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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* User Space Access Routines
*
* Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
* Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
* Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
* Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
* Copyright (C) 2017 Helge Deller <deller@gmx.de>
* Copyright (C) 2017 John David Anglin <dave.anglin@bell.net>
*/
/*
* These routines still have plenty of room for optimization
* (word & doubleword load/store, dual issue, store hints, etc.).
*/
/*
* The following routines assume that space register 3 (sr3) contains
* the space id associated with the current users address space.
*/
.text
#include <asm/assembly.h>
#include <asm/errno.h>
#include <linux/linkage.h>
/*
* unsigned long lclear_user(void *to, unsigned long n)
*
* Returns 0 for success.
* otherwise, returns number of bytes not transferred.
*/
ENTRY_CFI(lclear_user)
comib,=,n 0,%r25,$lclu_done
$lclu_loop:
addib,<> -1,%r25,$lclu_loop
1: stbs,ma %r0,1(%sr3,%r26)
$lclu_done:
bv %r0(%r2)
copy %r25,%r28
2: b $lclu_done
ldo 1(%r25),%r25
ASM_EXCEPTIONTABLE_ENTRY(1b,2b)
ENDPROC_CFI(lclear_user)
/*
* unsigned long pa_memcpy(void *dstp, const void *srcp, unsigned long len)
*
* Inputs:
* - sr1 already contains space of source region
* - sr2 already contains space of destination region
*
* Returns:
* - number of bytes that could not be copied.
* On success, this will be zero.
*
* This code is based on a C-implementation of a copy routine written by
* Randolph Chung, which in turn was derived from the glibc.
*
* Several strategies are tried to try to get the best performance for various
* conditions. In the optimal case, we copy by loops that copy 32- or 16-bytes
* at a time using general registers. Unaligned copies are handled either by
* aligning the destination and then using shift-and-write method, or in a few
* cases by falling back to a byte-at-a-time copy.
*
* Testing with various alignments and buffer sizes shows that this code is
* often >10x faster than a simple byte-at-a-time copy, even for strangely
* aligned operands. It is interesting to note that the glibc version of memcpy
* (written in C) is actually quite fast already. This routine is able to beat
* it by 30-40% for aligned copies because of the loop unrolling, but in some
* cases the glibc version is still slightly faster. This lends more
* credibility that gcc can generate very good code as long as we are careful.
*
* Possible optimizations:
* - add cache prefetching
* - try not to use the post-increment address modifiers; they may create
* additional interlocks. Assumption is that those were only efficient on old
* machines (pre PA8000 processors)
*/
dst = arg0
src = arg1
len = arg2
end = arg3
t1 = r19
t2 = r20
t3 = r21
t4 = r22
srcspc = sr1
dstspc = sr2
t0 = r1
a1 = t1
a2 = t2
a3 = t3
a0 = t4
save_src = ret0
save_dst = ret1
save_len = r31
ENTRY_CFI(pa_memcpy)
/* Last destination address */
add dst,len,end
/* short copy with less than 16 bytes? */
cmpib,COND(>>=),n 15,len,.Lbyte_loop
/* same alignment? */
xor src,dst,t0
extru t0,31,2,t1
cmpib,<>,n 0,t1,.Lunaligned_copy
#ifdef CONFIG_64BIT
/* only do 64-bit copies if we can get aligned. */
extru t0,31,3,t1
cmpib,<>,n 0,t1,.Lalign_loop32
/* loop until we are 64-bit aligned */
.Lalign_loop64:
extru dst,31,3,t1
cmpib,=,n 0,t1,.Lcopy_loop_16_start
20: ldb,ma 1(srcspc,src),t1
21: stb,ma t1,1(dstspc,dst)
b .Lalign_loop64
ldo -1(len),len
ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)
.Lcopy_loop_16_start:
ldi 31,t0
.Lcopy_loop_16:
cmpb,COND(>>=),n t0,len,.Lword_loop
10: ldd 0(srcspc,src),t1
11: ldd 8(srcspc,src),t2
ldo 16(src),src
12: std,ma t1,8(dstspc,dst)
13: std,ma t2,8(dstspc,dst)
14: ldd 0(srcspc,src),t1
15: ldd 8(srcspc,src),t2
ldo 16(src),src
16: std,ma t1,8(dstspc,dst)
17: std,ma t2,8(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(11b,.Lcopy16_fault)
ASM_EXCEPTIONTABLE_ENTRY(12b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(13b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(14b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(15b,.Lcopy16_fault)
ASM_EXCEPTIONTABLE_ENTRY(16b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(17b,.Lcopy_done)
b .Lcopy_loop_16
ldo -32(len),len
.Lword_loop:
cmpib,COND(>>=),n 3,len,.Lbyte_loop
20: ldw,ma 4(srcspc,src),t1
21: stw,ma t1,4(dstspc,dst)
b .Lword_loop
ldo -4(len),len
ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)
#endif /* CONFIG_64BIT */
/* loop until we are 32-bit aligned */
.Lalign_loop32:
extru dst,31,2,t1
cmpib,=,n 0,t1,.Lcopy_loop_8
20: ldb,ma 1(srcspc,src),t1
21: stb,ma t1,1(dstspc,dst)
b .Lalign_loop32
ldo -1(len),len
ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)
.Lcopy_loop_8:
cmpib,COND(>>=),n 15,len,.Lbyte_loop
10: ldw 0(srcspc,src),t1
11: ldw 4(srcspc,src),t2
12: stw,ma t1,4(dstspc,dst)
13: stw,ma t2,4(dstspc,dst)
14: ldw 8(srcspc,src),t1
15: ldw 12(srcspc,src),t2
ldo 16(src),src
16: stw,ma t1,4(dstspc,dst)
17: stw,ma t2,4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(11b,.Lcopy8_fault)
ASM_EXCEPTIONTABLE_ENTRY(12b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(13b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(14b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(15b,.Lcopy8_fault)
ASM_EXCEPTIONTABLE_ENTRY(16b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(17b,.Lcopy_done)
b .Lcopy_loop_8
ldo -16(len),len
.Lbyte_loop:
cmpclr,COND(<>) len,%r0,%r0
b,n .Lcopy_done
20: ldb 0(srcspc,src),t1
ldo 1(src),src
21: stb,ma t1,1(dstspc,dst)
b .Lbyte_loop
ldo -1(len),len
ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)
.Lcopy_done:
bv %r0(%r2)
sub end,dst,ret0
/* src and dst are not aligned the same way. */
/* need to go the hard way */
.Lunaligned_copy:
/* align until dst is 32bit-word-aligned */
extru dst,31,2,t1
cmpib,=,n 0,t1,.Lcopy_dstaligned
20: ldb 0(srcspc,src),t1
ldo 1(src),src
21: stb,ma t1,1(dstspc,dst)
b .Lunaligned_copy
ldo -1(len),len
ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)
ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)
.Lcopy_dstaligned:
/* store src, dst and len in safe place */
copy src,save_src
copy dst,save_dst
copy len,save_len
/* len now needs give number of words to copy */
SHRREG len,2,len
/*
* Copy from a not-aligned src to an aligned dst using shifts.
* Handles 4 words per loop.
*/
depw,z src,28,2,t0
subi 32,t0,t0
mtsar t0
extru len,31,2,t0
cmpib,= 2,t0,.Lcase2
/* Make src aligned by rounding it down. */
depi 0,31,2,src
cmpiclr,<> 3,t0,%r0
b,n .Lcase3
cmpiclr,<> 1,t0,%r0
b,n .Lcase1
.Lcase0:
cmpb,COND(=) %r0,len,.Lcda_finish
nop
1: ldw,ma 4(srcspc,src), a3
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
1: ldw,ma 4(srcspc,src), a0
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
b,n .Ldo3
.Lcase1:
1: ldw,ma 4(srcspc,src), a2
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
1: ldw,ma 4(srcspc,src), a3
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
ldo -1(len),len
cmpb,COND(=),n %r0,len,.Ldo0
.Ldo4:
1: ldw,ma 4(srcspc,src), a0
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
shrpw a2, a3, %sar, t0
1: stw,ma t0, 4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)
.Ldo3:
1: ldw,ma 4(srcspc,src), a1
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
shrpw a3, a0, %sar, t0
1: stw,ma t0, 4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)
.Ldo2:
1: ldw,ma 4(srcspc,src), a2
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
shrpw a0, a1, %sar, t0
1: stw,ma t0, 4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)
.Ldo1:
1: ldw,ma 4(srcspc,src), a3
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
shrpw a1, a2, %sar, t0
1: stw,ma t0, 4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)
ldo -4(len),len
cmpb,COND(<>) %r0,len,.Ldo4
nop
.Ldo0:
shrpw a2, a3, %sar, t0
1: stw,ma t0, 4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)
.Lcda_rdfault:
.Lcda_finish:
/* calculate new src, dst and len and jump to byte-copy loop */
sub dst,save_dst,t0
add save_src,t0,src
b .Lbyte_loop
sub save_len,t0,len
.Lcase3:
1: ldw,ma 4(srcspc,src), a0
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
1: ldw,ma 4(srcspc,src), a1
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
b .Ldo2
ldo 1(len),len
.Lcase2:
1: ldw,ma 4(srcspc,src), a1
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
1: ldw,ma 4(srcspc,src), a2
ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
b .Ldo1
ldo 2(len),len
/* fault exception fixup handlers: */
#ifdef CONFIG_64BIT
.Lcopy16_fault:
b .Lcopy_done
10: std,ma t1,8(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)
#endif
.Lcopy8_fault:
b .Lcopy_done
10: stw,ma t1,4(dstspc,dst)
ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)
ENDPROC_CFI(pa_memcpy)
.end
|
