[src/trunk]: src/sys/crypto/cprng_fast cprng(9): cprng_fast is no longer used...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e702b6b69a56
branches:  trunk
changeset: 366608:e702b6b69a56
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Jun 01 15:44:37 2022 +0000

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

Rip out logic to defer reseeding to softint.

diffstat:

 sys/crypto/cprng_fast/cprng_fast.c |  42 ++++++++++++-------------------------
 1 files changed, 14 insertions(+), 28 deletions(-)

diffs (118 lines):

diff -r 384a01cf070a -r e702b6b69a56 sys/crypto/cprng_fast/cprng_fast.c
--- a/sys/crypto/cprng_fast/cprng_fast.c        Wed Jun 01 15:40:15 2022 +0000
+++ b/sys/crypto/cprng_fast/cprng_fast.c        Wed Jun 01 15:44:37 2022 +0000
@@ -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 @@
 #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 @@
 };
 
 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_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_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 @@
        struct cprng_fast *cprng;
        int s;
 
+       KASSERT(!cpu_intr_p());
+
        *cprngp = cprng = percpu_getref(cprng_fast_percpu);
-       s = splvm();
+       s = splsoftserial();
 
-       if (__predict_false(cprng->epoch != entropy_epoch()))
-               cprng_fast_schedule_reseed(cprng);
+       if (__predict_false(cprng->epoch != entropy_epoch())) {
+               splx(s);
+               cprng_fast_reseed(cprng);
+               s = splsoftserial();
+       }
 
        return s;
 }
@@ -123,29 +119,19 @@
 }
 
 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));
 }