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/param.h> 30 #include <sys/kernel.h> 31 #include <sys/conf.h> 32 #include <sys/lock.h> 33 #include <sys/malloc.h> 34 #include <sys/module.h> 35 #include <sys/random.h> 36 #include <sys/systm.h> 37 38 #include <machine/segments.h> 39 #include <machine/pcb.h> 40 #include <machine/md_var.h> 41 #include <machine/specialreg.h> 42 43 #include <dev/random/randomdev.h> 44 45 static u_int random_nehemiah_read(void *, u_int); 46 47 static struct random_source random_nehemiah = { 48 .rs_ident = "VIA Nehemiah Padlock RNG", 49 .rs_source = RANDOM_PURE_NEHEMIAH, 50 .rs_read = random_nehemiah_read 51 }; 52 53 /* This H/W source never stores more than 8 bytes in one go */ 54 /* ARGSUSED */ 55 static __inline size_t 56 VIA_RNG_store(void *buf) 57 { 58 uint32_t retval = 0; 59 uint32_t rate = 0; 60 61 __asm __volatile( 62 "movl $0,%%edx\n\t" 63 ".byte 0x0f, 0xa7, 0xc0" 64 : "=a" (retval), "+d" (rate), "+D" (buf) 65 : 66 : "memory" 67 ); 68 if (rate == 0) 69 return (retval&0x1f); 70 return (0); 71 } 72 73 /* It is specifically allowed that buf is a multiple of sizeof(long) */ 74 static u_int 75 random_nehemiah_read(void *buf, u_int c) 76 { 77 uint8_t *b; 78 size_t count, ret; 79 uint64_t tmp; 80 81 fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); 82 b = buf; 83 for (count = c; count > 0; count -= ret) { 84 ret = MIN(VIA_RNG_store(&tmp), count); 85 memcpy(b, &tmp, ret); 86 b += ret; 87 } 88 fpu_kern_leave(curthread, NULL); 89 90 return (c); 91 } 92 93 static int 94 nehemiah_modevent(module_t mod, int type, void *unused) 95 { 96 int error = 0; 97 98 switch (type) { 99 case MOD_LOAD: 100 if (via_feature_rng & VIA_HAS_RNG) { 101 random_source_register(&random_nehemiah); 102 printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident); 103 } 104 break; 105 106 case MOD_UNLOAD: 107 if (via_feature_rng & VIA_HAS_RNG) { 108 random_source_deregister(&random_nehemiah); 109 } 110 break; 111 112 case MOD_SHUTDOWN: 113 break; 114 115 default: 116 error = EOPNOTSUPP; 117 break; 118 119 } 120 121 return (error); 122 } 123 124 static moduledata_t nehemiah_mod = { 125 "nehemiah", 126 nehemiah_modevent, 127 0 128 }; 129 130 DECLARE_MODULE(nehemiah, nehemiah_mod, SI_SUB_RANDOM, SI_ORDER_FOURTH); 131 MODULE_VERSION(nehemiah, 1); 132 MODULE_DEPEND(nehemiah, random_harvestq, 1, 1, 1); 133