Module Name: src
Committed By: riastradh
Date: Sun Feb 13 13:41:44 UTC 2022
Modified Files:
src/sys/arch/m68k/include: lock.h
Log Message:
m68k: __cpu_simple_unlock audit.
- Use `cc' clobbers in asm volatile because they touch the condition
codes.
- Use `memory' clobbers in asm volatile so the compiler doesn't move
up loads and stores in the critical section at _other_ addresses
than the lock so they happen before __cpu_simple_lock or
__cpu_simple_lock_try.
- Not sure if we have any (or if there even are any?) multicore m68k
systems out there, but __cpu_simple_unlock needs __insn_barrier
either way so the compiler doesn't delay loads and stores prior to
__cpu_simple_unlock so they happen after it.
To generate a diff of this commit:
cvs rdiff -u -r1.16 -r1.17 src/sys/arch/m68k/include/lock.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/m68k/include/lock.h
diff -u src/sys/arch/m68k/include/lock.h:1.16 src/sys/arch/m68k/include/lock.h:1.17
--- src/sys/arch/m68k/include/lock.h:1.16 Fri Nov 29 20:05:49 2019
+++ src/sys/arch/m68k/include/lock.h Sun Feb 13 13:41:44 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: lock.h,v 1.16 2019/11/29 20:05:49 riastradh Exp $ */
+/* $NetBSD: lock.h,v 1.17 2022/02/13 13:41:44 riastradh Exp $ */
/*-
* Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -75,7 +75,9 @@ __cpu_simple_lock(__cpu_simple_lock_t *a
__asm volatile(
"1: tas %0 \n"
" jne 1b \n"
- : "=m" (*alp));
+ : "=m" (*alp)
+ : /* no inputs */
+ : "cc", "memory");
}
static __inline int
@@ -89,7 +91,9 @@ __cpu_simple_lock_try(__cpu_simple_lock_
" jeq 1f \n"
" moveq #0, %1 \n"
"1: \n"
- : "=m" (*alp), "=d" (__rv));
+ : "=m" (*alp), "=d" (__rv)
+ : /* no inputs */
+ : "cc", "memory");
return (__rv);
}
@@ -98,6 +102,7 @@ static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *alp)
{
+ __insn_barrier();
*alp = __SIMPLELOCK_UNLOCKED;
}
