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Diffstat (limited to 'arch/x86/crypto/aes-xts-avx-x86_64.S')
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1 files changed, 800 insertions, 0 deletions
diff --git a/arch/x86/crypto/aes-xts-avx-x86_64.S b/arch/x86/crypto/aes-xts-avx-x86_64.S new file mode 100644 index 000000000000..a5e2783c46ec --- /dev/null +++ b/arch/x86/crypto/aes-xts-avx-x86_64.S @@ -0,0 +1,800 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * AES-XTS for modern x86_64 CPUs + * + * Copyright 2024 Google LLC + * + * Author: Eric Biggers <ebiggers@google.com> + */ + +/* + * This file implements AES-XTS for modern x86_64 CPUs. To handle the + * complexities of coding for x86 SIMD, e.g. where every vector length needs + * different code, it uses a macro to generate several implementations that + * share similar source code but are targeted at different CPUs, listed below: + * + * AES-NI + AVX + * - 128-bit vectors (1 AES block per vector) + * - VEX-coded instructions + * - xmm0-xmm15 + * - This is for older CPUs that lack VAES but do have AVX. + * + * VAES + VPCLMULQDQ + AVX2 + * - 256-bit vectors (2 AES blocks per vector) + * - VEX-coded instructions + * - ymm0-ymm15 + * - This is for CPUs that have VAES but lack AVX512 or AVX10, + * e.g. Intel's Alder Lake and AMD's Zen 3. + * + * VAES + VPCLMULQDQ + AVX10/256 + BMI2 + * - 256-bit vectors (2 AES blocks per vector) + * - EVEX-coded instructions + * - ymm0-ymm31 + * - This is for CPUs that have AVX512 but where using zmm registers causes + * downclocking, and for CPUs that have AVX10/256 but not AVX10/512. + * - By "AVX10/256" we really mean (AVX512BW + AVX512VL) || AVX10/256. + * To avoid confusion with 512-bit, we just write AVX10/256. + * + * VAES + VPCLMULQDQ + AVX10/512 + BMI2 + * - Same as the previous one, but upgrades to 512-bit vectors + * (4 AES blocks per vector) in zmm0-zmm31. + * - This is for CPUs that have good AVX512 or AVX10/512 support. + * + * This file doesn't have an implementation for AES-NI alone (without AVX), as + * the lack of VEX would make all the assembly code different. + * + * When we use VAES, we also use VPCLMULQDQ to parallelize the computation of + * the XTS tweaks. This avoids a bottleneck. Currently there don't seem to be + * any CPUs that support VAES but not VPCLMULQDQ. If that changes, we might + * need to start also providing an implementation using VAES alone. + * + * The AES-XTS implementations in this file support everything required by the + * crypto API, including support for arbitrary input lengths and multi-part + * processing. However, they are most heavily optimized for the common case of + * power-of-2 length inputs that are processed in a single part (disk sectors). + */ + +#include <linux/linkage.h> +#include <linux/cfi_types.h> + +.section .rodata +.p2align 4 +.Lgf_poly: + // The low 64 bits of this value represent the polynomial x^7 + x^2 + x + // + 1. It is the value that must be XOR'd into the low 64 bits of the + // tweak each time a 1 is carried out of the high 64 bits. + // + // The high 64 bits of this value is just the internal carry bit that + // exists when there's a carry out of the low 64 bits of the tweak. + .quad 0x87, 1 + + // This table contains constants for vpshufb and vpblendvb, used to + // handle variable byte shifts and blending during ciphertext stealing + // on CPUs that don't support AVX10-style masking. +.Lcts_permute_table: + .byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 + .byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 + .byte 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 + .byte 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f + .byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 + .byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 +.text + +// Function parameters +.set KEY, %rdi // Initially points to crypto_aes_ctx, then is + // advanced to point directly to the round keys +.set SRC, %rsi // Pointer to next source data +.set DST, %rdx // Pointer to next destination data +.set LEN, %rcx // Remaining length in bytes +.set TWEAK, %r8 // Pointer to next tweak + +// %r9d holds the AES key length in bytes. +.set KEYLEN, %r9d + +// %rax and %r10-r11 are available as temporaries. + +.macro _define_Vi i +.if VL == 16 + .set V\i, %xmm\i +.elseif VL == 32 + .set V\i, %ymm\i +.elseif VL == 64 + .set V\i, %zmm\i +.else + .error "Unsupported Vector Length (VL)" +.endif +.endm + +.macro _define_aliases + // Define register aliases V0-V15, or V0-V31 if all 32 SIMD registers + // are available, that map to the xmm, ymm, or zmm registers according + // to the selected Vector Length (VL). + _define_Vi 0 + _define_Vi 1 + _define_Vi 2 + _define_Vi 3 + _define_Vi 4 + _define_Vi 5 + _define_Vi 6 + _define_Vi 7 + _define_Vi 8 + _define_Vi 9 + _define_Vi 10 + _define_Vi 11 + _define_Vi 12 + _define_Vi 13 + _define_Vi 14 + _define_Vi 15 +.if USE_AVX10 + _define_Vi 16 + _define_Vi 17 + _define_Vi 18 + _define_Vi 19 + _define_Vi 20 + _define_Vi 21 + _define_Vi 22 + _define_Vi 23 + _define_Vi 24 + _define_Vi 25 + _define_Vi 26 + _define_Vi 27 + _define_Vi 28 + _define_Vi 29 + _define_Vi 30 + _define_Vi 31 +.endif + + // V0-V3 hold the data blocks during the main loop, or temporary values + // otherwise. V4-V5 hold temporary values. + + // V6-V9 hold XTS tweaks. Each 128-bit lane holds one tweak. + .set TWEAK0_XMM, %xmm6 + .set TWEAK0, V6 + .set TWEAK1_XMM, %xmm7 + .set TWEAK1, V7 + .set TWEAK2, V8 + .set TWEAK3, V9 + + // V10-V13 are used for computing the next values of TWEAK[0-3]. + .set NEXT_TWEAK0, V10 + .set NEXT_TWEAK1, V11 + .set NEXT_TWEAK2, V12 + .set NEXT_TWEAK3, V13 + + // V14 holds the constant from .Lgf_poly, copied to all 128-bit lanes. + .set GF_POLY_XMM, %xmm14 + .set GF_POLY, V14 + + // V15 holds the first AES round key, copied to all 128-bit lanes. + .set KEY0_XMM, %xmm15 + .set KEY0, V15 + + // If 32 SIMD registers are available, then V16-V29 hold the remaining + // AES round keys, copied to all 128-bit lanes. +.if USE_AVX10 + .set KEY1_XMM, %xmm16 + .set KEY1, V16 + .set KEY2_XMM, %xmm17 + .set KEY2, V17 + .set KEY3_XMM, %xmm18 + .set KEY3, V18 + .set KEY4_XMM, %xmm19 + .set KEY4, V19 + .set KEY5_XMM, %xmm20 + .set KEY5, V20 + .set KEY6_XMM, %xmm21 + .set KEY6, V21 + .set KEY7_XMM, %xmm22 + .set KEY7, V22 + .set KEY8_XMM, %xmm23 + .set KEY8, V23 + .set KEY9_XMM, %xmm24 + .set KEY9, V24 + .set KEY10_XMM, %xmm25 + .set KEY10, V25 + .set KEY11_XMM, %xmm26 + .set KEY11, V26 + .set KEY12_XMM, %xmm27 + .set KEY12, V27 + .set KEY13_XMM, %xmm28 + .set KEY13, V28 + .set KEY14_XMM, %xmm29 + .set KEY14, V29 +.endif + // V30-V31 are currently unused. +.endm + +// Move a vector between memory and a register. +.macro _vmovdqu src, dst +.if VL < 64 + vmovdqu \src, \dst +.else + vmovdqu8 \src, \dst +.endif +.endm + +// Broadcast a 128-bit value into a vector. +.macro _vbroadcast128 src, dst +.if VL == 16 && !USE_AVX10 + vmovdqu \src, \dst +.elseif VL == 32 && !USE_AVX10 + vbroadcasti128 \src, \dst +.else + vbroadcasti32x4 \src, \dst +.endif +.endm + +// XOR two vectors together. +.macro _vpxor src1, src2, dst +.if USE_AVX10 + vpxord \src1, \src2, \dst +.else + vpxor \src1, \src2, \dst +.endif +.endm + +// XOR three vectors together. +.macro _xor3 src1, src2, src3_and_dst +.if USE_AVX10 + // vpternlogd with immediate 0x96 is a three-argument XOR. + vpternlogd $0x96, \src1, \src2, \src3_and_dst +.else + vpxor \src1, \src3_and_dst, \src3_and_dst + vpxor \src2, \src3_and_dst, \src3_and_dst +.endif +.endm + +// Given a 128-bit XTS tweak in the xmm register \src, compute the next tweak +// (by multiplying by the polynomial 'x') and write it to \dst. +.macro _next_tweak src, tmp, dst + vpshufd $0x13, \src, \tmp + vpaddq \src, \src, \dst + vpsrad $31, \tmp, \tmp + vpand GF_POLY_XMM, \tmp, \tmp + vpxor \tmp, \dst, \dst +.endm + +// Given the XTS tweak(s) in the vector \src, compute the next vector of +// tweak(s) (by multiplying by the polynomial 'x^(VL/16)') and write it to \dst. +// +// If VL > 16, then there are multiple tweaks, and we use vpclmulqdq to compute +// all tweaks in the vector in parallel. If VL=16, we just do the regular +// computation without vpclmulqdq, as it's the faster method for a single tweak. +.macro _next_tweakvec src, tmp1, tmp2, dst +.if VL == 16 + _next_tweak \src, \tmp1, \dst +.else + vpsrlq $64 - VL/16, \src, \tmp1 + vpclmulqdq $0x01, GF_POLY, \tmp1, \tmp2 + vpslldq $8, \tmp1, \tmp1 + vpsllq $VL/16, \src, \dst + _xor3 \tmp1, \tmp2, \dst +.endif +.endm + +// Given the first XTS tweak at (TWEAK), compute the first set of tweaks and +// store them in the vector registers TWEAK0-TWEAK3. Clobbers V0-V5. +.macro _compute_first_set_of_tweaks + vmovdqu (TWEAK), TWEAK0_XMM + _vbroadcast128 .Lgf_poly(%rip), GF_POLY +.if VL == 16 + // With VL=16, multiplying by x serially is fastest. + _next_tweak TWEAK0, %xmm0, TWEAK1 + _next_tweak TWEAK1, %xmm0, TWEAK2 + _next_tweak TWEAK2, %xmm0, TWEAK3 +.else +.if VL == 32 + // Compute the second block of TWEAK0. + _next_tweak TWEAK0_XMM, %xmm0, %xmm1 + vinserti128 $1, %xmm1, TWEAK0, TWEAK0 +.elseif VL == 64 + // Compute the remaining blocks of TWEAK0. + _next_tweak TWEAK0_XMM, %xmm0, %xmm1 + _next_tweak %xmm1, %xmm0, %xmm2 + _next_tweak %xmm2, %xmm0, %xmm3 + vinserti32x4 $1, %xmm1, TWEAK0, TWEAK0 + vinserti32x4 $2, %xmm2, TWEAK0, TWEAK0 + vinserti32x4 $3, %xmm3, TWEAK0, TWEAK0 +.endif + // Compute TWEAK[1-3] from TWEAK0. + vpsrlq $64 - 1*VL/16, TWEAK0, V0 + vpsrlq $64 - 2*VL/16, TWEAK0, V2 + vpsrlq $64 - 3*VL/16, TWEAK0, V4 + vpclmulqdq $0x01, GF_POLY, V0, V1 + vpclmulqdq $0x01, GF_POLY, V2, V3 + vpclmulqdq $0x01, GF_POLY, V4, V5 + vpslldq $8, V0, V0 + vpslldq $8, V2, V2 + vpslldq $8, V4, V4 + vpsllq $1*VL/16, TWEAK0, TWEAK1 + vpsllq $2*VL/16, TWEAK0, TWEAK2 + vpsllq $3*VL/16, TWEAK0, TWEAK3 +.if USE_AVX10 + vpternlogd $0x96, V0, V1, TWEAK1 + vpternlogd $0x96, V2, V3, TWEAK2 + vpternlogd $0x96, V4, V5, TWEAK3 +.else + vpxor V0, TWEAK1, TWEAK1 + vpxor V2, TWEAK2, TWEAK2 + vpxor V4, TWEAK3, TWEAK3 + vpxor V1, TWEAK1, TWEAK1 + vpxor V3, TWEAK2, TWEAK2 + vpxor V5, TWEAK3, TWEAK3 +.endif +.endif +.endm + +// Do one step in computing the next set of tweaks using the method of just +// multiplying by x repeatedly (the same method _next_tweak uses). +.macro _tweak_step_mulx i +.if \i == 0 + .set PREV_TWEAK, TWEAK3 + .set NEXT_TWEAK, NEXT_TWEAK0 +.elseif \i == 5 + .set PREV_TWEAK, NEXT_TWEAK0 + .set NEXT_TWEAK, NEXT_TWEAK1 +.elseif \i == 10 + .set PREV_TWEAK, NEXT_TWEAK1 + .set NEXT_TWEAK, NEXT_TWEAK2 +.elseif \i == 15 + .set PREV_TWEAK, NEXT_TWEAK2 + .set NEXT_TWEAK, NEXT_TWEAK3 +.endif +.if \i < 20 && \i % 5 == 0 + vpshufd $0x13, PREV_TWEAK, V5 +.elseif \i < 20 && \i % 5 == 1 + vpaddq PREV_TWEAK, PREV_TWEAK, NEXT_TWEAK +.elseif \i < 20 && \i % 5 == 2 + vpsrad $31, V5, V5 +.elseif \i < 20 && \i % 5 == 3 + vpand GF_POLY, V5, V5 +.elseif \i < 20 && \i % 5 == 4 + vpxor V5, NEXT_TWEAK, NEXT_TWEAK +.elseif \i == 1000 + vmovdqa NEXT_TWEAK0, TWEAK0 + vmovdqa NEXT_TWEAK1, TWEAK1 + vmovdqa NEXT_TWEAK2, TWEAK2 + vmovdqa NEXT_TWEAK3, TWEAK3 +.endif +.endm + +// Do one step in computing the next set of tweaks using the VPCLMULQDQ method +// (the same method _next_tweakvec uses for VL > 16). This means multiplying +// each tweak by x^(4*VL/16) independently. Since 4*VL/16 is a multiple of 8 +// when VL > 16 (which it is here), the needed shift amounts are byte-aligned, +// which allows the use of vpsrldq and vpslldq to do 128-bit wide shifts. +.macro _tweak_step_pclmul i +.if \i == 2 + vpsrldq $(128 - 4*VL/16) / 8, TWEAK0, NEXT_TWEAK0 +.elseif \i == 4 + vpsrldq $(128 - 4*VL/16) / 8, TWEAK1, NEXT_TWEAK1 +.elseif \i == 6 + vpsrldq $(128 - 4*VL/16) / 8, TWEAK2, NEXT_TWEAK2 +.elseif \i == 8 + vpsrldq $(128 - 4*VL/16) / 8, TWEAK3, NEXT_TWEAK3 +.elseif \i == 10 + vpclmulqdq $0x00, GF_POLY, NEXT_TWEAK0, NEXT_TWEAK0 +.elseif \i == 12 + vpclmulqdq $0x00, GF_POLY, NEXT_TWEAK1, NEXT_TWEAK1 +.elseif \i == 14 + vpclmulqdq $0x00, GF_POLY, NEXT_TWEAK2, NEXT_TWEAK2 +.elseif \i == 16 + vpclmulqdq $0x00, GF_POLY, NEXT_TWEAK3, NEXT_TWEAK3 +.elseif \i == 1000 + vpslldq $(4*VL/16) / 8, TWEAK0, TWEAK0 + vpslldq $(4*VL/16) / 8, TWEAK1, TWEAK1 + vpslldq $(4*VL/16) / 8, TWEAK2, TWEAK2 + vpslldq $(4*VL/16) / 8, TWEAK3, TWEAK3 + _vpxor NEXT_TWEAK0, TWEAK0, TWEAK0 + _vpxor NEXT_TWEAK1, TWEAK1, TWEAK1 + _vpxor NEXT_TWEAK2, TWEAK2, TWEAK2 + _vpxor NEXT_TWEAK3, TWEAK3, TWEAK3 +.endif +.endm + +// _tweak_step does one step of the computation of the next set of tweaks from +// TWEAK[0-3]. To complete all steps, this must be invoked with \i values 0 +// through at least 19, then 1000 which signals the last step. +// +// This is used to interleave the computation of the next set of tweaks with the +// AES en/decryptions, which increases performance in some cases. +.macro _tweak_step i +.if VL == 16 + _tweak_step_mulx \i +.else + _tweak_step_pclmul \i +.endif +.endm + +// Load the round keys: just the first one if !USE_AVX10, otherwise all of them. +.macro _load_round_keys + _vbroadcast128 0*16(KEY), KEY0 +.if USE_AVX10 + _vbroadcast128 1*16(KEY), KEY1 + _vbroadcast128 2*16(KEY), KEY2 + _vbroadcast128 3*16(KEY), KEY3 + _vbroadcast128 4*16(KEY), KEY4 + _vbroadcast128 5*16(KEY), KEY5 + _vbroadcast128 6*16(KEY), KEY6 + _vbroadcast128 7*16(KEY), KEY7 + _vbroadcast128 8*16(KEY), KEY8 + _vbroadcast128 9*16(KEY), KEY9 + _vbroadcast128 10*16(KEY), KEY10 + // Note: if it's AES-128 or AES-192, the last several round keys won't + // be used. We do the loads anyway to save a conditional jump. + _vbroadcast128 11*16(KEY), KEY11 + _vbroadcast128 12*16(KEY), KEY12 + _vbroadcast128 13*16(KEY), KEY13 + _vbroadcast128 14*16(KEY), KEY14 +.endif +.endm + +// Do a single round of AES encryption (if \enc==1) or decryption (if \enc==0) +// on the block(s) in \data using the round key(s) in \key. The register length +// determines the number of AES blocks en/decrypted. +.macro _vaes enc, last, key, data +.if \enc +.if \last + vaesenclast \key, \data, \data +.else + vaesenc \key, \data, \data +.endif +.else +.if \last + vaesdeclast \key, \data, \data +.else + vaesdec \key, \data, \data +.endif +.endif +.endm + +// Do a single round of AES en/decryption on the block(s) in \data, using the +// same key for all block(s). The round key is loaded from the appropriate +// register or memory location for round \i. May clobber V4. +.macro _vaes_1x enc, last, i, xmm_suffix, data +.if USE_AVX10 + _vaes \enc, \last, KEY\i\xmm_suffix, \data +.else +.ifnb \xmm_suffix + _vaes \enc, \last, \i*16(KEY), \data +.else + _vbroadcast128 \i*16(KEY), V4 + _vaes \enc, \last, V4, \data +.endif +.endif +.endm + +// Do a single round of AES en/decryption on the blocks in registers V0-V3, +// using the same key for all blocks. The round key is loaded from the +// appropriate register or memory location for round \i. In addition, does step +// \i of the computation of the next set of tweaks. May clobber V4. +.macro _vaes_4x enc, last, i +.if USE_AVX10 + _tweak_step (2*(\i-1)) + _vaes \enc, \last, KEY\i, V0 + _vaes \enc, \last, KEY\i, V1 + _tweak_step (2*(\i-1) + 1) + _vaes \enc, \last, KEY\i, V2 + _vaes \enc, \last, KEY\i, V3 +.else + _vbroadcast128 \i*16(KEY), V4 + _tweak_step (2*(\i-1)) + _vaes \enc, \last, V4, V0 + _vaes \enc, \last, V4, V1 + _tweak_step (2*(\i-1) + 1) + _vaes \enc, \last, V4, V2 + _vaes \enc, \last, V4, V3 +.endif +.endm + +// Do tweaked AES en/decryption (i.e., XOR with \tweak, then AES en/decrypt, +// then XOR with \tweak again) of the block(s) in \data. To process a single +// block, use xmm registers and set \xmm_suffix=_XMM. To process a vector of +// length VL, use V* registers and leave \xmm_suffix empty. May clobber V4. +.macro _aes_crypt enc, xmm_suffix, tweak, data + _xor3 KEY0\xmm_suffix, \tweak, \data + _vaes_1x \enc, 0, 1, \xmm_suffix, \data + _vaes_1x \enc, 0, 2, \xmm_suffix, \data + _vaes_1x \enc, 0, 3, \xmm_suffix, \data + _vaes_1x \enc, 0, 4, \xmm_suffix, \data + _vaes_1x \enc, 0, 5, \xmm_suffix, \data + _vaes_1x \enc, 0, 6, \xmm_suffix, \data + _vaes_1x \enc, 0, 7, \xmm_suffix, \data + _vaes_1x \enc, 0, 8, \xmm_suffix, \data + _vaes_1x \enc, 0, 9, \xmm_suffix, \data + cmp $24, KEYLEN + jle .Laes_128_or_192\@ + _vaes_1x \enc, 0, 10, \xmm_suffix, \data + _vaes_1x \enc, 0, 11, \xmm_suffix, \data + _vaes_1x \enc, 0, 12, \xmm_suffix, \data + _vaes_1x \enc, 0, 13, \xmm_suffix, \data + _vaes_1x \enc, 1, 14, \xmm_suffix, \data + jmp .Laes_done\@ +.Laes_128_or_192\@: + je .Laes_192\@ + _vaes_1x \enc, 1, 10, \xmm_suffix, \data + jmp .Laes_done\@ +.Laes_192\@: + _vaes_1x \enc, 0, 10, \xmm_suffix, \data + _vaes_1x \enc, 0, 11, \xmm_suffix, \data + _vaes_1x \enc, 1, 12, \xmm_suffix, \data +.Laes_done\@: + _vpxor \tweak, \data, \data +.endm + +.macro _aes_xts_crypt enc + _define_aliases + + // Load the AES key length: 16 (AES-128), 24 (AES-192), or 32 (AES-256). + movl 480(KEY), KEYLEN + + // If decrypting, advance KEY to the decryption round keys. +.if !\enc + add $240, KEY +.endif + + // Check whether the data length is a multiple of the AES block length. + test $15, LEN + jnz .Lneed_cts\@ +.Lxts_init\@: + + // Cache as many round keys as possible. + _load_round_keys + + // Compute the first set of tweaks TWEAK[0-3]. + _compute_first_set_of_tweaks + + sub $4*VL, LEN + jl .Lhandle_remainder\@ + +.Lmain_loop\@: + // This is the main loop, en/decrypting 4*VL bytes per iteration. + + // XOR each source block with its tweak and the first round key. +.if USE_AVX10 + vmovdqu8 0*VL(SRC), V0 + vmovdqu8 1*VL(SRC), V1 + vmovdqu8 2*VL(SRC), V2 + vmovdqu8 3*VL(SRC), V3 + vpternlogd $0x96, TWEAK0, KEY0, V0 + vpternlogd $0x96, TWEAK1, KEY0, V1 + vpternlogd $0x96, TWEAK2, KEY0, V2 + vpternlogd $0x96, TWEAK3, KEY0, V3 +.else + vpxor 0*VL(SRC), KEY0, V0 + vpxor 1*VL(SRC), KEY0, V1 + vpxor 2*VL(SRC), KEY0, V2 + vpxor 3*VL(SRC), KEY0, V3 + vpxor TWEAK0, V0, V0 + vpxor TWEAK1, V1, V1 + vpxor TWEAK2, V2, V2 + vpxor TWEAK3, V3, V3 +.endif + // Do all the AES rounds on the data blocks, interleaved with + // the computation of the next set of tweaks. + _vaes_4x \enc, 0, 1 + _vaes_4x \enc, 0, 2 + _vaes_4x \enc, 0, 3 + _vaes_4x \enc, 0, 4 + _vaes_4x \enc, 0, 5 + _vaes_4x \enc, 0, 6 + _vaes_4x \enc, 0, 7 + _vaes_4x \enc, 0, 8 + _vaes_4x \enc, 0, 9 + // Try to optimize for AES-256 by keeping the code for AES-128 and + // AES-192 out-of-line. + cmp $24, KEYLEN + jle .Lencrypt_4x_aes_128_or_192\@ + _vaes_4x \enc, 0, 10 + _vaes_4x \enc, 0, 11 + _vaes_4x \enc, 0, 12 + _vaes_4x \enc, 0, 13 + _vaes_4x \enc, 1, 14 +.Lencrypt_4x_done\@: + + // XOR in the tweaks again. + _vpxor TWEAK0, V0, V0 + _vpxor TWEAK1, V1, V1 + _vpxor TWEAK2, V2, V2 + _vpxor TWEAK3, V3, V3 + + // Store the destination blocks. + _vmovdqu V0, 0*VL(DST) + _vmovdqu V1, 1*VL(DST) + _vmovdqu V2, 2*VL(DST) + _vmovdqu V3, 3*VL(DST) + + // Finish computing the next set of tweaks. + _tweak_step 1000 + + add $4*VL, SRC + add $4*VL, DST + sub $4*VL, LEN + jge .Lmain_loop\@ + + // Check for the uncommon case where the data length isn't a multiple of + // 4*VL. Handle it out-of-line in order to optimize for the common + // case. In the common case, just fall through to the ret. + test $4*VL-1, LEN + jnz .Lhandle_remainder\@ +.Ldone\@: + // Store the next tweak back to *TWEAK to support continuation calls. + vmovdqu TWEAK0_XMM, (TWEAK) +.if VL > 16 + vzeroupper +.endif + RET + +.Lhandle_remainder\@: + add $4*VL, LEN // Undo the extra sub from earlier. + + // En/decrypt any remaining full blocks, one vector at a time. +.if VL > 16 + sub $VL, LEN + jl .Lvec_at_a_time_done\@ +.Lvec_at_a_time\@: + _vmovdqu (SRC), V0 + _aes_crypt \enc, , TWEAK0, V0 + _vmovdqu V0, (DST) + _next_tweakvec TWEAK0, V0, V1, TWEAK0 + add $VL, SRC + add $VL, DST + sub $VL, LEN + jge .Lvec_at_a_time\@ +.Lvec_at_a_time_done\@: + add $VL-16, LEN // Undo the extra sub from earlier. +.else + sub $16, LEN +.endif + + // En/decrypt any remaining full blocks, one at a time. + jl .Lblock_at_a_time_done\@ +.Lblock_at_a_time\@: + vmovdqu (SRC), %xmm0 + _aes_crypt \enc, _XMM, TWEAK0_XMM, %xmm0 + vmovdqu %xmm0, (DST) + _next_tweak TWEAK0_XMM, %xmm0, TWEAK0_XMM + add $16, SRC + add $16, DST + sub $16, LEN + jge .Lblock_at_a_time\@ +.Lblock_at_a_time_done\@: + add $16, LEN // Undo the extra sub from earlier. + +.Lfull_blocks_done\@: + // Now 0 <= LEN <= 15. If LEN is nonzero, do ciphertext stealing to + // process the last 16 + LEN bytes. If LEN is zero, we're done. + test LEN, LEN + jnz .Lcts\@ + jmp .Ldone\@ + + // Out-of-line handling of AES-128 and AES-192 +.Lencrypt_4x_aes_128_or_192\@: + jz .Lencrypt_4x_aes_192\@ + _vaes_4x \enc, 1, 10 + jmp .Lencrypt_4x_done\@ +.Lencrypt_4x_aes_192\@: + _vaes_4x \enc, 0, 10 + _vaes_4x \enc, 0, 11 + _vaes_4x \enc, 1, 12 + jmp .Lencrypt_4x_done\@ + +.Lneed_cts\@: + // The data length isn't a multiple of the AES block length, so + // ciphertext stealing (CTS) will be needed. Subtract one block from + // LEN so that the main loop doesn't process the last full block. The + // CTS step will process it specially along with the partial block. + sub $16, LEN + jmp .Lxts_init\@ + +.Lcts\@: + // Do ciphertext stealing (CTS) to en/decrypt the last full block and + // the partial block. CTS needs two tweaks. TWEAK0_XMM contains the + // next tweak; compute the one after that. Decryption uses these two + // tweaks in reverse order, so also define aliases to handle that. + _next_tweak TWEAK0_XMM, %xmm0, TWEAK1_XMM +.if \enc + .set CTS_TWEAK0, TWEAK0_XMM + .set CTS_TWEAK1, TWEAK1_XMM +.else + .set CTS_TWEAK0, TWEAK1_XMM + .set CTS_TWEAK1, TWEAK0_XMM +.endif + + // En/decrypt the last full block. + vmovdqu (SRC), %xmm0 + _aes_crypt \enc, _XMM, CTS_TWEAK0, %xmm0 + +.if USE_AVX10 + // Create a mask that has the first LEN bits set. + mov $-1, %rax + bzhi LEN, %rax, %rax + kmovq %rax, %k1 + + // Swap the first LEN bytes of the above result with the partial block. + // Note that to support in-place en/decryption, the load from the src + // partial block must happen before the store to the dst partial block. + vmovdqa %xmm0, %xmm1 + vmovdqu8 16(SRC), %xmm0{%k1} + vmovdqu8 %xmm1, 16(DST){%k1} +.else + lea .Lcts_permute_table(%rip), %rax + + // Load the src partial block, left-aligned. Note that to support + // in-place en/decryption, this must happen before the store to the dst + // partial block. + vmovdqu (SRC, LEN, 1), %xmm1 + + // Shift the first LEN bytes of the en/decryption of the last full block + // to the end of a register, then store it to DST+LEN. This stores the + // dst partial block. It also writes to the second part of the dst last + // full block, but that part is overwritten later. + vpshufb (%rax, LEN, 1), %xmm0, %xmm2 + vmovdqu %xmm2, (DST, LEN, 1) + + // Make xmm3 contain [16-LEN,16-LEN+1,...,14,15,0x80,0x80,...]. + sub LEN, %rax + vmovdqu 32(%rax), %xmm3 + + // Shift the src partial block to the beginning of its register. + vpshufb %xmm3, %xmm1, %xmm1 + + // Do a blend to generate the src partial block followed by the second + // part of the en/decryption of the last full block. + vpblendvb %xmm3, %xmm0, %xmm1, %xmm0 +.endif + // En/decrypt again and store the last full block. + _aes_crypt \enc, _XMM, CTS_TWEAK1, %xmm0 + vmovdqu %xmm0, (DST) + jmp .Ldone\@ +.endm + +// void aes_xts_encrypt_iv(const struct crypto_aes_ctx *tweak_key, +// u8 iv[AES_BLOCK_SIZE]); +SYM_FUNC_START(aes_xts_encrypt_iv) + vmovdqu (%rsi), %xmm0 + vpxor 0*16(%rdi), %xmm0, %xmm0 + vaesenc 1*16(%rdi), %xmm0, %xmm0 + vaesenc 2*16(%rdi), %xmm0, %xmm0 + vaesenc 3*16(%rdi), %xmm0, %xmm0 + vaesenc 4*16(%rdi), %xmm0, %xmm0 + vaesenc 5*16(%rdi), %xmm0, %xmm0 + vaesenc 6*16(%rdi), %xmm0, %xmm0 + vaesenc 7*16(%rdi), %xmm0, %xmm0 + vaesenc 8*16(%rdi), %xmm0, %xmm0 + vaesenc 9*16(%rdi), %xmm0, %xmm0 + cmpl $24, 480(%rdi) + jle .Lencrypt_iv_aes_128_or_192 + vaesenc 10*16(%rdi), %xmm0, %xmm0 + vaesenc 11*16(%rdi), %xmm0, %xmm0 + vaesenc 12*16(%rdi), %xmm0, %xmm0 + vaesenc 13*16(%rdi), %xmm0, %xmm0 + vaesenclast 14*16(%rdi), %xmm0, %xmm0 +.Lencrypt_iv_done: + vmovdqu %xmm0, (%rsi) + RET + + // Out-of-line handling of AES-128 and AES-192 +.Lencrypt_iv_aes_128_or_192: + jz .Lencrypt_iv_aes_192 + vaesenclast 10*16(%rdi), %xmm0, %xmm0 + jmp .Lencrypt_iv_done +.Lencrypt_iv_aes_192: + vaesenc 10*16(%rdi), %xmm0, %xmm0 + vaesenc 11*16(%rdi), %xmm0, %xmm0 + vaesenclast 12*16(%rdi), %xmm0, %xmm0 + jmp .Lencrypt_iv_done +SYM_FUNC_END(aes_xts_encrypt_iv) + +// Below are the actual AES-XTS encryption and decryption functions, +// instantiated from the above macro. They all have the following prototype: +// +// void (*xts_asm_func)(const struct crypto_aes_ctx *key, +// const u8 *src, u8 *dst, size_t len, +// u8 tweak[AES_BLOCK_SIZE]); +// +// |key| is the data key. |tweak| contains the next tweak; the encryption of +// the original IV with the tweak key was already done. This function supports +// incremental computation, but |len| must always be >= 16 (AES_BLOCK_SIZE), and +// |len| must be a multiple of 16 except on the last call. If |len| is a +// multiple of 16, then this function updates |tweak| to contain the next tweak. |