[src/trunk]: src/sys/arch/aarch64/include The system registers we modify can ...

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

details:   https://anonhg.NetBSD.org/src/rev/576ff8c0d640
branches:  trunk
changeset: 974466:576ff8c0d640
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Aug 01 08:47:05 2020 +0000

description:
The system registers we modify can have an impact on memory accesses, and
we don't want the compiler to randomly re-order the instructions, so add
barriers. Same as WRMSR on x86.

diffstat:

 sys/arch/aarch64/include/armreg.h |  12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diffs (40 lines):

diff -r f4a6b326e8ff -r 576ff8c0d640 sys/arch/aarch64/include/armreg.h
--- a/sys/arch/aarch64/include/armreg.h Sat Aug 01 08:42:33 2020 +0000
+++ b/sys/arch/aarch64/include/armreg.h Sat Aug 01 08:47:05 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: armreg.h,v 1.50 2020/07/01 08:01:07 ryo Exp $ */
+/* $NetBSD: armreg.h,v 1.51 2020/08/01 08:47:05 maxv Exp $ */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
 {                                                              \
        __asm __volatile(                                       \
            ASM_ARCH(arch)                                      \
-           "msr " #regdesc ", %0" :: "r"(__val)                \
+           "msr " #regdesc ", %0" :: "r"(__val) : "memory"     \
        );                                                      \
 }
 
@@ -77,7 +77,9 @@
 static __inline void                                           \
 reg_##regname##_write(uint64_t __val)                          \
 {                                                              \
-       __asm __volatile("msr " #regdesc ", %0" :: "n"(__val)); \
+       __asm __volatile(                                       \
+           "msr " #regdesc ", %0" :: "n"(__val) : "memory"     \
+       );                                                      \
 }
 
 #define AARCH64REG_READ_INLINE(regname)                                \
@@ -97,7 +99,9 @@
 static __inline void                                           \
 reg_##regname##_write(uint64_t __val)                          \
 {                                                              \
-       __asm __volatile("at " #regdesc ", %0" :: "r"(__val));  \
+       __asm __volatile(                                       \
+           "at " #regdesc ", %0" :: "r"(__val) : "memory"      \
+       );                                                      \
 }
 
 #define AARCH64REG_ATWRITE_INLINE(regname)                     \