1 /*- 2 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include "opt_cpu.h" 32 33 #ifdef RDRAND_RNG 34 35 #include <sys/param.h> 36 #include <sys/time.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/selinfo.h> 40 #include <sys/systm.h> 41 #include <dev/random/randomdev.h> 42 43 #define RETRY_COUNT 10 44 45 static void random_ivy_init(void); 46 static void random_ivy_deinit(void); 47 static int random_ivy_read(void *, int); 48 49 struct random_systat random_ivy = { 50 .ident = "Hardware, Intel IvyBridge+ RNG", 51 .init = random_ivy_init, 52 .deinit = random_ivy_deinit, 53 .read = random_ivy_read, 54 .write = (random_write_func_t *)random_null_func, 55 .reseed = (random_reseed_func_t *)random_null_func, 56 .seeded = 1, 57 }; 58 59 static inline int 60 ivy_rng_store(long *tmp) 61 { 62 #ifdef __GNUCLIKE_ASM 63 uint32_t count; 64 65 __asm __volatile( 66 #ifdef __amd64__ 67 ".byte\t0x48,0x0f,0xc7,0xf0\n\t" /* rdrand %rax */ 68 "jnc\t1f\n\t" 69 "movq\t%%rax,%1\n\t" 70 "movl\t$8,%%eax\n" 71 #else /* i386 */ 72 ".byte\t0x0f,0xc7,0xf0\n\t" /* rdrand %eax */ 73 "jnc\t1f\n\t" 74 "movl\t%%eax,%1\n\t" 75 "movl\t$4,%%eax\n" 76 #endif 77 "1:\n" /* %eax is cleared by processor on failure */ 78 : "=a" (count), "=g" (*tmp) : "a" (0) : "cc"); 79 return (count); 80 #else /* __GNUCLIKE_ASM */ 81 return (0); 82 #endif 83 } 84 85 static void 86 random_ivy_init(void) 87 { 88 } 89 90 void 91 random_ivy_deinit(void) 92 { 93 } 94 95 static int 96 random_ivy_read(void *buf, int c) 97 { 98 char *b; 99 long tmp; 100 int count, res, retry; 101 102 for (count = c, b = buf; count > 0; count -= res, b += res) { 103 for (retry = 0; retry < RETRY_COUNT; retry++) { 104 res = ivy_rng_store(&tmp); 105 if (res != 0) 106 break; 107 } 108 if (res == 0) 109 break; 110 if (res > count) 111 res = count; 112 memcpy(b, &tmp, res); 113 } 114 return (c - count); 115 } 116 117 #endif 118