CODEWITHSUNDEEP
assemblyarmaesarm64
DamageInc
DamageInc

Reputation: 23

ARM assembly cryptography extensions

I'm working implementing AES-ECB encode/decode in ARM assembly. I'm working with a Jetson Nano which uses an ARM Cortex A57 which has cryptography extensions on hardware. The issue I'm running into is whenever I attempt to assemble my code, the assembler outputs the following.

aes.asm: Assembler messages:
aes.asm:14: Error: selected processor does not support `aese V0.16b,V0.16b'

Based on the documentation this CPU should support these instructions, I'm not sure what I am missing.

.section .text
.global _start
.arch armv8-a

_start:
        mov x8, 64
        mov x0, 1
        ldr x1, =str
        mov x2, str_len
        svc 0

        ldr x0, =a
        ldp q0, q1, [x0]
        aese V0.16b, V0.16b

        mov x8, 0x5D
        mov x0, 0x45
        svc 0


.section .data
str: .ascii "starting\n"
str_len = .-str

.balign 1
a: .skip 16
a_len = .-a

b: .single 3.4, 2.5, 4.4, 6.6, 7.7, 8.8
b_size = .-b

Upvotes: 2

Views: 1261

Answers (1)

Nate Eldredge
Nate Eldredge

Reputation: 58673

.arch armv8-a tells the assembler to only accept base ARMv8-A instructions. The crypto instructions are not in the base instruction set, so you have to tell the assembler if you want to use this extension. Try .arch armv8-a+crypto.

Keep in mind that the assembler has no knowledge of what extensions are supported by your target machine, unless you tell it.

See https://sourceware.org/binutils/docs/as/ARM-Options.html#ARM-Options for all architectures accepted by the -march command line option and the .arch directive.

Upvotes: 6

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