s390x: use DYNAMIC_ARCH's cpu detection for compile-time choice

On s390x, the run-time detection for DYNAMIC_ARCH and the compile-time
choice in cpuid_zarch use different methods for identifying the
supported CPU features. To make cpuid_zarch future-proof and both easier
to maintain, switch cpuid_zarch to the same mechanism as DYNAMIC_ZARCH
(i.e., derive the supported CPU features from hwcap flags) and share
code between both (in a new header cpuid_zarch.h).

Signed-off-by: Marius Hillenbrand <mhillen@linux.ibm.com>

cpuid_zarch.c

@@ -27,57 +27,11 @@
 
 #include <string.h>
 
-#define CPU_GENERIC     0
-#define CPU_Z13         1
-#define CPU_Z14         2
-#define CPU_Z15         3
+#include "cpuid_zarch.h"
 
-static char *cpuname[] = {
-  "ZARCH_GENERIC",
-  "Z13",
-  "Z14",
-  "Z15"
-};
-
-static char *cpuname_lower[] = {
-  "zarch_generic",
-  "z13",
-  "z14",
-  "z15"
-};
-
-int detect(void)
-{
-  FILE *infile;
-  char buffer[512], *p;
-
-  p = (char *)NULL;
-  infile = fopen("/proc/sysinfo", "r");
-  while (fgets(buffer, sizeof(buffer), infile)){
-    if (!strncmp("Type", buffer, 4)){
-        p = strchr(buffer, ':') + 2;
-#if 0
-        fprintf(stderr, "%s\n", p);
-#endif
-        break;
-      }
-  }
-
-  fclose(infile);
-
-  if (strstr(p, "2964")) return CPU_Z13;
-  if (strstr(p, "2965")) return CPU_Z13;
-  if (strstr(p, "3906")) return CPU_Z14;
-  if (strstr(p, "3907")) return CPU_Z14;
-  if (strstr(p, "8561")) return CPU_Z14;        // fallback z15 to z14
-  if (strstr(p, "8562")) return CPU_Z14;        // fallback z15 to z14
-
-  return CPU_GENERIC;
-}
 
 void get_libname(void)
 {
-
 	int d = detect();
 	printf("%s", cpuname_lower[d]);
 }

cpuid_zarch.h

@@ -0,0 +1,67 @@
+#include <stdlib.h>
+
+#define CPU_GENERIC     0
+#define CPU_Z13         1
+#define CPU_Z14         2
+#define CPU_Z15         3
+
+static char *cpuname[] = {
+  "ZARCH_GENERIC",
+  "Z13",
+  "Z14",
+  "Z15"
+};
+
+static char *cpuname_lower[] = {
+  "zarch_generic",
+  "z13",
+  "z14",
+  "z15"
+};
+
+// Guard the use of getauxval() on glibc version >= 2.16
+#ifdef __GLIBC__
+#include <features.h>
+#if __GLIBC_PREREQ(2, 16)
+#include <sys/auxv.h>
+#define HAVE_GETAUXVAL 1
+
+static unsigned long get_hwcap(void)
+{
+	unsigned long hwcap = getauxval(AT_HWCAP);
+	char *maskenv;
+
+	// honor requests for not using specific CPU features in LD_HWCAP_MASK
+	maskenv = getenv("LD_HWCAP_MASK");
+	if (maskenv)
+		hwcap &= strtoul(maskenv, NULL, 0);
+
+	return hwcap;
+	// note that a missing auxval is interpreted as no capabilities
+	// available, which is safe.
+}
+
+#else // __GLIBC_PREREQ(2, 16)
+#warn "Cannot detect SIMD support in Z13 or newer architectures since glibc is older than 2.16"
+
+static unsigned long get_hwcap(void) {
+	// treat missing support for getauxval() as no capabilities available,
+	// which is safe.
+	return 0;
+}
+#endif // __GLIBC_PREREQ(2, 16)
+#endif // __GLIBC
+
+static int detect(void)
+{
+	unsigned long hwcap = get_hwcap();
+
+	if ((hwcap & HWCAP_S390_VX) && (hwcap & HWCAP_S390_VXE))
+		return CPU_Z14;
+
+	if (hwcap & HWCAP_S390_VX)
+		return CPU_Z13;
+
+	return CPU_GENERIC;
+}
+

driver/others/dynamic_zarch.c

@@ -1,38 +1,7 @@
 #include "common.h"
+#include "cpuid_zarch.h"
 #include <stdbool.h>
 
-// Guard the use of getauxval() on glibc version >= 2.16
-#ifdef __GLIBC__
-#include <features.h>
-#if __GLIBC_PREREQ(2, 16)
-#include <sys/auxv.h>
-#define HAVE_GETAUXVAL 1
-
-static unsigned long get_hwcap(void)
-{
-	unsigned long hwcap = getauxval(AT_HWCAP);
-	char *maskenv;
-
-	// honor requests for not using specific CPU features in LD_HWCAP_MASK
-	maskenv = getenv("LD_HWCAP_MASK");
-	if (maskenv)
-		hwcap &= strtoul(maskenv, NULL, 0);
-
-	return hwcap;
-	// note that a missing auxval is interpreted as no capabilities
-	// available, which is safe.
-}
-
-#else // __GLIBC_PREREQ(2, 16)
-#warn "Cannot detect SIMD support in Z13 or newer architectures since glibc is older than 2.16"
-
-static unsigned long get_hwcap(void) {
-	// treat missing support for getauxval() as no capabilities available,
-	// which is safe.
-	return 0;
-}
-#endif // __GLIBC_PREREQ(2, 16)
-#endif // __GLIBC
 
 extern gotoblas_t gotoblas_ZARCH_GENERIC;
 #ifdef DYN_Z13
@@ -46,23 +15,16 @@ extern gotoblas_t gotoblas_Z14;
 
 extern void openblas_warning(int verbose, const char* msg);
 
-static char* corename[] = {
-	"unknown",
-	"Z13",
-	"Z14",
-	"ZARCH_GENERIC",
-};
-
 char* gotoblas_corename(void) {
 #ifdef DYN_Z13
-	if (gotoblas == &gotoblas_Z13)	return corename[1];
+	if (gotoblas == &gotoblas_Z13)	return cpuname[CPU_Z13];
 #endif
 #ifdef DYN_Z14
-	if (gotoblas == &gotoblas_Z14)	return corename[2];
+	if (gotoblas == &gotoblas_Z14)	return cpuname[CPU_Z14];
 #endif
-	if (gotoblas == &gotoblas_ZARCH_GENERIC) return corename[3];
+	if (gotoblas == &gotoblas_ZARCH_GENERIC) return cpuname[CPU_GENERIC];
 
-	return corename[0];
+	return "unknown";
 }
 
 #ifndef HWCAP_S390_VXE
@@ -79,25 +41,28 @@ char* gotoblas_corename(void) {
  */
 static gotoblas_t* get_coretype(void) {
 
-	unsigned long hwcap __attribute__((unused)) = get_hwcap();
+	int cpu = detect();
 
-#ifdef DYN_Z14
+	switch(cpu) {
 	// z14 and z15 systems: exploit Vector Facility (SIMD) and
 	// Vector-Enhancements Facility 1 (float SIMD instructions), if present.
-	if ((hwcap & HWCAP_S390_VX) && (hwcap & HWCAP_S390_VXE))
+	case CPU_Z14:
+#ifdef DYN_Z14
 		return &gotoblas_Z14;
 #endif
 
-#ifdef DYN_Z13
 	// z13: Vector Facility (SIMD for double)
-	if (hwcap & HWCAP_S390_VX)
+	case CPU_Z13:
+#ifdef DYN_Z13
 		return &gotoblas_Z13;
 #endif
 
+	default:
 	// fallback in case of missing compiler support, systems before z13, or
 	// when the OS does not advertise support for the Vector Facility (e.g.,
 	// missing support in the OS kernel)
-	return &gotoblas_ZARCH_GENERIC;
+		return &gotoblas_ZARCH_GENERIC;
+	}
 }
 
 static gotoblas_t* force_coretype(char* coretype) {
@@ -108,28 +73,28 @@ static gotoblas_t* force_coretype(char* coretype) {
 
 	for (i = 0; i < NUM_CORETYPES; i++)
 	{
-		if (!strncasecmp(coretype, corename[i], 20))
+		if (!strncasecmp(coretype, cpuname[i], 20))
 		{
 			found = i;
 			break;
 		}
 	}
 
-	if (found == 1) {
+	if (found == CPU_Z13) {
 #ifdef DYN_Z13
 		return &gotoblas_Z13;
 #else
 		openblas_warning(1, "Z13 support not compiled in");
 		return NULL;
 #endif
-	} else if (found == 2) {
+	} else if (found == CPU_Z14) {
 #ifdef DYN_Z14
 		return &gotoblas_Z14;
 #else
 		openblas_warning(1, "Z14 support not compiled in");
 		return NULL;
 #endif
-	} else if (found == 3) {
+	} else if (found == CPU_GENERIC) {
 		return &gotoblas_ZARCH_GENERIC;
 	}