--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Implementation of POLYVAL using ARMv8 Crypto Extensions.
+ *
+ * Copyright 2021 Google LLC
+ */
+/*
+ * This is an efficient implementation of POLYVAL using ARMv8 Crypto Extensions
+ * It works on 8 blocks at a time, by precomputing the first 8 keys powers h^8,
+ * ..., h^1 in the POLYVAL finite field. This precomputation allows us to split
+ * finite field multiplication into two steps.
+ *
+ * In the first step, we consider h^i, m_i as normal polynomials of degree less
+ * than 128. We then compute p(x) = h^8m_0 + ... + h^1m_7 where multiplication
+ * is simply polynomial multiplication.
+ *
+ * In the second step, we compute the reduction of p(x) modulo the finite field
+ * modulus g(x) = x^128 + x^127 + x^126 + x^121 + 1.
+ *
+ * This two step process is equivalent to computing h^8m_0 + ... + h^1m_7 where
+ * multiplication is finite field multiplication. The advantage is that the
+ * two-step process only requires 1 finite field reduction for every 8
+ * polynomial multiplications. Further parallelism is gained by interleaving the
+ * multiplications and polynomial reductions.
+ */
+
+#include <linux/linkage.h>
+#define STRIDE_BLOCKS 8
+
+KEY_POWERS .req x0
+MSG .req x1
+BLOCKS_LEFT .req x2
+ACCUMULATOR .req x3
+KEY_START .req x10
+EXTRA_BYTES .req x11
+TMP .req x13
+
+M0 .req v0
+M1 .req v1
+M2 .req v2
+M3 .req v3
+M4 .req v4
+M5 .req v5
+M6 .req v6
+M7 .req v7
+KEY8 .req v8
+KEY7 .req v9
+KEY6 .req v10
+KEY5 .req v11
+KEY4 .req v12
+KEY3 .req v13
+KEY2 .req v14
+KEY1 .req v15
+PL .req v16
+PH .req v17
+TMP_V .req v18
+LO .req v20
+MI .req v21
+HI .req v22
+SUM .req v23
+GSTAR .req v24
+
+ .text
+
+ .arch armv8-a+crypto
+ .align 4
+
+.Lgstar:
+ .quad 0xc200000000000000, 0xc200000000000000
+
+/*
+ * Computes the product of two 128-bit polynomials in X and Y and XORs the
+ * components of the 256-bit product into LO, MI, HI.
+ *
+ * Given:
+ * X = [X_1 : X_0]
+ * Y = [Y_1 : Y_0]
+ *
+ * We compute:
+ * LO += X_0 * Y_0
+ * MI += (X_0 + X_1) * (Y_0 + Y_1)
+ * HI += X_1 * Y_1
+ *
+ * Later, the 256-bit result can be extracted as:
+ * [HI_1 : HI_0 + HI_1 + MI_1 + LO_1 : LO_1 + HI_0 + MI_0 + LO_0 : LO_0]
+ * This step is done when computing the polynomial reduction for efficiency
+ * reasons.
+ *
+ * Karatsuba multiplication is used instead of Schoolbook multiplication because
+ * it was found to be slightly faster on ARM64 CPUs.
+ *
+ */
+.macro karatsuba1 X Y
+ X .req \X
+ Y .req \Y
+ ext v25.16b, X.16b, X.16b, #8
+ ext v26.16b, Y.16b, Y.16b, #8
+ eor v25.16b, v25.16b, X.16b
+ eor v26.16b, v26.16b, Y.16b
+ pmull2 v28.1q, X.2d, Y.2d
+ pmull v29.1q, X.1d, Y.1d
+ pmull v27.1q, v25.1d, v26.1d
+ eor HI.16b, HI.16b, v28.16b
+ eor LO.16b, LO.16b, v29.16b
+ eor MI.16b, MI.16b, v27.16b
+ .unreq X
+ .unreq Y
+.endm
+
+/*
+ * Same as karatsuba1, except overwrites HI, LO, MI rather than XORing into
+ * them.
+ */
+.macro karatsuba1_store X Y
+ X .req \X
+ Y .req \Y
+ ext v25.16b, X.16b, X.16b, #8
+ ext v26.16b, Y.16b, Y.16b, #8
+ eor v25.16b, v25.16b, X.16b
+ eor v26.16b, v26.16b, Y.16b
+ pmull2 HI.1q, X.2d, Y.2d
+ pmull LO.1q, X.1d, Y.1d
+ pmull MI.1q, v25.1d, v26.1d
+ .unreq X
+ .unreq Y
+.endm
+
+/*
+ * Computes the 256-bit polynomial represented by LO, HI, MI. Stores
+ * the result in PL, PH.
+ * [PH : PL] =
+ * [HI_1 : HI_1 + HI_0 + MI_1 + LO_1 : HI_0 + MI_0 + LO_1 + LO_0 : LO_0]
+ */
+.macro karatsuba2
+ // v4 = [HI_1 + MI_1 : HI_0 + MI_0]
+ eor v4.16b, HI.16b, MI.16b
+ // v4 = [HI_1 + MI_1 + LO_1 : HI_0 + MI_0 + LO_0]
+ eor v4.16b, v4.16b, LO.16b
+ // v5 = [HI_0 : LO_1]
+ ext v5.16b, LO.16b, HI.16b, #8
+ // v4 = [HI_1 + HI_0 + MI_1 + LO_1 : HI_0 + MI_0 + LO_1 + LO_0]
+ eor v4.16b, v4.16b, v5.16b
+ // HI = [HI_0 : HI_1]
+ ext HI.16b, HI.16b, HI.16b, #8
+ // LO = [LO_0 : LO_1]
+ ext LO.16b, LO.16b, LO.16b, #8
+ // PH = [HI_1 : HI_1 + HI_0 + MI_1 + LO_1]
+ ext PH.16b, v4.16b, HI.16b, #8
+ // PL = [HI_0 + MI_0 + LO_1 + LO_0 : LO_0]
+ ext PL.16b, LO.16b, v4.16b, #8
+.endm
+
+/*
+ * Computes the 128-bit reduction of PH : PL. Stores the result in dest.
+ *
+ * This macro computes p(x) mod g(x) where p(x) is in montgomery form and g(x) =
+ * x^128 + x^127 + x^126 + x^121 + 1.
+ *
+ * We have a 256-bit polynomial PH : PL = P_3 : P_2 : P_1 : P_0 that is the
+ * product of two 128-bit polynomials in Montgomery form. We need to reduce it
+ * mod g(x). Also, since polynomials in Montgomery form have an "extra" factor
+ * of x^128, this product has two extra factors of x^128. To get it back into
+ * Montgomery form, we need to remove one of these factors by dividing by x^128.
+ *
+ * To accomplish both of these goals, we add multiples of g(x) that cancel out
+ * the low 128 bits P_1 : P_0, leaving just the high 128 bits. Since the low
+ * bits are zero, the polynomial division by x^128 can be done by right
+ * shifting.
+ *
+ * Since the only nonzero term in the low 64 bits of g(x) is the constant term,
+ * the multiple of g(x) needed to cancel out P_0 is P_0 * g(x). The CPU can
+ * only do 64x64 bit multiplications, so split P_0 * g(x) into x^128 * P_0 +
+ * x^64 * g*(x) * P_0 + P_0, where g*(x) is bits 64-127 of g(x). Adding this to
+ * the original polynomial gives P_3 : P_2 + P_0 + T_1 : P_1 + T_0 : 0, where T
+ * = T_1 : T_0 = g*(x) * P_0. Thus, bits 0-63 got "folded" into bits 64-191.
+ *
+ * Repeating this same process on the next 64 bits "folds" bits 64-127 into bits
+ * 128-255, giving the answer in bits 128-255. This time, we need to cancel P_1
+ * + T_0 in bits 64-127. The multiple of g(x) required is (P_1 + T_0) * g(x) *
+ * x^64. Adding this to our previous computation gives P_3 + P_1 + T_0 + V_1 :
+ * P_2 + P_0 + T_1 + V_0 : 0 : 0, where V = V_1 : V_0 = g*(x) * (P_1 + T_0).
+ *
+ * So our final computation is:
+ * T = T_1 : T_0 = g*(x) * P_0
+ * V = V_1 : V_0 = g*(x) * (P_1 + T_0)
+ * p(x) / x^{128} mod g(x) = P_3 + P_1 + T_0 + V_1 : P_2 + P_0 + T_1 + V_0
+ *
+ * The implementation below saves a XOR instruction by computing P_1 + T_0 : P_0
+ * + T_1 and XORing into dest, rather than separately XORing P_1 : P_0 and T_0 :
+ * T_1 into dest. This allows us to reuse P_1 + T_0 when computing V.
+ */
+.macro montgomery_reduction dest
+ DEST .req \dest
+ // TMP_V = T_1 : T_0 = P_0 * g*(x)
+ pmull TMP_V.1q, PL.1d, GSTAR.1d
+ // TMP_V = T_0 : T_1
+ ext TMP_V.16b, TMP_V.16b, TMP_V.16b, #8
+ // TMP_V = P_1 + T_0 : P_0 + T_1
+ eor TMP_V.16b, PL.16b, TMP_V.16b
+ // PH = P_3 + P_1 + T_0 : P_2 + P_0 + T_1
+ eor PH.16b, PH.16b, TMP_V.16b
+ // TMP_V = V_1 : V_0 = (P_1 + T_0) * g*(x)
+ pmull2 TMP_V.1q, TMP_V.2d, GSTAR.2d
+ eor DEST.16b, PH.16b, TMP_V.16b
+ .unreq DEST
+.endm
+
+/*
+ * Compute Polyval on 8 blocks.
+ *
+ * If reduce is set, also computes the montgomery reduction of the
+ * previous full_stride call and XORs with the first message block.
+ * (m_0 + REDUCE(PL, PH))h^8 + ... + m_7h^1.
+ * I.e., the first multiplication uses m_0 + REDUCE(PL, PH) instead of m_0.
+ *
+ * Sets PL, PH.
+ */
+.macro full_stride reduce
+ eor LO.16b, LO.16b, LO.16b
+ eor MI.16b, MI.16b, MI.16b
+ eor HI.16b, HI.16b, HI.16b
+
+ ld1 {M0.16b, M1.16b, M2.16b, M3.16b}, [MSG], #64
+ ld1 {M4.16b, M5.16b, M6.16b, M7.16b}, [MSG], #64
+
+ karatsuba1 M7 KEY1
+ .if \reduce
+ pmull TMP_V.1q, PL.1d, GSTAR.1d
+ .endif
+
+ karatsuba1 M6 KEY2
+ .if \reduce
+ ext TMP_V.16b, TMP_V.16b, TMP_V.16b, #8
+ .endif
+
+ karatsuba1 M5 KEY3
+ .if \reduce
+ eor TMP_V.16b, PL.16b, TMP_V.16b
+ .endif
+
+ karatsuba1 M4 KEY4
+ .if \reduce
+ eor PH.16b, PH.16b, TMP_V.16b
+ .endif
+
+ karatsuba1 M3 KEY5
+ .if \reduce
+ pmull2 TMP_V.1q, TMP_V.2d, GSTAR.2d
+ .endif
+
+ karatsuba1 M2 KEY6
+ .if \reduce
+ eor SUM.16b, PH.16b, TMP_V.16b
+ .endif
+
+ karatsuba1 M1 KEY7
+ eor M0.16b, M0.16b, SUM.16b
+
+ karatsuba1 M0 KEY8
+ karatsuba2
+.endm
+
+/*
+ * Handle any extra blocks after full_stride loop.
+ */
+.macro partial_stride
+ add KEY_POWERS, KEY_START, #(STRIDE_BLOCKS << 4)
+ sub KEY_POWERS, KEY_POWERS, BLOCKS_LEFT, lsl #4
+ ld1 {KEY1.16b}, [KEY_POWERS], #16
+
+ ld1 {TMP_V.16b}, [MSG], #16
+ eor SUM.16b, SUM.16b, TMP_V.16b
+ karatsuba1_store KEY1 SUM
+ sub BLOCKS_LEFT, BLOCKS_LEFT, #1
+
+ tst BLOCKS_LEFT, #4
+ beq .Lpartial4BlocksDone
+ ld1 {M0.16b, M1.16b, M2.16b, M3.16b}, [MSG], #64
+ ld1 {KEY8.16b, KEY7.16b, KEY6.16b, KEY5.16b}, [KEY_POWERS], #64
+ karatsuba1 M0 KEY8
+ karatsuba1 M1 KEY7
+ karatsuba1 M2 KEY6
+ karatsuba1 M3 KEY5
+.Lpartial4BlocksDone:
+ tst BLOCKS_LEFT, #2
+ beq .Lpartial2BlocksDone
+ ld1 {M0.16b, M1.16b}, [MSG], #32
+ ld1 {KEY8.16b, KEY7.16b}, [KEY_POWERS], #32
+ karatsuba1 M0 KEY8
+ karatsuba1 M1 KEY7
+.Lpartial2BlocksDone:
+ tst BLOCKS_LEFT, #1
+ beq .LpartialDone
+ ld1 {M0.16b}, [MSG], #16
+ ld1 {KEY8.16b}, [KEY_POWERS], #16
+ karatsuba1 M0 KEY8
+.LpartialDone:
+ karatsuba2
+ montgomery_reduction SUM
+.endm
+
+/*
+ * Perform montgomery multiplication in GF(2^128) and store result in op1.
+ *
+ * Computes op1*op2*x^{-128} mod x^128 + x^127 + x^126 + x^121 + 1
+ * If op1, op2 are in montgomery form, this computes the montgomery
+ * form of op1*op2.
+ *
+ * void pmull_polyval_mul(u8 *op1, const u8 *op2);
+ */
+SYM_FUNC_START(pmull_polyval_mul)
+ adr TMP, .Lgstar
+ ld1 {GSTAR.2d}, [TMP]
+ ld1 {v0.16b}, [x0]
+ ld1 {v1.16b}, [x1]
+ karatsuba1_store v0 v1
+ karatsuba2
+ montgomery_reduction SUM
+ st1 {SUM.16b}, [x0]
+ ret
+SYM_FUNC_END(pmull_polyval_mul)
+
+/*
+ * Perform polynomial evaluation as specified by POLYVAL. This computes:
+ * h^n * accumulator + h^n * m_0 + ... + h^1 * m_{n-1}
+ * where n=nblocks, h is the hash key, and m_i are the message blocks.
+ *
+ * x0 - pointer to precomputed key powers h^8 ... h^1
+ * x1 - pointer to message blocks
+ * x2 - number of blocks to hash
+ * x3 - pointer to accumulator
+ *
+ * void pmull_polyval_update(const struct polyval_ctx *ctx, const u8 *in,
+ * size_t nblocks, u8 *accumulator);
+ */
+SYM_FUNC_START(pmull_polyval_update)
+ adr TMP, .Lgstar
+ mov KEY_START, KEY_POWERS
+ ld1 {GSTAR.2d}, [TMP]
+ ld1 {SUM.16b}, [ACCUMULATOR]
+ subs BLOCKS_LEFT, BLOCKS_LEFT, #STRIDE_BLOCKS
+ blt .LstrideLoopExit
+ ld1 {KEY8.16b, KEY7.16b, KEY6.16b, KEY5.16b}, [KEY_POWERS], #64
+ ld1 {KEY4.16b, KEY3.16b, KEY2.16b, KEY1.16b}, [KEY_POWERS], #64
+ full_stride 0
+ subs BLOCKS_LEFT, BLOCKS_LEFT, #STRIDE_BLOCKS
+ blt .LstrideLoopExitReduce
+.LstrideLoop:
+ full_stride 1
+ subs BLOCKS_LEFT, BLOCKS_LEFT, #STRIDE_BLOCKS
+ bge .LstrideLoop
+.LstrideLoopExitReduce:
+ montgomery_reduction SUM
+.LstrideLoopExit:
+ adds BLOCKS_LEFT, BLOCKS_LEFT, #STRIDE_BLOCKS
+ beq .LskipPartial
+ partial_stride
+.LskipPartial:
+ st1 {SUM.16b}, [ACCUMULATOR]
+ ret
+SYM_FUNC_END(pmull_polyval_update)
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Glue code for POLYVAL using ARMv8 Crypto Extensions
+ *
+ * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
+ * Copyright (c) 2009 Intel Corp.
+ * Author: Huang Ying <ying.huang@intel.com>
+ * Copyright 2021 Google LLC
+ */
+
+/*
+ * Glue code based on ghash-clmulni-intel_glue.c.
+ *
+ * This implementation of POLYVAL uses montgomery multiplication accelerated by
+ * ARMv8 Crypto Extensions instructions to implement the finite field operations.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/simd.h>
+#include <crypto/polyval.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/cpufeature.h>
+#include <asm/neon.h>
+#include <asm/simd.h>
+
+#define NUM_KEY_POWERS 8
+
+struct polyval_tfm_ctx {
+ /*
+ * These powers must be in the order h^8, ..., h^1.
+ */
+ u8 key_powers[NUM_KEY_POWERS][POLYVAL_BLOCK_SIZE];
+};
+
+struct polyval_desc_ctx {
+ u8 buffer[POLYVAL_BLOCK_SIZE];
+ u32 bytes;
+};
+
+asmlinkage void pmull_polyval_update(const struct polyval_tfm_ctx *keys,
+ const u8 *in, size_t nblocks, u8 *accumulator);
+asmlinkage void pmull_polyval_mul(u8 *op1, const u8 *op2);
+
+static void internal_polyval_update(const struct polyval_tfm_ctx *keys,
+ const u8 *in, size_t nblocks, u8 *accumulator)
+{
+ if (likely(crypto_simd_usable())) {
+ kernel_neon_begin();
+ pmull_polyval_update(keys, in, nblocks, accumulator);
+ kernel_neon_end();
+ } else {
+ polyval_update_non4k(keys->key_powers[NUM_KEY_POWERS-1], in,
+ nblocks, accumulator);
+ }
+}
+
+static void internal_polyval_mul(u8 *op1, const u8 *op2)
+{
+ if (likely(crypto_simd_usable())) {
+ kernel_neon_begin();
+ pmull_polyval_mul(op1, op2);
+ kernel_neon_end();
+ } else {
+ polyval_mul_non4k(op1, op2);
+ }
+}
+
+static int polyval_arm64_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ struct polyval_tfm_ctx *tctx = crypto_shash_ctx(tfm);
+ int i;
+
+ if (keylen != POLYVAL_BLOCK_SIZE)
+ return -EINVAL;
+
+ memcpy(tctx->key_powers[NUM_KEY_POWERS-1], key, POLYVAL_BLOCK_SIZE);
+
+ for (i = NUM_KEY_POWERS-2; i >= 0; i--) {
+ memcpy(tctx->key_powers[i], key, POLYVAL_BLOCK_SIZE);
+ internal_polyval_mul(tctx->key_powers[i],
+ tctx->key_powers[i+1]);
+ }
+
+ return 0;
+}
+
+static int polyval_arm64_init(struct shash_desc *desc)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+
+ memset(dctx, 0, sizeof(*dctx));
+
+ return 0;
+}
+
+static int polyval_arm64_update(struct shash_desc *desc,
+ const u8 *src, unsigned int srclen)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+ const struct polyval_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+ u8 *pos;
+ unsigned int nblocks;
+ unsigned int n;
+
+ if (dctx->bytes) {
+ n = min(srclen, dctx->bytes);
+ pos = dctx->buffer + POLYVAL_BLOCK_SIZE - dctx->bytes;
+
+ dctx->bytes -= n;
+ srclen -= n;
+
+ while (n--)
+ *pos++ ^= *src++;
+
+ if (!dctx->bytes)
+ internal_polyval_mul(dctx->buffer,
+ tctx->key_powers[NUM_KEY_POWERS-1]);
+ }
+
+ while (srclen >= POLYVAL_BLOCK_SIZE) {
+ /* allow rescheduling every 4K bytes */
+ nblocks = min(srclen, 4096U) / POLYVAL_BLOCK_SIZE;
+ internal_polyval_update(tctx, src, nblocks, dctx->buffer);
+ srclen -= nblocks * POLYVAL_BLOCK_SIZE;
+ src += nblocks * POLYVAL_BLOCK_SIZE;
+ }
+
+ if (srclen) {
+ dctx->bytes = POLYVAL_BLOCK_SIZE - srclen;
+ pos = dctx->buffer;
+ while (srclen--)
+ *pos++ ^= *src++;
+ }
+
+ return 0;
+}
+
+static int polyval_arm64_final(struct shash_desc *desc, u8 *dst)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+ const struct polyval_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+
+ if (dctx->bytes) {
+ internal_polyval_mul(dctx->buffer,
+ tctx->key_powers[NUM_KEY_POWERS-1]);
+ }
+
+ memcpy(dst, dctx->buffer, POLYVAL_BLOCK_SIZE);
+
+ return 0;
+}
+
+static struct shash_alg polyval_alg = {
+ .digestsize = POLYVAL_DIGEST_SIZE,
+ .init = polyval_arm64_init,
+ .update = polyval_arm64_update,
+ .final = polyval_arm64_final,
+ .setkey = polyval_arm64_setkey,
+ .descsize = sizeof(struct polyval_desc_ctx),
+ .base = {
+ .cra_name = "polyval",
+ .cra_driver_name = "polyval-ce",
+ .cra_priority = 200,
+ .cra_blocksize = POLYVAL_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct polyval_tfm_ctx),
+ .cra_module = THIS_MODULE,
+ },
+};
+
+static int __init polyval_ce_mod_init(void)
+{
+ return crypto_register_shash(&polyval_alg);
+}
+
+static void __exit polyval_ce_mod_exit(void)
+{
+ crypto_unregister_shash(&polyval_alg);
+}
+
+module_cpu_feature_match(PMULL, polyval_ce_mod_init)
+module_exit(polyval_ce_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("POLYVAL hash function accelerated by ARMv8 Crypto Extensions");
+MODULE_ALIAS_CRYPTO("polyval");
+MODULE_ALIAS_CRYPTO("polyval-ce");
projects / kernel.git / commitdiff