1 files changed, 73 insertions, 0 deletions

diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
new file mode 100644
index 000000000000..b7b5bc02e361
--- /dev/null
+++ b/arch/x86/include/asm/archrandom.h
@@ -0,0 +1,73 @@
+/*
+ * This file is part of the Linux kernel.
+ *
+ * Copyright (c) 2011, Intel Corporation
+ * Authors: Fenghua Yu <fenghua.yu@intel.com>,
+ *          H. Peter Anvin <hpa@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef ASM_X86_ARCHRANDOM_H
+#define ASM_X86_ARCHRANDOM_H
+
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative.h>
+#include <asm/nops.h>
+
+#define RDRAND_RETRY_LOOPS      10
+
+#define RDRAND_INT      ".byte 0x0f,0xc7,0xf0"
+#ifdef CONFIG_X86_64
+# define RDRAND_LONG    ".byte 0x48,0x0f,0xc7,0xf0"
+#else
+# define RDRAND_LONG    RDRAND_INT
+#endif
+
+#ifdef CONFIG_ARCH_RANDOM
+
+#define GET_RANDOM(name, type, rdrand, nop)                     \
+static inline int name(type *v)                                 \
+{                                                               \
+        int ok;                                                 \
+        alternative_io("movl $0, %0\n\t"                        \
+                       nop,                                     \
+                       "\n1: " rdrand "\n\t"                    \
+                       "jc 2f\n\t"                              \
+                       "decl %0\n\t"                            \
+                       "jnz 1b\n\t"                             \
+                       "2:",                                    \
+                       X86_FEATURE_RDRAND,                      \
+                       ASM_OUTPUT2("=r" (ok), "=a" (*v)),       \
+                       "0" (RDRAND_RETRY_LOOPS));               \
+        return ok;                                              \
+}
+
+#ifdef CONFIG_X86_64
+
+GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
+GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);
+
+#else
+
+GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
+GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);
+
+#endif /* CONFIG_X86_64 */
+
+#endif  /* CONFIG_ARCH_RANDOM */
+
+#endif /* ASM_X86_ARCHRANDOM_H */