y2038: uapi: change __kernel_time_t to __kernel_old_time_t

This is mainly a patch for clarification, and to let us remove
the time_t definition from the kernel to prevent new users from
creeping in that might not be y2038-safe.

All remaining uses of 'time_t' or '__kernel_time_t' are part of
the user API that cannot be changed by that either have a
replacement or that do not suffer from the y2038 overflow.

Acked-by: Deepa Dinamani <[e-mail]>
Acked-by: Christian Brauner <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

include/linux/syscalls.h

···
 asmlinkage long sys_alarm(unsigned int seconds);
 asmlinkage long sys_getpgrp(void);
 asmlinkage long sys_pause(void);
-asmlinkage long sys_time(time_t __user *tloc);
+asmlinkage long sys_time(__kernel_old_time_t __user *tloc);
 asmlinkage long sys_time32(old_time32_t __user *tloc);
 #ifdef __ARCH_WANT_SYS_UTIME
 asmlinkage long sys_utime(char __user *filename,
···
 asmlinkage long sys_fork(void);
 
 /* obsolete: kernel/time/time.c */
-asmlinkage long sys_stime(time_t __user *tptr);
+asmlinkage long sys_stime(__kernel_old_time_t __user *tptr);
 asmlinkage long sys_stime32(old_time32_t __user *tptr);
 
 /* obsolete: kernel/signal.c */

include/linux/time32.h

···
 #include <linux/time64.h>
 #include <linux/timex.h>
 
-#define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+#define TIME_T_MAX	(__kernel_old_time_t)((1UL << ((sizeof(__kernel_old_time_t) << 3) - 1)) - 1)
 
 typedef s32		old_time32_t;
 

include/linux/types.h

···
 
 #ifndef _TIME_T
 #define _TIME_T
-typedef __kernel_time_t		time_t;
+typedef __kernel_old_time_t	time_t;
 #endif
 
 #ifndef _CLOCK_T

include/uapi/linux/cyclades.h

···
  * open)
  */
 struct cyclades_idle_stats {
-    __kernel_time_t in_use;	/* Time device has been in use (secs) */
-    __kernel_time_t recv_idle;	/* Time since last char received (secs) */
-    __kernel_time_t xmit_idle;	/* Time since last char transmitted (secs) */
+    __kernel_old_time_t in_use;	/* Time device has been in use (secs) */
+    __kernel_old_time_t recv_idle; /* Time since last char received (secs) */
+    __kernel_old_time_t xmit_idle; /* Time since last char transmitted (secs) */
     unsigned long  recv_bytes;	/* Bytes received */
     unsigned long  xmit_bytes;	/* Bytes transmitted */
     unsigned long  overruns;	/* Input overruns */

include/uapi/linux/msg.h

···
 	struct ipc_perm msg_perm;
 	struct msg *msg_first;		/* first message on queue,unused  */
 	struct msg *msg_last;		/* last message in queue,unused */
-	__kernel_time_t msg_stime;	/* last msgsnd time */
-	__kernel_time_t msg_rtime;	/* last msgrcv time */
-	__kernel_time_t msg_ctime;	/* last change time */
+	__kernel_old_time_t msg_stime;	/* last msgsnd time */
+	__kernel_old_time_t msg_rtime;	/* last msgrcv time */
+	__kernel_old_time_t msg_ctime;	/* last change time */
 	unsigned long  msg_lcbytes;	/* Reuse junk fields for 32 bit */
 	unsigned long  msg_lqbytes;	/* ditto */
 	unsigned short msg_cbytes;	/* current number of bytes on queue */

include/uapi/linux/ppp_defs.h

···
  * the last NP packet was sent or received.
  */
 struct ppp_idle {
-    __kernel_time_t xmit_idle;	/* time since last NP packet sent */
-    __kernel_time_t recv_idle;	/* time since last NP packet received */
+    __kernel_old_time_t xmit_idle;	/* time since last NP packet sent */
+    __kernel_old_time_t recv_idle;	/* time since last NP packet received */
 };
 
 #endif /* _UAPI_PPP_DEFS_H_ */

include/uapi/linux/sem.h

···
 /* Obsolete, used only for backwards compatibility and libc5 compiles */
 struct semid_ds {
 	struct ipc_perm	sem_perm;		/* permissions .. see ipc.h */
-	__kernel_time_t	sem_otime;		/* last semop time */
-	__kernel_time_t	sem_ctime;		/* create/last semctl() time */
+	__kernel_old_time_t sem_otime;		/* last semop time */
+	__kernel_old_time_t sem_ctime;		/* create/last semctl() time */
 	struct sem	*sem_base;		/* ptr to first semaphore in array */
 	struct sem_queue *sem_pending;		/* pending operations to be processed */
 	struct sem_queue **sem_pending_last;	/* last pending operation */

include/uapi/linux/shm.h

···
 struct shmid_ds {
 	struct ipc_perm		shm_perm;	/* operation perms */
 	int			shm_segsz;	/* size of segment (bytes) */
-	__kernel_time_t		shm_atime;	/* last attach time */
-	__kernel_time_t		shm_dtime;	/* last detach time */
-	__kernel_time_t		shm_ctime;	/* last change time */
+	__kernel_old_time_t	shm_atime;	/* last attach time */
+	__kernel_old_time_t	shm_dtime;	/* last detach time */
+	__kernel_old_time_t	shm_ctime;	/* last change time */
 	__kernel_ipc_pid_t	shm_cpid;	/* pid of creator */
 	__kernel_ipc_pid_t	shm_lpid;	/* pid of last operator */
 	unsigned short		shm_nattch;	/* no. of current attaches */

include/uapi/linux/time.h

···
 #ifndef _STRUCT_TIMESPEC
 #define _STRUCT_TIMESPEC
 struct timespec {
-	__kernel_time_t	tv_sec;			/* seconds */
-	long		tv_nsec;		/* nanoseconds */
+	__kernel_old_time_t	tv_sec;		/* seconds */
+	long			tv_nsec;	/* nanoseconds */
 };
 #endif
 
 struct timeval {
-	__kernel_time_t		tv_sec;		/* seconds */
+	__kernel_old_time_t	tv_sec;		/* seconds */
 	__kernel_suseconds_t	tv_usec;	/* microseconds */
 };
 

include/uapi/linux/time_types.h

···
 #endif
 
 struct __kernel_old_timespec {
-	__kernel_time_t	tv_sec;			/* seconds */
-	long		tv_nsec;		/* nanoseconds */
+	__kernel_old_time_t	tv_sec;		/* seconds */
+	long			tv_nsec;	/* nanoseconds */
 };
 
 struct __kernel_sock_timeval {

include/uapi/linux/utime.h

···
 #include <linux/types.h>
 
 struct utimbuf {
-	__kernel_time_t actime;
-	__kernel_time_t modtime;
+	__kernel_old_time_t actime;
+	__kernel_old_time_t modtime;
 };
 
 #endif

kernel/time/time.c

···
  * why not move it into the appropriate arch directory (for those
  * architectures that need it).
  */
-SYSCALL_DEFINE1(time, time_t __user *, tloc)
+SYSCALL_DEFINE1(time, __kernel_old_time_t __user *, tloc)
 {
-	time_t i = (time_t)ktime_get_real_seconds();
+	__kernel_old_time_t i = (__kernel_old_time_t)ktime_get_real_seconds();
 
 	if (tloc) {
 		if (put_user(i,tloc))
···
  * architectures that need it).
  */
 
-SYSCALL_DEFINE1(stime, time_t __user *, tptr)
+SYSCALL_DEFINE1(stime, __kernel_old_time_t __user *, tptr)
 {
 	struct timespec64 tv;
 	int err;