ARM: 6502/1: Thumb-2: Fix CONFIG_THUMB2_KERNEL breakage in compressed/head.S

Some instruction operand combinations are used here which are nor
permitted in Thumb-2.

In particular, most uses of pc as an operand are disallowed in
Thumb-2, and deprecated in ARM from ARMv7 onwards.

The modified code introduced by this patch should be compatible
with all architecture versions >= v3, with or without
CONFIG_THUMB2_KERNEL.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9be21ba648cd..be97e0832d73 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -174,7 +174,8 @@ not_angel:
                 ldr     sp, [r0, #28]
 #ifdef CONFIG_AUTO_ZRELADDR
                 @ determine final kernel image address
-                and     r4, pc, #0xf8000000
+                mov     r4, pc
+                and     r4, r4, #0xf8000000
                 add     r4, r4, #TEXT_OFFSET
 #else
                 ldr     r4, =zreladdr
@@ -445,7 +446,8 @@ __setup_mmu:	sub	r3, r4, #16384		@ Page directory size
  */
                 mov     r1, #0x1e
                 orr     r1, r1, #3 << 10
-                mov     r2, pc, lsr #20
+                mov     r2, pc
+                mov     r2, r2, lsr #20
                 orr     r1, r1, r2, lsl #20
                 add     r0, r3, r2, lsl #2
                 str     r1, [r0], #4