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Diffstat (limited to 'arch/ia64/lib/copy_user.S')
| -rw-r--r-- | arch/ia64/lib/copy_user.S | 613 |
1 files changed, 0 insertions, 613 deletions
diff --git a/arch/ia64/lib/copy_user.S b/arch/ia64/lib/copy_user.S deleted file mode 100644 index 8daab72cfe..0000000000 --- a/arch/ia64/lib/copy_user.S +++ /dev/null @@ -1,613 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * - * Optimized version of the copy_user() routine. - * It is used to copy date across the kernel/user boundary. - * - * The source and destination are always on opposite side of - * the boundary. When reading from user space we must catch - * faults on loads. When writing to user space we must catch - * errors on stores. Note that because of the nature of the copy - * we don't need to worry about overlapping regions. - * - * - * Inputs: - * in0 address of source buffer - * in1 address of destination buffer - * in2 number of bytes to copy - * - * Outputs: - * ret0 0 in case of success. The number of bytes NOT copied in - * case of error. - * - * Copyright (C) 2000-2001 Hewlett-Packard Co - * Stephane Eranian <eranian@hpl.hp.com> - * - * Fixme: - * - handle the case where we have more than 16 bytes and the alignment - * are different. - * - more benchmarking - * - fix extraneous stop bit introduced by the EX() macro. - */ - -#include <linux/export.h> -#include <asm/asmmacro.h> - -// -// Tuneable parameters -// -#define COPY_BREAK 16 // we do byte copy below (must be >=16) -#define PIPE_DEPTH 21 // pipe depth - -#define EPI p[PIPE_DEPTH-1] - -// -// arguments -// -#define dst in0 -#define src in1 -#define len in2 - -// -// local registers -// -#define t1 r2 // rshift in bytes -#define t2 r3 // lshift in bytes -#define rshift r14 // right shift in bits -#define lshift r15 // left shift in bits -#define word1 r16 -#define word2 r17 -#define cnt r18 -#define len2 r19 -#define saved_lc r20 -#define saved_pr r21 -#define tmp r22 -#define val r23 -#define src1 r24 -#define dst1 r25 -#define src2 r26 -#define dst2 r27 -#define len1 r28 -#define enddst r29 -#define endsrc r30 -#define saved_pfs r31 - -GLOBAL_ENTRY(__copy_user) - .prologue - .save ar.pfs, saved_pfs - alloc saved_pfs=ar.pfs,3,((2*PIPE_DEPTH+7)&~7),0,((2*PIPE_DEPTH+7)&~7) - - .rotr val1[PIPE_DEPTH],val2[PIPE_DEPTH] - .rotp p[PIPE_DEPTH] - - adds len2=-1,len // br.ctop is repeat/until - mov ret0=r0 - - ;; // RAW of cfm when len=0 - cmp.eq p8,p0=r0,len // check for zero length - .save ar.lc, saved_lc - mov saved_lc=ar.lc // preserve ar.lc (slow) -(p8) br.ret.spnt.many rp // empty mempcy() - ;; - add enddst=dst,len // first byte after end of source - add endsrc=src,len // first byte after end of destination - .save pr, saved_pr - mov saved_pr=pr // preserve predicates - - .body - - mov dst1=dst // copy because of rotation - mov ar.ec=PIPE_DEPTH - mov pr.rot=1<<16 // p16=true all others are false - - mov src1=src // copy because of rotation - mov ar.lc=len2 // initialize lc for small count - cmp.lt p10,p7=COPY_BREAK,len // if len > COPY_BREAK then long copy - - xor tmp=src,dst // same alignment test prepare -(p10) br.cond.dptk .long_copy_user - ;; // RAW pr.rot/p16 ? - // - // Now we do the byte by byte loop with software pipeline - // - // p7 is necessarily false by now -1: - EX(.failure_in_pipe1,(p16) ld1 val1[0]=[src1],1) - EX(.failure_out,(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1) - br.ctop.dptk.few 1b - ;; - mov ar.lc=saved_lc - mov pr=saved_pr,0xffffffffffff0000 - mov ar.pfs=saved_pfs // restore ar.ec - br.ret.sptk.many rp // end of short memcpy - - // - // Not 8-byte aligned - // -.diff_align_copy_user: - // At this point we know we have more than 16 bytes to copy - // and also that src and dest do _not_ have the same alignment. - and src2=0x7,src1 // src offset - and dst2=0x7,dst1 // dst offset - ;; - // The basic idea is that we copy byte-by-byte at the head so - // that we can reach 8-byte alignment for both src1 and dst1. - // Then copy the body using software pipelined 8-byte copy, - // shifting the two back-to-back words right and left, then copy - // the tail by copying byte-by-byte. - // - // Fault handling. If the byte-by-byte at the head fails on the - // load, then restart and finish the pipleline by copying zeros - // to the dst1. Then copy zeros for the rest of dst1. - // If 8-byte software pipeline fails on the load, do the same as - // failure_in3 does. If the byte-by-byte at the tail fails, it is - // handled simply by failure_in_pipe1. - // - // The case p14 represents the source has more bytes in the - // the first word (by the shifted part), whereas the p15 needs to - // copy some bytes from the 2nd word of the source that has the - // tail of the 1st of the destination. - // - - // - // Optimization. If dst1 is 8-byte aligned (quite common), we don't need - // to copy the head to dst1, to start 8-byte copy software pipeline. - // We know src1 is not 8-byte aligned in this case. - // - cmp.eq p14,p15=r0,dst2 -(p15) br.cond.spnt 1f - ;; - sub t1=8,src2 - mov t2=src2 - ;; - shl rshift=t2,3 - sub len1=len,t1 // set len1 - ;; - sub lshift=64,rshift - ;; - br.cond.spnt .word_copy_user - ;; -1: - cmp.leu p14,p15=src2,dst2 - sub t1=dst2,src2 - ;; - .pred.rel "mutex", p14, p15 -(p14) sub word1=8,src2 // (8 - src offset) -(p15) sub t1=r0,t1 // absolute value -(p15) sub word1=8,dst2 // (8 - dst offset) - ;; - // For the case p14, we don't need to copy the shifted part to - // the 1st word of destination. - sub t2=8,t1 -(p14) sub word1=word1,t1 - ;; - sub len1=len,word1 // resulting len -(p15) shl rshift=t1,3 // in bits -(p14) shl rshift=t2,3 - ;; -(p14) sub len1=len1,t1 - adds cnt=-1,word1 - ;; - sub lshift=64,rshift - mov ar.ec=PIPE_DEPTH - mov pr.rot=1<<16 // p16=true all others are false - mov ar.lc=cnt - ;; -2: - EX(.failure_in_pipe2,(p16) ld1 val1[0]=[src1],1) - EX(.failure_out,(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1) - br.ctop.dptk.few 2b - ;; - clrrrb - ;; -.word_copy_user: - cmp.gtu p9,p0=16,len1 -(p9) br.cond.spnt 4f // if (16 > len1) skip 8-byte copy - ;; - shr.u cnt=len1,3 // number of 64-bit words - ;; - adds cnt=-1,cnt - ;; - .pred.rel "mutex", p14, p15 -(p14) sub src1=src1,t2 -(p15) sub src1=src1,t1 - // - // Now both src1 and dst1 point to an 8-byte aligned address. And - // we have more than 8 bytes to copy. - // - mov ar.lc=cnt - mov ar.ec=PIPE_DEPTH - mov pr.rot=1<<16 // p16=true all others are false - ;; -3: - // - // The pipleline consists of 3 stages: - // 1 (p16): Load a word from src1 - // 2 (EPI_1): Shift right pair, saving to tmp - // 3 (EPI): Store tmp to dst1 - // - // To make it simple, use at least 2 (p16) loops to set up val1[n] - // because we need 2 back-to-back val1[] to get tmp. - // Note that this implies EPI_2 must be p18 or greater. - // - -#define EPI_1 p[PIPE_DEPTH-2] -#define SWITCH(pred, shift) cmp.eq pred,p0=shift,rshift -#define CASE(pred, shift) \ - (pred) br.cond.spnt .copy_user_bit##shift -#define BODY(rshift) \ -.copy_user_bit##rshift: \ -1: \ - EX(.failure_out,(EPI) st8 [dst1]=tmp,8); \ -(EPI_1) shrp tmp=val1[PIPE_DEPTH-2],val1[PIPE_DEPTH-1],rshift; \ - EX(3f,(p16) ld8 val1[1]=[src1],8); \ -(p16) mov val1[0]=r0; \ - br.ctop.dptk 1b; \ - ;; \ - br.cond.sptk.many .diff_align_do_tail; \ -2: \ -(EPI) st8 [dst1]=tmp,8; \ -(EPI_1) shrp tmp=val1[PIPE_DEPTH-2],val1[PIPE_DEPTH-1],rshift; \ -3: \ -(p16) mov val1[1]=r0; \ -(p16) mov val1[0]=r0; \ - br.ctop.dptk 2b; \ - ;; \ - br.cond.sptk.many .failure_in2 - - // - // Since the instruction 'shrp' requires a fixed 128-bit value - // specifying the bits to shift, we need to provide 7 cases - // below. - // - SWITCH(p6, 8) - SWITCH(p7, 16) - SWITCH(p8, 24) - SWITCH(p9, 32) - SWITCH(p10, 40) - SWITCH(p11, 48) - SWITCH(p12, 56) - ;; - CASE(p6, 8) - CASE(p7, 16) - CASE(p8, 24) - CASE(p9, 32) - CASE(p10, 40) - CASE(p11, 48) - CASE(p12, 56) - ;; - BODY(8) - BODY(16) - BODY(24) - BODY(32) - BODY(40) - BODY(48) - BODY(56) - ;; -.diff_align_do_tail: - .pred.rel "mutex", p14, p15 -(p14) sub src1=src1,t1 -(p14) adds dst1=-8,dst1 -(p15) sub dst1=dst1,t1 - ;; -4: - // Tail correction. - // - // The problem with this piplelined loop is that the last word is not - // loaded and thus parf of the last word written is not correct. - // To fix that, we simply copy the tail byte by byte. - - sub len1=endsrc,src1,1 - clrrrb - ;; - mov ar.ec=PIPE_DEPTH - mov pr.rot=1<<16 // p16=true all others are false - mov ar.lc=len1 - ;; -5: - EX(.failure_in_pipe1,(p16) ld1 val1[0]=[src1],1) - EX(.failure_out,(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1) - br.ctop.dptk.few 5b - ;; - mov ar.lc=saved_lc - mov pr=saved_pr,0xffffffffffff0000 - mov ar.pfs=saved_pfs - br.ret.sptk.many rp - - // - // Beginning of long mempcy (i.e. > 16 bytes) - // -.long_copy_user: - tbit.nz p6,p7=src1,0 // odd alignment - and tmp=7,tmp - ;; - cmp.eq p10,p8=r0,tmp - mov len1=len // copy because of rotation -(p8) br.cond.dpnt .diff_align_copy_user - ;; - // At this point we know we have more than 16 bytes to copy - // and also that both src and dest have the same alignment - // which may not be the one we want. So for now we must move - // forward slowly until we reach 16byte alignment: no need to - // worry about reaching the end of buffer. - // - EX(.failure_in1,(p6) ld1 val1[0]=[src1],1) // 1-byte aligned -(p6) adds len1=-1,len1;; - tbit.nz p7,p0=src1,1 - ;; - EX(.failure_in1,(p7) ld2 val1[1]=[src1],2) // 2-byte aligned -(p7) adds len1=-2,len1;; - tbit.nz p8,p0=src1,2 - ;; - // - // Stop bit not required after ld4 because if we fail on ld4 - // we have never executed the ld1, therefore st1 is not executed. - // - EX(.failure_in1,(p8) ld4 val2[0]=[src1],4) // 4-byte aligned - ;; - EX(.failure_out,(p6) st1 [dst1]=val1[0],1) - tbit.nz p9,p0=src1,3 - ;; - // - // Stop bit not required after ld8 because if we fail on ld8 - // we have never executed the ld2, therefore st2 is not executed. - // - EX(.failure_in1,(p9) ld8 val2[1]=[src1],8) // 8-byte aligned - EX(.failure_out,(p7) st2 [dst1]=val1[1],2) -(p8) adds len1=-4,len1 - ;; - EX(.failure_out, (p8) st4 [dst1]=val2[0],4) -(p9) adds len1=-8,len1;; - shr.u cnt=len1,4 // number of 128-bit (2x64bit) words - ;; - EX(.failure_out, (p9) st8 [dst1]=val2[1],8) - tbit.nz p6,p0=len1,3 - cmp.eq p7,p0=r0,cnt - adds tmp=-1,cnt // br.ctop is repeat/until -(p7) br.cond.dpnt .dotail // we have less than 16 bytes left - ;; - adds src2=8,src1 - adds dst2=8,dst1 - mov ar.lc=tmp - ;; - // - // 16bytes/iteration - // -2: - EX(.failure_in3,(p16) ld8 val1[0]=[src1],16) -(p16) ld8 val2[0]=[src2],16 - - EX(.failure_out, (EPI) st8 [dst1]=val1[PIPE_DEPTH-1],16) -(EPI) st8 [dst2]=val2[PIPE_DEPTH-1],16 - br.ctop.dptk 2b - ;; // RAW on src1 when fall through from loop - // - // Tail correction based on len only - // - // No matter where we come from (loop or test) the src1 pointer - // is 16 byte aligned AND we have less than 16 bytes to copy. - // -.dotail: - EX(.failure_in1,(p6) ld8 val1[0]=[src1],8) // at least 8 bytes - tbit.nz p7,p0=len1,2 - ;; - EX(.failure_in1,(p7) ld4 val1[1]=[src1],4) // at least 4 bytes - tbit.nz p8,p0=len1,1 - ;; - EX(.failure_in1,(p8) ld2 val2[0]=[src1],2) // at least 2 bytes - tbit.nz p9,p0=len1,0 - ;; - EX(.failure_out, (p6) st8 [dst1]=val1[0],8) - ;; - EX(.failure_in1,(p9) ld1 val2[1]=[src1]) // only 1 byte left - mov ar.lc=saved_lc - ;; - EX(.failure_out,(p7) st4 [dst1]=val1[1],4) - mov pr=saved_pr,0xffffffffffff0000 - ;; - EX(.failure_out, (p8) st2 [dst1]=val2[0],2) - mov ar.pfs=saved_pfs - ;; - EX(.failure_out, (p9) st1 [dst1]=val2[1]) - br.ret.sptk.many rp - - - // - // Here we handle the case where the byte by byte copy fails - // on the load. - // Several factors make the zeroing of the rest of the buffer kind of - // tricky: - // - the pipeline: loads/stores are not in sync (pipeline) - // - // In the same loop iteration, the dst1 pointer does not directly - // reflect where the faulty load was. - // - // - pipeline effect - // When you get a fault on load, you may have valid data from - // previous loads not yet store in transit. Such data must be - // store normally before moving onto zeroing the rest. - // - // - single/multi dispersal independence. - // - // solution: - // - we don't disrupt the pipeline, i.e. data in transit in - // the software pipeline will be eventually move to memory. - // We simply replace the load with a simple mov and keep the - // pipeline going. We can't really do this inline because - // p16 is always reset to 1 when lc > 0. - // -.failure_in_pipe1: - sub ret0=endsrc,src1 // number of bytes to zero, i.e. not copied -1: -(p16) mov val1[0]=r0 -(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1 - br.ctop.dptk 1b - ;; - mov pr=saved_pr,0xffffffffffff0000 - mov ar.lc=saved_lc - mov ar.pfs=saved_pfs - br.ret.sptk.many rp - - // - // This is the case where the byte by byte copy fails on the load - // when we copy the head. We need to finish the pipeline and copy - // zeros for the rest of the destination. Since this happens - // at the top we still need to fill the body and tail. -.failure_in_pipe2: - sub ret0=endsrc,src1 // number of bytes to zero, i.e. not copied -2: -(p16) mov val1[0]=r0 -(EPI) st1 [dst1]=val1[PIPE_DEPTH-1],1 - br.ctop.dptk 2b - ;; - sub len=enddst,dst1,1 // precompute len - br.cond.dptk.many .failure_in1bis - ;; - - // - // Here we handle the head & tail part when we check for alignment. - // The following code handles only the load failures. The - // main diffculty comes from the fact that loads/stores are - // scheduled. So when you fail on a load, the stores corresponding - // to previous successful loads must be executed. - // - // However some simplifications are possible given the way - // things work. - // - // 1) HEAD - // Theory of operation: - // - // Page A | Page B - // ---------|----- - // 1|8 x - // 1 2|8 x - // 4|8 x - // 1 4|8 x - // 2 4|8 x - // 1 2 4|8 x - // |1 - // |2 x - // |4 x - // - // page_size >= 4k (2^12). (x means 4, 2, 1) - // Here we suppose Page A exists and Page B does not. - // - // As we move towards eight byte alignment we may encounter faults. - // The numbers on each page show the size of the load (current alignment). - // - // Key point: - // - if you fail on 1, 2, 4 then you have never executed any smaller - // size loads, e.g. failing ld4 means no ld1 nor ld2 executed - // before. - // - // This allows us to simplify the cleanup code, because basically you - // only have to worry about "pending" stores in the case of a failing - // ld8(). Given the way the code is written today, this means only - // worry about st2, st4. There we can use the information encapsulated - // into the predicates. - // - // Other key point: - // - if you fail on the ld8 in the head, it means you went straight - // to it, i.e. 8byte alignment within an unexisting page. - // Again this comes from the fact that if you crossed just for the ld8 then - // you are 8byte aligned but also 16byte align, therefore you would - // either go for the 16byte copy loop OR the ld8 in the tail part. - // The combination ld1, ld2, ld4, ld8 where you fail on ld8 is impossible - // because it would mean you had 15bytes to copy in which case you - // would have defaulted to the byte by byte copy. - // - // - // 2) TAIL - // Here we now we have less than 16 bytes AND we are either 8 or 16 byte - // aligned. - // - // Key point: - // This means that we either: - // - are right on a page boundary - // OR - // - are at more than 16 bytes from a page boundary with - // at most 15 bytes to copy: no chance of crossing. - // - // This allows us to assume that if we fail on a load we haven't possibly - // executed any of the previous (tail) ones, so we don't need to do - // any stores. For instance, if we fail on ld2, this means we had - // 2 or 3 bytes left to copy and we did not execute the ld8 nor ld4. - // - // This means that we are in a situation similar the a fault in the - // head part. That's nice! - // -.failure_in1: - sub ret0=endsrc,src1 // number of bytes to zero, i.e. not copied - sub len=endsrc,src1,1 - // - // we know that ret0 can never be zero at this point - // because we failed why trying to do a load, i.e. there is still - // some work to do. - // The failure_in1bis and length problem is taken care of at the - // calling side. - // - ;; -.failure_in1bis: // from (.failure_in3) - mov ar.lc=len // Continue with a stupid byte store. - ;; -5: - st1 [dst1]=r0,1 - br.cloop.dptk 5b - ;; - mov pr=saved_pr,0xffffffffffff0000 - mov ar.lc=saved_lc - mov ar.pfs=saved_pfs - br.ret.sptk.many rp - - // - // Here we simply restart the loop but instead - // of doing loads we fill the pipeline with zeroes - // We can't simply store r0 because we may have valid - // data in transit in the pipeline. - // ar.lc and ar.ec are setup correctly at this point - // - // we MUST use src1/endsrc here and not dst1/enddst because - // of the pipeline effect. - // -.failure_in3: - sub ret0=endsrc,src1 // number of bytes to zero, i.e. not copied - ;; -2: -(p16) mov val1[0]=r0 -(p16) mov val2[0]=r0 -(EPI) st8 [dst1]=val1[PIPE_DEPTH-1],16 -(EPI) st8 [dst2]=val2[PIPE_DEPTH-1],16 - br.ctop.dptk 2b - ;; - cmp.ne p6,p0=dst1,enddst // Do we need to finish the tail ? - sub len=enddst,dst1,1 // precompute len -(p6) br.cond.dptk .failure_in1bis - ;; - mov pr=saved_pr,0xffffffffffff0000 - mov ar.lc=saved_lc - mov ar.pfs=saved_pfs - br.ret.sptk.many rp - -.failure_in2: - sub ret0=endsrc,src1 - cmp.ne p6,p0=dst1,enddst // Do we need to finish the tail ? - sub len=enddst,dst1,1 // precompute len -(p6) br.cond.dptk .failure_in1bis - ;; - mov pr=saved_pr,0xffffffffffff0000 - mov ar.lc=saved_lc - mov ar.pfs=saved_pfs - br.ret.sptk.many rp - - // - // handling of failures on stores: that's the easy part - // -.failure_out: - sub ret0=enddst,dst1 - mov pr=saved_pr,0xffffffffffff0000 - mov ar.lc=saved_lc - - mov ar.pfs=saved_pfs - br.ret.sptk.many rp -END(__copy_user) -EXPORT_SYMBOL(__copy_user) |