ARM: p2v: fix handling of LPAE translation in BE mode

[ Upstream commit 4e79f02 ]

When running in BE mode on LPAE hardware with a PA-to-VA translation
that exceeds 4 GB, we patch bits 39:32 of the offset into the wrong
byte of the opcode. So fix that, by rotating the offset in r0 to the
right by 8 bits, which will put the 8-bit immediate in bits 31:24.

Note that this will also move bit Kwiboo#22 in its correct place when
applying the rotation to the constant #0x400000.

Fixes: d9a790d ("ARM: 7883/1: fix mov to mvn conversion in case of 64 bit phys_addr_t and BE")
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/arm/kernel/head.S

@@ -671,12 +671,8 @@ ARM_BE8(rev16	ip, ip)
 	ldrcc	r7, [r4], #4	@ use branch for delay slot
 	bcc	1b
 	bx	lr
-#else
-#ifdef CONFIG_CPU_ENDIAN_BE8
-	moveq	r0, #0x00004000	@ set bit 22, mov to mvn instruction
 #else
 	moveq	r0, #0x400000	@ set bit 22, mov to mvn instruction
-#endif
 	b	2f
 1:	ldr	ip, [r7, r3]
 #ifdef CONFIG_CPU_ENDIAN_BE8
@@ -685,7 +681,7 @@ ARM_BE8(rev16	ip, ip)
 	tst	ip, #0x000f0000	@ check the rotation field
 	orrne	ip, ip, r6, lsl #24 @ mask in offset bits 31-24
 	biceq	ip, ip, #0x00004000 @ clear bit 22
-	orreq	ip, ip, r0      @ mask in offset bits 7-0
+	orreq	ip, ip, r0, ror #8  @ mask in offset bits 7-0
 #else
 	bic	ip, ip, #0x000000ff
 	tst	ip, #0xf00	@ check the rotation field