[MIPS] Fix sigset_t endianess swapping issues in 32-bit compat code.

access_ok in compat-signal.h is wrong (checking destination instead of
source) and redundant (already checked before calling this function).

Also sf_mask in struct sigframe32 should be compat_sigset_t type.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/signal32.c

@@ -150,7 +150,7 @@ struct sigframe32 {
 	u32 sf_ass[4];		/* argument save space for o32 */
 	u32 sf_code[2];		/* signal trampoline */
 	struct sigcontext32 sf_sc;
-	sigset_t sf_mask;
+	compat_sigset_t sf_mask;
 };
 
 struct rt_sigframe32 {
@@ -166,7 +166,7 @@ struct sigframe32 {
 	u32 sf_ass[4];			/* argument save space for o32 */
 	u32 sf_pad[2];
 	struct sigcontext32 sf_sc;	/* hw context */
-	sigset_t sf_mask;
+	compat_sigset_t sf_mask;
 	u32 sf_code[8] ____cacheline_aligned;	/* signal trampoline */
 };
 

include/asm-mips/compat-signal.h

@@ -33,9 +33,6 @@ static inline int __copy_conv_sigset_from_user(sigset_t *d,
 	BUG_ON(sizeof(*d) != sizeof(*s));
 	BUG_ON(_NSIG_WORDS != 2);
 
-	if (unlikely(!access_ok(VERIFY_READ, d, sizeof(*d))))
-		return -EFAULT;
-
 #ifdef CONFIG_CPU_BIG_ENDIAN
 	err  = __get_user(u->c.sig[1], &s->sig[0]);
 	err |= __get_user(u->c.sig[0], &s->sig[1]);