y2038: powerpc: Extend sysvipc data structures

powerpc, uses a nonstandard variation of the generic sysvipc
data structures, intended to have the padding moved around
so it can deal with big-endian 32-bit user space that has
64-bit time_t.

powerpc has the same definition as parisc and sparc, but now also
supports little-endian mode, which is now wrong because the
padding is made for big-endian user space.

This takes just take the same approach here that we have for
the asm-generic headers and adds separate 32-bit fields for the
upper halves of the timestamps, to let libc deal with the mess
in user space.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/powerpc/include/asm/compat.h

@@ -162,10 +162,10 @@ struct compat_ipc64_perm {
 
 struct compat_semid64_ds {
 	struct compat_ipc64_perm sem_perm;
-	unsigned int __unused1;
-	compat_time_t sem_otime;
-	unsigned int __unused2;
-	compat_time_t sem_ctime;
+	unsigned int sem_otime_high;
+	unsigned int sem_otime;
+	unsigned int sem_ctime_high;
+	unsigned int sem_ctime;
 	compat_ulong_t sem_nsems;
 	compat_ulong_t __unused3;
 	compat_ulong_t __unused4;
@@ -173,12 +173,12 @@ struct compat_semid64_ds {
 
 struct compat_msqid64_ds {
 	struct compat_ipc64_perm msg_perm;
-	unsigned int __unused1;
-	compat_time_t msg_stime;
-	unsigned int __unused2;
-	compat_time_t msg_rtime;
-	unsigned int __unused3;
-	compat_time_t msg_ctime;
+	unsigned int msg_stime_high;
+	unsigned int msg_stime;
+	unsigned int msg_rtime_high;
+	unsigned int msg_rtime;
+	unsigned int msg_ctime_high;
+	unsigned int msg_ctime;
 	compat_ulong_t msg_cbytes;
 	compat_ulong_t msg_qnum;
 	compat_ulong_t msg_qbytes;
@@ -190,12 +190,12 @@ struct compat_msqid64_ds {
 
 struct compat_shmid64_ds {
 	struct compat_ipc64_perm shm_perm;
-	unsigned int __unused1;
-	compat_time_t shm_atime;
-	unsigned int __unused2;
-	compat_time_t shm_dtime;
-	unsigned int __unused3;
-	compat_time_t shm_ctime;
+	unsigned int shm_atime_high;
+	unsigned int shm_atime;
+	unsigned int shm_dtime_high;
+	unsigned int shm_dtime;
+	unsigned int shm_ctime_high;
+	unsigned int shm_ctime;
 	unsigned int __unused4;
 	compat_size_t shm_segsz;
 	compat_pid_t shm_cpid;

arch/powerpc/include/uapi/asm/msgbuf.h

@@ -10,18 +10,18 @@
 
 struct msqid64_ds {
 	struct ipc64_perm msg_perm;
-#ifndef __powerpc64__
-	unsigned int	__unused1;
-#endif
+#ifdef __powerpc64__
 	__kernel_time_t msg_stime;	/* last msgsnd time */
-#ifndef __powerpc64__
-	unsigned int	__unused2;
-#endif
 	__kernel_time_t msg_rtime;	/* last msgrcv time */
-#ifndef __powerpc64__
-	unsigned int	__unused3;
-#endif
 	__kernel_time_t msg_ctime;	/* last change time */
+#else
+	unsigned long  msg_stime_high;
+	unsigned long  msg_stime;	/* last msgsnd time */
+	unsigned long  msg_rtime_high;
+	unsigned long  msg_rtime;	/* last msgrcv time */
+	unsigned long  msg_ctime_high;
+	unsigned long  msg_ctime;	/* last change time */
+#endif
 	unsigned long  msg_cbytes;	/* current number of bytes on queue */
 	unsigned long  msg_qnum;	/* number of messages in queue */
 	unsigned long  msg_qbytes;	/* max number of bytes on queue */

arch/powerpc/include/uapi/asm/sembuf.h

@@ -15,20 +15,20 @@
  * between kernel and user space.
  *
  * Pad space is left for:
- * - 64-bit time_t to solve y2038 problem
- * - 2 miscellaneous 32-bit values
+ * - 2 miscellaneous 32/64-bit values
  */
 
 struct semid64_ds {
 	struct ipc64_perm sem_perm;	/* permissions .. see ipc.h */
 #ifndef __powerpc64__
-	unsigned long	__unused1;
-#endif
+	unsigned long	sem_otime_high;
+	unsigned long	sem_otime;	/* last semop time */
+	unsigned long	sem_ctime_high;
+	unsigned long	sem_ctime;	/* last change time */
+#else
 	__kernel_time_t	sem_otime;	/* last semop time */
-#ifndef __powerpc64__
-	unsigned long	__unused2;
-#endif
 	__kernel_time_t	sem_ctime;	/* last change time */
+#endif
 	unsigned long	sem_nsems;	/* no. of semaphores in array */
 	unsigned long	__unused3;
 	unsigned long	__unused4;

arch/powerpc/include/uapi/asm/shmbuf.h

@@ -16,25 +16,22 @@
  * between kernel and user space.
  *
  * Pad space is left for:
- * - 64-bit time_t to solve y2038 problem
  * - 2 miscellaneous 32-bit values
  */
 
 struct shmid64_ds {
 	struct ipc64_perm	shm_perm;	/* operation perms */
-#ifndef __powerpc64__
-	unsigned long		__unused1;
-#endif
+#ifdef __powerpc64__
 	__kernel_time_t		shm_atime;	/* last attach time */
-#ifndef __powerpc64__
-	unsigned long		__unused2;
-#endif
 	__kernel_time_t		shm_dtime;	/* last detach time */
-#ifndef __powerpc64__
-	unsigned long		__unused3;
-#endif
 	__kernel_time_t		shm_ctime;	/* last change time */
-#ifndef __powerpc64__
+#else
+	unsigned long		shm_atime_high;
+	unsigned long		shm_atime;	/* last attach time */
+	unsigned long		shm_dtime_high;
+	unsigned long		shm_dtime;	/* last detach time */
+	unsigned long		shm_ctime_high;
+	unsigned long		shm_ctime;	/* last change time */
 	unsigned long		__unused4;
 #endif
 	size_t			shm_segsz;	/* size of segment (bytes) */