[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>

diff --git a/arch/ppc/lib/string.S b/arch/ppc/lib/string.S
index 8d08a2e..36c9b97 100644 (file)
--- 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