[S390] broken copy_in_user function.

The copy_in_user primitive does not work as advertised. If the source
and target area are available copy_in_user copies one byte too much.
If one of the memory areas is not available it does not copy as much
data as it can, but up to 257 bytes less.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/lib/uaccess.S b/arch/s390/lib/uaccess.S
index 5d59e26..8372752 100644 (file)
--- a/arch/s390/lib/uaccess.S
+++ b/arch/s390/lib/uaccess.S
@@ -88,30 +88,31 @@ __copy_to_user_asm:
         .globl __copy_in_user_asm
        # %r2 = from, %r3 = n, %r4 = to
 __copy_in_user_asm:
+       ahi     %r3,-1
+       jo      6f
        sacf    256
-       bras    1,1f
-       mvc     0(1,%r4),0(%r2)
-0:     mvc     0(256,%r4),0(%r2)
-       la      %r2,256(%r2)
-       la      %r4,256(%r4)
-1:     ahi     %r3,-256
-       jnm     0b
-2:     ex      %r3,0(%r1)
-       sacf    0
-       slr     %r2,%r2
-       br      14
-3:     mvc     0(1,%r4),0(%r2)
+       bras    %r1,4f
+0:     ahi     %r3,257
+1:     mvc     0(1,%r4),0(%r2)
        la      %r2,1(%r2)
        la      %r4,1(%r4)
        ahi     %r3,-1
+       jnz     1b
+2:     lr      %r2,%r3
+       br      %r14
+3:     mvc     0(256,%r4),0(%r2)
+       la      %r2,256(%r2)
+       la      %r4,256(%r4)
+4:     ahi     %r3,-256
        jnm     3b
-4:     lr      %r2,%r3
+5:     ex      %r3,4(%r1)
        sacf    0
+6:     slr     %r2,%r2
        br      %r14
         .section __ex_table,"a"
-       .long   0b,3b
-       .long   2b,3b
-       .long   3b,4b
+       .long   1b,2b
+       .long   3b,0b
+       .long   5b,0b
         .previous
 
         .align 4

diff --git a/arch/s390/lib/uaccess64.S b/arch/s390/lib/uaccess64.S
index 19b41a3..1f755be 100644 (file)
--- a/arch/s390/lib/uaccess64.S
+++ b/arch/s390/lib/uaccess64.S
@@ -88,30 +88,31 @@ __copy_to_user_asm:
         .globl __copy_in_user_asm
        # %r2 = from, %r3 = n, %r4 = to
 __copy_in_user_asm:
+       aghi    %r3,-1
+       jo      6f
        sacf    256
-       bras    1,1f
-       mvc     0(1,%r4),0(%r2)
-0:     mvc     0(256,%r4),0(%r2)
-       la      %r2,256(%r2)
-       la      %r4,256(%r4)
-1:     aghi    %r3,-256
-       jnm     0b
-2:     ex      %r3,0(%r1)
-       sacf    0
-       slgr    %r2,%r2
-       br      14
-3:     mvc     0(1,%r4),0(%r2)
+       bras    %r1,4f
+0:     aghi    %r3,257
+1:     mvc     0(1,%r4),0(%r2)
        la      %r2,1(%r2)
        la      %r4,1(%r4)
        aghi    %r3,-1
+       jnz     1b
+2:     lgr     %r2,%r3
+       br      %r14
+3:     mvc     0(256,%r4),0(%r2)
+       la      %r2,256(%r2)
+       la      %r4,256(%r4)
+4:     aghi    %r3,-256
        jnm     3b
-4:     lgr     %r2,%r3
+5:     ex      %r3,4(%r1)
        sacf    0
-       br      %r14
+6:     slgr    %r2,%r2
+       br      14
         .section __ex_table,"a"
-       .quad   0b,3b
-       .quad   2b,3b
-       .quad   3b,4b
+       .quad   1b,2b
+       .quad   3b,0b
+       .quad   5b,0b
         .previous
 
         .align 4