[PATCH] ppc32: Fix __copy_tofrom_user return value

Recently the __copy_tofrom_user routine was modified to avoid doing
prefetches past the end of the source array.  However, in doing so we
introduced a bug in that it now returns the wrong value for the number
of bytes not copied when a fault is encountered.  This fixes it to
return the correct number.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/ppc/lib/string.S b/arch/ppc/lib/string.S
index 8d08a2eb225..36c9b97fd92 100644
--- a/arch/ppc/lib/string.S
+++ b/arch/ppc/lib/string.S
@@ -446,6 +446,7 @@ _GLOBAL(__copy_tofrom_user)
 #ifdef CONFIG_8xx
         /* Don't use prefetch on 8xx */
         mtctr   r0
+        li      r0,0
 53:     COPY_16_BYTES_WITHEX(0)
         bdnz    53b
 
@@ -564,7 +565,9 @@ _GLOBAL(__copy_tofrom_user)
 /* or write fault in cacheline loop */
 105:    li      r9,1
 92:     li      r3,LG_CACHELINE_BYTES
-        b       99f
+        mfctr   r8
+        add     r0,r0,r8
+        b       106f
 /* read fault in final word loop */
 108:    li      r9,0
         b       93f
@@ -585,7 +588,7 @@ _GLOBAL(__copy_tofrom_user)
  * r5 + (ctr << r3), and r9 is 0 for read or 1 for write.
  */
 99:     mfctr   r0
-        slw     r3,r0,r3
+106:    slw     r3,r0,r3
         add.    r3,r3,r5
         beq     120f                    /* shouldn't happen */
         cmpwi   0,r9,0