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| /* SPDX-License-Identifier: GPL-2.0-or-later */
| /*
| *
| * Copyright (C) IBM Corporation, 2012
| *
| * Author: Anton Blanchard <anton@au.ibm.com>
| */
|
| #include <asm/ppc_asm.h>
| #include <asm/linkage.h>
| #include <asm/asm-offsets.h>
| #include <asm/export.h>
|
| .section ".toc","aw"
| PPC64_CACHES:
| .tc ppc64_caches[TC],ppc64_caches
| .section ".text"
|
| /**
| * __arch_clear_user: - Zero a block of memory in user space, with less checking.
| * @to: Destination address, in user space.
| * @n: Number of bytes to zero.
| *
| * Zero a block of memory in user space. Caller must check
| * the specified block with access_ok() before calling this function.
| *
| * Returns number of bytes that could not be cleared.
| * On success, this will be zero.
| */
|
| .macro err1
| 100:
| EX_TABLE(100b,.Ldo_err1)
| .endm
|
| .macro err2
| 200:
| EX_TABLE(200b,.Ldo_err2)
| .endm
|
| .macro err3
| 300:
| EX_TABLE(300b,.Ldo_err3)
| .endm
|
| .Ldo_err1:
| mr r3,r8
|
| .Ldo_err2:
| mtctr r4
| 1:
| err3; stb r0,0(r3)
| addi r3,r3,1
| addi r4,r4,-1
| bdnz 1b
|
| .Ldo_err3:
| mr r3,r4
| blr
|
| _GLOBAL_TOC(__arch_clear_user)
| cmpdi r4,32
| neg r6,r3
| li r0,0
| blt .Lshort_clear
| mr r8,r3
| mtocrf 0x01,r6
| clrldi r6,r6,(64-3)
|
| /* Get the destination 8 byte aligned */
| bf cr7*4+3,1f
| err1; stb r0,0(r3)
| addi r3,r3,1
|
| 1: bf cr7*4+2,2f
| err1; sth r0,0(r3)
| addi r3,r3,2
|
| 2: bf cr7*4+1,3f
| err1; stw r0,0(r3)
| addi r3,r3,4
|
| 3: sub r4,r4,r6
|
| cmpdi r4,32
| cmpdi cr1,r4,512
| blt .Lshort_clear
| bgt cr1,.Llong_clear
|
| .Lmedium_clear:
| srdi r6,r4,5
| mtctr r6
|
| /* Do 32 byte chunks */
| 4:
| err2; std r0,0(r3)
| err2; std r0,8(r3)
| err2; std r0,16(r3)
| err2; std r0,24(r3)
| addi r3,r3,32
| addi r4,r4,-32
| bdnz 4b
|
| .Lshort_clear:
| /* up to 31 bytes to go */
| cmpdi r4,16
| blt 6f
| err2; std r0,0(r3)
| err2; std r0,8(r3)
| addi r3,r3,16
| addi r4,r4,-16
|
| /* Up to 15 bytes to go */
| 6: mr r8,r3
| clrldi r4,r4,(64-4)
| mtocrf 0x01,r4
| bf cr7*4+0,7f
| err1; std r0,0(r3)
| addi r3,r3,8
|
| 7: bf cr7*4+1,8f
| err1; stw r0,0(r3)
| addi r3,r3,4
|
| 8: bf cr7*4+2,9f
| err1; sth r0,0(r3)
| addi r3,r3,2
|
| 9: bf cr7*4+3,10f
| err1; stb r0,0(r3)
|
| 10: li r3,0
| blr
|
| .Llong_clear:
| ld r5,PPC64_CACHES@toc(r2)
|
| bf cr7*4+0,11f
| err2; std r0,0(r3)
| addi r3,r3,8
| addi r4,r4,-8
|
| /* Destination is 16 byte aligned, need to get it cache block aligned */
| 11: lwz r7,DCACHEL1LOGBLOCKSIZE(r5)
| lwz r9,DCACHEL1BLOCKSIZE(r5)
|
| /*
| * With worst case alignment the long clear loop takes a minimum
| * of 1 byte less than 2 cachelines.
| */
| sldi r10,r9,2
| cmpd r4,r10
| blt .Lmedium_clear
|
| neg r6,r3
| addi r10,r9,-1
| and. r5,r6,r10
| beq 13f
|
| srdi r6,r5,4
| mtctr r6
| mr r8,r3
| 12:
| err1; std r0,0(r3)
| err1; std r0,8(r3)
| addi r3,r3,16
| bdnz 12b
|
| sub r4,r4,r5
|
| 13: srd r6,r4,r7
| mtctr r6
| mr r8,r3
| 14:
| err1; dcbz 0,r3
| add r3,r3,r9
| bdnz 14b
|
| and r4,r4,r10
|
| cmpdi r4,32
| blt .Lshort_clear
| b .Lmedium_clear
| EXPORT_SYMBOL(__arch_clear_user)
|
|
