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s390/vdso: Get rid of permutation constants

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The three byte masks for VECTOR PERMUTE are not needed, since the
instruction VECTOR SHIFT LEFT DOUBLE BY BYTE can be used to implement
the required "rotate left" easily.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens
2024-09-19 14:40:04 +02:00
committed by Vasily Gorbik
parent 1ec6d09789
commit 8e391ae060
1 changed files with 10 additions and 15 deletions
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arch/s390/kernel/vdso64/vgetrandom-chacha.S
+10 -15
View File
@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/stringify.h>
#include <linux/linkage.h>
#include <asm/alternative.h>
#include <asm/fpu-insn.h>
@@ -12,9 +13,6 @@
#define COPY1 %v5
#define COPY2 %v6
#define COPY3 %v7
#define PERM4 %v16
#define PERM8 %v17
#define PERM12 %v18
#define BEPERM %v19
#define TMP0 %v20
#define TMP1 %v21
@@ -23,12 +21,9 @@
.section .rodata
.balign 128
.balign 32
.Lconstants:
.long 0x61707865,0x3320646e,0x79622d32,0x6b206574 # endian-neutral
.long 0x04050607,0x08090a0b,0x0c0d0e0f,0x00010203 # rotl 4 bytes
.long 0x08090a0b,0x0c0d0e0f,0x00010203,0x04050607 # rotl 8 bytes
.long 0x0c0d0e0f,0x00010203,0x04050607,0x08090a0b # rotl 12 bytes
.long 0x03020100,0x07060504,0x0b0a0908,0x0f0e0d0c # byte swap
.text
@@ -48,8 +43,8 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack)
/* COPY0 = "expand 32-byte k" */
VL COPY0,0,,%r1
/* PERM4-PERM12,BEPERM = byte selectors for VPERM */
VLM PERM4,BEPERM,16,%r1
/* BEPERM = byte selectors for VPERM */
ALTERNATIVE __stringify(VL BEPERM,16,,%r1), "brcl 0,0", ALT_FACILITY(148)
/* COPY1,COPY2 = key */
VLM COPY1,COPY2,0,%r3
@@ -89,11 +84,11 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack)
VERLLF STATE1,STATE1,7
/* STATE1[0,1,2,3] = STATE1[1,2,3,0] */
VPERM STATE1,STATE1,STATE1,PERM4
VSLDB STATE1,STATE1,STATE1,4
/* STATE2[0,1,2,3] = STATE2[2,3,0,1] */
VPERM STATE2,STATE2,STATE2,PERM8
VSLDB STATE2,STATE2,STATE2,8
/* STATE3[0,1,2,3] = STATE3[3,0,1,2] */
VPERM STATE3,STATE3,STATE3,PERM12
VSLDB STATE3,STATE3,STATE3,12
/* STATE0 += STATE1, STATE3 = rotl32(STATE3 ^ STATE0, 16) */
VAF STATE0,STATE0,STATE1
@@ -116,11 +111,11 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack)
VERLLF STATE1,STATE1,7
/* STATE1[0,1,2,3] = STATE1[3,0,1,2] */
VPERM STATE1,STATE1,STATE1,PERM12
VSLDB STATE1,STATE1,STATE1,12
/* STATE2[0,1,2,3] = STATE2[2,3,0,1] */
VPERM STATE2,STATE2,STATE2,PERM8
VSLDB STATE2,STATE2,STATE2,8
/* STATE3[0,1,2,3] = STATE3[1,2,3,0] */
VPERM STATE3,STATE3,STATE3,PERM4
VSLDB STATE3,STATE3,STATE3,4
brctg %r0,.Ldoubleround
/* OUTPUT0 = STATE0 + STATE0 */