MIPS: Provide correct siginfo_t.si_stime

Provide correct siginfo_t.si_stime on MIPS64

Bug description:
MIPS version of copy_siginfo() is not aware of alignment on platforms with
64-bit long integers, which leads to an incorrect si_stime passed to signal
handlers, because the last element (si_stime) of _sifields._sigchld is not
copied. If _MIPS_SZLONG is 64, then the _sifields starts at the offset of
4 * sizeof(int).

Patch description:
Use the generic copy_siginfo, which doesn't have this problem.
Signed-off-by: Petr Malat <oss@malat.biz>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8671/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/siginfo.h

-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1998, 1999, 2001, 2003 Ralf Baechle
- * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
- */
-#ifndef _ASM_SIGINFO_H
-#define _ASM_SIGINFO_H
-
-#include <uapi/asm/siginfo.h>
-
-
-/*
- * Duplicated here because of <asm-generic/siginfo.h> braindamage ...
- */
-#include <linux/string.h>
-
-static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
-{
-	if (from->si_code < 0)
-		memcpy(to, from, sizeof(*to));
-	else
-		/* _sigchld is currently the largest know union member */
-		memcpy(to, from, 3*sizeof(int) + sizeof(from->_sifields._sigchld));
-}
-
-#endif /* _ASM_SIGINFO_H */

arch/mips/include/uapi/asm/siginfo.h

@@ -15,13 +15,6 @@
 
 #define HAVE_ARCH_SIGINFO_T
 
-/*
- * We duplicate the generic versions - <asm-generic/siginfo.h> is just borked
- * by design ...
- */
-#define HAVE_ARCH_COPY_SIGINFO
-struct siginfo;
-
 /*
  * Careful to keep union _sifields from shifting ...
  */
@@ -35,8 +28,9 @@ struct siginfo;
 
 #define __ARCH_SIGSYS
 
-#include <asm-generic/siginfo.h>
+#include <uapi/asm-generic/siginfo.h>
 
+/* We can't use generic siginfo_t, because our si_code and si_errno are swapped */
 typedef struct siginfo {
 	int si_signo;
 	int si_code;
@@ -124,5 +118,6 @@ typedef struct siginfo {
 #define SI_TIMER __SI_CODE(__SI_TIMER, -3) /* sent by timer expiration */
 #define SI_MESGQ __SI_CODE(__SI_MESGQ, -4) /* sent by real time mesq state change */
 
+#include <asm-generic/siginfo.h>
 
 #endif /* _UAPI_ASM_SIGINFO_H */