mirror of
https://github.com/torvalds/linux.git
synced 2024-12-03 01:21:28 +00:00
467a3bf219
The return from the crc32_le_vgfm_16/crc32c_le_vgfm_16 and the
crc32_be_vgfm_16 functions are done with "br %r14". These are indirect
branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y.
Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
272 lines
7.7 KiB
ArmAsm
272 lines
7.7 KiB
ArmAsm
/* 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 bitreflected CRC-32 checksums for IEEE 802.3 Ethernet
|
|
* and Castagnoli.
|
|
*
|
|
* This CRC-32 implementation algorithm is bitreflected and processes
|
|
* the least-significant bit first (Little-Endian).
|
|
*
|
|
* 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_PERM_LE2BE %v9
|
|
#define CONST_R2R1 %v10
|
|
#define CONST_R4R3 %v11
|
|
#define CONST_R5 %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+32 mod P'(x) << 32)]' << 1
|
|
* R2 = [(x4*128-32 mod P'(x) << 32)]' << 1
|
|
* R3 = [(x128+32 mod P'(x) << 32)]' << 1
|
|
* R4 = [(x128-32 mod P'(x) << 32)]' << 1
|
|
* R5 = [(x64 mod P'(x) << 32)]' << 1
|
|
* R6 = [(x32 mod P'(x) << 32)]' << 1
|
|
*
|
|
* The bitreflected Barret reduction constant, u', is defined as
|
|
* the bit reversal of 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.
|
|
*
|
|
* CRC-32 (IEEE 802.3 Ethernet, ...) polynomials:
|
|
*
|
|
* P(x) = 0x04C11DB7
|
|
* P'(x) = 0xEDB88320
|
|
*
|
|
* CRC-32C (Castagnoli) polynomials:
|
|
*
|
|
* P(x) = 0x1EDC6F41
|
|
* P'(x) = 0x82F63B78
|
|
*/
|
|
|
|
.Lconstants_CRC_32_LE:
|
|
.octa 0x0F0E0D0C0B0A09080706050403020100 # BE->LE mask
|
|
.quad 0x1c6e41596, 0x154442bd4 # R2, R1
|
|
.quad 0x0ccaa009e, 0x1751997d0 # R4, R3
|
|
.octa 0x163cd6124 # R5
|
|
.octa 0x1F7011641 # u'
|
|
.octa 0x1DB710641 # P'(x) << 1
|
|
|
|
.Lconstants_CRC_32C_LE:
|
|
.octa 0x0F0E0D0C0B0A09080706050403020100 # BE->LE mask
|
|
.quad 0x09e4addf8, 0x740eef02 # R2, R1
|
|
.quad 0x14cd00bd6, 0xf20c0dfe # R4, R3
|
|
.octa 0x0dd45aab8 # R5
|
|
.octa 0x0dea713f1 # u'
|
|
.octa 0x105ec76f0 # P'(x) << 1
|
|
|
|
.previous
|
|
|
|
GEN_BR_THUNK %r14
|
|
|
|
.text
|
|
|
|
/*
|
|
* The CRC-32 functions 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: Constant for BE->LE conversion and shift operations
|
|
*
|
|
* V10..V14: CRC-32 constants.
|
|
*/
|
|
|
|
ENTRY(crc32_le_vgfm_16)
|
|
larl %r5,.Lconstants_CRC_32_LE
|
|
j crc32_le_vgfm_generic
|
|
|
|
ENTRY(crc32c_le_vgfm_16)
|
|
larl %r5,.Lconstants_CRC_32C_LE
|
|
j crc32_le_vgfm_generic
|
|
|
|
|
|
crc32_le_vgfm_generic:
|
|
/* Load CRC-32 constants */
|
|
VLM CONST_PERM_LE2BE,CONST_CRC_POLY,0,%r5
|
|
|
|
/*
|
|
* Load the initial CRC value.
|
|
*
|
|
* The CRC value is loaded into the rightmost word of the
|
|
* vector register and is later XORed with the LSB portion
|
|
* of the loaded input data.
|
|
*/
|
|
VZERO %v0 /* Clear V0 */
|
|
VLVGF %v0,%r2,3 /* Load CRC into rightmost word */
|
|
|
|
/* Load a 64-byte data chunk and XOR with CRC */
|
|
VLM %v1,%v4,0,%r3 /* 64-bytes into V1..V4 */
|
|
VPERM %v1,%v1,%v1,CONST_PERM_LE2BE
|
|
VPERM %v2,%v2,%v2,CONST_PERM_LE2BE
|
|
VPERM %v3,%v3,%v3,CONST_PERM_LE2BE
|
|
VPERM %v4,%v4,%v4,CONST_PERM_LE2BE
|
|
|
|
VX %v1,%v0,%v1 /* V1 ^= CRC */
|
|
aghi %r3,64 /* BUF = BUF + 64 */
|
|
aghi %r4,-64 /* LEN = LEN - 64 */
|
|
|
|
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
|
|
VPERM %v5,%v5,%v5,CONST_PERM_LE2BE
|
|
VPERM %v6,%v6,%v6,CONST_PERM_LE2BE
|
|
VPERM %v7,%v7,%v7,CONST_PERM_LE2BE
|
|
VPERM %v8,%v8,%v8,CONST_PERM_LE2BE
|
|
|
|
/*
|
|
* Perform a GF(2) multiplication of the doublewords in V1 with
|
|
* the R1 and R2 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_R2R1,%v1,%v5
|
|
VGFMAG %v2,CONST_R2R1,%v2,%v6
|
|
VGFMAG %v3,CONST_R2R1,%v3,%v7
|
|
VGFMAG %v4,CONST_R2R1,%v4,%v8
|
|
|
|
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. Multiply V1 with R3
|
|
* and R4 and accumulating the next 128-bit chunk until a single 128-bit
|
|
* value remains.
|
|
*/
|
|
VGFMAG %v1,CONST_R4R3,%v1,%v2
|
|
VGFMAG %v1,CONST_R4R3,%v1,%v3
|
|
VGFMAG %v1,CONST_R4R3,%v1,%v4
|
|
|
|
cghi %r4,16
|
|
jl .Lfinal_fold
|
|
|
|
.Lfold_16bytes_loop:
|
|
|
|
VL %v2,0,,%r3 /* Load next data chunk */
|
|
VPERM %v2,%v2,%v2,CONST_PERM_LE2BE
|
|
VGFMAG %v1,CONST_R4R3,%v1,%v2 /* Fold next data chunk */
|
|
|
|
aghi %r3,16
|
|
aghi %r4,-16
|
|
|
|
cghi %r4,16
|
|
jnl .Lfold_16bytes_loop
|
|
|
|
.Lfinal_fold:
|
|
/*
|
|
* Set up a vector register for byte shifts. The shift value must
|
|
* be loaded in bits 1-4 in byte element 7 of a vector register.
|
|
* Shift by 8 bytes: 0x40
|
|
* Shift by 4 bytes: 0x20
|
|
*/
|
|
VLEIB %v9,0x40,7
|
|
|
|
/*
|
|
* Prepare V0 for the next GF(2) multiplication: shift V0 by 8 bytes
|
|
* to move R4 into the rightmost doubleword and set the leftmost
|
|
* doubleword to 0x1.
|
|
*/
|
|
VSRLB %v0,CONST_R4R3,%v9
|
|
VLEIG %v0,1,0
|
|
|
|
/*
|
|
* Compute GF(2) product of V1 and V0. The rightmost doubleword
|
|
* of V1 is multiplied with R4. The leftmost doubleword of V1 is
|
|
* multiplied by 0x1 and is then XORed with rightmost product.
|
|
* Implicitly, the intermediate leftmost product becomes padded
|
|
*/
|
|
VGFMG %v1,%v0,%v1
|
|
|
|
/*
|
|
* Now do the final 32-bit fold by multiplying the rightmost word
|
|
* in V1 with R5 and XOR the result with the remaining bits in V1.
|
|
*
|
|
* To achieve this by a single VGFMAG, right shift V1 by a word
|
|
* and store the result in V2 which is then accumulated. Use the
|
|
* vector unpack instruction to load the rightmost half of the
|
|
* doubleword into the rightmost doubleword element of V1; the other
|
|
* half is loaded in the leftmost doubleword.
|
|
* The vector register with CONST_R5 contains the R5 constant in the
|
|
* rightmost doubleword and the leftmost doubleword is zero to ignore
|
|
* the leftmost product of V1.
|
|
*/
|
|
VLEIB %v9,0x20,7 /* Shift by words */
|
|
VSRLB %v2,%v1,%v9 /* Store remaining bits in V2 */
|
|
VUPLLF %v1,%v1 /* Split rightmost doubleword */
|
|
VGFMAG %v1,CONST_R5,%v1,%v2 /* V1 = (V1 * R5) XOR V2 */
|
|
|
|
/*
|
|
* Apply a Barret reduction to compute the final 32-bit CRC value.
|
|
*
|
|
* 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: The leftmost doubleword of vector register containing
|
|
* CONST_RU_POLY is zero and, thus, the intermediate GF(2) product
|
|
* is zero and does not contribute to the final result.
|
|
*/
|
|
|
|
/* 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 with T1(x) in
|
|
* V2 and XOR the intermediate result, T2(x), with the value in V1.
|
|
* The final result is stored in word element 2 of V2.
|
|
*/
|
|
VUPLLF %v2,%v2
|
|
VGFMAG %v2,CONST_CRC_POLY,%v2,%v1
|
|
|
|
.Ldone:
|
|
VLGVF %r2,%v2,2
|
|
BR_EX %r14
|
|
|
|
.previous
|