[src/trunk]: src/sys/kern Do not cast memcpy arguments when the intention is ...

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

details:   https://anonhg.NetBSD.org/src/rev/840dd153c394
branches:  trunk
changeset: 959263:840dd153c394
user:      joerg <joerg%NetBSD.org@localhost>
date:      Sat Feb 06 13:54:48 2021 +0000

description:
Do not cast memcpy arguments when the intention is unaligned access.
The standard is pretty explicit that misaligned pointers is UB and LLVM
does exploit the promised alignment on SPARC, resulting in kernel
crashes during early boot.

diffstat:

 sys/kern/subr_kmem.c |  10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diffs (43 lines):

diff -r eb7d44f89342 -r 840dd153c394 sys/kern/subr_kmem.c
--- a/sys/kern/subr_kmem.c      Sat Feb 06 13:02:28 2021 +0000
+++ b/sys/kern/subr_kmem.c      Sat Feb 06 13:54:48 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_kmem.c,v 1.81 2021/01/24 17:29:11 thorpej Exp $   */
+/*     $NetBSD: subr_kmem.c,v 1.82 2021/02/06 13:54:48 joerg Exp $     */
 
 /*
  * Copyright (c) 2009-2020 The NetBSD Foundation, Inc.
@@ -78,7 +78,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.81 2021/01/24 17:29:11 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.82 2021/02/06 13:54:48 joerg Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kmem.h"
@@ -505,7 +505,7 @@
 static void
 kmem_size_set(void *p, size_t sz)
 {
-       memcpy((size_t *)((uintptr_t)p + sz), &sz, sizeof(size_t));
+       memcpy((char *)p + sz, &sz, sizeof(size_t));
 }
 
 static void
@@ -513,13 +513,13 @@
 {
        size_t hsz;
 
-       memcpy(&hsz, (size_t *)((uintptr_t)p + sz), sizeof(size_t));
+       memcpy(&hsz, (char *)p + sz, sizeof(size_t));
 
        if (hsz != sz) {
                panic("kmem_free(%p, %zu) != allocated size %zu; overwrote?",
                    p, sz, hsz);
        }
 
-       memset((size_t *)((uintptr_t)p + sz), 0xff, sizeof(size_t));
+       memset((char *)p + sz, 0xff, sizeof(size_t));
 }
 #endif /* defined(KMEM_SIZE) */