--- /dev/null
+/* 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.
projects / linux.git / commitdiff