849ce31a82
No implementation of fpu_kern_enter() can fail, and it was causing needless error checking boilerplate and confusion. Change the return code to void to match reality. (This trivial change took nine days to land because of the commit hook on sys/dev/random. Please consider removing the hook or otherwise lowering the bar -- secteam never seems to have free time to review patches.) Reported by: Lachlan McIlroy <Lachlan.McIlroy AT isilon.com> Reviewed by: delphij Approved by: secteam (delphij) Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D14380
152 lines
3.7 KiB
C
152 lines
3.7 KiB
C
/*-
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* Copyright (c) 2013-2015 Mark R V Murray
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* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/conf.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/random.h>
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#include <sys/systm.h>
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#include <machine/segments.h>
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#include <machine/pcb.h>
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#include <machine/md_var.h>
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#include <machine/specialreg.h>
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#include <dev/random/randomdev.h>
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static void random_nehemiah_init(void);
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static void random_nehemiah_deinit(void);
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static u_int random_nehemiah_read(void *, u_int);
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static struct random_source random_nehemiah = {
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.rs_ident = "VIA Nehemiah Padlock RNG",
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.rs_source = RANDOM_PURE_NEHEMIAH,
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.rs_read = random_nehemiah_read
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};
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static struct fpu_kern_ctx *fpu_ctx_save;
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/* This H/W source never stores more than 8 bytes in one go */
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/* ARGSUSED */
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static __inline size_t
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VIA_RNG_store(void *buf)
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{
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uint32_t retval = 0;
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uint32_t rate = 0;
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#ifdef __GNUCLIKE_ASM
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__asm __volatile(
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"movl $0,%%edx\n\t"
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"xstore"
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: "=a" (retval), "+d" (rate), "+D" (buf)
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:
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: "memory"
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);
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#endif
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if (rate == 0)
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return (retval&0x1f);
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return (0);
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}
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static void
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random_nehemiah_init(void)
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{
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fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
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}
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static void
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random_nehemiah_deinit(void)
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{
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fpu_kern_free_ctx(fpu_ctx_save);
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}
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/* It is specifically allowed that buf is a multiple of sizeof(long) */
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static u_int
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random_nehemiah_read(void *buf, u_int c)
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{
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uint8_t *b;
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size_t count, ret;
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uint64_t tmp;
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fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL);
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b = buf;
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for (count = c; count > 0; count -= ret) {
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ret = MIN(VIA_RNG_store(&tmp), count);
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memcpy(b, &tmp, ret);
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b += ret;
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}
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fpu_kern_leave(curthread, fpu_ctx_save);
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return (c);
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}
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static int
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nehemiah_modevent(module_t mod, int type, void *unused)
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{
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int error = 0;
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switch (type) {
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case MOD_LOAD:
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if (via_feature_rng & VIA_HAS_RNG) {
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random_source_register(&random_nehemiah);
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printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident);
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random_nehemiah_init();
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}
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break;
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case MOD_UNLOAD:
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if (via_feature_rng & VIA_HAS_RNG) {
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random_nehemiah_deinit();
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random_source_deregister(&random_nehemiah);
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}
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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DEV_MODULE(nehemiah, nehemiah_modevent, NULL);
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MODULE_VERSION(nehemiah, 1);
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MODULE_DEPEND(nehemiah, random_device, 1, 1, 1);
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