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diff --git a/arch/x86/crypto/aes-gcm-avx10-x86_64.S b/arch/x86/crypto/aes-gcm-avx10-x86_64.S new file mode 100644 index 000000000000..97e0ee515fc5 --- /dev/null +++ b/arch/x86/crypto/aes-gcm-avx10-x86_64.S @@ -0,0 +1,1222 @@ +/* SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause */ +// +// VAES and VPCLMULQDQ optimized AES-GCM for x86_64 +// +// Copyright 2024 Google LLC +// +// Author: Eric Biggers <ebiggers@google.com> +// +//------------------------------------------------------------------------------ +// +// This file is dual-licensed, meaning that you can use it under your choice of +// either of the following two licenses: +// +// Licensed under the Apache License 2.0 (the "License"). You may obtain a copy +// of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// or +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, +// this list of conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE +// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +// POSSIBILITY OF SUCH DAMAGE. +// +//------------------------------------------------------------------------------ +// +// This file implements AES-GCM (Galois/Counter Mode) for x86_64 CPUs that +// support VAES (vector AES), VPCLMULQDQ (vector carryless multiplication), and +// either AVX512 or AVX10. Some of the functions, notably the encryption and +// decryption update functions which are the most performance-critical, are +// provided in two variants generated from a macro: one using 256-bit vectors +// (suffix: vaes_avx10_256) and one using 512-bit vectors (vaes_avx10_512). The +// other, "shared" functions (vaes_avx10) use at most 256-bit vectors. +// +// The functions that use 512-bit vectors are intended for CPUs that support +// 512-bit vectors *and* where using them doesn't cause significant +// downclocking. They require the following CPU features: +// +// VAES && VPCLMULQDQ && BMI2 && ((AVX512BW && AVX512VL) || AVX10/512) +// +// The other functions require the following CPU features: +// +// VAES && VPCLMULQDQ && BMI2 && ((AVX512BW && AVX512VL) || AVX10/256) +// +// All functions use the "System V" ABI. The Windows ABI is not supported. +// +// Note that we use "avx10" in the names of the functions as a shorthand to +// really mean "AVX10 or a certain set of AVX512 features". Due to Intel's +// introduction of AVX512 and then its replacement by AVX10, there doesn't seem +// to be a simple way to name things that makes sense on all CPUs. +// +// Note that the macros that support both 256-bit and 512-bit vectors could +// fairly easily be changed to support 128-bit too. However, this would *not* +// be sufficient to allow the code to run on CPUs without AVX512 or AVX10, +// because the code heavily uses several features of these extensions other than +// the vector length: the increase in the number of SIMD registers from 16 to +// 32, masking support, and new instructions such as vpternlogd (which can do a +// three-argument XOR). These features are very useful for AES-GCM. + +#include <linux/linkage.h> + +.section .rodata +.p2align 6 + + // A shuffle mask that reflects the bytes of 16-byte blocks +.Lbswap_mask: + .octa 0x000102030405060708090a0b0c0d0e0f + + // This is the GHASH reducing polynomial without its constant term, i.e. + // x^128 + x^7 + x^2 + x, represented using the backwards mapping + // between bits and polynomial coefficients. + // + // Alternatively, it can be interpreted as the naturally-ordered + // representation of the polynomial x^127 + x^126 + x^121 + 1, i.e. the + // "reversed" GHASH reducing polynomial without its x^128 term. +.Lgfpoly: + .octa 0xc2000000000000000000000000000001 + + // Same as above, but with the (1 << 64) bit set. +.Lgfpoly_and_internal_carrybit: + .octa 0xc2000000000000010000000000000001 + + // The below constants are used for incrementing the counter blocks. + // ctr_pattern points to the four 128-bit values [0, 1, 2, 3]. + // inc_2blocks and inc_4blocks point to the single 128-bit values 2 and + // 4. Note that the same '2' is reused in ctr_pattern and inc_2blocks. +.Lctr_pattern: + .octa 0 + .octa 1 +.Linc_2blocks: + .octa 2 + .octa 3 +.Linc_4blocks: + .octa 4 + +// Number of powers of the hash key stored in the key struct. The powers are +// stored from highest (H^NUM_H_POWERS) to lowest (H^1). +#define NUM_H_POWERS 16 + +// Offset to AES key length (in bytes) in the key struct +#define OFFSETOF_AESKEYLEN 480 + +// Offset to start of hash key powers array in the key struct +#define OFFSETOF_H_POWERS 512 + +// Offset to end of hash key powers array in the key struct. +// +// This is immediately followed by three zeroized padding blocks, which are +// included so that partial vectors can be handled more easily. E.g. if VL=64 +// and two blocks remain, we load the 4 values [H^2, H^1, 0, 0]. The most +// padding blocks needed is 3, which occurs if [H^1, 0, 0, 0] is loaded. +#define OFFSETOFEND_H_POWERS (OFFSETOF_H_POWERS + (NUM_H_POWERS * 16)) + +.text + +// Set the vector length in bytes. This sets the VL variable and defines +// register aliases V0-V31 that map to the ymm or zmm registers. +.macro _set_veclen vl + .set VL, \vl +.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15, \ + 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31 +.if VL == 32 + .set V\i, %ymm\i +.elseif VL == 64 + .set V\i, %zmm\i +.else + .error "Unsupported vector length" +.endif +.endr +.endm + +// The _ghash_mul_step macro does one step of GHASH multiplication of the +// 128-bit lanes of \a by the corresponding 128-bit lanes of \b and storing the +// reduced products in \dst. \t0, \t1, and \t2 are temporary registers of the +// same size as \a and \b. To complete all steps, this must invoked with \i=0 +// through \i=9. The division into steps allows users of this macro to +// optionally interleave the computation with other instructions. Users of this +// macro must preserve the parameter registers across steps. +// +// The multiplications are done in GHASH's representation of the finite field +// GF(2^128). Elements of GF(2^128) are represented as binary polynomials +// (i.e. polynomials whose coefficients are bits) modulo a reducing polynomial +// G. The GCM specification uses G = x^128 + x^7 + x^2 + x + 1. Addition is +// just XOR, while multiplication is more complex and has two parts: (a) do +// carryless multiplication of two 128-bit input polynomials to get a 256-bit +// intermediate product polynomial, and (b) reduce the intermediate product to +// 128 bits by adding multiples of G that cancel out terms in it. (Adding +// multiples of G doesn't change which field element the polynomial represents.) +// +// Unfortunately, the GCM specification maps bits to/from polynomial +// coefficients backwards from the natural order. In each byte it specifies the +// highest bit to be the lowest order polynomial coefficient, *not* the highest! +// This makes it nontrivial to work with the GHASH polynomials. We could +// reflect the bits, but x86 doesn't have an instruction that does that. +// +// Instead, we operate on the values without bit-reflecting them. This *mostly* +// just works, since XOR and carryless multiplication are symmetric with respect +// to bit order, but it has some consequences. First, due to GHASH's byte +// order, by skipping bit reflection, *byte* reflection becomes necessary to +// give the polynomial terms a consistent order. E.g., considering an N-bit +// value interpreted using the G = x^128 + x^7 + x^2 + x + 1 convention, bits 0 +// through N-1 of the byte-reflected value represent the coefficients of x^(N-1) +// through x^0, whereas bits 0 through N-1 of the non-byte-reflected value +// represent x^7...x^0, x^15...x^8, ..., x^(N-1)...x^(N-8) which can't be worked +// with. Fortunately, x86's vpshufb instruction can do byte reflection. +// +// Second, forgoing the bit reflection causes an extra multiple of x (still +// using the G = x^128 + x^7 + x^2 + x + 1 convention) to be introduced by each +// multiplication. This is because an M-bit by N-bit carryless multiplication +// really produces a (M+N-1)-bit product, but in practice it's zero-extended to +// M+N bits. In the G = x^128 + x^7 + x^2 + x + 1 convention, which maps bits +// to polynomial coefficients backwards, this zero-extension actually changes +// the product by introducing an extra factor of x. Therefore, users of this +// macro must ensure that one of the inputs has an extra factor of x^-1, i.e. +// the multiplicative inverse of x, to cancel out the extra x. +// +// Third, the backwards coefficients convention is just confusing to work with, +// since it makes "low" and "high" in the polynomial math mean the opposite of +// their normal meaning in computer programming. This can be solved by using an +// alternative interpretation: the polynomial coefficients are understood to be +// in the natural order, and the multiplication is actually \a * \b * x^-128 mod +// x^128 + x^127 + x^126 + x^121 + 1. This doesn't change the inputs, outputs, +// or the implementation at all; it just changes the mathematical interpretation +// of what each instruction is doing. Starting from here, we'll use this +// alternative interpretation, as it's easier to understand the code that way. +// +// Moving onto the implementation, the vpclmulqdq instruction does 64 x 64 => +// 128-bit carryless multiplication, so we break the 128 x 128 multiplication +// into parts as follows (the _L and _H suffixes denote low and high 64 bits): +// +// LO = a_L * b_L +// MI = (a_L * b_H) + (a_H * b_L) +// HI = a_H * b_H +// +// The 256-bit product is x^128*HI + x^64*MI + LO. LO, MI, and HI are 128-bit. +// Note that MI "overlaps" with LO and HI. We don't consolidate MI into LO and +// HI right away, since the way the reduction works makes that unnecessary. +// +// For the reduction, we cancel out the low 128 bits by adding multiples of G = +// x^128 + x^127 + x^126 + x^121 + 1. This is done by two iterations, each of +// which cancels out the next lowest 64 bits. Consider a value x^64*A + B, +// where A and B are 128-bit. Adding B_L*G to that value gives: +// +// x^64*A + B + B_L*G +// = x^64*A + x^64*B_H + B_L + B_L*(x^128 + x^127 + x^126 + x^121 + 1) +// = x^64*A + x^64*B_H + B_L + x^128*B_L + x^64*B_L*(x^63 + x^62 + x^57) + B_L +// = x^64*A + x^64*B_H + x^128*B_L + x^64*B_L*(x^63 + x^62 + x^57) + B_L + B_L +// = x^64*(A + B_H + x^64*B_L + B_L*(x^63 + x^62 + x^57)) +// +// So: if we sum A, B with its halves swapped, and the low half of B times x^63 +// + x^62 + x^57, we get a 128-bit value C where x^64*C is congruent to the +// original value x^64*A + B. I.e., the low 64 bits got canceled out. +// +// We just need to apply this twice: first to fold LO into MI, and second to +// fold the updated MI into HI. +// +// The needed three-argument XORs are done using the vpternlogd instruction with +// immediate 0x96, since this is faster than two vpxord instructions. +// +// A potential optimization, assuming that b is fixed per-key (if a is fixed +// per-key it would work the other way around), is to use one iteration of the +// reduction described above to precompute a value c such that x^64*c = b mod G, +// and then multiply a_L by c (and implicitly by x^64) instead of by b: +// +// MI = (a_L * c_L) + (a_H * b_L) +// HI = (a_L * c_H) + (a_H * b_H) +// +// This would eliminate the LO part of the intermediate product, which would +// eliminate the need to fold LO into MI. This would save two instructions, +// including a vpclmulqdq. However, we currently don't use this optimization +// because it would require twice as many per-key precomputed values. +// +// Using Karatsuba multiplication instead of "schoolbook" multiplication +// similarly would save a vpclmulqdq but does not seem to be worth it. +.macro _ghash_mul_step i, a, b, dst, gfpoly, t0, t1, t2 +.if \i == 0 + vpclmulqdq $0x00, \a, \b, \t0 // LO = a_L * b_L + vpclmulqdq $0x01, \a, \b, \t1 // MI_0 = a_L * b_H +.elseif \i == 1 + vpclmulqdq $0x10, \a, \b, \t2 // MI_1 = a_H * b_L +.elseif \i == 2 + vpxord \t2, \t1, \t1 // MI = MI_0 + MI_1 +.elseif \i == 3 + vpclmulqdq $0x01, \t0, \gfpoly, \t2 // LO_L*(x^63 + x^62 + x^57) +.elseif \i == 4 + vpshufd $0x4e, \t0, \t0 // Swap halves of LO +.elseif \i == 5 + vpternlogd $0x96, \t2, \t0, \t1 // Fold LO into MI +.elseif \i == 6 + vpclmulqdq $0x11, \a, \b, \dst // HI = a_H * b_H +.elseif \i == 7 + vpclmulqdq $0x01, \t1, \gfpoly, \t0 // MI_L*(x^63 + x^62 + x^57) +.elseif \i == 8 + vpshufd $0x4e, \t1, \t1 // Swap halves of MI +.elseif \i == 9 + vpternlogd $0x96, \t0, \t1, \dst // Fold MI into HI +.endif +.endm + +// GHASH-multiply the 128-bit lanes of \a by the 128-bit lanes of \b and store +// the reduced products in \dst. See _ghash_mul_step for full explanation. +.macro _ghash_mul a, b, dst, gfpoly, t0, t1, t2 +.irp i, 0,1,2,3,4,5,6,7,8,9 + _ghash_mul_step \i, \a, \b, \dst, \gfpoly, \t0, \t1, \t2 +.endr +.endm + +// GHASH-multiply the 128-bit lanes of \a by the 128-bit lanes of \b and add the +// *unreduced* products to \lo, \mi, and \hi. +.macro _ghash_mul_noreduce a, b, lo, mi, hi, t0, t1, t2, t3 + vpclmulqdq $0x00, \a, \b, \t0 // a_L * b_L + vpclmulqdq $0x01, \a, \b, \t1 // a_L * b_H + vpclmulqdq $0x10, \a, \b, \t2 // a_H * b_L + vpclmulqdq $0x11, \a, \b, \t3 // a_H * b_H + vpxord \t0, \lo, \lo + vpternlogd $0x96, \t2, \t1, \mi + vpxord \t3, \hi, \hi +.endm + +// Reduce the unreduced products from \lo, \mi, and \hi and store the 128-bit +// reduced products in \hi. See _ghash_mul_step for explanation of reduction. +.macro _ghash_reduce lo, mi, hi, gfpoly, t0 + vpclmulqdq $0x01, \lo, \gfpoly, \t0 + vpshufd $0x4e, \lo, \lo + vpternlogd $0x96, \t0, \lo, \mi + vpclmulqdq $0x01, \mi, \gfpoly, \t0 + vpshufd $0x4e, \mi, \mi + vpternlogd $0x96, \t0, \mi, \hi +.endm + +// void aes_gcm_precompute_##suffix(struct aes_gcm_key_avx10 *key); +// +// Given the expanded AES key |key->aes_key|, this function derives the GHASH +// subkey and initializes |key->ghash_key_powers| with powers of it. +// +// The number of key powers initialized is NUM_H_POWERS, and they are stored in +// the order H^NUM_H_POWERS to H^1. The zeroized padding blocks after the key +// powers themselves are also initialized. +// +// This macro supports both VL=32 and VL=64. _set_veclen must have been invoked +// with the desired length. In the VL=32 case, the function computes twice as +// many key powers than are actually used by the VL=32 GCM update functions. +// This is done to keep the key format the same regardless of vector length. +.macro _aes_gcm_precompute + + // Function arguments + .set KEY, %rdi + + // Additional local variables. V0-V2 and %rax are used as temporaries. + .set POWERS_PTR, %rsi + .set RNDKEYLAST_PTR, %rdx + .set H_CUR, V3 + .set H_CUR_YMM, %ymm3 + .set H_CUR_XMM, %xmm3 + .set H_INC, V4 + .set H_INC_YMM, %ymm4 + .set H_INC_XMM, %xmm4 + .set GFPOLY, V5 + .set GFPOLY_YMM, %ymm5 + .set GFPOLY_XMM, %xmm5 + + // Get pointer to lowest set of key powers (located at end of array). + lea OFFSETOFEND_H_POWERS-VL(KEY), POWERS_PTR + + // Encrypt an all-zeroes block to get the raw hash subkey. + movl OFFSETOF_AESKEYLEN(KEY), %eax + lea 6*16(KEY,%rax,4), RNDKEYLAST_PTR + vmovdqu (KEY), %xmm0 // Zero-th round key XOR all-zeroes block + add $16, KEY +1: + vaesenc (KEY), %xmm0, %xmm0 + add $16, KEY + cmp KEY, RNDKEYLAST_PTR + jne 1b + vaesenclast (RNDKEYLAST_PTR), %xmm0, %xmm0 + + // Reflect the bytes of the raw hash subkey. + vpshufb .Lbswap_mask(%rip), %xmm0, H_CUR_XMM + + // Zeroize the padding blocks. + vpxor %xmm0, %xmm0, %xmm0 + vmovdqu %ymm0, VL(POWERS_PTR) + vmovdqu %xmm0, VL+2*16(POWERS_PTR) + + // Finish preprocessing the first key power, H^1. Since this GHASH + // implementation operates directly on values with the backwards bit + // order specified by the GCM standard, it's necessary to preprocess the + // raw key as follows. First, reflect its bytes. Second, multiply it + // by x^-1 mod x^128 + x^7 + x^2 + x + 1 (if using the backwards + // interpretation of polynomial coefficients), which can also be + // interpreted as multiplication by x mod x^128 + x^127 + x^126 + x^121 + // + 1 using the alternative, natural interpretation of polynomial + // coefficients. For details, see the comment above _ghash_mul_step. + // + // Either way, for the multiplication the concrete operation performed + // is a left shift of the 128-bit value by 1 bit, then an XOR with (0xc2 + // << 120) | 1 if a 1 bit was carried out. However, there's no 128-bit + // wide shift instruction, so instead double each of the two 64-bit + // halves and incorporate the internal carry bit into the value XOR'd. + vpshufd $0xd3, H_CUR_XMM, %xmm0 + vpsrad $31, %xmm0, %xmm0 + vpaddq H_CUR_XMM, H_CUR_XMM, H_CUR_XMM + vpand .Lgfpoly_and_internal_carrybit(%rip), %xmm0, %xmm0 + vpxor %xmm0, H_CUR_XMM, H_CUR_XMM + + // Load the gfpoly constant. + vbroadcasti32x4 .Lgfpoly(%rip), GFPOLY + + // Square H^1 to get H^2. + // + // Note that as with H^1, all higher key powers also need an extra + // factor of x^-1 (or x using the natural interpretation). Nothing + // special needs to be done to make this happen, though: H^1 * H^1 would + // end up with two factors of x^-1, but the multiplication consumes one. + // So the product H^2 ends up with the desired one factor of x^-1. + _ghash_mul H_CUR_XMM, H_CUR_XMM, H_INC_XMM, GFPOLY_XMM, \ + %xmm0, %xmm1, %xmm2 + + // Create H_CUR_YMM = [H^2, H^1] and H_INC_YMM = [H^2, H^2]. + vinserti128 $1, H_CUR_XMM, H_INC_YMM, H_CUR_YMM + vinserti128 $1, H_INC_XMM, H_INC_YMM, H_INC_YMM + +.if VL == 64 + // Create H_CUR = [H^4, H^3, H^2, H^1] and H_INC = [H^4, H^4, H^4, H^4]. + _ghash_mul H_INC_YMM, H_CUR_YMM, H_INC_YMM, GFPOLY_YMM, \ + %ymm0, %ymm1, %ymm2 + vinserti64x4 $1, H_CUR_YMM, H_INC, H_CUR + vshufi64x2 $0, H_INC, H_INC, H_INC +.endif + + // Store the lowest set of key powers. + vmovdqu8 H_CUR, (POWERS_PTR) + + // Compute and store the remaining key powers. With VL=32, repeatedly + // multiply [H^(i+1), H^i] by [H^2, H^2] to get [H^(i+3), H^(i+2)]. + // With VL=64, repeatedly multiply [H^(i+3), H^(i+2), H^(i+1), H^i] by + // [H^4, H^4, H^4, H^4] to get [H^(i+7), H^(i+6), H^(i+5), H^(i+4)]. + mov $(NUM_H_POWERS*16/VL) - 1, %eax +.Lprecompute_next\@: + sub $VL, POWERS_PTR + _ghash_mul H_INC, H_CUR, H_CUR, GFPOLY, V0, V1, V2 + vmovdqu8 H_CUR, (POWERS_PTR) + dec %eax + jnz .Lprecompute_next\@ + + vzeroupper // This is needed after using ymm or zmm registers. + RET +.endm + +// XOR together the 128-bit lanes of \src (whose low lane is \src_xmm) and store +// the result in \dst_xmm. This implicitly zeroizes the other lanes of dst. +.macro _horizontal_xor src, src_xmm, dst_xmm, t0_xmm, t1_xmm, t2_xmm + vextracti32x4 $1, \src, \t0_xmm +.if VL == 32 + vpxord \t0_xmm, \src_xmm, \dst_xmm +.elseif VL == 64 + vextracti32x4 $2, \src, \t1_xmm + vextracti32x4 $3, \src, \t2_xmm + vpxord \t0_xmm, \src_xmm, \dst_xmm + vpternlogd $0x96, \t1_xmm, \t2_xmm, \dst_xmm +.else + .error "Unsupported vector length" +.endif +.endm + +// Do one step of the GHASH update of the data blocks given in the vector +// registers GHASHDATA[0-3]. \i specifies the step to do, 0 through 9. The +// division into steps allows users of this macro to optionally interleave the +// computation with other instructions. This macro uses the vector register +// GHASH_ACC as input/output; GHASHDATA[0-3] as inputs that are clobbered; +// H_POW[4-1], GFPOLY, and BSWAP_MASK as inputs that aren't clobbered; and +// GHASHTMP[0-2] as temporaries. This macro handles the byte-reflection of the +// data blocks. The parameter registers must be preserved across steps. +// +// The GHASH update does: GHASH_ACC = H_POW4*(GHASHDATA0 + GHASH_ACC) + +// H_POW3*GHASHDATA1 + H_POW2*GHASHDATA2 + H_POW1*GHASHDATA3, where the +// operations are vectorized operations on vectors of 16-byte blocks. E.g., +// with VL=32 there are 2 blocks per vector and the vectorized terms correspond +// to the following non-vectorized terms: +// +// H_POW4*(GHASHDATA0 + GHASH_ACC) => H^8*(blk0 + GHASH_ACC_XMM) and H^7*(blk1 + 0) +// H_POW3*GHASHDATA1 => H^6*blk2 and H^5*blk3 +// H_POW2*GHASHDATA2 => H^4*blk4 and H^3*blk5 +// H_POW1*GHASHDATA3 => H^2*blk6 and H^1*blk7 +// +// With VL=64, we use 4 blocks/vector, H^16 through H^1, and blk0 through blk15. +// +// More concretely, this code does: +// - Do vectorized "schoolbook" multiplications to compute the intermediate +// 256-bit product of each block and its corresponding hash key power. +// There are 4*VL/16 of these intermediate products. +// - Sum (XOR) the intermediate 256-bit products across vectors. This leaves +// VL/16 256-bit intermediate values. +// - Do a vectorized reduction of these 256-bit intermediate values to +// 128-bits each. This leaves VL/16 128-bit intermediate values. +// - Sum (XOR) these values and store the 128-bit result in GHASH_ACC_XMM. +// +// See _ghash_mul_step for the full explanation of the operations performed for +// each individual finite field multiplication and reduction. +.macro _ghash_step_4x i +.if \i == 0 + vpshufb BSWAP_MASK, GHASHDATA0, GHASHDATA0 + vpxord GHASH_ACC, GHASHDATA0, GHASHDATA0 + vpshufb BSWAP_MASK, GHASHDATA1, GHASHDATA1 + vpshufb BSWAP_MASK, GHASHDATA2, GHASHDATA2 +.elseif \i == 1 + vpshufb BSWAP_MASK, GHASHDATA3, GHASHDATA3 + vpclmulqdq $0x00, H_POW4, GHASHDATA0, GHASH_ACC // LO_0 + vpclmulqdq $0x00, H_POW3, GHASHDATA1, GHASHTMP0 // LO_1 + vpclmulqdq $0x00, H_POW2, GHASHDATA2, GHASHTMP1 // LO_2 +.elseif \i == 2 + vpxord GHASHTMP0, GHASH_ACC, GHASH_ACC // sum(LO_{1,0}) + vpclmulqdq $0x00, H_POW1, GHASHDATA3, GHASHTMP2 // LO_3 + vpternlogd $0x96, GHASHTMP2, GHASHTMP1, GHASH_ACC // LO = sum(LO_{3,2,1,0}) + vpclmulqdq $0x01, H_POW4, GHASHDATA0, GHASHTMP0 // MI_0 +.elseif \i == 3 + vpclmulqdq $0x01, H_POW3, GHASHDATA1, GHASHTMP1 // MI_1 + vpclmulqdq $0x01, H_POW2, GHASHDATA2, GHASHTMP2 // MI_2 + vpternlogd $0x96, GHASHTMP2, GHASHTMP1, GHASHTMP0 // sum(MI_{2,1,0}) + vpclmulqdq $0x01, H_POW1, GHASHDATA3, GHASHTMP1 // MI_3 +.elseif \i == 4 + vpclmulqdq $0x10, H_POW4, GHASHDATA0, GHASHTMP2 // MI_4 + vpternlogd $0x96, GHASHTMP2, GHASHTMP1, GHASHTMP0 // sum(MI_{4,3,2,1,0}) + vpclmulqdq $0x10, H_POW3, GHASHDATA1, GHASHTMP1 // MI_5 + vpclmulqdq $0x10, H_POW2, GHASHDATA2, GHASHTMP2 // MI_6 +.elseif \i == 5 + vpternlogd $0x96, GHASHTMP2, GHASHTMP1, GHASHTMP0 // sum(MI_{6,5,4,3,2,1,0}) + vpclmulqdq $0x01, GHASH_ACC, GFPOLY, GHASHTMP2 // LO_L*(x^63 + x^62 + x^57) + vpclmulqdq $0x10, H_POW1, GHASHDATA3, GHASHTMP1 // MI_7 + vpxord GHASHTMP1, GHASHTMP0, GHASHTMP0 // MI = sum(MI_{7,6,5,4,3,2,1,0}) +.elseif \i == 6 + vpshufd $0x4e, GHASH_ACC, GHASH_ACC // Swap halves of LO + vpclmulqdq $0x11, H_POW4, GHASHDATA0, GHASHDATA0 // HI_0 + vpclmulqdq $0x11, H_POW3, GHASHDATA1, GHASHDATA1 // HI_1 + vpclmulqdq $0x11, H_POW2, GHASHDATA2, GHASHDATA2 // HI_2 +.elseif \i == 7 + vpternlogd $0x96, GHASHTMP2, GHASH_ACC, GHASHTMP0 // Fold LO into MI + vpclmulqdq $0x11, H_POW1, GHASHDATA3, GHASHDATA3 // HI_3 + vpternlogd $0x96, GHASHDATA2, GHASHDATA1, GHASHDATA0 // sum(HI_{2,1,0}) + vpclmulqdq $0x01, GHASHTMP0, GFPOLY, GHASHTMP1 // MI_L*(x^63 + x^62 + x^57) +.elseif \i == 8 + vpxord GHASHDATA3, GHASHDATA0, GHASH_ACC // HI = sum(HI_{3,2,1,0}) + vpshufd $0x4e, GHASHTMP0, GHASHTMP0 // Swap halves of MI + vpternlogd $0x96, GHASHTMP1, GHASHTMP0, GHASH_ACC // Fold MI into HI +.elseif \i == 9 + _horizontal_xor GHASH_ACC, GHASH_ACC_XMM, GHASH_ACC_XMM, \ + GHASHDATA0_XMM, GHASHDATA1_XMM, GHASHDATA2_XMM +.endif +.endm + +// Do one non-last round of AES encryption on the counter blocks in V0-V3 using +// the round key that has been broadcast to all 128-bit lanes of \round_key. +.macro _vaesenc_4x round_key + vaesenc \round_key, V0, V0 + vaesenc \round_key, V1, V1 + vaesenc \round_key, V2, V2 + vaesenc \round_key, V3, V3 +.endm + +// Start the AES encryption of four vectors of counter blocks. +.macro _ctr_begin_4x + + // Increment LE_CTR four times to generate four vectors of little-endian + // counter blocks, swap each to big-endian, and store them in V0-V3. + vpshufb BSWAP_MASK, LE_CTR, V0 + vpaddd LE_CTR_INC, LE_CTR, LE_CTR + vpshufb BSWAP_MASK, LE_CTR, V1 + vpaddd LE_CTR_INC, LE_CTR, LE_CTR + vpshufb BSWAP_MASK, LE_CTR, V2 + vpaddd LE_CTR_INC, LE_CTR, LE_CTR + vpshufb BSWAP_MASK, LE_CTR, V3 + vpaddd LE_CTR_INC, LE_CTR, LE_CTR + + // AES "round zero": XOR in the zero-th round key. + vpxord RNDKEY0, V0, V0 + vpxord RNDKEY0, V1, V1 + vpxord RNDKEY0, V2, V2 + vpxord RNDKEY0, V3, V3 +.endm + +// void aes_gcm_{enc,dec}_update_##suffix(const struct aes_gcm_key_avx10 *key, +// const u32 le_ctr[4], u8 ghash_acc[16], +// const u8 *src, u8 *dst, int datalen); +// +// This macro generates a GCM encryption or decryption update function with the +// above prototype (with \enc selecting which one). This macro supports both +// VL=32 and VL=64. _set_veclen must have been invoked with the desired length. +// +// This function computes the next portion of the CTR keystream, XOR's it with +// |datalen| bytes from |src|, and writes the resulting encrypted or decrypted +// data to |dst|. It also updates the GHASH accumulator |ghash_acc| using the +// next |datalen| ciphertext bytes. +// +// |datalen| must be a multiple of 16, except on the last call where it can be +// any length. The caller must do any buffering needed to ensure this. Both +// in-place and out-of-place en/decryption are supported. +// +// |le_ctr| must give the current counter in little-endian format. For a new +// message, the low word of the counter must be 2. This function loads the +// counter from |le_ctr| and increments the loaded counter as needed, but it +// does *not* store the updated counter back to |le_ctr|. The caller must +// update |le_ctr| if any more data segments follow. Internally, only the low +// 32-bit word of the counter is incremented, following the GCM standard. +.macro _aes_gcm_update enc + + // Function arguments + .set KEY, %rdi + .set LE_CTR_PTR, %rsi + .set GHASH_ACC_PTR, %rdx + .set SRC, %rcx + .set DST, %r8 + .set DATALEN, %r9d + .set DATALEN64, %r9 // Zero-extend DATALEN before using! + + // Additional local variables + + // %rax and %k1 are used as temporary registers. LE_CTR_PTR is also + // available as a temporary register after the counter is loaded. + + // AES key length in bytes + .set AESKEYLEN, %r10d + .set AESKEYLEN64, %r10 + + // Pointer to the last AES round key for the chosen AES variant + .set RNDKEYLAST_PTR, %r11 + + // In the main loop, V0-V3 are used as AES input and output. Elsewhere + // they are used as temporary registers. + + // GHASHDATA[0-3] hold the ciphertext blocks and GHASH input data. + .set GHASHDATA0, V4 + .set GHASHDATA0_XMM, %xmm4 + .set GHASHDATA1, V5 + .set GHASHDATA1_XMM, %xmm5 + .set GHASHDATA2, V6 + .set GHASHDATA2_XMM, %xmm6 + .set GHASHDATA3, V7 + + // BSWAP_MASK is the shuffle mask for byte-reflecting 128-bit values + // using vpshufb, copied to all 128-bit lanes. + .set BSWAP_MASK, V8 + + // RNDKEY temporarily holds the next AES round key. + .set RNDKEY, V9 + + // GHASH_ACC is the accumulator variable for GHASH. When fully reduced, + // only the lowest 128-bit lane can be nonzero. When not fully reduced, + // more than one lane may be used, and they need to be XOR'd together. + .set GHASH_ACC, V10 + .set GHASH_ACC_XMM, %xmm10 + + // LE_CTR_INC is the vector of 32-bit words that need to be added to a + // vector of little-endian counter blocks to advance it forwards. + .set LE_CTR_INC, V11 + + // LE_CTR contains the next set of little-endian counter blocks. + .set LE_CTR, V12 + + // RNDKEY0, RNDKEYLAST, and RNDKEY_M[9-5] contain cached AES round keys, + // copied to all 128-bit lanes. RNDKEY0 is the zero-th round key, + // RNDKEYLAST the last, and RNDKEY_M\i the one \i-th from the last. + .set RNDKEY0, V13 + .set RNDKEYLAST, V14 + .set RNDKEY_M9, V15 + .set RNDKEY_M8, V16 + .set RNDKEY_M7, V17 + .set RNDKEY_M6, V18 + .set RNDKEY_M5, V19 + + // RNDKEYLAST[0-3] temporarily store the last AES round key XOR'd with + // the corresponding block of source data. This is useful because + // vaesenclast(key, a) ^ b == vaesenclast(key ^ b, a), and key ^ b can + // be computed in parallel with the AES rounds. + .set RNDKEYLAST0, V20 + .set RNDKEYLAST1, V21 + .set RNDKEYLAST2, V22 + .set RNDKEYLAST3, V23 + + // GHASHTMP[0-2] are temporary variables used by _ghash_step_4x. These + // cannot coincide with anything used for AES encryption, since for + // performance reasons GHASH and AES encryption are interleaved. + .set GHASHTMP0, V24 + .set GHASHTMP1, V25 + .set GHASHTMP2, V26 + + // H_POW[4-1] contain the powers of the hash key H^(4*VL/16)...H^1. The + // descending numbering reflects the order of the key powers. + .set H_POW4, V27 + .set H_POW3, V28 + .set H_POW2, V29 + .set H_POW1, V30 + + // GFPOLY contains the .Lgfpoly constant, copied to all 128-bit lanes. + .set GFPOLY, V31 + + // Load some constants. + vbroadcasti32x4 .Lbswap_mask(%rip), BSWAP_MASK + vbroadcasti32x4 .Lgfpoly(%rip), GFPOLY + + // Load the GHASH accumulator and the starting counter. + vmovdqu (GHASH_ACC_PTR), GHASH_ACC_XMM + vbroadcasti32x4 (LE_CTR_PTR), LE_CTR + + // Load the AES key length in bytes. + movl OFFSETOF_AESKEYLEN(KEY), AESKEYLEN + + // Make RNDKEYLAST_PTR point to the last AES round key. This is the + // round key with index 10, 12, or 14 for AES-128, AES-192, or AES-256 + // respectively. Then load the zero-th and last round keys. + lea 6*16(KEY,AESKEYLEN64,4), RNDKEYLAST_PTR + vbroadcasti32x4 (KEY), RNDKEY0 + vbroadcasti32x4 (RNDKEYLAST_PTR), RNDKEYLAST + + // Finish initializing LE_CTR by adding [0, 1, ...] to its low words. + vpaddd .Lctr_pattern(%rip), LE_CTR, LE_CTR + + // Initialize LE_CTR_INC to contain VL/16 in all 128-bit lanes. +.if VL == 32 + vbroadcasti32x4 .Linc_2blocks(%rip), LE_CTR_INC +.elseif VL == 64 + vbroadcasti32x4 .Linc_4blocks(%rip), LE_CTR_INC +.else + .error "Unsupported vector length" +.endif + + // If there are at least 4*VL bytes of data, then continue into the loop + // that processes 4*VL bytes of data at a time. Otherwise skip it. + // + // Pre-subtracting 4*VL from DATALEN saves an instruction from the main + // loop and also ensures that at least one write always occurs to + // DATALEN, zero-extending it and allowing DATALEN64 to be used later. + sub $4*VL, DATALEN + jl .Lcrypt_loop_4x_done\@ + + // Load powers of the hash key. + vmovdqu8 OFFSETOFEND_H_POWERS-4*VL(KEY), H_POW4 + vmovdqu8 OFFSETOFEND_H_POWERS-3*VL(KEY), H_POW3 + vmovdqu8 OFFSETOFEND_H_POWERS-2*VL(KEY), H_POW2 + vmovdqu8 OFFSETOFEND_H_POWERS-1*VL(KEY), H_POW1 + + // Main loop: en/decrypt and hash 4 vectors at a time. + // + // When possible, interleave the AES encryption of the counter blocks + // with the GHASH update of the ciphertext blocks. This improves + // performance on many CPUs because the execution ports used by the VAES + // instructions often differ from those used by vpclmulqdq and other + // instructions used in GHASH. For example, many Intel CPUs dispatch + // vaesenc to ports 0 and 1 and vpclmulqdq to port 5. + // + // The interleaving is easiest to do during decryption, since during + // decryption the ciphertext blocks are immediately available. For + // encryption, instead encrypt the first set of blocks, then hash those + // blocks while encrypting the next set of blocks, repeat that as + // needed, and finally hash the last set of blocks. + +.if \enc + // Encrypt the first 4 vectors of plaintext blocks. Leave the resulting + // ciphertext in GHASHDATA[0-3] for GHASH. + _ctr_begin_4x + lea 16(KEY), %rax +1: + vbroadcasti32x4 (%rax), RNDKEY + _vaesenc_4x RNDKEY + add $16, %rax + cmp %rax, RNDKEYLAST_PTR + jne 1b + vpxord 0*VL(SRC), RNDKEYLAST, RNDKEYLAST0 + vpxord 1*VL(SRC), RNDKEYLAST, RNDKEYLAST1 + vpxord 2*VL(SRC), RNDKEYLAST, RNDKEYLAST2 + vpxord 3*VL(SRC), RNDKEYLAST, RNDKEYLAST3 + vaesenclast RNDKEYLAST0, V0, GHASHDATA0 + vaesenclast RNDKEYLAST1, V1, GHASHDATA1 + vaesenclast RNDKEYLAST2, V2, GHASHDATA2 + vaesenclast RNDKEYLAST3, V3, GHASHDATA3 + vmovdqu8 GHASHDATA0, 0*VL(DST) + vmovdqu8 GHASHDATA1, 1*VL(DST) + vmovdqu8 GHASHDATA2, 2*VL(DST) + vmovdqu8 GHASHDATA3, 3*VL(DST) + add $4*VL, SRC + add $4*VL, DST + sub $4*VL, DATALEN + jl .Lghash_last_ciphertext_4x\@ +.endif + + // Cache as many additional AES round keys as possible. +.irp i, 9,8,7,6,5 + vbroadcasti32x4 -\i*16(RNDKEYLAST_PTR), RNDKEY_M\i +.endr + +.Lcrypt_loop_4x\@: + + // If decrypting, load more ciphertext blocks into GHASHDATA[0-3]. If + // encrypting, GHASHDATA[0-3] already contain the previous ciphertext. +.if !\enc + vmovdqu8 0*VL(SRC), GHASHDATA0 + vmovdqu8 1*VL(SRC), GHASHDATA1 + vmovdqu8 2*VL(SRC), GHASHDATA2 + vmovdqu8 3*VL(SRC), GHASHDATA3 +.endif + + // Start the AES encryption of the counter blocks. + _ctr_begin_4x + cmp $24, AESKEYLEN + jl 128f // AES-128? + je 192f // AES-192? + // AES-256 + vbroadcasti32x4 -13*16(RNDKEYLAST_PTR), RNDKEY + _vaesenc_4x RNDKEY + vbroadcasti32x4 -12*16(RNDKEYLAST_PTR), RNDKEY + _vaesenc_4x RNDKEY +192: + vbroadcasti32x4 -11*16(RNDKEYLAST_PTR), RNDKEY + _vaesenc_4x RNDKEY + vbroadcasti32x4 -10*16(RNDKEYLAST_PTR), RNDKEY + _vaesenc_4x RNDKEY +128: + + // XOR the source data with the last round key, saving the result in + // RNDKEYLAST[0-3]. This reduces latency by taking advantage of the + // property vaesenclast(key, a) ^ b == vaesenclast(key ^ b, a). +.if \enc + vpxord 0*VL(SRC), RNDKEYLAST, RNDKEYLAST0 + vpxord 1*VL(SRC), RNDKEYLAST, RNDKEYLAST1 + vpxord 2*VL(SRC), RNDKEYLAST, RNDKEYLAST2 + vpxord 3*VL(SRC), RNDKEYLAST, RNDKEYLAST3 +.else + vpxord GHASHDATA0, RNDKEYLAST, RNDKEYLAST0 + vpxord GHASHDATA1, RNDKEYLAST, RNDKEYLAST1 + vpxord GHASHDATA2, RNDKEYLAST, RNDKEYLAST2 + vpxord GHASHDATA3, RNDKEYLAST, RNDKEYLAST3 +.endif + + // Finish the AES encryption of the counter blocks in V0-V3, interleaved + // with the GHASH update of the ciphertext blocks in GHASHDATA[0-3]. +.irp i, 9,8,7,6,5 + _vaesenc_4x RNDKEY_M\i + _ghash_step_4x (9 - \i) +.endr +.irp i, 4,3,2,1 + vbroadcasti32x4 -\i*16(RNDKEYLAST_PTR), RNDKEY + _vaesenc_4x RNDKEY + _ghash_step_4x (9 - \i) +.endr + _ghash_step_4x 9 + + // Do the last AES round. This handles the XOR with the source data + // too, as per the optimization described above. + vaesenclast RNDKEYLAST0, V0, GHASHDATA0 + vaesenclast RNDKEYLAST1, V1, GHASHDATA1 + vaesenclast RNDKEYLAST2, V2, GHASHDATA2 + vaesenclast RNDKEYLAST3, V3, GHASHDATA3 + + // Store the en/decrypted data to DST. + vmovdqu8 GHASHDATA0, 0*VL(DST) + vmovdqu8 GHASHDATA1, 1*VL(DST) + vmovdqu8 GHASHDATA2, 2*VL(DST) + vmovdqu8 GHASHDATA3, 3*VL(DST) + + add $4*VL, SRC + add $4*VL, DST + sub $4*VL, DATALEN + jge .Lcrypt_loop_4x\@ + +.if \enc +.Lghash_last_ciphertext_4x\@: + // Update GHASH with the last set of ciphertext blocks. +.irp i, 0,1,2,3,4,5,6,7,8,9 + _ghash_step_4x \i +.endr +.endif + +.Lcrypt_loop_4x_done\@: + + // Undo the extra subtraction by 4*VL and check whether data remains. + add $4*VL, DATALEN + jz .Ldone\@ + + // The data length isn't a multiple of 4*VL. Process the remaining data + // of length 1 <= DATALEN < 4*VL, up to one vector (VL bytes) at a time. + // Going one vector at a time may seem inefficient compared to having + // separate code paths for each possible number of vectors remaining. + // However, using a loop keeps the code size down, and it performs + // surprising well; modern CPUs will start executing the next iteration + // before the previous one finishes and also predict the number of loop + // iterations. For a similar reason, we roll up the AES rounds. + // + // On the last iteration, the remaining length may be less than VL. + // Handle this using masking. + // + // Since there are enough key powers available for all remaining data, + // there is no need to do a GHASH reduction after each iteration. + // Instead, multiply each remaining block by its own key power, and only + // do a GHASH reduction at the very end. + + // Make POWERS_PTR point to the key powers [H^N, H^(N-1), ...] where N + // is the number of blocks that remain. + .set POWERS_PTR, LE_CTR_PTR // LE_CTR_PTR is free to be reused. + mov DATALEN, %eax + neg %rax + and $~15, %rax // -round_up(DATALEN, 16) + lea OFFSETOFEND_H_POWERS(KEY,%rax), POWERS_PTR + + // Start collecting the unreduced GHASH intermediate value LO, MI, HI. + .set LO, GHASHDATA0 + .set LO_XMM, GHASHDATA0_XMM + .set MI, GHASHDATA1 + .set MI_XMM, GHASHDATA1_XMM + .set HI, GHASHDATA2 + .set HI_XMM, GHASHDATA2_XMM + vpxor LO_XMM, LO_XMM, LO_XMM + vpxor MI_XMM, MI_XMM, MI_XMM + vpxor HI_XMM, HI_XMM, HI_XMM + +.Lcrypt_loop_1x\@: + + // Select the appropriate mask for this iteration: all 1's if + // DATALEN >= VL, otherwise DATALEN 1's. Do this branchlessly using the + // bzhi instruction from BMI2. (This relies on DATALEN <= 255.) +.if VL < 64 + mov $-1, %eax + bzhi DATALEN, %eax, %eax + kmovd %eax, %k1 +.else + mov $-1, %rax + bzhi DATALEN64, %rax, %rax + kmovq %rax, %k1 +.endif + + // Encrypt a vector of counter blocks. This does not need to be masked. + vpshufb BSWAP_MASK, LE_CTR, V0 + vpaddd LE_CTR_INC, LE_CTR, LE_CTR + vpxord RNDKEY0, V0, V0 + lea 16(KEY), %rax +1: + vbroadcasti32x4 (%rax), RNDKEY + vaesenc RNDKEY, V0, V0 + add $16, %rax + cmp %rax, RNDKEYLAST_PTR + jne 1b + vaesenclast RNDKEYLAST, V0, V0 + + // XOR the data with the appropriate number of keystream bytes. + vmovdqu8 (SRC), V1{%k1}{z} + vpxord V1, V0, V0 + vmovdqu8 V0, (DST){%k1} + + // Update GHASH with the ciphertext block(s), without reducing. + // + // In the case of DATALEN < VL, the ciphertext is zero-padded to VL. + // (If decrypting, it's done by the above masked load. If encrypting, + // it's done by the below masked register-to-register move.) Note that + // if DATALEN <= VL - 16, there will be additional padding beyond the + // padding of the last block specified by GHASH itself; i.e., there may + // be whole block(s) that get processed by the GHASH multiplication and + // reduction instructions but should not actually be included in the + // GHASH. However, any such blocks are all-zeroes, and the values that + // they're multiplied with are also all-zeroes. Therefore they just add + // 0 * 0 = 0 to the final GHASH result, which makes no difference. + vmovdqu8 (POWERS_PTR), H_POW1 +.if \enc + vmovdqu8 V0, V1{%k1}{z} +.endif + vpshufb BSWAP_MASK, V1, V0 + vpxord GHASH_ACC, V0, V0 + _ghash_mul_noreduce H_POW1, V0, LO, MI, HI, GHASHDATA3, V1, V2, V3 + vpxor GHASH_ACC_XMM, GHASH_ACC_XMM, GHASH_ACC_XMM + + add $VL, POWERS_PTR + add $VL, SRC + add $VL, DST + sub $VL, DATALEN + jg .Lcrypt_loop_1x\@ + + // Finally, do the GHASH reduction. + _ghash_reduce LO, MI, HI, GFPOLY, V0 + _horizontal_xor HI, HI_XMM, GHASH_ACC_XMM, %xmm0, %xmm1, %xmm2 + +.Ldone\@: + // Store the updated GHASH accumulator back to memory. + vmovdqu GHASH_ACC_XMM, (GHASH_ACC_PTR) + + vzeroupper // This is needed after using ymm or zmm registers. + RET +.endm + +// void aes_gcm_enc_final_vaes_avx10(const struct aes_gcm_key_avx10 *key, +// const u32 le_ctr[4], u8 ghash_acc[16], +// u64 total_aadlen, u64 total_datalen); +// bool aes_gcm_dec_final_vaes_avx10(const struct aes_gcm_key_avx10 *key, +// const u32 le_ctr[4], +// const u8 ghash_acc[16], +// u64 total_aadlen, u64 total_datalen, +// const u8 tag[16], int taglen); +// +// This macro generates one of the above two functions (with \enc selecting +// which one). Both functions finish computing the GCM authentication tag by +// updating GHASH with the lengths block and encrypting the GHASH accumulator. +// |total_aadlen| and |total_datalen| must be the total length of the additional +// authenticated data and the en/decrypted data in bytes, respectively. +// +// The encryption function then stores the full-length (16-byte) computed +// authentication tag to |ghash_acc|. The decryption function instead loads the +// expected authentication tag (the one that was transmitted) from the 16-byte +// buffer |tag|, compares the first 4 <= |taglen| <= 16 bytes of it to the +// computed tag in constant time, and returns true if and only if they match. +.macro _aes_gcm_final enc + + // Function arguments + .set KEY, %rdi + .set LE_CTR_PTR, %rsi + .set GHASH_ACC_PTR, %rdx + .set TOTAL_AADLEN, %rcx + .set TOTAL_DATALEN, %r8 + .set TAG, %r9 + .set TAGLEN, %r10d // Originally at 8(%rsp) + + // Additional local variables. + // %rax, %xmm0-%xmm3, and %k1 are used as temporary registers. + .set AESKEYLEN, %r11d + .set AESKEYLEN64, %r11 + .set GFPOLY, %xmm4 + .set BSWAP_MASK, %xmm5 + .set LE_CTR, %xmm6 + .set GHASH_ACC, %xmm7 + .set H_POW1, %xmm8 + + // Load some constants. + vmovdqa .Lgfpoly(%rip), GFPOLY + vmovdqa .Lbswap_mask(%rip), BSWAP_MASK + + // Load the AES key length in bytes. + movl OFFSETOF_AESKEYLEN(KEY), AESKEYLEN + + // Set up a counter block with 1 in the low 32-bit word. This is the + // counter that produces the ciphertext needed to encrypt the auth tag. + // GFPOLY has 1 in the low word, so grab the 1 from there using a blend. + vpblendd $0xe, (LE_CTR_PTR), GFPOLY, LE_CTR + + // Build the lengths block and XOR it with the GHASH accumulator. + // Although the lengths block is defined as the AAD length followed by + // the en/decrypted data length, both in big-endian byte order, a byte + // reflection of the full block is needed because of the way we compute + // GHASH (see _ghash_mul_step). By using little-endian values in the + // opposite order, we avoid having to reflect any bytes here. + vmovq TOTAL_DATALEN, %xmm0 + vpinsrq $1, TOTAL_AADLEN, %xmm0, %xmm0 + vpsllq $3, %xmm0, %xmm0 // Bytes to bits + vpxor (GHASH_ACC_PTR), %xmm0, GHASH_ACC + + // Load the first hash key power (H^1), which is stored last. + vmovdqu8 OFFSETOFEND_H_POWERS-16(KEY), H_POW1 + +.if !\enc + // Prepare a mask of TAGLEN one bits. + movl 8(%rsp), TAGLEN + mov $-1, %eax + bzhi TAGLEN, %eax, %eax + kmovd %eax, %k1 +.endif + + // Make %rax point to the last AES round key for the chosen AES variant. + lea 6*16(KEY,AESKEYLEN64,4), %rax + + // Start the AES encryption of the counter block by swapping the counter + // block to big-endian and XOR-ing it with the zero-th AES round key. + vpshufb BSWAP_MASK, LE_CTR, %xmm0 + vpxor (KEY), %xmm0, %xmm0 + + // Complete the AES encryption and multiply GHASH_ACC by H^1. + // Interleave the AES and GHASH instructions to improve performance. + cmp $24, AESKEYLEN + jl 128f // AES-128? + je 192f // AES-192? + // AES-256 + vaesenc -13*16(%rax), %xmm0, %xmm0 + vaesenc -12*16(%rax), %xmm0, %xmm0 +192: + vaesenc -11*16(%rax), %xmm0, %xmm0 + vaesenc -10*16(%rax), %xmm0, %xmm0 +128: +.irp i, 0,1,2,3,4,5,6,7,8 + _ghash_mul_step \i, H_POW1, GHASH_ACC, GHASH_ACC, GFPOLY, \ + %xmm1, %xmm2, %xmm3 + vaesenc (\i-9)*16(%rax), %xmm0, %xmm0 +.endr + _ghash_mul_step 9, H_POW1, GHASH_ACC, GHASH_ACC, GFPOLY, \ + %xmm1, %xmm2, %xmm3 + + // Undo the byte reflection of the GHASH accumulator. + vpshufb BSWAP_MASK, GHASH_ACC, GHASH_ACC + + // Do the last AES round and XOR the resulting keystream block with the + // GHASH accumulator to produce the full computed authentication tag. + // + // Reduce latency by taking advantage of the property vaesenclast(key, + // a) ^ b == vaesenclast(key ^ b, a). I.e., XOR GHASH_ACC into the last + // round key, instead of XOR'ing the final AES output with GHASH_ACC. + // + // enc_final then returns the computed auth tag, while dec_final + // compares it with the transmitted one and returns a bool. To compare + // the tags, dec_final XORs them together and uses vptest to check + // whether the result is all-zeroes. This should be constant-time. + // dec_final applies the vaesenclast optimization to this additional + // value XOR'd too, using vpternlogd to XOR the last round key, GHASH + // accumulator, and transmitted auth tag together in one instruction. +.if \enc + vpxor (%rax), GHASH_ACC, %xmm1 + vaesenclast %xmm1, %xmm0, GHASH_ACC + vmovdqu GHASH_ACC, (GHASH_ACC_PTR) +.else + vmovdqu (TAG), %xmm1 + vpternlogd $0x96, (%rax), GHASH_ACC, %xmm1 + vaesenclast %xmm1, %xmm0, %xmm0 + xor %eax, %eax + vmovdqu8 %xmm0, %xmm0{%k1}{z} // Truncate to TAGLEN bytes + vptest %xmm0, %xmm0 + sete %al +.endif + // No need for vzeroupper here, since only used xmm registers were used. + RET +.endm + +_set_veclen 32 +SYM_FUNC_START(aes_gcm_precompute_vaes_avx10_256) + _aes_gcm_precompute +SYM_FUNC_END(aes_gcm_precompute_vaes_avx10_256) +SYM_FUNC_START(aes_gcm_enc_update_vaes_avx10_256) + _aes_gcm_update 1 +SYM_FUNC_END(aes_gcm_enc_update_vaes_avx10_256) +SYM_FUNC_START(aes_gcm_dec_update_vaes_avx10_256) + _aes_gcm_update 0 +SYM_FUNC_END(aes_gcm_dec_update_vaes_avx10_256) + +_set_veclen 64 +SYM_FUNC_START(aes_gcm_precompute_vaes_avx10_512) + _aes_gcm_precompute +SYM_FUNC_END(aes_gcm_precompute_vaes_avx10_512) +SYM_FUNC_START(aes_gcm_enc_update_vaes_avx10_512) + _aes_gcm_update 1 +SYM_FUNC_END(aes_gcm_enc_update_vaes_avx10_512) +SYM_FUNC_START(aes_gcm_dec_update_vaes_avx10_512) + _aes_gcm_update 0 +SYM_FUNC_END(aes_gcm_dec_update_vaes_avx10_512) + +// void aes_gcm_aad_update_vaes_avx10(const struct aes_gcm_key_avx10 *key, +// u8 ghash_acc[16], +// const u8 *aad, int aadlen); +// +// This function processes the AAD (Additional Authenticated Data) in GCM. +// Using the key |key|, it updates the GHASH accumulator |ghash_acc| with the +// data given by |aad| and |aadlen|. |key->ghash_key_powers| must have been +// initialized. On the first call, |ghash_acc| must be all zeroes. |aadlen| +// must be a multiple of 16, except on the last call where it can be any length. +// The caller must do any buffering needed to ensure this. +// +// AES-GCM is almost always used with small amounts of AAD, less than 32 bytes. +// Therefore, for AAD processing we currently only provide this implementation +// which uses 256-bit vectors (ymm registers) and only has a 1x-wide loop. This +// keeps the code size down, and it enables some micro-optimizations, e.g. using +// VEX-coded instructions instead of EVEX-coded to save some instruction bytes. +// To optimize for large amounts of AAD, we could implement a 4x-wide loop and +// provide a version using 512-bit vectors, but that doesn't seem to be useful. +SYM_FUNC_START(aes_gcm_aad_update_vaes_avx10) + + // Function arguments + .set KEY, %rdi + .set GHASH_ACC_PTR, %rsi + .set AAD, %rdx + .set AADLEN, %ecx + .set AADLEN64, %rcx // Zero-extend AADLEN before using! + + // Additional local variables. + // %rax, %ymm0-%ymm3, and %k1 are used as temporary registers. + .set BSWAP_MASK, %ymm4 + .set GFPOLY, %ymm5 + .set GHASH_ACC, %ymm6 + .set GHASH_ACC_XMM, %xmm6 + .set H_POW1, %ymm7 + + // Load some constants. + vbroadcasti128 .Lbswap_mask(%rip), BSWAP_MASK + vbroadcasti128 .Lgfpoly(%rip), GFPOLY + + // Load the GHASH accumulator. + vmovdqu (GHASH_ACC_PTR), GHASH_ACC_XMM + + // Update GHASH with 32 bytes of AAD at a time. + // + // Pre-subtracting 32 from AADLEN saves an instruction from the loop and + // also ensures that at least one write always occurs to AADLEN, + // zero-extending it and allowing AADLEN64 to be used later. + sub $32, AADLEN + jl .Laad_loop_1x_done + vmovdqu8 OFFSETOFEND_H_POWERS-32(KEY), H_POW1 // [H^2, H^1] +.Laad_loop_1x: + vmovdqu (AAD), %ymm0 + vpshufb BSWAP_MASK, %ymm0, %ymm0 + vpxor %ymm0, GHASH_ACC, GHASH_ACC + _ghash_mul H_POW1, GHASH_ACC, GHASH_ACC, GFPOLY, \ + %ymm0, %ymm1, %ymm2 + vextracti128 $1, GHASH_ACC, %xmm0 + vpxor %xmm0, GHASH_ACC_XMM, GHASH_ACC_XMM + add $32, AAD + sub $32, AADLEN + jge .Laad_loop_1x +.Laad_loop_1x_done: + add $32, AADLEN + jz .Laad_done + + // Update GHASH with the remaining 1 <= AADLEN < 32 bytes of AAD. + mov $-1, %eax + bzhi AADLEN, %eax, %eax + kmovd %eax, %k1 + vmovdqu8 (AAD), %ymm0{%k1}{z} + neg AADLEN64 + and $~15, AADLEN64 // -round_up(AADLEN, 16) + vmovdqu8 OFFSETOFEND_H_POWERS(KEY,AADLEN64), H_POW1 + vpshufb BSWAP_MASK, %ymm0, %ymm0 + vpxor %ymm0, GHASH_ACC, GHASH_ACC + _ghash_mul H_POW1, GHASH_ACC, GHASH_ACC, GFPOLY, \ + %ymm0, %ymm1, %ymm2 + vextracti128 $1, GHASH_ACC, %xmm0 + vpxor %xmm0, GHASH_ACC_XMM, GHASH_ACC_XMM + +.Laad_done: + // Store the updated GHASH accumulator back to memory. + vmovdqu GHASH_ACC_XMM, (GHASH_ACC_PTR) + + vzeroupper // This is needed after using ymm or zmm registers. + RET +SYM_FUNC_END(aes_gcm_aad_update_vaes_avx10) + +SYM_FUNC_START(aes_gcm_enc_final_vaes_avx10) + _aes_gcm_final 1 +SYM_FUNC_END(aes_gcm_enc_final_vaes_avx10) +SYM_FUNC_START(aes_gcm_dec_final_vaes_avx10) + _aes_gcm_final 0 +SYM_FUNC_END(aes_gcm_dec_final_vaes_avx10) |