New upstream version 18.08

[deb_dpdk.git] / lib / librte_eal / linuxapp / eal / eal_cpuflags.c

diff --git a/lib/librte_eal/linuxapp/eal/eal_cpuflags.c b/lib/librte_eal/linuxapp/eal/eal_cpuflags.c
new file mode 100644 (file)
index 0000000..d38296e
--- /dev/null
+++ b/lib/librte_eal/linuxapp/eal/eal_cpuflags.c
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2018 Red Hat, Inc.
+ */
+
+#include <elf.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 16)
+#include <sys/auxv.h>
+#define HAS_AUXV 1
+#endif
+#endif
+
+#include <rte_cpuflags.h>
+
+#ifndef HAS_AUXV
+static unsigned long
+getauxval(unsigned long type __rte_unused)
+{
+       errno = ENOTSUP;
+       return 0;
+}
+#endif
+
+#ifdef RTE_ARCH_64
+typedef Elf64_auxv_t Internal_Elfx_auxv_t;
+#else
+typedef Elf32_auxv_t Internal_Elfx_auxv_t;
+#endif
+
+/**
+ * Provides a method for retrieving values from the auxiliary vector and
+ * possibly running a string comparison.
+ *
+ * @return Always returns a result.  When the result is 0, check errno
+ * to see if an error occurred during processing.
+ */
+static unsigned long
+_rte_cpu_getauxval(unsigned long type, const char *str)
+{
+       unsigned long val;
+
+       errno = 0;
+       val = getauxval(type);
+
+       if (!val && (errno == ENOTSUP || errno == ENOENT)) {
+               int auxv_fd = open("/proc/self/auxv", O_RDONLY);
+               Internal_Elfx_auxv_t auxv;
+
+               if (auxv_fd == -1)
+                       return 0;
+
+               errno = ENOENT;
+               while (read(auxv_fd, &auxv, sizeof(auxv)) == sizeof(auxv)) {
+                       if (auxv.a_type == type) {
+                               errno = 0;
+                               val = auxv.a_un.a_val;
+                               if (str)
+                                       val = strcmp((const char *)val, str);
+                               break;
+                       }
+               }
+               close(auxv_fd);
+       }
+
+       return val;
+}
+
+unsigned long
+rte_cpu_getauxval(unsigned long type)
+{
+       return _rte_cpu_getauxval(type, NULL);
+}
+
+int
+rte_cpu_strcmp_auxval(unsigned long type, const char *str)
+{
+       return _rte_cpu_getauxval(type, str);
+}