powerpc/64: Make exception table clearer in __copy_tofrom_user_base

This aims to make the generation of exception table entries for the
loads and stores in __copy_tofrom_user_base clearer and easier to
verify.  Instead of having a series of local labels on the loads and
stores, with a series of corresponding labels later for the exception
handlers, we now use macros to generate exception table entries at the
point of each load and store that could potentially trap.  We do this
with the macros lex (load exception) and stex (store exception).
These macros are used right before the load or store to which they
apply.

Some complexity is introduced by the fact that we have some more work
to do after hitting an exception, because we need to calculate and
return the number of bytes not copied.  The code uses r3 as the
current pointer into the destination buffer, that is, the address of
the first byte of the destination that has not been modified.
However, at various points in the copy loops, r3 can be 4, 8, 16 or 24
bytes behind that point.

To express this offset in an understandable way, we define a symbol
r3_offset which is updated at various points so that it equal to the
difference between the address of the first unmodified byte of the
destination and the value in r3.  (In fact it only needs to be
accurate at the point of each lex or stex macro invocation.)

The rules for updating r3_offset are as follows:

* It starts out at 0
* An addi r3,r3,N instruction decreases r3_offset by N
* A store instruction (stb, sth, stw, std) to N(r3)
  increases r3_offset by the width of the store (1, 2, 4, 8)
* A store with update instruction (stbu, sthu, stwu, stdu) to N(r3)
  sets r3_offset to the width of the store.

There is some trickiness to the way that the lex and stex macros and
the associated exception handlers work.  I would have liked to use
the current value of r3_offset in the name of the symbol used as
the exception handler, as in ".Lld_exc_$(r3_offset)" and then
have symbols .Lld_exc_0, .Lld_exc_8, .Lld_exc_16 etc. corresponding
to the offsets that needed to be added to r3.  However, I couldn't
see a way to do that with gas.

Instead, the exception handler address is .Lld_exc - r3_offset or
.Lst_exc - r3_offset, that is, the distance ahead of .Lld_exc/.Lst_exc
that we start executing is equal to the amount that we need to add to
r3.  This works because r3_offset is always a small multiple of 4,
and our instructions are 4 bytes long.  This means that before
.Lld_exc and .Lst_exc, we have a sequence of instructions that
increments r3 by 4, 8, 16 or 24 depending on where we start.  The
sequence increments r3 by 4 per instruction (on average).

We also replace the exception table for the 4k copy loop by a
macro per load or store.  These loads and stores all use exactly
the same exception handler, which simply resets the argument registers
r3, r4 and r5 to there original values and re-does the whole copy
using the slower loop.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/lib/copyuser_64.S b/arch/powerpc/lib/copyuser_64.S
index 2d6f128d3ebe9e77be87f4e09347267508bcf4ad..8c5033c85e37ecf471f42f8b899ebe65c60dc43c 100644 (file)
--- a/arch/powerpc/lib/copyuser_64.S
+++ b/arch/powerpc/lib/copyuser_64.S
@@ -20,6 +20,28 @@
 #define sHd sld                /* Shift towards high-numbered address. */
 #endif
 
+/*
+ * These macros are used to generate exception table entries.
+ * The exception handlers below use the original arguments
+ * (stored on the stack) and the point where we're up to in
+ * the destination buffer, i.e. the address of the first
+ * unmodified byte.  Generally r3 points into the destination
+ * buffer, but the first unmodified byte is at a variable
+ * offset from r3.  In the code below, the symbol r3_offset
+ * is set to indicate the current offset at each point in
+ * the code.  This offset is then used as a negative offset
+ * from the exception handler code, and those instructions
+ * before the exception handlers are addi instructions that
+ * adjust r3 to point to the correct place.
+ */
+       .macro  lex             /* exception handler for load */
+100:   EX_TABLE(100b, .Lld_exc - r3_offset)
+       .endm
+
+       .macro  stex            /* exception handler for store */
+100:   EX_TABLE(100b, .Lst_exc - r3_offset)
+       .endm
+
        .align  7
 _GLOBAL_TOC(__copy_tofrom_user)
 #ifdef CONFIG_PPC_BOOK3S_64
@@ -30,7 +52,7 @@ FTR_SECTION_ELSE
 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_VMX_COPY)
 #endif
 _GLOBAL(__copy_tofrom_user_base)
-       /* first check for a whole page copy on a page boundary */
+       /* first check for a 4kB copy on a 4kB boundary */
        cmpldi  cr1,r5,16
        cmpdi   cr6,r5,4096
        or      r0,r3,r4
@@ -59,6 +81,7 @@ ALT_FTR_SECTION_END(CPU_FTR_UNALIGNED_LD_STD | CPU_FTR_CP_USE_DCBTZ, \
                    CPU_FTR_UNALIGNED_LD_STD)
 .Ldst_aligned:
        addi    r3,r3,-16
+r3_offset = 16
 BEGIN_FTR_SECTION
        andi.   r0,r4,7
        bne     .Lsrc_unaligned
@@ -66,57 +89,69 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        blt     cr1,.Ldo_tail           /* if < 16 bytes to copy */
        srdi    r0,r5,5
        cmpdi   cr1,r0,0
-20:    ld      r7,0(r4)
-220:   ld      r6,8(r4)
+lex;   ld      r7,0(r4)
+lex;   ld      r6,8(r4)
        addi    r4,r4,16
        mtctr   r0
        andi.   r0,r5,0x10
        beq     22f
        addi    r3,r3,16
+r3_offset = 0
        addi    r4,r4,-16
        mr      r9,r7
        mr      r8,r6
        beq     cr1,72f
-21:    ld      r7,16(r4)
-221:   ld      r6,24(r4)
+21:
+lex;   ld      r7,16(r4)
+lex;   ld      r6,24(r4)
        addi    r4,r4,32
-70:    std     r9,0(r3)
-270:   std     r8,8(r3)
-22:    ld      r9,0(r4)
-222:   ld      r8,8(r4)
-71:    std     r7,16(r3)
-271:   std     r6,24(r3)
+stex;  std     r9,0(r3)
+r3_offset = 8
+stex;  std     r8,8(r3)
+r3_offset = 16
+22:
+lex;   ld      r9,0(r4)
+lex;   ld      r8,8(r4)
+stex;  std     r7,16(r3)
+r3_offset = 24
+stex;  std     r6,24(r3)
        addi    r3,r3,32
+r3_offset = 0
        bdnz    21b
-72:    std     r9,0(r3)
-272:   std     r8,8(r3)
+72:
+stex;  std     r9,0(r3)
+r3_offset = 8
+stex;  std     r8,8(r3)
+r3_offset = 16
        andi.   r5,r5,0xf
        beq+    3f
        addi    r4,r4,16
 .Ldo_tail:
        addi    r3,r3,16
+r3_offset = 0
        bf      cr7*4+0,246f
-244:   ld      r9,0(r4)
+lex;   ld      r9,0(r4)
        addi    r4,r4,8
-245:   std     r9,0(r3)
+stex;  std     r9,0(r3)
        addi    r3,r3,8
 246:   bf      cr7*4+1,1f
-23:    lwz     r9,0(r4)
+lex;   lwz     r9,0(r4)
        addi    r4,r4,4
-73:    stw     r9,0(r3)
+stex;  stw     r9,0(r3)
        addi    r3,r3,4
 1:     bf      cr7*4+2,2f
-44:    lhz     r9,0(r4)
+lex;   lhz     r9,0(r4)
        addi    r4,r4,2
-74:    sth     r9,0(r3)
+stex;  sth     r9,0(r3)
        addi    r3,r3,2
 2:     bf      cr7*4+3,3f
-45:    lbz     r9,0(r4)
-75:    stb     r9,0(r3)
+lex;   lbz     r9,0(r4)
+stex;  stb     r9,0(r3)
 3:     li      r3,0
        blr
 
 .Lsrc_unaligned:
+r3_offset = 16
        srdi    r6,r5,3
        addi    r5,r5,-16
        subf    r4,r0,r4
@@ -129,58 +164,69 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        add     r5,r5,r0
        bt      cr7*4+0,28f
 
-24:    ld      r9,0(r4)        /* 3+2n loads, 2+2n stores */
-25:    ld      r0,8(r4)
+lex;   ld      r9,0(r4)        /* 3+2n loads, 2+2n stores */
+lex;   ld      r0,8(r4)
        sLd     r6,r9,r10
-26:    ldu     r9,16(r4)
+lex;   ldu     r9,16(r4)
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        or      r7,r7,r6
        blt     cr6,79f
-27:    ld      r0,8(r4)
+lex;   ld      r0,8(r4)
        b       2f
 
-28:    ld      r0,0(r4)        /* 4+2n loads, 3+2n stores */
-29:    ldu     r9,8(r4)
+28:
+lex;   ld      r0,0(r4)        /* 4+2n loads, 3+2n stores */
+lex;   ldu     r9,8(r4)
        sLd     r8,r0,r10
        addi    r3,r3,-8
+r3_offset = 24
        blt     cr6,5f
-30:    ld      r0,8(r4)
+lex;   ld      r0,8(r4)
        sHd     r12,r9,r11
        sLd     r6,r9,r10
-31:    ldu     r9,16(r4)
+lex;   ldu     r9,16(r4)
        or      r12,r8,r12
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        addi    r3,r3,16
+r3_offset = 8
        beq     cr6,78f
 
 1:     or      r7,r7,r6
-32:    ld      r0,8(r4)
-76:    std     r12,8(r3)
+lex;   ld      r0,8(r4)
+stex;  std     r12,8(r3)
+r3_offset = 16
 2:     sHd     r12,r9,r11
        sLd     r6,r9,r10
-33:    ldu     r9,16(r4)
+lex;   ldu     r9,16(r4)
        or      r12,r8,r12
-77:    stdu    r7,16(r3)
+stex;  stdu    r7,16(r3)
+r3_offset = 8
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        bdnz    1b
 
-78:    std     r12,8(r3)
+78:
+stex;  std     r12,8(r3)
+r3_offset = 16
        or      r7,r7,r6
-79:    std     r7,16(r3)
+79:
+stex;  std     r7,16(r3)
+r3_offset = 24
 5:     sHd     r12,r9,r11
        or      r12,r8,r12
-80:    std     r12,24(r3)
+stex;  std     r12,24(r3)
+r3_offset = 32
        bne     6f
        li      r3,0
        blr
 6:     cmpwi   cr1,r5,8
        addi    r3,r3,32
+r3_offset = 0
        sLd     r9,r9,r10
        ble     cr1,7f
-34:    ld      r0,8(r4)
+lex;   ld      r0,8(r4)
        sHd     r7,r0,r11
        or      r9,r7,r9
 7:
@@ -188,7 +234,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
 #ifdef __BIG_ENDIAN__
        rotldi  r9,r9,32
 #endif
-94:    stw     r9,0(r3)
+stex;  stw     r9,0(r3)
 #ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,32
 #endif
@@ -197,7 +243,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
 #ifdef __BIG_ENDIAN__
        rotldi  r9,r9,16
 #endif
-95:    sth     r9,0(r3)
+stex;  sth     r9,0(r3)
 #ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,16
 #endif
@@ -206,7 +252,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
 #ifdef __BIG_ENDIAN__
        rotldi  r9,r9,8
 #endif
-96:    stb     r9,0(r3)
+stex;  stb     r9,0(r3)
 #ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,8
 #endif
@@ -214,47 +260,55 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        blr
 
 .Ldst_unaligned:
+r3_offset = 0
        PPC_MTOCRF(0x01,r6)             /* put #bytes to 8B bdry into cr7 */
        subf    r5,r6,r5
        li      r7,0
        cmpldi  cr1,r5,16
        bf      cr7*4+3,1f
-35:    lbz     r0,0(r4)
-81:    stb     r0,0(r3)
+100:   EX_TABLE(100b, .Lld_exc_r7)
+       lbz     r0,0(r4)
+100:   EX_TABLE(100b, .Lst_exc_r7)
+       stb     r0,0(r3)
        addi    r7,r7,1
 1:     bf      cr7*4+2,2f
-36:    lhzx    r0,r7,r4
-82:    sthx    r0,r7,r3
+100:   EX_TABLE(100b, .Lld_exc_r7)
+       lhzx    r0,r7,r4
+100:   EX_TABLE(100b, .Lst_exc_r7)
+       sthx    r0,r7,r3
        addi    r7,r7,2
 2:     bf      cr7*4+1,3f
-37:    lwzx    r0,r7,r4
-83:    stwx    r0,r7,r3
+100:   EX_TABLE(100b, .Lld_exc_r7)
+       lwzx    r0,r7,r4
+100:   EX_TABLE(100b, .Lst_exc_r7)
+       stwx    r0,r7,r3
 3:     PPC_MTOCRF(0x01,r5)
        add     r4,r6,r4
        add     r3,r6,r3
        b       .Ldst_aligned
 
 .Lshort_copy:
+r3_offset = 0
        bf      cr7*4+0,1f
-38:    lwz     r0,0(r4)
-39:    lwz     r9,4(r4)
+lex;   lwz     r0,0(r4)
+lex;   lwz     r9,4(r4)
        addi    r4,r4,8
-84:    stw     r0,0(r3)
-85:    stw     r9,4(r3)
+stex;  stw     r0,0(r3)
+stex;  stw     r9,4(r3)
        addi    r3,r3,8
 1:     bf      cr7*4+1,2f
-40:    lwz     r0,0(r4)
+lex;   lwz     r0,0(r4)
        addi    r4,r4,4
-86:    stw     r0,0(r3)
+stex;  stw     r0,0(r3)
        addi    r3,r3,4
 2:     bf      cr7*4+2,3f
-41:    lhz     r0,0(r4)
+lex;   lhz     r0,0(r4)
        addi    r4,r4,2
-87:    sth     r0,0(r3)
+stex;  sth     r0,0(r3)
        addi    r3,r3,2
 3:     bf      cr7*4+3,4f
-42:    lbz     r0,0(r4)
-88:    stb     r0,0(r3)
+lex;   lbz     r0,0(r4)
+stex;  stb     r0,0(r3)
 4:     li      r3,0
        blr
 
@@ -262,48 +316,34 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
  * exception handlers follow
  * we have to return the number of bytes not copied
  * for an exception on a load, we set the rest of the destination to 0
+ * Note that the number of bytes of instructions for adjusting r3 needs
+ * to equal the amount of the adjustment, due to the trick of using
+ * .Lld_exc - r3_offset as the handler address.
  */
 
-136:
-137:
+.Lld_exc_r7:
        add     r3,r3,r7
-       b       1f
-130:
-131:
+       b       .Lld_exc
+
+       /* adjust by 24 */
        addi    r3,r3,8
-120:
-320:
-122:
-322:
-124:
-125:
-126:
-127:
-128:
-129:
-133:
+       nop
+       /* adjust by 16 */
        addi    r3,r3,8
-132:
+       nop
+       /* adjust by 8 */
        addi    r3,r3,8
-121:
-321:
-344:
-134:
-135:
-138:
-139:
-140:
-141:
-142:
-123:
-144:
-145:
+       nop
 
 /*
- * here we have had a fault on a load and r3 points to the first
- * unmodified byte of the destination
+ * Here we have had a fault on a load and r3 points to the first
+ * unmodified byte of the destination.  We use the original arguments
+ * and r3 to work out how much wasn't copied.  Since we load some
+ * distance ahead of the stores, we continue copying byte-by-byte until
+ * we hit the load fault again in order to copy as much as possible.
  */
-1:     ld      r6,-24(r1)
+.Lld_exc:
+       ld      r6,-24(r1)
        ld      r4,-16(r1)
        ld      r5,-8(r1)
        subf    r6,r6,r3
@@ -314,9 +354,11 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
  * first see if we can copy any more bytes before hitting another exception
  */
        mtctr   r5
+r3_offset = 0
+100:   EX_TABLE(100b, .Ldone)
 43:    lbz     r0,0(r4)
        addi    r4,r4,1
-89:    stb     r0,0(r3)
+stex;  stb     r0,0(r3)
        addi    r3,r3,1
        bdnz    43b
        li      r3,0            /* huh? all copied successfully this time? */
@@ -325,116 +367,46 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
 /*
  * here we have trapped again, amount remaining is in ctr.
  */
-143:   mfctr   r3
+.Ldone:
+       mfctr   r3
        blr
 
 /*
  * exception handlers for stores: we just need to work
  * out how many bytes weren't copied
+ * Note that the number of bytes of instructions for adjusting r3 needs
+ * to equal the amount of the adjustment, due to the trick of using
+ * .Lst_exc - r3_offset as the handler address.
  */
-182:
-183:
+.Lst_exc_r7:
        add     r3,r3,r7
-       b       1f
-371:
-180:
+       b       .Lst_exc
+
+       /* adjust by 24 */
        addi    r3,r3,8
-171:
-177:
-179:
+       nop
+       /* adjust by 16 */
        addi    r3,r3,8
-370:
-372:
-176:
-178:
+       nop
+       /* adjust by 8 */
        addi    r3,r3,4
-185:
+       /* adjust by 4 */
        addi    r3,r3,4
-170:
-172:
-345:
-173:
-174:
-175:
-181:
-184:
-186:
-187:
-188:
-189:   
-194:
-195:
-196:
-1:
+.Lst_exc:
        ld      r6,-24(r1)
        ld      r5,-8(r1)
        add     r6,r6,r5
-       subf    r3,r3,r6        /* #bytes not copied */
+       subf    r3,r3,r6        /* #bytes not copied in r3 */
        blr
 
-       EX_TABLE(20b,120b)
-       EX_TABLE(220b,320b)
-       EX_TABLE(21b,121b)
-       EX_TABLE(221b,321b)
-       EX_TABLE(70b,170b)
-       EX_TABLE(270b,370b)
-       EX_TABLE(22b,122b)
-       EX_TABLE(222b,322b)
-       EX_TABLE(71b,171b)
-       EX_TABLE(271b,371b)
-       EX_TABLE(72b,172b)
-       EX_TABLE(272b,372b)
-       EX_TABLE(244b,344b)
-       EX_TABLE(245b,345b)
-       EX_TABLE(23b,123b)
-       EX_TABLE(73b,173b)
-       EX_TABLE(44b,144b)
-       EX_TABLE(74b,174b)
-       EX_TABLE(45b,145b)
-       EX_TABLE(75b,175b)
-       EX_TABLE(24b,124b)
-       EX_TABLE(25b,125b)
-       EX_TABLE(26b,126b)
-       EX_TABLE(27b,127b)
-       EX_TABLE(28b,128b)
-       EX_TABLE(29b,129b)
-       EX_TABLE(30b,130b)
-       EX_TABLE(31b,131b)
-       EX_TABLE(32b,132b)
-       EX_TABLE(76b,176b)
-       EX_TABLE(33b,133b)
-       EX_TABLE(77b,177b)
-       EX_TABLE(78b,178b)
-       EX_TABLE(79b,179b)
-       EX_TABLE(80b,180b)
-       EX_TABLE(34b,134b)
-       EX_TABLE(94b,194b)
-       EX_TABLE(95b,195b)
-       EX_TABLE(96b,196b)
-       EX_TABLE(35b,135b)
-       EX_TABLE(81b,181b)
-       EX_TABLE(36b,136b)
-       EX_TABLE(82b,182b)
-       EX_TABLE(37b,137b)
-       EX_TABLE(83b,183b)
-       EX_TABLE(38b,138b)
-       EX_TABLE(39b,139b)
-       EX_TABLE(84b,184b)
-       EX_TABLE(85b,185b)
-       EX_TABLE(40b,140b)
-       EX_TABLE(86b,186b)
-       EX_TABLE(41b,141b)
-       EX_TABLE(87b,187b)
-       EX_TABLE(42b,142b)
-       EX_TABLE(88b,188b)
-       EX_TABLE(43b,143b)
-       EX_TABLE(89b,189b)
-
 /*
  * Routine to copy a whole page of data, optimized for POWER4.
  * On POWER4 it is more than 50% faster than the simple loop
  * above (following the .Ldst_aligned label).
  */
+       .macro  exc
+100:   EX_TABLE(100b, .Labort)
+       .endm
 .Lcopy_page_4K:
        std     r31,-32(1)
        std     r30,-40(1)
@@ -453,86 +425,86 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        li      r0,5
 0:     addi    r5,r5,-24
        mtctr   r0
-20:    ld      r22,640(4)
-21:    ld      r21,512(4)
-22:    ld      r20,384(4)
-23:    ld      r11,256(4)
-24:    ld      r9,128(4)
-25:    ld      r7,0(4)
-26:    ld      r25,648(4)
-27:    ld      r24,520(4)
-28:    ld      r23,392(4)
-29:    ld      r10,264(4)
-30:    ld      r8,136(4)
-31:    ldu     r6,8(4)
+exc;   ld      r22,640(4)
+exc;   ld      r21,512(4)
+exc;   ld      r20,384(4)
+exc;   ld      r11,256(4)
+exc;   ld      r9,128(4)
+exc;   ld      r7,0(4)
+exc;   ld      r25,648(4)
+exc;   ld      r24,520(4)
+exc;   ld      r23,392(4)
+exc;   ld      r10,264(4)
+exc;   ld      r8,136(4)
+exc;   ldu     r6,8(4)
        cmpwi   r5,24
 1:
-32:    std     r22,648(3)
-33:    std     r21,520(3)
-34:    std     r20,392(3)
-35:    std     r11,264(3)
-36:    std     r9,136(3)
-37:    std     r7,8(3)
-38:    ld      r28,648(4)
-39:    ld      r27,520(4)
-40:    ld      r26,392(4)
-41:    ld      r31,264(4)
-42:    ld      r30,136(4)
-43:    ld      r29,8(4)
-44:    std     r25,656(3)
-45:    std     r24,528(3)
-46:    std     r23,400(3)
-47:    std     r10,272(3)
-48:    std     r8,144(3)
-49:    std     r6,16(3)
-50:    ld      r22,656(4)
-51:    ld      r21,528(4)
-52:    ld      r20,400(4)
-53:    ld      r11,272(4)
-54:    ld      r9,144(4)
-55:    ld      r7,16(4)
-56:    std     r28,664(3)
-57:    std     r27,536(3)
-58:    std     r26,408(3)
-59:    std     r31,280(3)
-60:    std     r30,152(3)
-61:    stdu    r29,24(3)
-62:    ld      r25,664(4)
-63:    ld      r24,536(4)
-64:    ld      r23,408(4)
-65:    ld      r10,280(4)
-66:    ld      r8,152(4)
-67:    ldu     r6,24(4)
+exc;   std     r22,648(3)
+exc;   std     r21,520(3)
+exc;   std     r20,392(3)
+exc;   std     r11,264(3)
+exc;   std     r9,136(3)
+exc;   std     r7,8(3)
+exc;   ld      r28,648(4)
+exc;   ld      r27,520(4)
+exc;   ld      r26,392(4)
+exc;   ld      r31,264(4)
+exc;   ld      r30,136(4)
+exc;   ld      r29,8(4)
+exc;   std     r25,656(3)
+exc;   std     r24,528(3)
+exc;   std     r23,400(3)
+exc;   std     r10,272(3)
+exc;   std     r8,144(3)
+exc;   std     r6,16(3)
+exc;   ld      r22,656(4)
+exc;   ld      r21,528(4)
+exc;   ld      r20,400(4)
+exc;   ld      r11,272(4)
+exc;   ld      r9,144(4)
+exc;   ld      r7,16(4)
+exc;   std     r28,664(3)
+exc;   std     r27,536(3)
+exc;   std     r26,408(3)
+exc;   std     r31,280(3)
+exc;   std     r30,152(3)
+exc;   stdu    r29,24(3)
+exc;   ld      r25,664(4)
+exc;   ld      r24,536(4)
+exc;   ld      r23,408(4)
+exc;   ld      r10,280(4)
+exc;   ld      r8,152(4)
+exc;   ldu     r6,24(4)
        bdnz    1b
-68:    std     r22,648(3)
-69:    std     r21,520(3)
-70:    std     r20,392(3)
-71:    std     r11,264(3)
-72:    std     r9,136(3)
-73:    std     r7,8(3)
-74:    addi    r4,r4,640
-75:    addi    r3,r3,648
+exc;   std     r22,648(3)
+exc;   std     r21,520(3)
+exc;   std     r20,392(3)
+exc;   std     r11,264(3)
+exc;   std     r9,136(3)
+exc;   std     r7,8(3)
+       addi    r4,r4,640
+       addi    r3,r3,648
        bge     0b
        mtctr   r5
-76:    ld      r7,0(4)
-77:    ld      r8,8(4)
-78:    ldu     r9,16(4)
+exc;   ld      r7,0(4)
+exc;   ld      r8,8(4)
+exc;   ldu     r9,16(4)
 3:
-79:    ld      r10,8(4)
-80:    std     r7,8(3)
-81:    ld      r7,16(4)
-82:    std     r8,16(3)
-83:    ld      r8,24(4)
-84:    std     r9,24(3)
-85:    ldu     r9,32(4)
-86:    stdu    r10,32(3)
+exc;   ld      r10,8(4)
+exc;   std     r7,8(3)
+exc;   ld      r7,16(4)
+exc;   std     r8,16(3)
+exc;   ld      r8,24(4)
+exc;   std     r9,24(3)
+exc;   ldu     r9,32(4)
+exc;   stdu    r10,32(3)
        bdnz    3b
 4:
-87:    ld      r10,8(4)
-88:    std     r7,8(3)
-89:    std     r8,16(3)
-90:    std     r9,24(3)
-91:    std     r10,32(3)
+exc;   ld      r10,8(4)
+exc;   std     r7,8(3)
+exc;   std     r8,16(3)
+exc;   std     r9,24(3)
+exc;   std     r10,32(3)
 9:     ld      r20,-120(1)
        ld      r21,-112(1)
        ld      r22,-104(1)
@@ -552,7 +524,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
  * on an exception, reset to the beginning and jump back into the
  * standard __copy_tofrom_user
  */
-100:   ld      r20,-120(1)
+.Labort:
+       ld      r20,-120(1)
        ld      r21,-112(1)
        ld      r22,-104(1)
        ld      r23,-96(1)
@@ -568,78 +541,4 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        ld      r4,-16(r1)
        li      r5,4096
        b       .Ldst_aligned
-
-       EX_TABLE(20b,100b)
-       EX_TABLE(21b,100b)
-       EX_TABLE(22b,100b)
-       EX_TABLE(23b,100b)
-       EX_TABLE(24b,100b)
-       EX_TABLE(25b,100b)
-       EX_TABLE(26b,100b)
-       EX_TABLE(27b,100b)
-       EX_TABLE(28b,100b)
-       EX_TABLE(29b,100b)
-       EX_TABLE(30b,100b)
-       EX_TABLE(31b,100b)
-       EX_TABLE(32b,100b)
-       EX_TABLE(33b,100b)
-       EX_TABLE(34b,100b)
-       EX_TABLE(35b,100b)
-       EX_TABLE(36b,100b)
-       EX_TABLE(37b,100b)
-       EX_TABLE(38b,100b)
-       EX_TABLE(39b,100b)
-       EX_TABLE(40b,100b)
-       EX_TABLE(41b,100b)
-       EX_TABLE(42b,100b)
-       EX_TABLE(43b,100b)
-       EX_TABLE(44b,100b)
-       EX_TABLE(45b,100b)
-       EX_TABLE(46b,100b)
-       EX_TABLE(47b,100b)
-       EX_TABLE(48b,100b)
-       EX_TABLE(49b,100b)
-       EX_TABLE(50b,100b)
-       EX_TABLE(51b,100b)
-       EX_TABLE(52b,100b)
-       EX_TABLE(53b,100b)
-       EX_TABLE(54b,100b)
-       EX_TABLE(55b,100b)
-       EX_TABLE(56b,100b)
-       EX_TABLE(57b,100b)
-       EX_TABLE(58b,100b)
-       EX_TABLE(59b,100b)
-       EX_TABLE(60b,100b)
-       EX_TABLE(61b,100b)
-       EX_TABLE(62b,100b)
-       EX_TABLE(63b,100b)
-       EX_TABLE(64b,100b)
-       EX_TABLE(65b,100b)
-       EX_TABLE(66b,100b)
-       EX_TABLE(67b,100b)
-       EX_TABLE(68b,100b)
-       EX_TABLE(69b,100b)
-       EX_TABLE(70b,100b)
-       EX_TABLE(71b,100b)
-       EX_TABLE(72b,100b)
-       EX_TABLE(73b,100b)
-       EX_TABLE(74b,100b)
-       EX_TABLE(75b,100b)
-       EX_TABLE(76b,100b)
-       EX_TABLE(77b,100b)
-       EX_TABLE(78b,100b)
-       EX_TABLE(79b,100b)
-       EX_TABLE(80b,100b)
-       EX_TABLE(81b,100b)
-       EX_TABLE(82b,100b)
-       EX_TABLE(83b,100b)
-       EX_TABLE(84b,100b)
-       EX_TABLE(85b,100b)
-       EX_TABLE(86b,100b)
-       EX_TABLE(87b,100b)
-       EX_TABLE(88b,100b)
-       EX_TABLE(89b,100b)
-       EX_TABLE(90b,100b)
-       EX_TABLE(91b,100b)
-
 EXPORT_SYMBOL(__copy_tofrom_user)