1 /*- 2 * Copyright (c) 2013-2015 Mark R V Murray 3 * Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer 11 * in this position and unchanged. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/param.h> 31 #include <sys/kernel.h> 32 #include <sys/conf.h> 33 #include <sys/lock.h> 34 #include <sys/malloc.h> 35 #include <sys/module.h> 36 #include <sys/random.h> 37 #include <sys/systm.h> 38 39 #include <machine/segments.h> 40 #include <machine/pcb.h> 41 #include <machine/md_var.h> 42 #include <machine/specialreg.h> 43 44 #include <dev/random/randomdev.h> 45 46 static u_int random_nehemiah_read(void *, u_int); 47 48 static struct random_source random_nehemiah = { 49 .rs_ident = "VIA Nehemiah Padlock RNG", 50 .rs_source = RANDOM_PURE_NEHEMIAH, 51 .rs_read = random_nehemiah_read 52 }; 53 54 /* This H/W source never stores more than 8 bytes in one go */ 55 /* ARGSUSED */ 56 static __inline size_t 57 VIA_RNG_store(void *buf) 58 { 59 uint32_t retval = 0; 60 uint32_t rate = 0; 61 62 __asm __volatile( 63 "movl $0,%%edx\n\t" 64 ".byte 0x0f, 0xa7, 0xc0" 65 : "=a" (retval), "+d" (rate), "+D" (buf) 66 : 67 : "memory" 68 ); 69 if (rate == 0) 70 return (retval&0x1f); 71 return (0); 72 } 73 74 /* It is specifically allowed that buf is a multiple of sizeof(long) */ 75 static u_int 76 random_nehemiah_read(void *buf, u_int c) 77 { 78 uint8_t *b; 79 size_t count, ret; 80 uint64_t tmp; 81 82 fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); 83 b = buf; 84 for (count = c; count > 0; count -= ret) { 85 ret = MIN(VIA_RNG_store(&tmp), count); 86 memcpy(b, &tmp, ret); 87 b += ret; 88 } 89 fpu_kern_leave(curthread, NULL); 90 91 return (c); 92 } 93 94 static int 95 nehemiah_modevent(module_t mod, int type, void *unused) 96 { 97 int error = 0; 98 99 switch (type) { 100 case MOD_LOAD: 101 if (via_feature_rng & VIA_HAS_RNG) { 102 random_source_register(&random_nehemiah); 103 printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident); 104 } 105 break; 106 107 case MOD_UNLOAD: 108 if (via_feature_rng & VIA_HAS_RNG) { 109 random_source_deregister(&random_nehemiah); 110 } 111 break; 112 113 case MOD_SHUTDOWN: 114 break; 115 116 default: 117 error = EOPNOTSUPP; 118 break; 119 120 } 121 122 return (error); 123 } 124 125 static moduledata_t nehemiah_mod = { 126 "nehemiah", 127 nehemiah_modevent, 128 0 129 }; 130 131 DECLARE_MODULE(nehemiah, nehemiah_mod, SI_SUB_RANDOM, SI_ORDER_FOURTH); 132 MODULE_VERSION(nehemiah, 1); 133 MODULE_DEPEND(nehemiah, random_harvestq, 1, 1, 1); 134