1 files changed, 84 insertions, 0 deletions
diff --git a/src/cpu.h b/src/cpu.h
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+/*
+ * Copyright (c) 2011-2015 Richard Braun.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ */
+
+#ifndef _CPU_H
+#define _CPU_H
+
+#include <sched.h>
+
+#include "macros.h"
+
+/*
+ * Maximum number of supported processors.
+ */
+#define NR_CPUS CONFIG_NR_CPUS
+
+/*
+ * Filter invalid values.
+ *
+ * The maximum number of processors must be a power-of-two in order to avoid
+ * divisions.
+ */
+#if (NR_CPUS < 1) || !ISP2(NR_CPUS)
+#error "invalid number of configured processors"
+#endif
+
+/*
+ * L1 cache line shift and size.
+ */
+#define CPU_L1_SHIFT    CONFIG_CPU_L1_SHIFT
+#define CPU_L1_SIZE     (1 << CPU_L1_SHIFT)
+
+/*
+ * Return the ID of the currently running CPU.
+ *
+ * This implementation uses a glibc-specific function that relies on a
+ * Linux-specific system call to obtain the CPU ID. If this function fails
+ * (e.g. when run in valgrind), 0 is returned.
+ *
+ * The returned CPU ID cannot be greater than the maximum number of supported
+ * processors.
+ */
+static inline int
+cpu_id(void)
+{
+#if NR_CPUS == 1
+    return 0;
+#else
+    int id;
+
+    id = sched_getcpu();
+
+    if (id == -1) {
+        return 0;
+    } else if (id >= NR_CPUS) {
+        id &= (NR_CPUS - 1);
+    }
+
+    return id;
+#endif
+}
+
+#endif /* _CPU_H */