| /* |
| * Scalar AES core transform |
| * |
| * Copyright (C) 2017 Linaro Ltd. |
| * Author: Ard Biesheuvel <ard.biesheuvel@linaro.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/linkage.h> |
| #include <asm/assembler.h> |
| #include <asm/cache.h> |
| |
| .text |
| .align 5 |
| |
| rk .req r0 |
| rounds .req r1 |
| in .req r2 |
| out .req r3 |
| ttab .req ip |
| |
| t0 .req lr |
| t1 .req r2 |
| t2 .req r3 |
| |
| .macro __select, out, in, idx |
| .if __LINUX_ARM_ARCH__ < 7 |
| and \out, \in, #0xff << (8 * \idx) |
| .else |
| ubfx \out, \in, #(8 * \idx), #8 |
| .endif |
| .endm |
| |
| .macro __load, out, in, idx, sz, op |
| .if __LINUX_ARM_ARCH__ < 7 && \idx > 0 |
| ldr\op \out, [ttab, \in, lsr #(8 * \idx) - \sz] |
| .else |
| ldr\op \out, [ttab, \in, lsl #\sz] |
| .endif |
| .endm |
| |
| .macro __hround, out0, out1, in0, in1, in2, in3, t3, t4, enc, sz, op, oldcpsr |
| __select \out0, \in0, 0 |
| __select t0, \in1, 1 |
| __load \out0, \out0, 0, \sz, \op |
| __load t0, t0, 1, \sz, \op |
| |
| .if \enc |
| __select \out1, \in1, 0 |
| __select t1, \in2, 1 |
| .else |
| __select \out1, \in3, 0 |
| __select t1, \in0, 1 |
| .endif |
| __load \out1, \out1, 0, \sz, \op |
| __select t2, \in2, 2 |
| __load t1, t1, 1, \sz, \op |
| __load t2, t2, 2, \sz, \op |
| |
| eor \out0, \out0, t0, ror #24 |
| |
| __select t0, \in3, 3 |
| .if \enc |
| __select \t3, \in3, 2 |
| __select \t4, \in0, 3 |
| .else |
| __select \t3, \in1, 2 |
| __select \t4, \in2, 3 |
| .endif |
| __load \t3, \t3, 2, \sz, \op |
| __load t0, t0, 3, \sz, \op |
| __load \t4, \t4, 3, \sz, \op |
| |
| .ifnb \oldcpsr |
| /* |
| * This is the final round and we're done with all data-dependent table |
| * lookups, so we can safely re-enable interrupts. |
| */ |
| restore_irqs \oldcpsr |
| .endif |
| |
| eor \out1, \out1, t1, ror #24 |
| eor \out0, \out0, t2, ror #16 |
| ldm rk!, {t1, t2} |
| eor \out1, \out1, \t3, ror #16 |
| eor \out0, \out0, t0, ror #8 |
| eor \out1, \out1, \t4, ror #8 |
| eor \out0, \out0, t1 |
| eor \out1, \out1, t2 |
| .endm |
| |
| .macro fround, out0, out1, out2, out3, in0, in1, in2, in3, sz=2, op, oldcpsr |
| __hround \out0, \out1, \in0, \in1, \in2, \in3, \out2, \out3, 1, \sz, \op |
| __hround \out2, \out3, \in2, \in3, \in0, \in1, \in1, \in2, 1, \sz, \op, \oldcpsr |
| .endm |
| |
| .macro iround, out0, out1, out2, out3, in0, in1, in2, in3, sz=2, op, oldcpsr |
| __hround \out0, \out1, \in0, \in3, \in2, \in1, \out2, \out3, 0, \sz, \op |
| __hround \out2, \out3, \in2, \in1, \in0, \in3, \in1, \in0, 0, \sz, \op, \oldcpsr |
| .endm |
| |
| .macro __rev, out, in |
| .if __LINUX_ARM_ARCH__ < 6 |
| lsl t0, \in, #24 |
| and t1, \in, #0xff00 |
| and t2, \in, #0xff0000 |
| orr \out, t0, \in, lsr #24 |
| orr \out, \out, t1, lsl #8 |
| orr \out, \out, t2, lsr #8 |
| .else |
| rev \out, \in |
| .endif |
| .endm |
| |
| .macro __adrl, out, sym, c |
| .if __LINUX_ARM_ARCH__ < 7 |
| ldr\c \out, =\sym |
| .else |
| movw\c \out, #:lower16:\sym |
| movt\c \out, #:upper16:\sym |
| .endif |
| .endm |
| |
| .macro do_crypt, round, ttab, ltab, bsz |
| push {r3-r11, lr} |
| |
| // Load keys first, to reduce latency in case they're not cached yet. |
| ldm rk!, {r8-r11} |
| |
| ldr r4, [in] |
| ldr r5, [in, #4] |
| ldr r6, [in, #8] |
| ldr r7, [in, #12] |
| |
| #ifdef CONFIG_CPU_BIG_ENDIAN |
| __rev r4, r4 |
| __rev r5, r5 |
| __rev r6, r6 |
| __rev r7, r7 |
| #endif |
| |
| eor r4, r4, r8 |
| eor r5, r5, r9 |
| eor r6, r6, r10 |
| eor r7, r7, r11 |
| |
| __adrl ttab, \ttab |
| /* |
| * Disable interrupts and prefetch the 1024-byte 'ft' or 'it' table into |
| * L1 cache, assuming cacheline size >= 32. This is a hardening measure |
| * intended to make cache-timing attacks more difficult. They may not |
| * be fully prevented, however; see the paper |
| * https://cr.yp.to/antiforgery/cachetiming-20050414.pdf |
| * ("Cache-timing attacks on AES") for a discussion of the many |
| * difficulties involved in writing truly constant-time AES software. |
| */ |
| save_and_disable_irqs t0 |
| .set i, 0 |
| .rept 1024 / 128 |
| ldr r8, [ttab, #i + 0] |
| ldr r9, [ttab, #i + 32] |
| ldr r10, [ttab, #i + 64] |
| ldr r11, [ttab, #i + 96] |
| .set i, i + 128 |
| .endr |
| push {t0} // oldcpsr |
| |
| tst rounds, #2 |
| bne 1f |
| |
| 0: \round r8, r9, r10, r11, r4, r5, r6, r7 |
| \round r4, r5, r6, r7, r8, r9, r10, r11 |
| |
| 1: subs rounds, rounds, #4 |
| \round r8, r9, r10, r11, r4, r5, r6, r7 |
| bls 2f |
| \round r4, r5, r6, r7, r8, r9, r10, r11 |
| b 0b |
| |
| 2: .ifb \ltab |
| add ttab, ttab, #1 |
| .else |
| __adrl ttab, \ltab |
| // Prefetch inverse S-box for final round; see explanation above |
| .set i, 0 |
| .rept 256 / 64 |
| ldr t0, [ttab, #i + 0] |
| ldr t1, [ttab, #i + 32] |
| .set i, i + 64 |
| .endr |
| .endif |
| |
| pop {rounds} // oldcpsr |
| \round r4, r5, r6, r7, r8, r9, r10, r11, \bsz, b, rounds |
| |
| #ifdef CONFIG_CPU_BIG_ENDIAN |
| __rev r4, r4 |
| __rev r5, r5 |
| __rev r6, r6 |
| __rev r7, r7 |
| #endif |
| |
| ldr out, [sp] |
| |
| str r4, [out] |
| str r5, [out, #4] |
| str r6, [out, #8] |
| str r7, [out, #12] |
| |
| pop {r3-r11, pc} |
| |
| .align 3 |
| .ltorg |
| .endm |
| |
| ENTRY(__aes_arm_encrypt) |
| do_crypt fround, crypto_ft_tab,, 2 |
| ENDPROC(__aes_arm_encrypt) |
| |
| .align 5 |
| ENTRY(__aes_arm_decrypt) |
| do_crypt iround, crypto_it_tab, __aes_arm_inverse_sbox, 0 |
| ENDPROC(__aes_arm_decrypt) |
| |
| .section ".rodata", "a" |
| .align L1_CACHE_SHIFT |
| .type __aes_arm_inverse_sbox, %object |
| __aes_arm_inverse_sbox: |
| .byte 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38 |
| .byte 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb |
| .byte 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87 |
| .byte 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb |
| .byte 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d |
| .byte 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e |
| .byte 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2 |
| .byte 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25 |
| .byte 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16 |
| .byte 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92 |
| .byte 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda |
| .byte 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84 |
| .byte 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a |
| .byte 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06 |
| .byte 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02 |
| .byte 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b |
| .byte 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea |
| .byte 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73 |
| .byte 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85 |
| .byte 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e |
| .byte 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89 |
| .byte 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b |
| .byte 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20 |
| .byte 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4 |
| .byte 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31 |
| .byte 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f |
| .byte 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d |
| .byte 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef |
| .byte 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0 |
| .byte 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61 |
| .byte 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26 |
| .byte 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d |
| .size __aes_arm_inverse_sbox, . - __aes_arm_inverse_sbox |