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 <[e-mail]>
Signed-off-by: Dave Martin <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Acked-by: Nicolas Pitre <[e-mail]>
Signed-off-by: Russell King <[e-mail]>

arch/arm/boot/compressed/head.S

···
 		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
···
  */
 		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