From 45a4777e5b3826cb614263b200a46d305cb95c39 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 16 Sep 2020 15:36:40 +0300 Subject: [PATCH] crypto: arm/aes-neonbs - avoid hacks to prevent Thumb2 mode switches Instead of using a homegrown macrofied version of the adr instruction that sets the Thumb bit in the output value, only to ensure that any bx instructions consuming that value will not switch out of Thumb mode when branching, use non-interworking mov (to PC) instructions, which achieve the same thing. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm/crypto/aes-neonbs-core.S | 49 ++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 27 deletions(-) diff --git a/arch/arm/crypto/aes-neonbs-core.S b/arch/arm/crypto/aes-neonbs-core.S index cfaed4e..07cde13 100644 --- a/arch/arm/crypto/aes-neonbs-core.S +++ b/arch/arm/crypto/aes-neonbs-core.S @@ -77,11 +77,6 @@ vldr \out\()h, \sym + 8 .endm - .macro __adr, reg, lbl - adr \reg, \lbl -THUMB( orr \reg, \reg, #1 ) - .endm - .macro in_bs_ch, b0, b1, b2, b3, b4, b5, b6, b7 veor \b2, \b2, \b1 veor \b5, \b5, \b6 @@ -629,11 +624,11 @@ ENDPROC(aesbs_decrypt8) push {r4-r6, lr} ldr r5, [sp, #16] // number of blocks -99: __adr ip, 0f +99: adr ip, 0f and lr, r5, #7 cmp r5, #8 sub ip, ip, lr, lsl #2 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q0}, [r1]! vld1.8 {q1}, [r1]! @@ -648,11 +643,11 @@ ENDPROC(aesbs_decrypt8) mov rounds, r3 bl \do8 - __adr ip, 1f + adr ip, 1f and lr, r5, #7 cmp r5, #8 sub ip, ip, lr, lsl #2 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vst1.8 {\o0}, [r0]! vst1.8 {\o1}, [r0]! @@ -689,12 +684,12 @@ ENTRY(aesbs_cbc_decrypt) push {r4-r6, lr} ldm ip, {r5-r6} // load args 4-5 -99: __adr ip, 0f +99: adr ip, 0f and lr, r5, #7 cmp r5, #8 sub ip, ip, lr, lsl #2 mov lr, r1 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q0}, [lr]! vld1.8 {q1}, [lr]! @@ -718,11 +713,11 @@ ENTRY(aesbs_cbc_decrypt) vmov q14, q8 vmov q15, q8 - __adr ip, 1f + adr ip, 1f and lr, r5, #7 cmp r5, #8 sub ip, ip, lr, lsl #2 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q9}, [r1]! vld1.8 {q10}, [r1]! @@ -733,9 +728,9 @@ ENTRY(aesbs_cbc_decrypt) vld1.8 {q15}, [r1]! W(nop) -1: __adr ip, 2f +1: adr ip, 2f sub ip, ip, lr, lsl #3 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 veor q0, q0, q8 vst1.8 {q0}, [r0]! @@ -804,13 +799,13 @@ ENTRY(aesbs_ctr_encrypt) vmov q6, q0 vmov q7, q0 - __adr ip, 0f + adr ip, 0f sub lr, r5, #1 and lr, lr, #7 cmp r5, #8 sub ip, ip, lr, lsl #5 sub ip, ip, lr, lsl #2 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 next_ctr q1 next_ctr q2 @@ -824,13 +819,13 @@ ENTRY(aesbs_ctr_encrypt) mov rounds, r3 bl aesbs_encrypt8 - __adr ip, 1f + adr ip, 1f and lr, r5, #7 cmp r5, #8 movgt r4, #0 ldrle r4, [sp, #40] // load final in the last round sub ip, ip, lr, lsl #2 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q8}, [r1]! vld1.8 {q9}, [r1]! @@ -843,10 +838,10 @@ ENTRY(aesbs_ctr_encrypt) 1: bne 2f vld1.8 {q15}, [r1]! -2: __adr ip, 3f +2: adr ip, 3f cmp r5, #8 sub ip, ip, lr, lsl #3 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 veor q0, q0, q8 vst1.8 {q0}, [r0]! @@ -900,12 +895,12 @@ __xts_prepare8: vshr.u64 d30, d31, #7 vmov q12, q14 - __adr ip, 0f + adr ip, 0f and r4, r6, #7 cmp r6, #8 sub ip, ip, r4, lsl #5 mov r4, sp - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q0}, [r1]! next_tweak q12, q14, q15, q13 @@ -973,12 +968,12 @@ ENDPROC(__xts_prepare8) mov rounds, r3 bl \do8 - __adr ip, 0f + adr ip, 0f and lr, r6, #7 cmp r6, #8 sub ip, ip, lr, lsl #2 mov r4, sp - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 vld1.8 {q8}, [r4, :128]! vld1.8 {q9}, [r4, :128]! @@ -989,9 +984,9 @@ ENDPROC(__xts_prepare8) vld1.8 {q14}, [r4, :128]! vld1.8 {q15}, [r4, :128] -0: __adr ip, 1f +0: adr ip, 1f sub ip, ip, lr, lsl #3 - bxlt ip // computed goto if blocks < 8 + movlt pc, ip // computed goto if blocks < 8 veor \o0, \o0, q8 vst1.8 {\o0}, [r0]! -- 2.7.4