[PATCH v2] ARM: fix Thumb-2 bug in AES assembler code

[Nicolas Pitre]

On Tue, 17 Sep 2013, Ard Biesheuvel wrote:

> Patch 638591c enabled building the AES assembler code in Thumb2 mode.
> However, this code used arithmetic involving PC rather than adr{l}
> instructions to generate PC-relative references to the lookup tables,
> and this break in Thumb mode due to the different PC offset.
> 
> Use adr instructions instead.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> ---
> 
> v2:
> - use 'adr' instruction rather than explicit PC arithmetic
> - move the tables around so they are in range for 'adr' in each mode
> 
>  arch/arm/crypto/aes-armv4.S | 388 ++++++++++++++++++++++----------------------
>  1 file changed, 193 insertions(+), 195 deletions(-)

No no no.  NAK.

This makes the patch completely unreviewable.  And unacceptable for 
inclusion into the stable tree.

Also, why do you have to move tables around?

Isn't the following sufficient to fix the issue?

diff --git a/arch/arm/crypto/aes-armv4.S b/arch/arm/crypto/aes-armv4.S
index 19d6cd6f29..3a14ea8fe9 100644
--- a/arch/arm/crypto/aes-armv4.S
+++ b/arch/arm/crypto/aes-armv4.S
@@ -148,7 +148,7 @@ AES_Te:
 @ 		 const AES_KEY *key) {
 .align	5
 ENTRY(AES_encrypt)
-	sub	r3,pc,#8		@ AES_encrypt
+	adr	r3,AES_encrypt
 	stmdb   sp!,{r1,r4-r12,lr}
 	mov	r12,r0		@ inp
 	mov	r11,r2
@@ -381,7 +381,7 @@ _armv4_AES_encrypt:
 .align	5
 ENTRY(private_AES_set_encrypt_key)
 _armv4_AES_set_encrypt_key:
-	sub	r3,pc,#8		@ AES_set_encrypt_key
+	adr	r3,_armv4_AES_set_encrypt_key
 	teq	r0,#0
 	moveq	r0,#-1
 	beq	.Labrt
@@ -843,7 +843,7 @@ AES_Td:
 @ 		 const AES_KEY *key) {
 .align	5
 ENTRY(AES_decrypt)
-	sub	r3,pc,#8		@ AES_decrypt
+	adr	r3,AES_decrypt
 	stmdb   sp!,{r1,r4-r12,lr}
 	mov	r12,r0		@ inp
 	mov	r11,r2