| /* |
| * 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 = cnt |
| (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) |