[RFC PATCH 2/3] ARM: iwmmxt: Port problematic iwmmxt support code to v7/Thumb-2

[Dave Martin]

The iwmmxt code contains some code to implement a pseudo-ISB, but
this is not buildable for Thumb-2.

This patch replaces the pseudo-ISB with a real one for Thumb-2
kernels.

Signed-off-by: Dave Martin <dave.martin at linaro.org>
---
 arch/arm/kernel/iwmmxt.S |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
index a087838..bee8a74 100644
--- a/arch/arm/kernel/iwmmxt.S
+++ b/arch/arm/kernel/iwmmxt.S
@@ -319,8 +319,17 @@ ENTRY(iwmmxt_task_switch)
 	PJ4(eor r1, r1, #0xf)
 	PJ4(mcr	p15, 0, r1, c1, c0, 2)
 
+/*
+ * When enough people have binutils which support -march=...+iwmmxt, this
+ * should change to #if __LINUX_ARM_ARCH__ < 7.
+ */
+#ifndef CONFIG_THUMB2_KERNEL
 	mrc	p15, 0, r1, c2, c0, 0
 	sub	pc, lr, r1, lsr #32		@ cpwait and return
+#else
+	isb					@ ISB needed instead on ARMv7
+	mov	pc, lr
+#endif
 
 /*
  * Remove Concan ownership of given task
-- 
1.7.4.1