random: Add arch_has_random[_seed]()

[mirror_ubuntu-jammy-kernel.git] / arch / x86 / include / asm / archrandom.h

diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
index e6a92455740e6a5dfc64c5b1a1193a693594feab..69f1366f1aa33721ea160cc831a1345867b7a4b3 100644 (file)
--- a/arch/x86/include/asm/archrandom.h
+++ b/arch/x86/include/asm/archrandom.h
@@ -1,7 +1,7 @@
 /*
  * This file is part of the Linux kernel.
  *
- * Copyright (c) 2011, Intel Corporation
+ * Copyright (c) 2011-2014, Intel Corporation
  * Authors: Fenghua Yu <fenghua.yu@intel.com>,
  *          H. Peter Anvin <hpa@linux.intel.com>
  *
@@ -31,10 +31,13 @@
 #define RDRAND_RETRY_LOOPS     10
 
 #define RDRAND_INT     ".byte 0x0f,0xc7,0xf0"
+#define RDSEED_INT     ".byte 0x0f,0xc7,0xf8"
 #ifdef CONFIG_X86_64
 # define RDRAND_LONG   ".byte 0x48,0x0f,0xc7,0xf0"
+# define RDSEED_LONG   ".byte 0x48,0x0f,0xc7,0xf8"
 #else
 # define RDRAND_LONG   RDRAND_INT
+# define RDSEED_LONG   RDSEED_INT
 #endif
 
 #ifdef CONFIG_ARCH_RANDOM
@@ -53,6 +56,16 @@ static inline int rdrand_long(unsigned long *v)
        return ok;
 }
 
+/* A single attempt at RDSEED */
+static inline bool rdseed_long(unsigned long *v)
+{
+       unsigned char ok;
+       asm volatile(RDSEED_LONG "\n\t"
+                    "setc %0"
+                    : "=qm" (ok), "=a" (*v));
+       return ok;
+}
+
 #define GET_RANDOM(name, type, rdrand, nop)                    \
 static inline int name(type *v)                                        \
 {                                                              \
@@ -70,18 +83,40 @@ static inline int name(type *v)                                     \
        return ok;                                              \
 }
 
+#define GET_SEED(name, type, rdseed, nop)                      \
+static inline int name(type *v)                                        \
+{                                                              \
+       unsigned char ok;                                       \
+       alternative_io("movb $0, %0\n\t"                        \
+                      nop,                                     \
+                      rdseed "\n\t"                            \
+                      "setc %0",                               \
+                      X86_FEATURE_RDSEED,                      \
+                      ASM_OUTPUT2("=q" (ok), "=a" (*v)));      \
+       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);
 
+GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP5);
+GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_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);
 
+GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP4);
+GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);
+
 #endif /* CONFIG_X86_64 */
 
+#define arch_has_random()      static_cpu_has(X86_FEATURE_RDRAND)
+#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED)
+
 #else
 
 static inline int rdrand_long(unsigned long *v)
@@ -89,6 +124,11 @@ static inline int rdrand_long(unsigned long *v)
        return 0;
 }
 
+static inline bool rdseed_long(unsigned long *v)
+{
+       return 0;
+}
+
 #endif  /* CONFIG_ARCH_RANDOM */
 
 extern void x86_init_rdrand(struct cpuinfo_x86 *c);