[PATCH v2 01/10] ARM: p2v: fix handling of LPAE translation in BE mode

[Ard Biesheuvel]

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 #22 in its correct place when
applying the rotation to the constant #0x400000.

Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
 arch/arm/kernel/head.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index f8904227e7fd..98c1e68bdfcb 100644
--- a/arch/arm/kernel/head.S
+++ b/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
-- 
2.17.1