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Diffstat (limited to 'arch/ia64/lib/memcpy_mck.S')
| -rw-r--r-- | arch/ia64/lib/memcpy_mck.S | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/arch/ia64/lib/memcpy_mck.S b/arch/ia64/lib/memcpy_mck.S new file mode 100644 index 000000000000..6f26ef7cc236 --- /dev/null +++ b/arch/ia64/lib/memcpy_mck.S @@ -0,0 +1,661 @@ +/* + * Itanium 2-optimized version of memcpy and copy_user function + * + * Inputs: + * in0: destination address + * in1: source address + * in2: number of bytes to copy + * Output: + * 0 if success, or number of byte NOT copied if error occurred. + * + * Copyright (C) 2002 Intel Corp. + * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com> + */ +#include <linux/config.h> +#include <asm/asmmacro.h> +#include <asm/page.h> + +#define EK(y...) EX(y) + +/* McKinley specific optimization */ + +#define retval r8 +#define saved_pfs r31 +#define saved_lc r10 +#define saved_pr r11 +#define saved_in0 r14 +#define saved_in1 r15 +#define saved_in2 r16 + +#define src0 r2 +#define src1 r3 +#define dst0 r17 +#define dst1 r18 +#define cnt r9 + +/* r19-r30 are temp for each code section */ +#define PREFETCH_DIST 8 +#define src_pre_mem r19 +#define dst_pre_mem r20 +#define src_pre_l2 r21 +#define dst_pre_l2 r22 +#define t1 r23 +#define t2 r24 +#define t3 r25 +#define t4 r26 +#define t5 t1 // alias! +#define t6 t2 // alias! +#define t7 t3 // alias! +#define n8 r27 +#define t9 t5 // alias! +#define t10 t4 // alias! +#define t11 t7 // alias! +#define t12 t6 // alias! +#define t14 t10 // alias! +#define t13 r28 +#define t15 r29 +#define tmp r30 + +/* defines for long_copy block */ +#define A 0 +#define B (PREFETCH_DIST) +#define C (B + PREFETCH_DIST) +#define D (C + 1) +#define N (D + 1) +#define Nrot ((N + 7) & ~7) + +/* alias */ +#define in0 r32 +#define in1 r33 +#define in2 r34 + +GLOBAL_ENTRY(memcpy) + and r28=0x7,in0 + and r29=0x7,in1 + mov f6=f0 + br.cond.sptk .common_code + ;; +GLOBAL_ENTRY(__copy_user) + .prologue +// check dest alignment + and r28=0x7,in0 + and r29=0x7,in1 + mov f6=f1 + mov saved_in0=in0 // save dest pointer + mov saved_in1=in1 // save src pointer + mov saved_in2=in2 // save len + ;; +.common_code: + cmp.gt p15,p0=8,in2 // check for small size + cmp.ne p13,p0=0,r28 // check dest alignment + cmp.ne p14,p0=0,r29 // check src alignment + add src0=0,in1 + sub r30=8,r28 // for .align_dest + mov retval=r0 // initialize return value + ;; + add dst0=0,in0 + add dst1=1,in0 // dest odd index + cmp.le p6,p0 = 1,r30 // for .align_dest +(p15) br.cond.dpnt .memcpy_short +(p13) br.cond.dpnt .align_dest +(p14) br.cond.dpnt .unaligned_src + ;; + +// both dest and src are aligned on 8-byte boundary +.aligned_src: + .save ar.pfs, saved_pfs + alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot + .save pr, saved_pr + mov saved_pr=pr + + shr.u cnt=in2,7 // this much cache line + ;; + cmp.lt p6,p0=2*PREFETCH_DIST,cnt + cmp.lt p7,p8=1,cnt + .save ar.lc, saved_lc + mov saved_lc=ar.lc + .body + add cnt=-1,cnt + add src_pre_mem=0,in1 // prefetch src pointer + add dst_pre_mem=0,in0 // prefetch dest pointer + ;; +(p7) mov ar.lc=cnt // prefetch count +(p8) mov ar.lc=r0 +(p6) br.cond.dpnt .long_copy + ;; + +.prefetch: + lfetch.fault [src_pre_mem], 128 + lfetch.fault.excl [dst_pre_mem], 128 + br.cloop.dptk.few .prefetch + ;; + +.medium_copy: + and tmp=31,in2 // copy length after iteration + shr.u r29=in2,5 // number of 32-byte iteration + add dst1=8,dst0 // 2nd dest pointer + ;; + add cnt=-1,r29 // ctop iteration adjustment + cmp.eq p10,p0=r29,r0 // do we really need to loop? + add src1=8,src0 // 2nd src pointer + cmp.le p6,p0=8,tmp + ;; + cmp.le p7,p0=16,tmp + mov ar.lc=cnt // loop setup + cmp.eq p16,p17 = r0,r0 + mov ar.ec=2 +(p10) br.dpnt.few .aligned_src_tail + ;; + TEXT_ALIGN(32) +1: +EX(.ex_handler, (p16) ld8 r34=[src0],16) +EK(.ex_handler, (p16) ld8 r38=[src1],16) +EX(.ex_handler, (p17) st8 [dst0]=r33,16) +EK(.ex_handler, (p17) st8 [dst1]=r37,16) + ;; +EX(.ex_handler, (p16) ld8 r32=[src0],16) +EK(.ex_handler, (p16) ld8 r36=[src1],16) +EX(.ex_handler, (p16) st8 [dst0]=r34,16) +EK(.ex_handler, (p16) st8 [dst1]=r38,16) + br.ctop.dptk.few 1b + ;; + +.aligned_src_tail: +EX(.ex_handler, (p6) ld8 t1=[src0]) + mov ar.lc=saved_lc + mov ar.pfs=saved_pfs +EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8) + cmp.le p8,p0=24,tmp + and r21=-8,tmp + ;; +EX(.ex_hndlr_s, (p8) ld8 t3=[src1]) +EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1 + and in2=7,tmp // remaining length +EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2 + add src0=src0,r21 // setting up src pointer + add dst0=dst0,r21 // setting up dest pointer + ;; +EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3 + mov pr=saved_pr,-1 + br.dptk.many .memcpy_short + ;; + +/* code taken from copy_page_mck */ +.long_copy: + .rotr v[2*PREFETCH_DIST] + .rotp p[N] + + mov src_pre_mem = src0 + mov pr.rot = 0x10000 + mov ar.ec = 1 // special unrolled loop + + mov dst_pre_mem = dst0 + + add src_pre_l2 = 8*8, src0 + add dst_pre_l2 = 8*8, dst0 + ;; + add src0 = 8, src_pre_mem // first t1 src + mov ar.lc = 2*PREFETCH_DIST - 1 + shr.u cnt=in2,7 // number of lines + add src1 = 3*8, src_pre_mem // first t3 src + add dst0 = 8, dst_pre_mem // first t1 dst + add dst1 = 3*8, dst_pre_mem // first t3 dst + ;; + and tmp=127,in2 // remaining bytes after this block + add cnt = -(2*PREFETCH_DIST) - 1, cnt + // same as .line_copy loop, but with all predicated-off instructions removed: +.prefetch_loop: +EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 +EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 + br.ctop.sptk .prefetch_loop + ;; + cmp.eq p16, p0 = r0, r0 // reset p16 to 1 + mov ar.lc = cnt + mov ar.ec = N // # of stages in pipeline + ;; +.line_copy: +EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0 +EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1 +EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory +EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2 + ;; +EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory +EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2 +EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2 +EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3 + ;; +EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8) +EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8) +EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8) +EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8) + ;; +EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8) +EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8) +EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8) +EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8) + ;; +EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8) +EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8) +EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8) +EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8) + ;; +EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8) +EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8) +EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8) +EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8) + ;; +EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8) +EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8) +EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8) +EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8) + ;; +EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8) +EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8) +EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8) +EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8) + br.ctop.sptk .line_copy + ;; + + add dst0=-8,dst0 + add src0=-8,src0 + mov in2=tmp + .restore sp + br.sptk.many .medium_copy + ;; + +#define BLOCK_SIZE 128*32 +#define blocksize r23 +#define curlen r24 + +// dest is on 8-byte boundary, src is not. We need to do +// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle. +.unaligned_src: + .prologue + .save ar.pfs, saved_pfs + alloc saved_pfs=ar.pfs,3,5,0,8 + .save ar.lc, saved_lc + mov saved_lc=ar.lc + .save pr, saved_pr + mov saved_pr=pr + .body +.4k_block: + mov saved_in0=dst0 // need to save all input arguments + mov saved_in2=in2 + mov blocksize=BLOCK_SIZE + ;; + cmp.lt p6,p7=blocksize,in2 + mov saved_in1=src0 + ;; +(p6) mov in2=blocksize + ;; + shr.u r21=in2,7 // this much cache line + shr.u r22=in2,4 // number of 16-byte iteration + and curlen=15,in2 // copy length after iteration + and r30=7,src0 // source alignment + ;; + cmp.lt p7,p8=1,r21 + add cnt=-1,r21 + ;; + + add src_pre_mem=0,src0 // prefetch src pointer + add dst_pre_mem=0,dst0 // prefetch dest pointer + and src0=-8,src0 // 1st src pointer +(p7) mov ar.lc = r21 +(p8) mov ar.lc = r0 + ;; + TEXT_ALIGN(32) +1: lfetch.fault [src_pre_mem], 128 + lfetch.fault.excl [dst_pre_mem], 128 + br.cloop.dptk.few 1b + ;; + + shladd dst1=r22,3,dst0 // 2nd dest pointer + shladd src1=r22,3,src0 // 2nd src pointer + cmp.eq p8,p9=r22,r0 // do we really need to loop? + cmp.le p6,p7=8,curlen; // have at least 8 byte remaining? + add cnt=-1,r22 // ctop iteration adjustment + ;; +EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer +EK(.ex_handler, (p9) ld8 r37=[src1],8) +(p8) br.dpnt.few .noloop + ;; + +// The jump address is calculated based on src alignment. The COPYU +// macro below need to confine its size to power of two, so an entry +// can be caulated using shl instead of an expensive multiply. The +// size is then hard coded by the following #define to match the +// actual size. This make it somewhat tedious when COPYU macro gets +// changed and this need to be adjusted to match. +#define LOOP_SIZE 6 +1: + mov r29=ip // jmp_table thread + mov ar.lc=cnt + ;; + add r29=.jump_table - 1b - (.jmp1-.jump_table), r29 + shl r28=r30, LOOP_SIZE // jmp_table thread + mov ar.ec=2 // loop setup + ;; + add r29=r29,r28 // jmp_table thread + cmp.eq p16,p17=r0,r0 + ;; + mov b6=r29 // jmp_table thread + ;; + br.cond.sptk.few b6 + +// for 8-15 byte case +// We will skip the loop, but need to replicate the side effect +// that the loop produces. +.noloop: +EX(.ex_handler, (p6) ld8 r37=[src1],8) + add src0=8,src0 +(p6) shl r25=r30,3 + ;; +EX(.ex_handler, (p6) ld8 r27=[src1]) +(p6) shr.u r28=r37,r25 +(p6) sub r26=64,r25 + ;; +(p6) shl r27=r27,r26 + ;; +(p6) or r21=r28,r27 + +.unaligned_src_tail: +/* check if we have more than blocksize to copy, if so go back */ + cmp.gt p8,p0=saved_in2,blocksize + ;; +(p8) add dst0=saved_in0,blocksize +(p8) add src0=saved_in1,blocksize +(p8) sub in2=saved_in2,blocksize +(p8) br.dpnt .4k_block + ;; + +/* we have up to 15 byte to copy in the tail. + * part of work is already done in the jump table code + * we are at the following state. + * src side: + * + * xxxxxx xx <----- r21 has xxxxxxxx already + * -------- -------- -------- + * 0 8 16 + * ^ + * | + * src1 + * + * dst + * -------- -------- -------- + * ^ + * | + * dst1 + */ +EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy +(p6) add curlen=-8,curlen // update length + mov ar.pfs=saved_pfs + ;; + mov ar.lc=saved_lc + mov pr=saved_pr,-1 + mov in2=curlen // remaining length + mov dst0=dst1 // dest pointer + add src0=src1,r30 // forward by src alignment + ;; + +// 7 byte or smaller. +.memcpy_short: + cmp.le p8,p9 = 1,in2 + cmp.le p10,p11 = 2,in2 + cmp.le p12,p13 = 3,in2 + cmp.le p14,p15 = 4,in2 + add src1=1,src0 // second src pointer + add dst1=1,dst0 // second dest pointer + ;; + +EX(.ex_handler_short, (p8) ld1 t1=[src0],2) +EK(.ex_handler_short, (p10) ld1 t2=[src1],2) +(p9) br.ret.dpnt rp // 0 byte copy + ;; + +EX(.ex_handler_short, (p8) st1 [dst0]=t1,2) +EK(.ex_handler_short, (p10) st1 [dst1]=t2,2) +(p11) br.ret.dpnt rp // 1 byte copy + +EX(.ex_handler_short, (p12) ld1 t3=[src0],2) +EK(.ex_handler_short, (p14) ld1 t4=[src1],2) +(p13) br.ret.dpnt rp // 2 byte copy + ;; + + cmp.le p6,p7 = 5,in2 + cmp.le p8,p9 = 6,in2 + cmp.le p10,p11 = 7,in2 + +EX(.ex_handler_short, (p12) st1 [dst0]=t3,2) +EK(.ex_handler_short, (p14) st1 [dst1]=t4,2) +(p15) br.ret.dpnt rp // 3 byte copy + ;; + +EX(.ex_handler_short, (p6) ld1 t5=[src0],2) +EK(.ex_handler_short, (p8) ld1 t6=[src1],2) +(p7) br.ret.dpnt rp // 4 byte copy + ;; + +EX(.ex_handler_short, (p6) st1 [dst0]=t5,2) +EK(.ex_handler_short, (p8) st1 [dst1]=t6,2) +(p9) br.ret.dptk rp // 5 byte copy + +EX(.ex_handler_short, (p10) ld1 t7=[src0],2) +(p11) br.ret.dptk rp // 6 byte copy + ;; + +EX(.ex_handler_short, (p10) st1 [dst0]=t7,2) + br.ret.dptk rp // done all cases + + +/* Align dest to nearest 8-byte boundary. We know we have at + * least 7 bytes to copy, enough to crawl to 8-byte boundary. + * Actual number of byte to crawl depend on the dest alignment. + * 7 byte or less is taken care at .memcpy_short + + * src0 - source even index + * src1 - source odd index + * dst0 - dest even index + * dst1 - dest odd index + * r30 - distance to 8-byte boundary + */ + +.align_dest: + add src1=1,in1 // source odd index + cmp.le p7,p0 = 2,r30 // for .align_dest + cmp.le p8,p0 = 3,r30 // for .align_dest +EX(.ex_handler_short, (p6) ld1 t1=[src0],2) + cmp.le p9,p0 = 4,r30 // for .align_dest + cmp.le p10,p0 = 5,r30 + ;; +EX(.ex_handler_short, (p7) ld1 t2=[src1],2) +EK(.ex_handler_short, (p8) ld1 t3=[src0],2) + cmp.le p11,p0 = 6,r30 +EX(.ex_handler_short, (p6) st1 [dst0] = t1,2) + cmp.le p12,p0 = 7,r30 + ;; +EX(.ex_handler_short, (p9) ld1 t4=[src1],2) +EK(.ex_handler_short, (p10) ld1 t5=[src0],2) +EX(.ex_handler_short, (p7) st1 [dst1] = t2,2) +EK(.ex_handler_short, (p8) st1 [dst0] = t3,2) + ;; +EX(.ex_handler_short, (p11) ld1 t6=[src1],2) +EK(.ex_handler_short, (p12) ld1 t7=[src0],2) + cmp.eq p6,p7=r28,r29 +EX(.ex_handler_short, (p9) st1 [dst1] = t4,2) +EK(.ex_handler_short, (p10) st1 [dst0] = t5,2) + sub in2=in2,r30 + ;; +EX(.ex_handler_short, (p11) st1 [dst1] = t6,2) +EK(.ex_handler_short, (p12) st1 [dst0] = t7) + add dst0=in0,r30 // setup arguments + add src0=in1,r30 +(p6) br.cond.dptk .aligned_src +(p7) br.cond.dpnt .unaligned_src + ;; + +/* main loop body in jump table format */ +#define COPYU(shift) \ +1: \ +EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \ +EK(.ex_handler, (p16) ld8 r36=[src1],8); \ + (p17) shrp r35=r33,r34,shift;; /* 1 */ \ +EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \ + nop.m 0; \ + (p16) shrp r38=r36,r37,shift; \ +EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \ +EK(.ex_handler, (p17) st8 [dst1]=r39,8); \ + br.ctop.dptk.few 1b;; \ + (p7) add src1=-8,src1; /* back out for <8 byte case */ \ + shrp r21=r22,r38,shift; /* speculative work */ \ + br.sptk.few .unaligned_src_tail /* branch out of jump table */ \ + ;; + TEXT_ALIGN(32) +.jump_table: + COPYU(8) // unaligned cases +.jmp1: + COPYU(16) + COPYU(24) + COPYU(32) + COPYU(40) + COPYU(48) + COPYU(56) + +#undef A +#undef B +#undef C +#undef D +END(memcpy) + +/* + * Due to lack of local tag support in gcc 2.x assembler, it is not clear which + * instruction failed in the bundle. The exception algorithm is that we + * first figure out the faulting address, then detect if there is any + * progress made on the copy, if so, redo the copy from last known copied + * location up to the faulting address (exclusive). In the copy_from_user + * case, remaining byte in kernel buffer will be zeroed. + * + * Take copy_from_user as an example, in the code there are multiple loads + * in a bundle and those multiple loads could span over two pages, the + * faulting address is calculated as page_round_down(max(src0, src1)). + * This is based on knowledge that if we can access one byte in a page, we + * can access any byte in that page. + * + * predicate used in the exception handler: + * p6-p7: direction + * p10-p11: src faulting addr calculation + * p12-p13: dst faulting addr calculation + */ + +#define A r19 +#define B r20 +#define C r21 +#define D r22 +#define F r28 + +#define memset_arg0 r32 +#define memset_arg2 r33 + +#define saved_retval loc0 +#define saved_rtlink loc1 +#define saved_pfs_stack loc2 + +.ex_hndlr_s: + add src0=8,src0 + br.sptk .ex_handler + ;; +.ex_hndlr_d: + add dst0=8,dst0 + br.sptk .ex_handler + ;; +.ex_hndlr_lcpy_1: + mov src1=src_pre_mem + mov dst1=dst_pre_mem + cmp.gtu p10,p11=src_pre_mem,saved_in1 + cmp.gtu p12,p13=dst_pre_mem,saved_in0 + ;; +(p10) add src0=8,saved_in1 +(p11) mov src0=saved_in1 +(p12) add dst0=8,saved_in0 +(p13) mov dst0=saved_in0 + br.sptk .ex_handler +.ex_handler_lcpy: + // in line_copy block, the preload addresses should always ahead + // of the other two src/dst pointers. Furthermore, src1/dst1 should + // always ahead of src0/dst0. + mov src1=src_pre_mem + mov dst1=dst_pre_mem +.ex_handler: + mov pr=saved_pr,-1 // first restore pr, lc, and pfs + mov ar.lc=saved_lc + mov ar.pfs=saved_pfs + ;; +.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs + cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction + cmp.ltu p10,p11=src0,src1 + cmp.ltu p12,p13=dst0,dst1 + fcmp.eq p8,p0=f6,f0 // is it memcpy? + mov tmp = dst0 + ;; +(p11) mov src1 = src0 // pick the larger of the two +(p13) mov dst0 = dst1 // make dst0 the smaller one +(p13) mov dst1 = tmp // and dst1 the larger one + ;; +(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary +(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary + ;; +(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store +(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load + mov retval=saved_in2 +(p8) ld1 tmp=[src1] // force an oops for memcpy call +(p8) st1 [dst1]=r0 // force an oops for memcpy call +(p14) br.ret.sptk.many rp + +/* + * The remaining byte to copy is calculated as: + * + * A = (faulting_addr - orig_src) -> len to faulting ld address + * or + * (faulting_addr - orig_dst) -> len to faulting st address + * B = (cur_dst - orig_dst) -> len copied so far + * C = A - B -> len need to be copied + * D = orig_len - A -> len need to be zeroed + */ +(p6) sub A = F, saved_in0 +(p7) sub A = F, saved_in1 + clrrrb + ;; + alloc saved_pfs_stack=ar.pfs,3,3,3,0 + sub B = dst0, saved_in0 // how many byte copied so far + ;; + sub C = A, B + sub D = saved_in2, A + ;; + cmp.gt p8,p0=C,r0 // more than 1 byte? + add memset_arg0=saved_in0, A +(p6) mov memset_arg2=0 // copy_to_user should not call memset +(p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed + mov r8=0 + mov saved_retval = D + mov saved_rtlink = b0 + + add out0=saved_in0, B + add out1=saved_in1, B + mov out2=C +(p8) br.call.sptk.few b0=__copy_user // recursive call + ;; + + add saved_retval=saved_retval,r8 // above might return non-zero value + cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte? + mov out0=memset_arg0 // *s + mov out1=r0 // c + mov out2=memset_arg2 // n +(p8) br.call.sptk.few b0=memset + ;; + + mov retval=saved_retval + mov ar.pfs=saved_pfs_stack + mov b0=saved_rtlink + br.ret.sptk.many rp + +/* end of McKinley specific optimization */ +END(__copy_user) |