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cprng(9): cprng_fast is no longer used from interrupt context. 

Rip out logic to defer reseeding to softint.
This commit is contained in:
riastradh 2022-06-01 15:44:37 +00:00
parent 8449a122ed
commit caa8fd7fab
1 changed files with 15 additions and 29 deletions
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44
sys/crypto/cprng_fast/cprng_fast.c
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@ -1,4 +1,4 @@
/* $NetBSD: cprng_fast.c,v 1.16 2020/07/28 20:15:07 riastradh Exp $ */
/* $NetBSD: cprng_fast.c,v 1.17 2022/06/01 15:44:37 riastradh Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cprng_fast.c,v 1.16 2020/07/28 20:15:07 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: cprng_fast.c,v 1.17 2022/06/01 15:44:37 riastradh Exp $");
#include <sys/types.h>
#include <sys/param.h>
@ -39,7 +39,6 @@ __KERNEL_RCSID(0, "$NetBSD: cprng_fast.c,v 1.16 2020/07/28 20:15:07 riastradh Ex
#include <sys/cpu.h>
#include <sys/entropy.h>
#include <sys/evcnt.h>
#include <sys/intr.h>
#include <sys/kmem.h>
#include <sys/percpu.h>
@ -58,8 +57,7 @@ struct cprng_fast {
};
static void cprng_fast_init_cpu(void *, void *, struct cpu_info *);
static void cprng_fast_schedule_reseed(struct cprng_fast *);
static void cprng_fast_intr(void *);
static void cprng_fast_reseed(struct cprng_fast *);
static void cprng_fast_seed(struct cprng_fast *, const void *);
static void cprng_fast_buf(struct cprng_fast *, void *, unsigned);
@ -68,7 +66,6 @@ static void cprng_fast_buf_short(void *, size_t);
static void cprng_fast_buf_long(void *, size_t);
static percpu_t *cprng_fast_percpu __read_mostly;
static void *cprng_fast_softint __read_mostly;
void
cprng_fast_init(void)
@ -76,20 +73,14 @@ cprng_fast_init(void)
cprng_fast_percpu = percpu_create(sizeof(struct cprng_fast),
cprng_fast_init_cpu, NULL, NULL);
cprng_fast_softint = softint_establish(SOFTINT_SERIAL|SOFTINT_MPSAFE,
&cprng_fast_intr, NULL);
}
static void
cprng_fast_init_cpu(void *p, void *arg __unused, struct cpu_info *ci)
{
struct cprng_fast *const cprng = p;
uint8_t seed[CPRNG_FAST_SEED_BYTES];
cprng->epoch = entropy_epoch();
cprng_strong(kern_cprng, seed, sizeof seed, 0);
cprng_fast_seed(cprng, seed);
(void)explicit_memset(seed, 0, sizeof seed);
cprng->epoch = 0;
cprng->reseed_evcnt = kmem_alloc(sizeof(*cprng->reseed_evcnt),
KM_SLEEP);
@ -103,11 +94,16 @@ cprng_fast_get(struct cprng_fast **cprngp)
struct cprng_fast *cprng;
int s;
*cprngp = cprng = percpu_getref(cprng_fast_percpu);
s = splvm();
KASSERT(!cpu_intr_p());
if (__predict_false(cprng->epoch != entropy_epoch()))
cprng_fast_schedule_reseed(cprng);
*cprngp = cprng = percpu_getref(cprng_fast_percpu);
s = splsoftserial();
if (__predict_false(cprng->epoch != entropy_epoch())) {
splx(s);
cprng_fast_reseed(cprng);
s = splsoftserial();
}
return s;
}
@ -123,29 +119,19 @@ cprng_fast_put(struct cprng_fast *cprng, int s)
}
static void
cprng_fast_schedule_reseed(struct cprng_fast *cprng __unused)
{
softint_schedule(cprng_fast_softint);
}
static void
cprng_fast_intr(void *cookie __unused)
cprng_fast_reseed(struct cprng_fast *cprng)
{
unsigned epoch = entropy_epoch();
struct cprng_fast *cprng;
uint8_t seed[CPRNG_FAST_SEED_BYTES];
int s;
cprng_strong(kern_cprng, seed, sizeof(seed), 0);
cprng = percpu_getref(cprng_fast_percpu);
s = splvm();
s = splsoftserial();
cprng_fast_seed(cprng, seed);
cprng->epoch = epoch;
cprng->reseed_evcnt->ev_count++;
splx(s);
percpu_putref(cprng_fast_percpu);
explicit_memset(seed, 0, sizeof(seed));
}