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>

diff --git a/arch/tile/lib/usercopy_32.S b/arch/tile/lib/usercopy_32.S
index bb4c127..1bc1622 100644 (file)
--- 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:

diff --git a/arch/tile/lib/usercopy_64.S b/arch/tile/lib/usercopy_64.S
index 0d94844..b3b31a3 100644 (file)
--- a/arch/tile/lib/usercopy_64.S
+++ b/arch/tile/lib/usercopy_64.S
@@ -48,12 +48,13 @@ strnlen_user_fault:
  */
 STD_ENTRY(strncpy_from_user_asm)
        { beqz r2, 2f; move r3, r0 }
-1:      { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
+1:     { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
        { st1 r0, r4; addi r0, r0, 1 }
-       beqz r2, 2f
-       bnezt r4, 1b
-       addi r0, r0, -1   /* don't count the trailing NUL */
-2:      { sub r0, r0, r3; jrp lr }
+       beqz r4, 2f
+       bnezt 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: