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/*
* Copyright 2017, Matt Brown, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* vpermxor$#.c
*
* Based on H. Peter Anvin's paper - The mathematics of RAID-6
*
* $#-way unrolled portable integer math RAID-6 instruction set
* This file is postprocessed using unroll.awk
*
* vpermxor$#.c makes use of the vpermxor instruction to optimise the RAID6 Q
* syndrome calculations.
* This can be run on systems which have both Altivec and vpermxor instruction.
*
* This instruction was introduced in POWER8 - ISA v2.07.
*/
#include <linux/raid/pq.h>
#ifdef CONFIG_ALTIVEC
#include <altivec.h>
#ifdef __KERNEL__
#include <asm/cputable.h>
#include <asm/ppc-opcode.h>
#include <asm/switch_to.h>
#endif
typedef vector unsigned char unative_t;
#define NSIZE sizeof(unative_t)
static const vector unsigned char gf_low = {0x1e, 0x1c, 0x1a, 0x18, 0x16, 0x14,
0x12, 0x10, 0x0e, 0x0c, 0x0a, 0x08,
0x06, 0x04, 0x02,0x00};
static const vector unsigned char gf_high = {0xfd, 0xdd, 0xbd, 0x9d, 0x7d, 0x5d,
0x3d, 0x1d, 0xe0, 0xc0, 0xa0, 0x80,
0x60, 0x40, 0x20, 0x00};
static void noinline raid6_vpermxor$#_gen_syndrome_real(int disks, size_t bytes,
void **ptrs)
{
u8 **dptr = (u8 **)ptrs;
u8 *p, *q;
int d, z, z0;
unative_t wp$$, wq$$, wd$$;
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
for (d = 0; d < bytes; d += NSIZE*$#) {
wp$$ = wq$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
for (z = z0-1; z>=0; z--) {
wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
/* P syndrome */
wp$$ = vec_xor(wp$$, wd$$);
/* Q syndrome */
asm(VPERMXOR(%0,%1,%2,%3):"=v"(wq$$):"v"(gf_high), "v"(gf_low), "v"(wq$$));
wq$$ = vec_xor(wq$$, wd$$);
}
*(unative_t *)&p[d+NSIZE*$$] = wp$$;
*(unative_t *)&q[d+NSIZE*$$] = wq$$;
}
}
static void raid6_vpermxor$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
preempt_disable();
enable_kernel_altivec();
raid6_vpermxor$#_gen_syndrome_real(disks, bytes, ptrs);
disable_kernel_altivec();
preempt_enable();
}
int raid6_have_altivec_vpermxor(void);
#if $# == 1
int raid6_have_altivec_vpermxor(void)
{
/* Check if arch has both altivec and the vpermxor instructions */
# ifdef __KERNEL__
return (cpu_has_feature(CPU_FTR_ALTIVEC_COMP) &&
cpu_has_feature(CPU_FTR_ARCH_207S));
# else
return 1;
#endif
}
#endif
const struct raid6_calls raid6_vpermxor$# = {
raid6_vpermxor$#_gen_syndrome,
NULL,
raid6_have_altivec_vpermxor,
"vpermxor$#",
0
};
#endif
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