linux/arch/ia64/lib/memcpy.S

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
*
* Optimized version of the standard memcpy() function
*
* Inputs:
* in0: destination address
* in1: source address
* in2: number of bytes to copy
* Output:
* no return value
*
* Copyright (C) 2000-2001 Hewlett-Packard Co
* Stephane Eranian <eranian@hpl.hp.com>
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <asm/asmmacro.h>
#include <asm/export.h>
GLOBAL_ENTRY(memcpy)
# define MEM_LAT 21 /* latency to memory */
# define dst r2
# define src r3
# define retval r8
# define saved_pfs r9
# define saved_lc r10
# define saved_pr r11
# define cnt r16
# define src2 r17
# define t0 r18
# define t1 r19
# define t2 r20
# define t3 r21
# define t4 r22
# define src_end r23
# define N (MEM_LAT + 4)
# define Nrot ((N + 7) & ~7)
/*
* First, check if everything (src, dst, len) is a multiple of eight. If
* so, we handle everything with no taken branches (other than the loop
* itself) and a small icache footprint. Otherwise, we jump off to
* the more general copy routine handling arbitrary
* sizes/alignment etc.
*/
.prologue
.save ar.pfs, saved_pfs
alloc saved_pfs=ar.pfs,3,Nrot,0,Nrot
.save ar.lc, saved_lc
mov saved_lc=ar.lc
or t0=in0,in1
;;
or t0=t0,in2
.save pr, saved_pr
mov saved_pr=pr
.body
cmp.eq p6,p0=in2,r0 // zero length?
mov retval=in0 // return dst
(p6) br.ret.spnt.many rp // zero length, return immediately
;;
mov dst=in0 // copy because of rotation
shr.u cnt=in2,3 // number of 8-byte words to copy
mov pr.rot=1<<16
;;
adds cnt=-1,cnt // br.ctop is repeat/until
cmp.gtu p7,p0=16,in2 // copying less than 16 bytes?
mov ar.ec=N
;;
and t0=0x7,t0
mov ar.lc=cnt
;;
cmp.ne p6,p0=t0,r0
mov src=in1 // copy because of rotation
(p7) br.cond.spnt.few .memcpy_short
(p6) br.cond.spnt.few .memcpy_long
;;
nop.m 0
;;
nop.m 0
nop.i 0
;;
nop.m 0
;;
.rotr val[N]
.rotp p[N]
.align 32
1: { .mib
(p[0]) ld8 val[0]=[src],8
nop.i 0
brp.loop.imp 1b, 2f
}
2: { .mfb
(p[N-1])st8 [dst]=val[N-1],8
nop.f 0
br.ctop.dptk.few 1b
}
;;
mov ar.lc=saved_lc
mov pr=saved_pr,-1
mov ar.pfs=saved_pfs
br.ret.sptk.many rp
/*
* Small (<16 bytes) unaligned copying is done via a simple byte-at-the-time
* copy loop. This performs relatively poorly on Itanium, but it doesn't
* get used very often (gcc inlines small copies) and due to atomicity
* issues, we want to avoid read-modify-write of entire words.
*/
.align 32
.memcpy_short:
adds cnt=-1,in2 // br.ctop is repeat/until
mov ar.ec=MEM_LAT
brp.loop.imp 1f, 2f
;;
mov ar.lc=cnt
;;
nop.m 0
;;
nop.m 0
nop.i 0
;;
nop.m 0
;;
nop.m 0
;;
/*
* It is faster to put a stop bit in the loop here because it makes
* the pipeline shorter (and latency is what matters on short copies).
*/
.align 32
1: { .mib
(p[0]) ld1 val[0]=[src],1
nop.i 0
brp.loop.imp 1b, 2f
} ;;
2: { .mfb
(p[MEM_LAT-1])st1 [dst]=val[MEM_LAT-1],1
nop.f 0
br.ctop.dptk.few 1b
} ;;
mov ar.lc=saved_lc
mov pr=saved_pr,-1
mov ar.pfs=saved_pfs
br.ret.sptk.many rp
/*
* Large (>= 16 bytes) copying is done in a fancy way. Latency isn't
* an overriding concern here, but throughput is. We first do
* sub-word copying until the destination is aligned, then we check
* if the source is also aligned. If so, we do a simple load/store-loop
* until there are less than 8 bytes left over and then we do the tail,
* by storing the last few bytes using sub-word copying. If the source
* is not aligned, we branch off to the non-congruent loop.
*
* stage: op:
* 0 ld
* :
* MEM_LAT+3 shrp
* MEM_LAT+4 st
*
* On Itanium, the pipeline itself runs without stalls. However, br.ctop
* seems to introduce an unavoidable bubble in the pipeline so the overall
* latency is 2 cycles/iteration. This gives us a _copy_ throughput
* of 4 byte/cycle. Still not bad.
*/
# undef N
# undef Nrot
# define N (MEM_LAT + 5) /* number of stages */
# define Nrot ((N+1 + 2 + 7) & ~7) /* number of rotating regs */
#define LOG_LOOP_SIZE 6
.memcpy_long:
alloc t3=ar.pfs,3,Nrot,0,Nrot // resize register frame
and t0=-8,src // t0 = src & ~7
and t2=7,src // t2 = src & 7
;;
ld8 t0=[t0] // t0 = 1st source word
adds src2=7,src // src2 = (src + 7)
sub t4=r0,dst // t4 = -dst
;;
and src2=-8,src2 // src2 = (src + 7) & ~7
shl t2=t2,3 // t2 = 8*(src & 7)
shl t4=t4,3 // t4 = 8*(dst & 7)
;;
ld8 t1=[src2] // t1 = 1st source word if src is 8-byte aligned, 2nd otherwise
sub t3=64,t2 // t3 = 64-8*(src & 7)
shr.u t0=t0,t2
;;
add src_end=src,in2
shl t1=t1,t3
mov pr=t4,0x38 // (p5,p4,p3)=(dst & 7)
;;
or t0=t0,t1
mov cnt=r0
adds src_end=-1,src_end
;;
(p3) st1 [dst]=t0,1
(p3) shr.u t0=t0,8
(p3) adds cnt=1,cnt
;;
(p4) st2 [dst]=t0,2
(p4) shr.u t0=t0,16
(p4) adds cnt=2,cnt
;;
(p5) st4 [dst]=t0,4
(p5) adds cnt=4,cnt
and src_end=-8,src_end // src_end = last word of source buffer
;;
// At this point, dst is aligned to 8 bytes and there at least 16-7=9 bytes left to copy:
1:{ add src=cnt,src // make src point to remainder of source buffer
sub cnt=in2,cnt // cnt = number of bytes left to copy
mov t4=ip
} ;;
and src2=-8,src // align source pointer
adds t4=.memcpy_loops-1b,t4
mov ar.ec=N
and t0=7,src // t0 = src & 7
shr.u t2=cnt,3 // t2 = number of 8-byte words left to copy
shl cnt=cnt,3 // move bits 0-2 to 3-5
;;
.rotr val[N+1], w[2]
.rotp p[N]
cmp.ne p6,p0=t0,r0 // is src aligned, too?
shl t0=t0,LOG_LOOP_SIZE // t0 = 8*(src & 7)
adds t2=-1,t2 // br.ctop is repeat/until
;;
add t4=t0,t4
mov pr=cnt,0x38 // set (p5,p4,p3) to # of bytes last-word bytes to copy
mov ar.lc=t2
;;
nop.m 0
;;
nop.m 0
nop.i 0
;;
nop.m 0
;;
(p6) ld8 val[1]=[src2],8 // prime the pump...
mov b6=t4
br.sptk.few b6
;;
.memcpy_tail:
// At this point, (p5,p4,p3) are set to the number of bytes left to copy (which is
// less than 8) and t0 contains the last few bytes of the src buffer:
(p5) st4 [dst]=t0,4
(p5) shr.u t0=t0,32
mov ar.lc=saved_lc
;;
(p4) st2 [dst]=t0,2
(p4) shr.u t0=t0,16
mov ar.pfs=saved_pfs
;;
(p3) st1 [dst]=t0
mov pr=saved_pr,-1
br.ret.sptk.many rp
///////////////////////////////////////////////////////
.align 64
#define COPY(shift,index) \
1: { .mib \
(p[0]) ld8 val[0]=[src2],8; \
(p[MEM_LAT+3]) shrp w[0]=val[MEM_LAT+3],val[MEM_LAT+4-index],shift; \
brp.loop.imp 1b, 2f \
}; \
2: { .mfb \
(p[MEM_LAT+4]) st8 [dst]=w[1],8; \
nop.f 0; \
br.ctop.dptk.few 1b; \
}; \
;; \
ld8 val[N-1]=[src_end]; /* load last word (may be same as val[N]) */ \
;; \
shrp t0=val[N-1],val[N-index],shift; \
br .memcpy_tail
.memcpy_loops:
COPY(0, 1) /* no point special casing this---it doesn't go any faster without shrp */
COPY(8, 0)
COPY(16, 0)
COPY(24, 0)
COPY(32, 0)
COPY(40, 0)
COPY(48, 0)
COPY(56, 0)
END(memcpy)
EXPORT_SYMBOL(memcpy)