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__FBSDID("$FreeBSD$"); 31 32#include <sys/param.h> 33#include <sys/kernel.h> 34#include <sys/conf.h> 35#include <sys/lock.h> 36#include <sys/malloc.h> 37#include <sys/module.h> 38#include <sys/random.h> 39#include <sys/systm.h> 40 41#include <machine/segments.h> 42#include <machine/pcb.h> 43#include <machine/md_var.h> 44#include <machine/specialreg.h> 45 46#include <dev/random/randomdev.h> 47 48static void random_nehemiah_init(void); 49static void random_nehemiah_deinit(void); 50static u_int random_nehemiah_read(void *, u_int); 51 52static struct random_source random_nehemiah = { 53 .rs_ident = "VIA Nehemiah Padlock RNG", 54 .rs_source = RANDOM_PURE_NEHEMIAH, 55 .rs_read = random_nehemiah_read 56}; 57 58static struct fpu_kern_ctx *fpu_ctx_save; 59 60/* This H/W source never stores more than 8 bytes in one go */ 61/* ARGSUSED */ 62static __inline size_t 63VIA_RNG_store(void *buf) 64{ 65 uint32_t retval = 0; 66 uint32_t rate = 0; 67 68#ifdef __GNUCLIKE_ASM 69 __asm __volatile( 70 "movl $0,%%edx\n\t" 71 "xstore" 72 : "=a" (retval), "+d" (rate), "+D" (buf) 73 : 74 : "memory" 75 ); 76#endif 77 if (rate == 0) 78 return (retval&0x1f); 79 return (0); 80} 81 82static void 83random_nehemiah_init(void) 84{ 85 86 fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL); 87} 88 89static void 90random_nehemiah_deinit(void) 91{ 92 93 fpu_kern_free_ctx(fpu_ctx_save); 94} 95 96/* It is specifically allowed that buf is a multiple of sizeof(long) */ 97static u_int 98random_nehemiah_read(void *buf, u_int c) 99{ 100 uint8_t *b; 101 size_t count, ret; 102 uint64_t tmp; 103 104 fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL); 105 b = buf; 106 for (count = c; count > 0; count -= ret) { 107 ret = MIN(VIA_RNG_store(&tmp), count); 108 memcpy(b, &tmp, ret); 109 b += ret; 110 } 111 fpu_kern_leave(curthread, fpu_ctx_save); 112 113 return (c); 114} 115 116static int 117nehemiah_modevent(module_t mod, int type, void *unused) 118{ 119 int error = 0; 120 121 switch (type) { 122 case MOD_LOAD: 123 if (via_feature_rng & VIA_HAS_RNG) { 124 random_source_register(&random_nehemiah); 125 printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident); 126 random_nehemiah_init(); 127 } 128 break; 129 130 case MOD_UNLOAD: 131 if (via_feature_rng & VIA_HAS_RNG) { 132 random_nehemiah_deinit(); 133 random_source_deregister(&random_nehemiah); 134 } 135 break; 136 137 case MOD_SHUTDOWN: 138 break; 139 140 default: 141 error = EOPNOTSUPP; 142 break; 143 144 } 145 146 return (error); 147} 148 149DEV_MODULE(nehemiah, nehemiah_modevent, NULL); 150MODULE_VERSION(nehemiah, 1); 151MODULE_DEPEND(nehemiah, random_device, 1, 1, 1); 152