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)