// SPDX-License-Identifier: GPL-2.0 /* * NEON-accelerated implementation of Speck128-XTS and Speck64-XTS * * Copyright (c) 2018 Google, Inc * * Author: Eric Biggers */ #include .text .fpu neon // arguments ROUND_KEYS .req r0 // const {u64,u32} *round_keys NROUNDS .req r1 // int nrounds DST .req r2 // void *dst SRC .req r3 // const void *src NBYTES .req r4 // unsigned int nbytes TWEAK .req r5 // void *tweak // registers which hold the data being encrypted/decrypted X0 .req q0 X0_L .req d0 X0_H .req d1 Y0 .req q1 Y0_H .req d3 X1 .req q2 X1_L .req d4 X1_H .req d5 Y1 .req q3 Y1_H .req d7 X2 .req q4 X2_L .req d8 X2_H .req d9 Y2 .req q5 Y2_H .req d11 X3 .req q6 X3_L .req d12 X3_H .req d13 Y3 .req q7 Y3_H .req d15 // the round key, duplicated in all lanes ROUND_KEY .req q8 ROUND_KEY_L .req d16 ROUND_KEY_H .req d17 // index vector for vtbl-based 8-bit rotates ROTATE_TABLE .req d18 // multiplication table for updating XTS tweaks GF128MUL_TABLE .req d19 GF64MUL_TABLE .req d19 // current XTS tweak value(s) TWEAKV .req q10 TWEAKV_L .req d20 TWEAKV_H .req d21 TMP0 .req q12 TMP0_L .req d24 TMP0_H .req d25 TMP1 .req q13 TMP2 .req q14 TMP3 .req q15 .align 4 .Lror64_8_table: .byte 1, 2, 3, 4, 5, 6, 7, 0 .Lror32_8_table: .byte 1, 2, 3, 0, 5, 6, 7, 4 .Lrol64_8_table: .byte 7, 0, 1, 2, 3, 4, 5, 6 .Lrol32_8_table: .byte 3, 0, 1, 2, 7, 4, 5, 6 .Lgf128mul_table: .byte 0, 0x87 .fill 14 .Lgf64mul_table: .byte 0, 0x1b, (0x1b << 1), (0x1b << 1) ^ 0x1b .fill 12 /* * _speck_round_128bytes() - Speck encryption round on 128 bytes at a time * * Do one Speck encryption round on the 128 bytes (8 blocks for Speck128, 16 for * Speck64) stored in X0-X3 and Y0-Y3, using the round key stored in all lanes * of ROUND_KEY. 'n' is the lane size: 64 for Speck128, or 32 for Speck64. * * The 8-bit rotates are implemented using vtbl instead of vshr + vsli because * the vtbl approach is faster on some processors and the same speed on others. */ .macro _speck_round_128bytes n // x = ror(x, 8) vtbl.8 X0_L, {X0_L}, ROTATE_TABLE vtbl.8 X0_H, {X0_H}, ROTATE_TABLE vtbl.8 X1_L, {X1_L}, ROTATE_TABLE vtbl.8 X1_H, {X1_H}, ROTATE_TABLE vtbl.8 X2_L, {X2_L}, ROTATE_TABLE vtbl.8 X2_H, {X2_H}, ROTATE_TABLE vtbl.8 X3_L, {X3_L}, ROTATE_TABLE vtbl.8 X3_H, {X3_H}, ROTATE_TABLE // x += y vadd.u\n X0, Y0 vadd.u\n X1, Y1 vadd.u\n X2, Y2 vadd.u\n X3, Y3 // x ^= k veor X0, ROUND_KEY veor X1, ROUND_KEY veor X2, ROUND_KEY veor X3, ROUND_KEY // y = rol(y, 3) vshl.u\n TMP0, Y0, #3 vshl.u\n TMP1, Y1, #3 vshl.u\n TMP2, Y2, #3 vshl.u\n TMP3, Y3, #3 vsri.u\n TMP0, Y0, #(\n - 3) vsri.u\n TMP1, Y1, #(\n - 3) vsri.u\n TMP2, Y2, #(\n - 3) vsri.u\n TMP3, Y3, #(\n - 3) // y ^= x veor Y0, TMP0, X0 veor Y1, TMP1, X1 veor Y2, TMP2, X2 veor Y3, TMP3, X3 .endm /* * _speck_unround_128bytes() - Speck decryption round on 128 bytes at a time * * This is the inverse of _speck_round_128bytes(). */ .macro _speck_unround_128bytes n // y ^= x veor TMP0, Y0, X0 veor TMP1, Y1, X1 veor TMP2, Y2, X2 veor TMP3, Y3, X3 // y = ror(y, 3) vshr.u\n Y0, TMP0, #3 vshr.u\n Y1, TMP1, #3 vshr.u\n Y2, TMP2, #3 vshr.u\n Y3, TMP3, #3 vsli.u\n Y0, TMP0, #(\n - 3) vsli.u\n Y1, TMP1, #(\n - 3) vsli.u\n Y2, TMP2, #(\n - 3) vsli.u\n Y3, TMP3, #(\n - 3) // x ^= k veor X0, ROUND_KEY veor X1, ROUND_KEY veor X2, ROUND_KEY veor X3, ROUND_KEY // x -= y vsub.u\n X0, Y0 vsub.u\n X1, Y1 vsub.u\n X2, Y2 vsub.u\n X3, Y3 // x = rol(x, 8); vtbl.8 X0_L, {X0_L}, ROTATE_TABLE vtbl.8 X0_H, {X0_H}, ROTATE_TABLE vtbl.8 X1_L, {X1_L}, ROTATE_TABLE vtbl.8 X1_H, {X1_H}, ROTATE_TABLE vtbl.8 X2_L, {X2_L}, ROTATE_TABLE vtbl.8 X2_H, {X2_H}, ROTATE_TABLE vtbl.8 X3_L, {X3_L}, ROTATE_TABLE vtbl.8 X3_H, {X3_H}, ROTATE_TABLE .endm .macro _xts128_precrypt_one dst_reg, tweak_buf, tmp // Load the next source block vld1.8 {\dst_reg}, [SRC]! // Save the current tweak in the tweak buffer vst1.8 {TWEAKV}, [\tweak_buf:128]! // XOR the next source block with the current tweak veor \dst_reg, TWEAKV /* * Calculate the next tweak by multiplying the current one by x, * modulo p(x) = x^128 + x^7 + x^2 + x + 1. */ vshr.u64 \tmp, TWEAKV, #63 vshl.u64 TWEAKV, #1 veor TWEAKV_H, \tmp\()_L vtbl.8 \tmp\()_H, {GF128MUL_TABLE}, \tmp\()_H veor TWEAKV_L, \tmp\()_H .endm .macro _xts64_precrypt_two dst_reg, tweak_buf, tmp // Load the next two source blocks vld1.8 {\dst_reg}, [SRC]! // Save the current two tweaks in the tweak buffer vst1.8 {TWEAKV}, [\tweak_buf:128]! // XOR the next two source blocks with the current two tweaks veor \dst_reg, TWEAKV /* * Calculate the next two tweaks by multiplying the current ones by x^2, * modulo p(x) = x^64 + x^4 + x^3 + x + 1. */ vshr.u64 \tmp, TWEAKV, #62 vshl.u64 TWEAKV, #2 vtbl.8 \tmp\()_L, {GF64MUL_TABLE}, \tmp\()_L vtbl.8 \tmp\()_H, {GF64MUL_TABLE}, \tmp\()_H veor TWEAKV, \tmp .endm /* * _speck_xts_crypt() - Speck-XTS encryption/decryption * * Encrypt or decrypt NBYTES bytes of data from the SRC buffer to the DST buffer * using Speck-XTS, specifically the variant with a block size of '2n' and round * count given by NROUNDS. The expanded round keys are given in ROUND_KEYS, and * the current XTS tweak value is given in TWEAK. It's assumed that NBYTES is a * nonzero multiple of 128. */ .macro _speck_xts_crypt n, decrypting push {r4-r7} mov r7, sp /* * The first four parameters were passed in registers r0-r3. Load the * additional parameters, which were passed on the stack. */ ldr NBYTES, [sp, #16] ldr TWEAK, [sp, #20] /* * If decrypting, modify the ROUND_KEYS parameter to point to the last * round key rather than the first, since for decryption the round keys * are used in reverse order. */ .if \decrypting .if \n == 64 add ROUND_KEYS, ROUND_KEYS, NROUNDS, lsl #3 sub ROUND_KEYS, #8 .else add ROUND_KEYS, ROUND_KEYS, NROUNDS, lsl #2 sub ROUND_KEYS, #4 .endif .endif // Load the index vector for vtbl-based 8-bit rotates .if \decrypting ldr r12, =.Lrol\n\()_8_table .else ldr r12, =.Lror\n\()_8_table .endif vld1.8 {ROTATE_TABLE}, [r12:64] // One-time XTS preparation /* * Allocate stack space to store 128 bytes worth of tweaks. For * performance, this space is aligned to a 16-byte boundary so that we * can use the load/store instructions that declare 16-byte alignment. * For Thumb2 compatibility, don't do the 'bic' directly on 'sp'. */ sub r12, sp, #128 bic r12, #0xf mov sp, r12 .if \n == 64 // Load first tweak vld1.8 {TWEAKV}, [TWEAK] // Load GF(2^128) multiplication table ldr r12, =.Lgf128mul_table vld1.8 {GF128MUL_TABLE}, [r12:64] .else // Load first tweak vld1.8 {TWEAKV_L}, [TWEAK] // Load GF(2^64) multiplication table ldr r12, =.Lgf64mul_table vld1.8 {GF64MUL_TABLE}, [r12:64] // Calculate second tweak, packing it together with the first vshr.u64 TMP0_L, TWEAKV_L, #63 vtbl.u8 TMP0_L, {GF64MUL_TABLE}, TMP0_L vshl.u64 TWEAKV_H, TWEAKV_L, #1 veor TWEAKV_H, TMP0_L .endif .Lnext_128bytes_\@: /* * Load the source blocks into {X,Y}[0-3], XOR them with their XTS tweak * values, and save the tweaks on the stack for later. Then * de-interleave the 'x' and 'y' elements of each block, i.e. make it so * that the X[0-3] registers contain only the second halves of blocks, * and the Y[0-3] registers contain only the first halves of blocks. * (Speck uses the order (y, x) rather than the more intuitive (x, y).) */ mov r12, sp .if \n == 64 _xts128_precrypt_one X0, r12, TMP0 _xts128_precrypt_one Y0, r12, TMP0 _xts128_precrypt_one X1, r12, TMP0 _xts128_precrypt_one Y1, r12, TMP0 _xts128_precrypt_one X2, r12, TMP0 _xts128_precrypt_one Y2, r12, TMP0 _xts128_precrypt_one X3, r12, TMP0 _xts128_precrypt_one Y3, r12, TMP0 vswp X0_L, Y0_H vswp X1_L, Y1_H vswp X2_L, Y2_H vswp X3_L, Y3_H .else _xts64_precrypt_two X0, r12, TMP0 _xts64_precrypt_two Y0, r12, TMP0 _xts64_precrypt_two X1, r12, TMP0 _xts64_precrypt_two Y1, r12, TMP0 _xts64_precrypt_two X2, r12, TMP0 _xts64_precrypt_two Y2, r12, TMP0 _xts64_precrypt_two X3, r12, TMP0 _xts64_precrypt_two Y3, r12, TMP0 vuzp.32 Y0, X0 vuzp.32 Y1, X1 vuzp.32 Y2, X2 vuzp.32 Y3, X3 .endif // Do the cipher rounds mov r12, ROUND_KEYS mov r6, NROUNDS .Lnext_round_\@: .if \decrypting .if \n == 64 vld1.64 ROUND_KEY_L, [r12] sub r12, #8 vmov ROUND_KEY_H, ROUND_KEY_L .else vld1.32 {ROUND_KEY_L[],ROUND_KEY_H[]}, [r12] sub r12, #4 .endif _speck_unround_128bytes \n .else .if \n == 64 vld1.64 ROUND_KEY_L, [r12]! vmov ROUND_KEY_H, ROUND_KEY_L .else vld1.32 {ROUND_KEY_L[],ROUND_KEY_H[]}, [r12]! .endif _speck_round_128bytes \n .endif subs r6, r6, #1 bne .Lnext_round_\@ // Re-interleave the 'x' and 'y' elements of each block .if \n == 64 vswp X0_L, Y0_H vswp X1_L, Y1_H vswp X2_L, Y2_H vswp X3_L, Y3_H .else vzip.32 Y0, X0 vzip.32 Y1, X1 vzip.32 Y2, X2 vzip.32 Y3, X3 .endif // XOR the encrypted/decrypted blocks with the tweaks we saved earlier mov r12, sp vld1.8 {TMP0, TMP1}, [r12:128]! vld1.8 {TMP2, TMP3}, [r12:128]! veor X0, TMP0 veor Y0, TMP1 veor X1, TMP2 veor Y1, TMP3 vld1.8 {TMP0, TMP1}, [r12:128]! vld1.8 {TMP2, TMP3}, [r12:128]! veor X2, TMP0 veor Y2, TMP1 veor X3, TMP2 veor Y3, TMP3 // Store the ciphertext in the destination buffer vst1.8 {X0, Y0}, [DST]! vst1.8 {X1, Y1}, [DST]! vst1.8 {X2, Y2}, [DST]! vst1.8 {X3, Y3}, [DST]! // Continue if there are more 128-byte chunks remaining, else return subs NBYTES, #128 bne .Lnext_128bytes_\@ // Store the next tweak .if \n == 64 vst1.8 {TWEAKV}, [TWEAK] .else vst1.8 {TWEAKV_L}, [TWEAK] .endif mov sp, r7 pop {r4-r7} bx lr .endm ENTRY(speck128_xts_encrypt_neon) _speck_xts_crypt n=64, decrypting=0 ENDPROC(speck128_xts_encrypt_neon) ENTRY(speck128_xts_decrypt_neon) _speck_xts_crypt n=64, decrypting=1 ENDPROC(speck128_xts_decrypt_neon) ENTRY(speck64_xts_encrypt_neon) _speck_xts_crypt n=32, decrypting=0 ENDPROC(speck64_xts_encrypt_neon) ENTRY(speck64_xts_decrypt_neon) _speck_xts_crypt n=32, decrypting=1 ENDPROC(speck64_xts_decrypt_neon)