ARM: v6k: select clear exclusive code seqences according to V6 variants
If CONFIG_CPU_V6 is enabled, then the kernel must support ARMv6 CPUs
which don't have the V6K extensions implemented. Always use the
dummy store-exclusive method to ensure that the exclusive monitors are
cleared.
If CONFIG_CPU_V6 is not set, but CONFIG_CPU_32v6K is enabled, then we
have the K extensions available on all CPUs we're building support for,
so we can use the new clear-exclusive instruction.
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/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index ae94649..051166c 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -76,13 +76,13 @@
#ifndef CONFIG_THUMB2_KERNEL
.macro svc_exit, rpsr
msr spsr_cxsf, \rpsr
-#if defined(CONFIG_CPU_32v6K)
- clrex @ clear the exclusive monitor
- ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
-#elif defined (CONFIG_CPU_V6)
+#if defined(CONFIG_CPU_V6)
ldr r0, [sp]
strex r1, r2, [sp] @ clear the exclusive monitor
ldmib sp, {r1 - pc}^ @ load r1 - pc, cpsr
+#elif defined(CONFIG_CPU_32v6K)
+ clrex @ clear the exclusive monitor
+ ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
#else
ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
#endif
@@ -92,10 +92,10 @@
ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr
ldr lr, [sp, #\offset + S_PC]! @ get pc
msr spsr_cxsf, r1 @ save in spsr_svc
-#if defined(CONFIG_CPU_32v6K)
- clrex @ clear the exclusive monitor
-#elif defined (CONFIG_CPU_V6)
+#if defined(CONFIG_CPU_V6)
strex r1, r2, [sp] @ clear the exclusive monitor
+#elif defined(CONFIG_CPU_32v6K)
+ clrex @ clear the exclusive monitor
#endif
.if \fast
ldmdb sp, {r1 - lr}^ @ get calling r1 - lr