arch/s390/crypto/crc32be-vx.S - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Hardware-accelerated CRC-32 variants for Linux on z Systems
  *
  * Use the z/Architecture Vector Extension Facility to accelerate the
  * computing of CRC-32 checksums.
  *
  * This CRC-32 implementation algorithm processes the most-significant
  * bit first (BE).
  *
  * Copyright IBM Corp. 2015
  * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  */

 #include <linux/linkage.h>
 #include <asm/nospec-insn.h>
 #include <asm/vx-insn.h>

 /* Vector register range containing CRC-32 constants */
 #define CONST_R1R2		%v9
 #define CONST_R3R4		%v10
 #define CONST_R5		%v11
 #define CONST_R6		%v12
 #define CONST_RU_POLY		%v13
 #define CONST_CRC_POLY		%v14

 .data
 .align 8

 /*
  * The CRC-32 constant block contains reduction constants to fold and
  * process particular chunks of the input data stream in parallel.
  *
  * For the CRC-32 variants, the constants are precomputed according to
  * these definitions:
  *
  *	R1 = x4*128+64 mod P(x)
  *	R2 = x4*128    mod P(x)
  *	R3 = x128+64   mod P(x)
  *	R4 = x128      mod P(x)
  *	R5 = x96       mod P(x)
  *	R6 = x64       mod P(x)
  *
  *	Barret reduction constant, u, is defined as floor(x**64 / P(x)).
  *
  *	where P(x) is the polynomial in the normal domain and the P'(x) is the
  *	polynomial in the reversed (bitreflected) domain.
  *
  * Note that the constant definitions below are extended in order to compute
  * intermediate results with a single VECTOR GALOIS FIELD MULTIPLY instruction.
  * The righmost doubleword can be 0 to prevent contribution to the result or
  * can be multiplied by 1 to perform an XOR without the need for a separate
  * VECTOR EXCLUSIVE OR instruction.
  *
  * CRC-32 (IEEE 802.3 Ethernet, ...) polynomials:
  *
  *	P(x)  = 0x04C11DB7
  *	P'(x) = 0xEDB88320
  */

 .Lconstants_CRC_32_BE:
 	.quad		0x08833794c, 0x0e6228b11	# R1, R2
 	.quad		0x0c5b9cd4c, 0x0e8a45605	# R3, R4
 	.quad		0x0f200aa66, 1 << 32		# R5, x32
 	.quad		0x0490d678d, 1			# R6, 1
 	.quad		0x104d101df, 0			# u
 	.quad		0x104C11DB7, 0			# P(x)

 .previous

 	GEN_BR_THUNK %r14

 .text
 /*
  * The CRC-32 function(s) use these calling conventions:
  *
  * Parameters:
  *
  *	%r2:	Initial CRC value, typically ~0; and final CRC (return) value.
  *	%r3:	Input buffer pointer, performance might be improved if the
  *		buffer is on a doubleword boundary.
  *	%r4:	Length of the buffer, must be 64 bytes or greater.
  *
  * Register usage:
  *
  *	%r5:	CRC-32 constant pool base pointer.
  *	V0:	Initial CRC value and intermediate constants and results.
  *	V1..V4:	Data for CRC computation.
  *	V5..V8:	Next data chunks that are fetched from the input buffer.
  *
  *	V9..V14: CRC-32 constants.
  */
 ENTRY(crc32_be_vgfm_16)
 	/* Load CRC-32 constants */
 	larl	%r5,.Lconstants_CRC_32_BE
 	VLM	CONST_R1R2,CONST_CRC_POLY,0,%r5

 	/* Load the initial CRC value into the leftmost word of V0. */
 	VZERO	%v0
 	VLVGF	%v0,%r2,0

 	/* Load a 64-byte data chunk and XOR with CRC */
 	VLM	%v1,%v4,0,%r3		/* 64-bytes into V1..V4 */
 	VX	%v1,%v0,%v1		/* V1 ^= CRC */
 	aghi	%r3,64			/* BUF = BUF + 64 */
 	aghi	%r4,-64			/* LEN = LEN - 64 */

 	/* Check remaining buffer size and jump to proper folding method */
 	cghi	%r4,64
 	jl	.Lless_than_64bytes

 .Lfold_64bytes_loop:
 	/* Load the next 64-byte data chunk into V5 to V8 */
 	VLM	%v5,%v8,0,%r3

 	/*
 	 * Perform a GF(2) multiplication of the doublewords in V1 with
 	 * the reduction constants in V0.  The intermediate result is
 	 * then folded (accumulated) with the next data chunk in V5 and
 	 * stored in V1.  Repeat this step for the register contents
 	 * in V2, V3, and V4 respectively.
 	 */
 	VGFMAG	%v1,CONST_R1R2,%v1,%v5
 	VGFMAG	%v2,CONST_R1R2,%v2,%v6
 	VGFMAG	%v3,CONST_R1R2,%v3,%v7
 	VGFMAG	%v4,CONST_R1R2,%v4,%v8

 	/* Adjust buffer pointer and length for next loop */
 	aghi	%r3,64			/* BUF = BUF + 64 */
 	aghi	%r4,-64			/* LEN = LEN - 64 */

 	cghi	%r4,64
 	jnl	.Lfold_64bytes_loop

 .Lless_than_64bytes:
 	/* Fold V1 to V4 into a single 128-bit value in V1 */
 	VGFMAG	%v1,CONST_R3R4,%v1,%v2
 	VGFMAG	%v1,CONST_R3R4,%v1,%v3
 	VGFMAG	%v1,CONST_R3R4,%v1,%v4

 	/* Check whether to continue with 64-bit folding */
 	cghi	%r4,16
 	jl	.Lfinal_fold

 .Lfold_16bytes_loop:

 	VL	%v2,0,,%r3		/* Load next data chunk */
 	VGFMAG	%v1,CONST_R3R4,%v1,%v2	/* Fold next data chunk */

 	/* Adjust buffer pointer and size for folding next data chunk */
 	aghi	%r3,16
 	aghi	%r4,-16

 	/* Process remaining data chunks */
 	cghi	%r4,16
 	jnl	.Lfold_16bytes_loop

 .Lfinal_fold:
 	/*
 	 * The R5 constant is used to fold a 128-bit value into an 96-bit value
 	 * that is XORed with the next 96-bit input data chunk.  To use a single
 	 * VGFMG instruction, multiply the rightmost 64-bit with x^32 (1<<32) to
 	 * form an intermediate 96-bit value (with appended zeros) which is then
 	 * XORed with the intermediate reduction result.
 	 */
 	VGFMG	%v1,CONST_R5,%v1

 	/*
 	 * Further reduce the remaining 96-bit value to a 64-bit value using a
 	 * single VGFMG, the rightmost doubleword is multiplied with 0x1. The
 	 * intermediate result is then XORed with the product of the leftmost
 	 * doubleword with R6.	The result is a 64-bit value and is subject to
 	 * the Barret reduction.
 	 */
 	VGFMG	%v1,CONST_R6,%v1

 	/*
 	 * The input values to the Barret reduction are the degree-63 polynomial
 	 * in V1 (R(x)), degree-32 generator polynomial, and the reduction
 	 * constant u.	The Barret reduction result is the CRC value of R(x) mod
 	 * P(x).
 	 *
 	 * The Barret reduction algorithm is defined as:
 	 *
 	 *    1. T1(x) = floor( R(x) / x^32 ) GF2MUL u
 	 *    2. T2(x) = floor( T1(x) / x^32 ) GF2MUL P(x)
 	 *    3. C(x)  = R(x) XOR T2(x) mod x^32
 	 *
 	 * Note: To compensate the division by x^32, use the vector unpack
 	 * instruction to move the leftmost word into the leftmost doubleword
 	 * of the vector register.  The rightmost doubleword is multiplied
 	 * with zero to not contribute to the intermediate results.
 	 */

 	/* T1(x) = floor( R(x) / x^32 ) GF2MUL u */
 	VUPLLF	%v2,%v1
 	VGFMG	%v2,CONST_RU_POLY,%v2

 	/*
 	 * Compute the GF(2) product of the CRC polynomial in VO with T1(x) in
 	 * V2 and XOR the intermediate result, T2(x),  with the value in V1.
 	 * The final result is in the rightmost word of V2.
 	 */
 	VUPLLF	%v2,%v2
 	VGFMAG	%v2,CONST_CRC_POLY,%v2,%v1

 .Ldone:
 	VLGVF	%r2,%v2,3
 	BR_EX	%r14
 ENDPROC(crc32_be_vgfm_16)

 .previous
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* Hardware-accelerated CRC-32 variants for Linux on z Systems
	*
	* Use the z/Architecture Vector Extension Facility to accelerate the
	* computing of CRC-32 checksums.
	*
	* This CRC-32 implementation algorithm processes the most-significant
	* bit first (BE).
	*
	* Copyright IBM Corp. 2015
	* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
	*/

	#include <linux/linkage.h>
	#include <asm/nospec-insn.h>
	#include <asm/vx-insn.h>

	/* Vector register range containing CRC-32 constants */
	#define CONST_R1R2 %v9
	#define CONST_R3R4 %v10
	#define CONST_R5 %v11
	#define CONST_R6 %v12
	#define CONST_RU_POLY %v13
	#define CONST_CRC_POLY %v14

	.data
	.align 8

	/*
	* The CRC-32 constant block contains reduction constants to fold and
	* process particular chunks of the input data stream in parallel.
	*
	* For the CRC-32 variants, the constants are precomputed according to
	* these definitions:
	*
	* R1 = x4*128+64 mod P(x)
	* R2 = x4*128 mod P(x)
	* R3 = x128+64 mod P(x)
	* R4 = x128 mod P(x)
	* R5 = x96 mod P(x)
	* R6 = x64 mod P(x)
	*
	* Barret reduction constant, u, is defined as floor(x**64 / P(x)).
	*
	* where P(x) is the polynomial in the normal domain and the P'(x) is the
	* polynomial in the reversed (bitreflected) domain.
	*
	* Note that the constant definitions below are extended in order to compute
	* intermediate results with a single VECTOR GALOIS FIELD MULTIPLY instruction.
	* The righmost doubleword can be 0 to prevent contribution to the result or
	* can be multiplied by 1 to perform an XOR without the need for a separate
	* VECTOR EXCLUSIVE OR instruction.
	*
	* CRC-32 (IEEE 802.3 Ethernet, ...) polynomials:
	*
	* P(x) = 0x04C11DB7
	* P'(x) = 0xEDB88320
	*/

	.Lconstants_CRC_32_BE:
	.quad 0x08833794c, 0x0e6228b11 # R1, R2
	.quad 0x0c5b9cd4c, 0x0e8a45605 # R3, R4
	.quad 0x0f200aa66, 1 << 32 # R5, x32
	.quad 0x0490d678d, 1 # R6, 1
	.quad 0x104d101df, 0 # u
	.quad 0x104C11DB7, 0 # P(x)

	.previous

	GEN_BR_THUNK %r14

	.text
	/*
	* The CRC-32 function(s) use these calling conventions:
	*
	* Parameters:
	*
	* %r2: Initial CRC value, typically ~0; and final CRC (return) value.
	* %r3: Input buffer pointer, performance might be improved if the
	* buffer is on a doubleword boundary.
	* %r4: Length of the buffer, must be 64 bytes or greater.
	*
	* Register usage:
	*
	* %r5: CRC-32 constant pool base pointer.
	* V0: Initial CRC value and intermediate constants and results.
	* V1..V4: Data for CRC computation.
	* V5..V8: Next data chunks that are fetched from the input buffer.
	*
	* V9..V14: CRC-32 constants.
	*/
	ENTRY(crc32_be_vgfm_16)
	/* Load CRC-32 constants */
	larl %r5,.Lconstants_CRC_32_BE
	VLM CONST_R1R2,CONST_CRC_POLY,0,%r5

	/* Load the initial CRC value into the leftmost word of V0. */
	VZERO %v0
	VLVGF %v0,%r2,0

	/* Load a 64-byte data chunk and XOR with CRC */
	VLM %v1,%v4,0,%r3 /* 64-bytes into V1..V4 */
	VX %v1,%v0,%v1 /* V1 ^= CRC */
	aghi %r3,64 /* BUF = BUF + 64 */
	aghi %r4,-64 /* LEN = LEN - 64 */

	/* Check remaining buffer size and jump to proper folding method */
	cghi %r4,64
	jl .Lless_than_64bytes

	.Lfold_64bytes_loop:
	/* Load the next 64-byte data chunk into V5 to V8 */
	VLM %v5,%v8,0,%r3

	/*
	* Perform a GF(2) multiplication of the doublewords in V1 with
	* the reduction constants in V0. The intermediate result is
	* then folded (accumulated) with the next data chunk in V5 and
	* stored in V1. Repeat this step for the register contents
	* in V2, V3, and V4 respectively.
	*/
	VGFMAG %v1,CONST_R1R2,%v1,%v5
	VGFMAG %v2,CONST_R1R2,%v2,%v6
	VGFMAG %v3,CONST_R1R2,%v3,%v7
	VGFMAG %v4,CONST_R1R2,%v4,%v8

	/* Adjust buffer pointer and length for next loop */
	aghi %r3,64 /* BUF = BUF + 64 */
	aghi %r4,-64 /* LEN = LEN - 64 */

	cghi %r4,64
	jnl .Lfold_64bytes_loop

	.Lless_than_64bytes:
	/* Fold V1 to V4 into a single 128-bit value in V1 */
	VGFMAG %v1,CONST_R3R4,%v1,%v2
	VGFMAG %v1,CONST_R3R4,%v1,%v3
	VGFMAG %v1,CONST_R3R4,%v1,%v4

	/* Check whether to continue with 64-bit folding */
	cghi %r4,16
	jl .Lfinal_fold

	.Lfold_16bytes_loop:

	VL %v2,0,,%r3 /* Load next data chunk */
	VGFMAG %v1,CONST_R3R4,%v1,%v2 /* Fold next data chunk */

	/* Adjust buffer pointer and size for folding next data chunk */
	aghi %r3,16
	aghi %r4,-16

	/* Process remaining data chunks */
	cghi %r4,16
	jnl .Lfold_16bytes_loop

	.Lfinal_fold:
	/*
	* The R5 constant is used to fold a 128-bit value into an 96-bit value
	* that is XORed with the next 96-bit input data chunk. To use a single
	* VGFMG instruction, multiply the rightmost 64-bit with x^32 (1<<32) to
	* form an intermediate 96-bit value (with appended zeros) which is then
	* XORed with the intermediate reduction result.
	*/
	VGFMG %v1,CONST_R5,%v1

	/*
	* Further reduce the remaining 96-bit value to a 64-bit value using a
	* single VGFMG, the rightmost doubleword is multiplied with 0x1. The
	* intermediate result is then XORed with the product of the leftmost
	* doubleword with R6. The result is a 64-bit value and is subject to
	* the Barret reduction.
	*/
	VGFMG %v1,CONST_R6,%v1

	/*
	* The input values to the Barret reduction are the degree-63 polynomial
	* in V1 (R(x)), degree-32 generator polynomial, and the reduction
	* constant u. The Barret reduction result is the CRC value of R(x) mod
	* P(x).
	*
	* The Barret reduction algorithm is defined as:
	*
	* 1. T1(x) = floor( R(x) / x^32 ) GF2MUL u
	* 2. T2(x) = floor( T1(x) / x^32 ) GF2MUL P(x)
	* 3. C(x) = R(x) XOR T2(x) mod x^32
	*
	* Note: To compensate the division by x^32, use the vector unpack
	* instruction to move the leftmost word into the leftmost doubleword
	* of the vector register. The rightmost doubleword is multiplied
	* with zero to not contribute to the intermediate results.
	*/

	/* T1(x) = floor( R(x) / x^32 ) GF2MUL u */
	VUPLLF %v2,%v1
	VGFMG %v2,CONST_RU_POLY,%v2

	/*
	* Compute the GF(2) product of the CRC polynomial in VO with T1(x) in
	* V2 and XOR the intermediate result, T2(x), with the value in V1.
	* The final result is in the rightmost word of V2.
	*/
	VUPLLF %v2,%v2
	VGFMAG %v2,CONST_CRC_POLY,%v2,%v1

	.Ldone:
	VLGVF %r2,%v2,3
	BR_EX %r14
	ENDPROC(crc32_be_vgfm_16)

	.previous