ARM: v6k: select cmpxchg code sequences according to V6 variants
If CONFIG_CPU_V6 is enabled, we must avoid the byte/halfword/doubleword
exclusive operations, which aren't implemented before V6K. Use the
generic versions (or omit them) instead.
If CONFIG_CPU_V6 is not set, but CONFIG_CPU_32v6K is enabled, we have
the K extnesions, so use these new instructions.
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 97f6d60..9a87823 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -347,6 +347,7 @@
#include <asm-generic/cmpxchg-local.h>
#if __LINUX_ARM_ARCH__ < 6
+/* min ARCH < ARMv6 */
#ifdef CONFIG_SMP
#error "SMP is not supported on this platform"
@@ -365,7 +366,7 @@
#include <asm-generic/cmpxchg.h>
#endif
-#else /* __LINUX_ARM_ARCH__ >= 6 */
+#else /* min ARCH >= ARMv6 */
extern void __bad_cmpxchg(volatile void *ptr, int size);
@@ -379,7 +380,7 @@
unsigned long oldval, res;
switch (size) {
-#ifdef CONFIG_CPU_32v6K
+#ifndef CONFIG_CPU_V6 /* min ARCH >= ARMv6K */
case 1:
do {
asm volatile("@ __cmpxchg1\n"
@@ -404,7 +405,7 @@
: "memory", "cc");
} while (res);
break;
-#endif /* CONFIG_CPU_32v6K */
+#endif
case 4:
do {
asm volatile("@ __cmpxchg4\n"
@@ -450,12 +451,12 @@
unsigned long ret;
switch (size) {
-#ifndef CONFIG_CPU_32v6K
+#ifdef CONFIG_CPU_V6 /* min ARCH == ARMv6 */
case 1:
case 2:
ret = __cmpxchg_local_generic(ptr, old, new, size);
break;
-#endif /* !CONFIG_CPU_32v6K */
+#endif
default:
ret = __cmpxchg(ptr, old, new, size);
}
@@ -469,7 +470,7 @@
(unsigned long)(n), \
sizeof(*(ptr))))
-#ifdef CONFIG_CPU_32v6K
+#ifndef CONFIG_CPU_V6 /* min ARCH >= ARMv6K */
/*
* Note : ARMv7-M (currently unsupported by Linux) does not support
@@ -524,11 +525,11 @@
(unsigned long long)(o), \
(unsigned long long)(n)))
-#else /* !CONFIG_CPU_32v6K */
+#else /* min ARCH = ARMv6 */
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
-#endif /* CONFIG_CPU_32v6K */
+#endif
#endif /* __LINUX_ARM_ARCH__ >= 6 */