assembler supports zSeries instructions])
+fi
+
+
 #######################################
 #### Checks for library functions. ####
 #######################################
@@ -2962,6 +3014,10 @@ case "$mpi_cpu_arch" in
         AC_DEFINE(HAVE_CPU_ARCH_ARM, 1,   [Defined for ARM AArch64 platforms])
         GCRYPT_HWF_MODULES="libgcrypt_la-hwf-arm.lo"
         ;;
+     s390x)
+        AC_DEFINE(HAVE_CPU_ARCH_S390X, 1, [Defined for s390x/zSeries platforms])
+        GCRYPT_HWF_MODULES="libgcrypt_la-hwf-s390x.lo"
+        ;;
 esac
 AC_SUBST([GCRYPT_HWF_MODULES])
 
diff --git a/mpi/config.links b/mpi/config.links
index ce6822db..e4fc4fc4 100644
--- a/mpi/config.links
+++ b/mpi/config.links
@@ -246,6 +246,11 @@ case "${host}" in
        path="mips2"
        mpi_cpu_arch="mips"
        ;;
+    s390x*-*-*)
+       echo '/* No working assembler modules available */' >>./mpi/asm-syntax.h
+       path=""
+       mpi_cpu_arch="s390x"
+       ;;
 
     # Motorola 68k configurations.  Let m68k mean 68020-68040.
     # mc68000 or mc68060 configurations need to be specified explicitly
diff --git a/src/Makefile.am b/src/Makefile.am
index 74772857..31aa6660 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -66,7 +66,7 @@ libgcrypt_la_SOURCES = \
 	hmac256.c hmac256.h context.c context.h \
 	ec-context.h
 
-EXTRA_libgcrypt_la_SOURCES = hwf-x86.c hwf-arm.c hwf-ppc.c
+EXTRA_libgcrypt_la_SOURCES = hwf-x86.c hwf-arm.c hwf-ppc.c hwf-s390x.c
 gcrypt_hwf_modules = @GCRYPT_HWF_MODULES@
 
 
diff --git a/src/g10lib.h b/src/g10lib.h
index ffd71018..665c2175 100644
--- a/src/g10lib.h
+++ b/src/g10lib.h
@@ -246,6 +246,10 @@ char **_gcry_strtokenize (const char *string, const char *delim);
 #define HWF_PPC_ARCH_3_00       (1 << 23)
 #define HWF_PPC_ARCH_2_07       (1 << 24)
 
+#define HWF_S390X_MSA           (1 << 25)
+#define HWF_S390X_MSA_4         (1 << 26)
+#define HWF_S390X_MSA_8         (1 << 27)
+
 gpg_err_code_t _gcry_disable_hw_feature (const char *name);
 void _gcry_detect_hw_features (void);
 unsigned int _gcry_get_hw_features (void);
diff --git a/src/hwf-common.h b/src/hwf-common.h
index 76f346e9..b10f86be 100644
--- a/src/hwf-common.h
+++ b/src/hwf-common.h
@@ -23,5 +23,6 @@
 unsigned int _gcry_hwf_detect_x86 (void);
 unsigned int _gcry_hwf_detect_arm (void);
 unsigned int _gcry_hwf_detect_ppc (void);
+unsigned int _gcry_hwf_detect_s390x (void);
 
 #endif /*HWF_COMMON_H*/
diff --git a/src/hwf-s390x.c b/src/hwf-s390x.c
new file mode 100644
index 00000000..991e8c4c
--- /dev/null
+++ b/src/hwf-s390x.c
@@ -0,0 +1,224 @@
+/* hwf-s390x.c - Detect hardware features - s390x/zSeries part
+ * Copyright (C) 2020 Jussi Kivilinna <jussi.kivilinna@iki.fi>
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt 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.
+ *
+ * Libgcrypt 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <errno.h>
+#if defined(HAVE_SYS_AUXV_H) && (defined(HAVE_GETAUXVAL) || \
+    defined(HAVE_ELF_AUX_INFO))
+#include <sys/auxv.h>
+#endif
+
+#include "g10lib.h"
+#include "hwf-common.h"
+
+#if !defined (__s390x__)
+# error Module build for wrong CPU.
+#endif
+
+#undef HAVE_STFLE
+#ifdef HAVE_GCC_INLINE_ASM_S390X
+# define HAVE_STFLE 1
+#endif
+
+struct feature_map_s
+  {
+    unsigned int facilities_bit;
+    unsigned int hwcap_flag;
+    unsigned int hwf_flag;
+  };
+
+static const struct feature_map_s s390x_features[] =
+  {
+    { 17,  0, HWF_S390X_MSA },
+    { 77,  0, HWF_S390X_MSA_4 },
+    { 146, 0, HWF_S390X_MSA_8 },
+  };
+
+#if defined(HAVE_SYS_AUXV_H) && defined(HAVE_ELF_AUX_INFO) && \
+    !defined(HAVE_GETAUXVAL) && defined(AT_HWCAP)
+#define HAVE_GETAUXVAL
+static unsigned long getauxval(unsigned long type)
+{
+  unsigned long auxval = 0;
+  int err;
+
+  /* FreeBSD provides 'elf_aux_info' function that does the same as
+   * 'getauxval' on Linux. */
+
+  err = elf_aux_info (type, &auxval, sizeof(auxval));
+  if (err)
+    {
+      errno = err;
+      auxval = 0;
+    }
+
+  return auxval;
+}
+#endif
+
+
+#undef HAS_SYS_AT_HWCAP
+#if defined(__linux__) || \
+    (defined(HAVE_SYS_AUXV_H) && defined(HAVE_GETAUXVAL))
+#define HAS_SYS_AT_HWCAP 1
+
+struct facilities_s
+  {
+    u64 bits[3];
+  };
+
+#ifndef AT_HWCAP
+# define AT_HWCAP         16
+#endif
+#ifndef HWCAP_S390_STFLE
+# define HWCAP_S390_STFLE 4
+#endif
+
+static int
+get_hwcap(unsigned int *hwcap)
+{
+  struct { unsigned long a_type; unsigned long a_val; } auxv;
+  FILE *f;
+  int err = -1;
+  static int hwcap_initialized = 0;
+  static unsigned int stored_hwcap = 0;
+
+  if (hwcap_initialized)
+    {
+      *hwcap = stored_hwcap;
+      return 0;
+    }
+
+#if defined(HAVE_SYS_AUXV_H) && defined(HAVE_GETAUXVAL)
+  errno = 0;
+  auxv.a_val = getauxval (AT_HWCAP);
+  if (errno == 0)
+    {
+      stored_hwcap |= auxv.a_val;
+      hwcap_initialized = 1;
+    }
+
+  if (hwcap_initialized && stored_hwcap)
+    {
+      *hwcap = stored_hwcap;
+      return 0;
+    }
+#endif
+
+  f = fopen("/proc/self/auxv", "r");
+  if (!f)
+    {
+      *hwcap = stored_hwcap;
+      return -1;
+    }
+
+  while (fread(&auxv, sizeof(auxv), 1, f) > 0)
+    {
+      if (auxv.a_type == AT_HWCAP)
+        {
+          stored_hwcap |= auxv.a_val;
+          hwcap_initialized = 1;
+        }
+    }
+
+  if (hwcap_initialized)
+      err = 0;
+
+  fclose(f);
+
+  *hwcap = stored_hwcap;
+  return err;
+}
+#endif
+
+#ifdef HAVE_STFLE
+static void
+get_stfle(struct facilities_s *out)
+{
+  static int stfle_initialized = 0;
+  static struct facilities_s stored_facilities;
+
+  if (!stfle_initialized)
+    {
+      register unsigned long reg0 asm("0") = DIM(stored_facilities.bits) - 1;
+
+      asm ("stfle %1\n\t"
+	   : "+d" (reg0),
+	     "=Q" (stored_facilities.bits[0])
+	   :
+	   : "cc", "memory");
+
+      stfle_initialized = 1;
+    }
+
+  *out = stored_facilities;
+}
+#endif
+
+static unsigned int
+detect_s390x_features(void)
+{
+  struct facilities_s facilities = { { 0, } };
+  unsigned int hwcap = 0;
+  unsigned int features = 0;
+  unsigned int i;
+
+#if defined (HAS_SYS_AT_HWCAP)
+  if (get_hwcap(&hwcap) < 0)
+    return features;
+#endif
+
+  if ((hwcap & HWCAP_S390_STFLE) == 0)
+    return features;
+
+#ifdef HAVE_STFLE
+  get_stfle(&facilities);
+#endif
+
+  for (i = 0; i < DIM(s390x_features); i++)
+    {
+      if (s390x_features[i].hwcap_flag == 0 ||
+	  (s390x_features[i].hwcap_flag & hwcap))
+	{
+	  unsigned int idx = s390x_features[i].facilities_bit;
+	  unsigned int u64_idx = idx / 64;
+	  unsigned int u64_bit = 63 - (idx % 64);
+
+	  if (facilities.bits[u64_idx] & (U64_C(1) << u64_bit))
+	    features |= s390x_features[i].hwf_flag;
+	}
+    }
+
+  return features;
+}
+
+unsigned int
+_gcry_hwf_detect_s390x (void)
+{
+  unsigned int ret = 0;
+
+  ret |= detect_s390x_features ();
+
+  return ret;
+}
diff --git a/src/hwfeatures.c b/src/hwfeatures.c
index bff0f1c8..d7f2047c 100644
--- a/src/hwfeatures.c
+++ b/src/hwfeatures.c
@@ -70,6 +70,10 @@ static struct
     { HWF_PPC_VCRYPTO,         "ppc-vcrypto" },
     { HWF_PPC_ARCH_3_00,       "ppc-arch_3_00" },
     { HWF_PPC_ARCH_2_07,       "ppc-arch_2_07" },
+#elif defined(HAVE_CPU_ARCH_S390X)
+    { HWF_S390X_MSA,           "s390x-msa" },
+    { HWF_S390X_MSA_4,         "s390x-msa-4" },
+    { HWF_S390X_MSA_8,         "s390x-msa-8" },
 #endif
   };
 
@@ -223,6 +227,10 @@ _gcry_detect_hw_features (void)
   {
     hw_features = _gcry_hwf_detect_ppc ();
   }
+#elif defined (HAVE_CPU_ARCH_S390X)
+  {
+    hw_features = _gcry_hwf_detect_s390x ();
+  }
 #endif
   hw_features &= ~disabled_hw_features;
 }