bd067f83b0
In a number of places we called "cache line size" what is actually the cache block size, which in the powerpc architecture, means the effective size to use with cache management instructions (it can be different from the actual cache line size). We fix the naming across the board and properly retrieve both pieces of information when available in the device-tree. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
197 lines
3.4 KiB
ArmAsm
197 lines
3.4 KiB
ArmAsm
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2012
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*
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* Author: Anton Blanchard <anton@au.ibm.com>
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*/
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#include <asm/ppc_asm.h>
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#include <asm/linkage.h>
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#include <asm/asm-offsets.h>
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#include <asm/export.h>
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.section ".toc","aw"
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PPC64_CACHES:
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.tc ppc64_caches[TC],ppc64_caches
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.section ".text"
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/**
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* __clear_user: - Zero a block of memory in user space, with less checking.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be cleared.
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* On success, this will be zero.
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*/
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.macro err1
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100:
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EX_TABLE(100b,.Ldo_err1)
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.endm
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.macro err2
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200:
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EX_TABLE(200b,.Ldo_err2)
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.endm
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.macro err3
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300:
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EX_TABLE(300b,.Ldo_err3)
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.endm
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.Ldo_err1:
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mr r3,r8
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.Ldo_err2:
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mtctr r4
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1:
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err3; stb r0,0(r3)
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addi r3,r3,1
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addi r4,r4,-1
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bdnz 1b
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.Ldo_err3:
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mr r3,r4
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blr
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_GLOBAL_TOC(__clear_user)
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cmpdi r4,32
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neg r6,r3
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li r0,0
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blt .Lshort_clear
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mr r8,r3
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mtocrf 0x01,r6
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clrldi r6,r6,(64-3)
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/* Get the destination 8 byte aligned */
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bf cr7*4+3,1f
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err1; stb r0,0(r3)
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addi r3,r3,1
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1: bf cr7*4+2,2f
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err1; sth r0,0(r3)
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addi r3,r3,2
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2: bf cr7*4+1,3f
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err1; stw r0,0(r3)
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addi r3,r3,4
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3: sub r4,r4,r6
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cmpdi r4,32
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cmpdi cr1,r4,512
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blt .Lshort_clear
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bgt cr1,.Llong_clear
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.Lmedium_clear:
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srdi r6,r4,5
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mtctr r6
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/* Do 32 byte chunks */
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4:
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err2; std r0,0(r3)
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err2; std r0,8(r3)
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err2; std r0,16(r3)
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err2; std r0,24(r3)
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addi r3,r3,32
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addi r4,r4,-32
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bdnz 4b
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.Lshort_clear:
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/* up to 31 bytes to go */
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cmpdi r4,16
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blt 6f
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err2; std r0,0(r3)
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err2; std r0,8(r3)
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addi r3,r3,16
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addi r4,r4,-16
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/* Up to 15 bytes to go */
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6: mr r8,r3
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clrldi r4,r4,(64-4)
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mtocrf 0x01,r4
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bf cr7*4+0,7f
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err1; std r0,0(r3)
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addi r3,r3,8
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7: bf cr7*4+1,8f
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err1; stw r0,0(r3)
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addi r3,r3,4
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8: bf cr7*4+2,9f
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err1; sth r0,0(r3)
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addi r3,r3,2
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9: bf cr7*4+3,10f
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err1; stb r0,0(r3)
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10: li r3,0
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blr
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.Llong_clear:
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ld r5,PPC64_CACHES@toc(r2)
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bf cr7*4+0,11f
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err2; std r0,0(r3)
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addi r3,r3,8
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addi r4,r4,-8
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/* Destination is 16 byte aligned, need to get it cache block aligned */
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11: lwz r7,DCACHEL1LOGBLOCKSIZE(r5)
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lwz r9,DCACHEL1BLOCKSIZE(r5)
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/*
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* With worst case alignment the long clear loop takes a minimum
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* of 1 byte less than 2 cachelines.
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*/
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sldi r10,r9,2
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cmpd r4,r10
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blt .Lmedium_clear
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neg r6,r3
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addi r10,r9,-1
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and. r5,r6,r10
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beq 13f
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srdi r6,r5,4
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mtctr r6
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mr r8,r3
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12:
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err1; std r0,0(r3)
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err1; std r0,8(r3)
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addi r3,r3,16
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bdnz 12b
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sub r4,r4,r5
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13: srd r6,r4,r7
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mtctr r6
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mr r8,r3
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14:
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err1; dcbz r0,r3
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add r3,r3,r9
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bdnz 14b
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and r4,r4,r10
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cmpdi r4,32
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blt .Lshort_clear
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b .Lmedium_clear
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EXPORT_SYMBOL(__clear_user)
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