tile: fix strncpy_from_user bug

In strncpy_from_user_asm, when the destination buffer length was the
same as the actual string length, we were returning the size of the
destination buffer.  But since it's a NUL terminated string, we should
return the length of the string instead.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/tile/lib/usercopy_32.S b/arch/tile/lib/usercopy_32.S
index bb4c127be6e9..1bc162224638 100644
--- a/arch/tile/lib/usercopy_32.S
+++ b/arch/tile/lib/usercopy_32.S
@@ -48,12 +48,13 @@ strnlen_user_fault:
  */
 STD_ENTRY(strncpy_from_user_asm)
         { bz r2, 2f; move r3, r0 }
-1:      { lb_u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
+1:      { lb_u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
         { sb r0, r4; addi r0, r0, 1 }
-        bz r2, 2f
-        bnzt r4, 1b
-        addi r0, r0, -1   /* don't count the trailing NUL */
-2:      { sub r0, r0, r3; jrp lr }
+        bz r4, 2f
+        bnzt r2, 1b
+        { sub r0, r0, r3; jrp lr }
+2:      addi r0, r0, -1   /* don't count the trailing NUL */
+        { sub r0, r0, r3; jrp lr }
         STD_ENDPROC(strncpy_from_user_asm)
         .pushsection .fixup,"ax"
 strncpy_from_user_fault: