[src/trunk]: src/sys/arch/x86/x86 Check for undefined behaviour when doing ri...

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

details:   https://anonhg.NetBSD.org/src/rev/b9ff2c41904e
branches:  trunk
changeset: 829387:b9ff2c41904e
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Sun Jan 28 15:00:42 2018 +0000

description:
Check for undefined behaviour when doing right-shift.

diffstat:

 sys/arch/x86/x86/cpu_topology.c |  9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diffs (30 lines):

diff -r b791fed4a61e -r b9ff2c41904e sys/arch/x86/x86/cpu_topology.c
--- a/sys/arch/x86/x86/cpu_topology.c   Sun Jan 28 14:34:26 2018 +0000
+++ b/sys/arch/x86/x86/cpu_topology.c   Sun Jan 28 15:00:42 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu_topology.c,v 1.10 2017/09/07 06:40:42 msaitoh Exp $        */
+/*     $NetBSD: cpu_topology.c,v 1.11 2018/01/28 15:00:42 mlelstv Exp $        */
 
 /*-
  * Copyright (c) 2009 Mindaugas Rasiukevicius <rmind at NetBSD org>,
@@ -36,7 +36,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu_topology.c,v 1.10 2017/09/07 06:40:42 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu_topology.c,v 1.11 2018/01/28 15:00:42 mlelstv Exp $");
 
 #include <sys/param.h>
 #include <sys/bitops.h>
@@ -151,7 +151,10 @@
        }
 
        if (smt_bits + core_bits) {
-               ci->ci_package_id = apic_id >> (smt_bits + core_bits);
+               if (smt_bits + core_bits < sizeof(apic_id) * NBBY)
+                       ci->ci_package_id = apic_id >> (smt_bits + core_bits);
+               else
+                       ci->ci_package_id = 0;
        }
        if (core_bits) {
                u_int core_mask = __BITS(smt_bits, smt_bits + core_bits - 1);