diff options
Diffstat (limited to 'arch/parisc/lib/lusercopy.S')
| -rw-r--r-- | arch/parisc/lib/lusercopy.S | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S index 56845de6b5df..85c28bb80fb7 100644 --- a/arch/parisc/lib/lusercopy.S +++ b/arch/parisc/lib/lusercopy.S @@ -5,6 +5,8 @@ * 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> * * * This program is free software; you can redistribute it and/or modify @@ -132,4 +134,321 @@ ENDPROC_CFI(lstrnlen_user) .procend + + +/* + * 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) + .proc + .callinfo NO_CALLS + .entry + + /* 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) + + .exit +ENDPROC_CFI(pa_memcpy) + .procend + .end |
