alpha: get rid of tail-zeroing in __copy_user()

... and adjust copy_from_user() accordingly

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h
index 466e42e..94f5875 100644 (file)
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -396,11 +396,12 @@ copy_to_user(void __user *to, const void *from, long n)
 extern inline long
 copy_from_user(void *to, const void __user *from, long n)
 {
+       long res = n;
        if (likely(__access_ok((unsigned long)from, n, get_fs())))
-               n = __copy_tofrom_user_nocheck(to, (__force void *)from, n);
-       else
-               memset(to, 0, n);
-       return n;
+               res = __copy_from_user_inatomic(to, from, n);
+       if (unlikely(res))
+               memset(to + (n - res), 0, res);
+       return res;
 }
 
 extern void __do_clear_user(void);

diff --git a/arch/alpha/lib/copy_user.S b/arch/alpha/lib/copy_user.S
index 6f3fab9..ac9c376 100644 (file)
--- a/arch/alpha/lib/copy_user.S
+++ b/arch/alpha/lib/copy_user.S
@@ -124,22 +124,8 @@ $65:
        bis $31,$31,$0
 $41:
 $35:
-$exitout:
-       ret $31,($28),1
-
 $exitin:
-       /* A stupid byte-by-byte zeroing of the rest of the output
-          buffer.  This cures security holes by never leaving 
-          random kernel data around to be copied elsewhere.  */
-
-       mov $0,$1
-$101:
-       EXO ( ldq_u $2,0($6) )
-       subq $1,1,$1
-       mskbl $2,$6,$2
-       EXO ( stq_u $2,0($6) )
-       addq $6,1,$6
-       bgt $1,$101
+$exitout:
        ret $31,($28),1
 
        .end __copy_user

diff --git a/arch/alpha/lib/ev6-copy_user.S b/arch/alpha/lib/ev6-copy_user.S
index db42ffe..c4d0689 100644 (file)
--- a/arch/alpha/lib/ev6-copy_user.S
+++ b/arch/alpha/lib/ev6-copy_user.S
@@ -227,33 +227,12 @@ $dirtyentry:
        bgt $0,$onebyteloop     # U  .. .. ..   : U L U L
 
 $zerolength:
+$exitin:
 $exitout:                      # Destination for exception recovery(?)
        nop                     # .. .. .. E
        nop                     # .. .. E  ..
        nop                     # .. E  .. ..
        ret $31,($28),1         # L0 .. .. ..   : L U L U
 
-$exitin:
-
-       /* A stupid byte-by-byte zeroing of the rest of the output
-          buffer.  This cures security holes by never leaving 
-          random kernel data around to be copied elsewhere.  */
-
-       nop
-       nop
-       nop
-       mov     $0,$1
-
-$101:
-       EXO ( stb $31,0($6) )   # L
-       subq $1,1,$1            # E
-       addq $6,1,$6            # E
-       bgt $1,$101             # U
-
-       nop
-       nop
-       nop
-       ret $31,($28),1         # L0
-
        .end __copy_user