y2038: globally rename compat_time to old_time32

Christoph Hellwig suggested a slightly different path for handling
backwards compatibility with the 32-bit time_t based system calls:

Rather than simply reusing the compat_sys_* entry points on 32-bit
architectures unchanged, we get rid of those entry points and the
compat_time types by renaming them to something that makes more sense
on 32-bit architectures (which don't have a compat mode otherwise),
and then share the entry points under the new name with the 64-bit
architectures that use them for implementing the compatibility.

The following types and interfaces are renamed here, and moved
from linux/compat_time.h to linux/time32.h:

old				new
---				---
compat_time_t			old_time32_t
struct compat_timeval		struct old_timeval32
struct compat_timespec		struct old_timespec32
struct compat_itimerspec	struct old_itimerspec32
ns_to_compat_timeval()		ns_to_old_timeval32()
get_compat_itimerspec64()	get_old_itimerspec32()
put_compat_itimerspec64()	put_old_itimerspec32()
compat_get_timespec64()		get_old_timespec32()
compat_put_timespec64()		put_old_timespec32()

As we already have aliases in place, this patch addresses only the
instances that are relevant to the system call interface in particular,
not those that occur in device drivers and other modules. Those
will get handled separately, while providing the 64-bit version
of the respective interfaces.

I'm not renaming the timex, rusage and itimerval structures, as we are
still debating what the new interface will look like, and whether we
will need a replacement at all.

This also doesn't change the names of the syscall entry points, which can
be done more easily when we actually switch over the 32-bit architectures
to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to
SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

6 files changed, 91 insertions, 99 deletions

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 1a3c4f37e908..0e058792ecf6 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -7,7 +7,7 @@
  */
 
 #include <linux/types.h>
-#include <linux/compat_time.h>
+#include <linux/time.h>
 
 #include <linux/stat.h>
 #include <linux/param.h>	/* for HZ */
@@ -116,13 +116,13 @@ struct compat_sel_arg_struct;
 struct rusage;
 
 struct compat_utimbuf {
-	compat_time_t		actime;
-	compat_time_t		modtime;
+	old_time32_t		actime;
+	old_time32_t		modtime;
 };
 
 struct compat_itimerval {
-	struct compat_timeval	it_interval;
-	struct compat_timeval	it_value;
+	struct old_timeval32	it_interval;
+	struct old_timeval32	it_value;
 };
 
 struct itimerval;
@@ -146,7 +146,7 @@ struct compat_timex {
 	compat_long_t constant;
 	compat_long_t precision;
 	compat_long_t tolerance;
-	struct compat_timeval time;
+	struct old_timeval32 time;
 	compat_long_t tick;
 	compat_long_t ppsfreq;
 	compat_long_t jitter;
@@ -307,8 +307,8 @@ struct compat_rlimit {
 };
 
 struct compat_rusage {
-	struct compat_timeval ru_utime;
-	struct compat_timeval ru_stime;
+	struct old_timeval32 ru_utime;
+	struct old_timeval32 ru_stime;
 	compat_long_t	ru_maxrss;
 	compat_long_t	ru_ixrss;
 	compat_long_t	ru_idrss;
@@ -457,8 +457,8 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *fr
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
 
-static inline int compat_timeval_compare(struct compat_timeval *lhs,
-					struct compat_timeval *rhs)
+static inline int old_timeval32_compare(struct old_timeval32 *lhs,
+					struct old_timeval32 *rhs)
 {
 	if (lhs->tv_sec < rhs->tv_sec)
 		return -1;
@@ -467,8 +467,8 @@ static inline int compat_timeval_compare(struct compat_timeval *lhs,
 	return lhs->tv_usec - rhs->tv_usec;
 }
 
-static inline int compat_timespec_compare(struct compat_timespec *lhs,
-					struct compat_timespec *rhs)
+static inline int old_timespec32_compare(struct old_timespec32 *lhs,
+					struct old_timespec32 *rhs)
 {
 	if (lhs->tv_sec < rhs->tv_sec)
 		return -1;
@@ -552,12 +552,12 @@ asmlinkage long compat_sys_io_getevents(compat_aio_context_t ctx_id,
 					compat_long_t min_nr,
 					compat_long_t nr,
 					struct io_event __user *events,
-					struct compat_timespec __user *timeout);
+					struct old_timespec32 __user *timeout);
 asmlinkage long compat_sys_io_pgetevents(compat_aio_context_t ctx_id,
 					compat_long_t min_nr,
 					compat_long_t nr,
 					struct io_event __user *events,
-					struct compat_timespec __user *timeout,
+					struct old_timespec32 __user *timeout,
 					const struct __compat_aio_sigset __user *usig);
 
 /* fs/cookies.c */
@@ -642,11 +642,11 @@ asmlinkage long compat_sys_sendfile64(int out_fd, int in_fd,
 asmlinkage long compat_sys_pselect6(int n, compat_ulong_t __user *inp,
 				    compat_ulong_t __user *outp,
 				    compat_ulong_t __user *exp,
-				    struct compat_timespec __user *tsp,
+				    struct old_timespec32 __user *tsp,
 				    void __user *sig);
 asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds,
 				 unsigned int nfds,
-				 struct compat_timespec __user *tsp,
+				 struct old_timespec32 __user *tsp,
 				 const compat_sigset_t __user *sigmask,
 				 compat_size_t sigsetsize);
 
@@ -671,15 +671,15 @@ asmlinkage long compat_sys_newfstat(unsigned int fd,
 
 /* fs/timerfd.c */
 asmlinkage long compat_sys_timerfd_gettime(int ufd,
-				   struct compat_itimerspec __user *otmr);
+				   struct old_itimerspec32 __user *otmr);
 asmlinkage long compat_sys_timerfd_settime(int ufd, int flags,
-				   const struct compat_itimerspec __user *utmr,
-				   struct compat_itimerspec __user *otmr);
+				   const struct old_itimerspec32 __user *utmr,
+				   struct old_itimerspec32 __user *otmr);
 
 /* fs/utimes.c */
 asmlinkage long compat_sys_utimensat(unsigned int dfd,
 				     const char __user *filename,
-				     struct compat_timespec __user *t,
+				     struct old_timespec32 __user *t,
 				     int flags);
 
 /* kernel/exit.c */
@@ -691,7 +691,7 @@ asmlinkage long compat_sys_waitid(int, compat_pid_t,
 
 /* kernel/futex.c */
 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
-		struct compat_timespec __user *utime, u32 __user *uaddr2,
+		struct old_timespec32 __user *utime, u32 __user *uaddr2,
 		u32 val3);
 asmlinkage long
 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
@@ -701,8 +701,8 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
 			   compat_size_t __user *len_ptr);
 
 /* kernel/hrtimer.c */
-asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
-				     struct compat_timespec __user *rmtp);
+asmlinkage long compat_sys_nanosleep(struct old_timespec32 __user *rqtp,
+				     struct old_timespec32 __user *rmtp);
 
 /* kernel/itimer.c */
 asmlinkage long compat_sys_getitimer(int which,
@@ -722,19 +722,19 @@ asmlinkage long compat_sys_timer_create(clockid_t which_clock,
 			struct compat_sigevent __user *timer_event_spec,
 			timer_t __user *created_timer_id);
 asmlinkage long compat_sys_timer_gettime(timer_t timer_id,
-				 struct compat_itimerspec __user *setting);
+				 struct old_itimerspec32 __user *setting);
 asmlinkage long compat_sys_timer_settime(timer_t timer_id, int flags,
-					 struct compat_itimerspec __user *new,
-					 struct compat_itimerspec __user *old);
+					 struct old_itimerspec32 __user *new,
+					 struct old_itimerspec32 __user *old);
 asmlinkage long compat_sys_clock_settime(clockid_t which_clock,
-					 struct compat_timespec __user *tp);
+					 struct old_timespec32 __user *tp);
 asmlinkage long compat_sys_clock_gettime(clockid_t which_clock,
-					 struct compat_timespec __user *tp);
+					 struct old_timespec32 __user *tp);
 asmlinkage long compat_sys_clock_getres(clockid_t which_clock,
-					struct compat_timespec __user *tp);
+					struct old_timespec32 __user *tp);
 asmlinkage long compat_sys_clock_nanosleep(clockid_t which_clock, int flags,
-					   struct compat_timespec __user *rqtp,
-					   struct compat_timespec __user *rmtp);
+					   struct old_timespec32 __user *rqtp,
+					   struct old_timespec32 __user *rmtp);
 
 /* kernel/ptrace.c */
 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
@@ -748,7 +748,7 @@ asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid,
 				     unsigned int len,
 				     compat_ulong_t __user *user_mask_ptr);
 asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
-						 struct compat_timespec __user *interval);
+						 struct old_timespec32 __user *interval);
 
 /* kernel/signal.c */
 asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr,
@@ -768,7 +768,7 @@ asmlinkage long compat_sys_rt_sigpending(compat_sigset_t __user *uset,
 					 compat_size_t sigsetsize);
 asmlinkage long compat_sys_rt_sigtimedwait(compat_sigset_t __user *uthese,
 		struct compat_siginfo __user *uinfo,
-		struct compat_timespec __user *uts, compat_size_t sigsetsize);
+		struct old_timespec32 __user *uts, compat_size_t sigsetsize);
 asmlinkage long compat_sys_rt_sigqueueinfo(compat_pid_t pid, int sig,
 				struct compat_siginfo __user *uinfo);
 /* No generic prototype for rt_sigreturn */
@@ -782,9 +782,9 @@ asmlinkage long compat_sys_setrlimit(unsigned int resource,
 asmlinkage long compat_sys_getrusage(int who, struct compat_rusage __user *ru);
 
 /* kernel/time.c */
-asmlinkage long compat_sys_gettimeofday(struct compat_timeval __user *tv,
+asmlinkage long compat_sys_gettimeofday(struct old_timeval32 __user *tv,
 		struct timezone __user *tz);
-asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
+asmlinkage long compat_sys_settimeofday(struct old_timeval32 __user *tv,
 		struct timezone __user *tz);
 asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
 
@@ -798,11 +798,11 @@ asmlinkage long compat_sys_mq_open(const char __user *u_name,
 asmlinkage long compat_sys_mq_timedsend(mqd_t mqdes,
 			const char __user *u_msg_ptr,
 			compat_size_t msg_len, unsigned int msg_prio,
-			const struct compat_timespec __user *u_abs_timeout);
+			const struct old_timespec32 __user *u_abs_timeout);
 asmlinkage ssize_t compat_sys_mq_timedreceive(mqd_t mqdes,
 			char __user *u_msg_ptr,
 			compat_size_t msg_len, unsigned int __user *u_msg_prio,
-			const struct compat_timespec __user *u_abs_timeout);
+			const struct old_timespec32 __user *u_abs_timeout);
 asmlinkage long compat_sys_mq_notify(mqd_t mqdes,
 			const struct compat_sigevent __user *u_notification);
 asmlinkage long compat_sys_mq_getsetattr(mqd_t mqdes,
@@ -819,7 +819,7 @@ asmlinkage long compat_sys_msgsnd(int msqid, compat_uptr_t msgp,
 /* ipc/sem.c */
 asmlinkage long compat_sys_semctl(int semid, int semnum, int cmd, int arg);
 asmlinkage long compat_sys_semtimedop(int semid, struct sembuf __user *tsems,
-		unsigned nsems, const struct compat_timespec __user *timeout);
+		unsigned nsems, const struct old_timespec32 __user *timeout);
 
 /* ipc/shm.c */
 asmlinkage long compat_sys_shmctl(int first, int second, void __user *uptr);
@@ -876,7 +876,7 @@ asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid,
 					struct compat_siginfo __user *uinfo);
 asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
 				    unsigned vlen, unsigned int flags,
-				    struct compat_timespec __user *timeout);
+				    struct old_timespec32 __user *timeout);
 asmlinkage long compat_sys_wait4(compat_pid_t pid,
 				 compat_uint_t __user *stat_addr, int options,
 				 struct compat_rusage __user *ru);
@@ -928,7 +928,7 @@ asmlinkage long compat_sys_pwritev64v2(unsigned long fd,
 asmlinkage long compat_sys_open(const char __user *filename, int flags,
 				umode_t mode);
 asmlinkage long compat_sys_utimes(const char __user *filename,
-				  struct compat_timeval __user *t);
+				  struct old_timeval32 __user *t);
 
 /* __ARCH_WANT_SYSCALL_NO_FLAGS */
 asmlinkage long compat_sys_signalfd(int ufd,
@@ -942,15 +942,15 @@ asmlinkage long compat_sys_newlstat(const char __user *filename,
 				    struct compat_stat __user *statbuf);
 
 /* __ARCH_WANT_SYSCALL_DEPRECATED */
-asmlinkage long compat_sys_time(compat_time_t __user *tloc);
+asmlinkage long compat_sys_time(old_time32_t __user *tloc);
 asmlinkage long compat_sys_utime(const char __user *filename,
 				 struct compat_utimbuf __user *t);
 asmlinkage long compat_sys_futimesat(unsigned int dfd,
 				     const char __user *filename,
-				     struct compat_timeval __user *t);
+				     struct old_timeval32 __user *t);
 asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
 		compat_ulong_t __user *outp, compat_ulong_t __user *exp,
-		struct compat_timeval __user *tvp);
+		struct old_timeval32 __user *tvp);
 asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u32);
 asmlinkage long compat_sys_recv(int fd, void __user *buf, compat_size_t len,
 				unsigned flags);
@@ -983,7 +983,7 @@ asmlinkage long compat_sys_sigaction(int sig,
 #endif
 
 /* obsolete: kernel/time/time.c */
-asmlinkage long compat_sys_stime(compat_time_t __user *tptr);
+asmlinkage long compat_sys_stime(old_time32_t __user *tptr);
 
 /* obsolete: net/socket.c */
 asmlinkage long compat_sys_socketcall(int call, u32 __user *args);
@@ -1002,15 +1002,15 @@ static inline bool in_compat_syscall(void) { return is_compat_task(); }
 #endif
 
 /**
- * ns_to_compat_timeval - Compat version of ns_to_timeval
+ * ns_to_old_timeval32 - Compat version of ns_to_timeval
  * @nsec:	the nanoseconds value to be converted
  *
- * Returns the compat_timeval representation of the nsec parameter.
+ * Returns the old_timeval32 representation of the nsec parameter.
  */
-static inline struct compat_timeval ns_to_compat_timeval(s64 nsec)
+static inline struct old_timeval32 ns_to_old_timeval32(s64 nsec)
 {
 	struct timeval tv;
-	struct compat_timeval ctv;
+	struct old_timeval32 ctv;
 
 	tv = ns_to_timeval(nsec);
 	ctv.tv_sec = tv.tv_sec;
diff --git a/include/linux/compat_time.h b/include/linux/compat_time.h
deleted file mode 100644
index e70bfd1d2c3f..000000000000
--- a/include/linux/compat_time.h
+++ /dev/null
@@ -1,32 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_COMPAT_TIME_H
-#define _LINUX_COMPAT_TIME_H
-
-#include <linux/types.h>
-#include <linux/time64.h>
-
-typedef s32		compat_time_t;
-
-struct compat_timespec {
-	compat_time_t	tv_sec;
-	s32		tv_nsec;
-};
-
-struct compat_timeval {
-	compat_time_t	tv_sec;
-	s32		tv_usec;
-};
-
-struct compat_itimerspec {
-	struct compat_timespec it_interval;
-	struct compat_timespec it_value;
-};
-
-extern int compat_get_timespec64(struct timespec64 *, const void __user *);
-extern int compat_put_timespec64(const struct timespec64 *, void __user *);
-extern int get_compat_itimerspec64(struct itimerspec64 *its,
-			const struct compat_itimerspec __user *uits);
-extern int put_compat_itimerspec64(const struct itimerspec64 *its,
-			struct compat_itimerspec __user *uits);
-
-#endif /* _LINUX_COMPAT_TIME_H */
diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
index b5f2efdd05e0..7a37f4ce9fd2 100644
--- a/include/linux/elfcore-compat.h
+++ b/include/linux/elfcore-compat.h
@@ -27,10 +27,10 @@ struct compat_elf_prstatus
 	compat_pid_t			pr_ppid;
 	compat_pid_t			pr_pgrp;
 	compat_pid_t			pr_sid;
-	struct compat_timeval		pr_utime;
-	struct compat_timeval		pr_stime;
-	struct compat_timeval		pr_cutime;
-	struct compat_timeval		pr_cstime;
+	struct old_timeval32		pr_utime;
+	struct old_timeval32		pr_stime;
+	struct old_timeval32		pr_cutime;
+	struct old_timeval32		pr_cstime;
 	compat_elf_gregset_t		pr_reg;
 #ifdef CONFIG_BINFMT_ELF_FDPIC
 	compat_ulong_t			pr_exec_fdpic_loadmap;
diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
index 5d83d0c1d06c..bba2920e9c05 100644
--- a/include/linux/restart_block.h
+++ b/include/linux/restart_block.h
@@ -10,7 +10,7 @@
 #include <linux/time64.h>
 
 struct timespec;
-struct compat_timespec;
+struct old_timespec32;
 struct pollfd;
 
 enum timespec_type {
@@ -40,7 +40,7 @@ struct restart_block {
 			enum timespec_type type;
 			union {
 				struct __kernel_timespec __user *rmtp;
-				struct compat_timespec __user *compat_rmtp;
+				struct old_timespec32 __user *compat_rmtp;
 			};
 			u64 expires;
 		} nanosleep;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 2ff814c92f7f..b3e27e5ee322 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -60,7 +60,7 @@ struct tms;
 struct utimbuf;
 struct mq_attr;
 struct compat_stat;
-struct compat_timeval;
+struct old_timeval32;
 struct robust_list_head;
 struct getcpu_cache;
 struct old_linux_dirent;
diff --git a/include/linux/time32.h b/include/linux/time32.h
index 92c0ca092d93..0e0d7304d1a8 100644
--- a/include/linux/time32.h
+++ b/include/linux/time32.h
@@ -13,6 +13,31 @@
 
 #define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
 
+typedef s32		old_time32_t;
+
+struct old_timespec32 {
+	old_time32_t	tv_sec;
+	s32		tv_nsec;
+};
+
+struct old_timeval32 {
+	old_time32_t	tv_sec;
+	s32		tv_usec;
+};
+
+struct old_itimerspec32 {
+	struct old_timespec32 it_interval;
+	struct old_timespec32 it_value;
+};
+
+extern int get_old_timespec32(struct timespec64 *, const void __user *);
+extern int put_old_timespec32(const struct timespec64 *, void __user *);
+extern int get_old_itimerspec32(struct itimerspec64 *its,
+			const struct old_itimerspec32 __user *uits);
+extern int put_old_itimerspec32(const struct itimerspec64 *its,
+			struct old_itimerspec32 __user *uits);
+
+
 #if __BITS_PER_LONG == 64
 
 /* timespec64 is defined as timespec here */
@@ -183,18 +208,17 @@ extern struct timeval ns_to_timeval(const s64 nsec);
 extern struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec);
 
 /*
- * New aliases for compat time functions. These will be used to replace
- * the compat code so it can be shared between 32-bit and 64-bit builds
- * both of which provide compatibility with old 32-bit tasks.
+ * Old names for the 32-bit time_t interfaces, these will be removed
+ * when everything uses the new names.
  */
-#define old_time32_t		compat_time_t
-#define old_timeval32		compat_timeval
-#define old_timespec32		compat_timespec
-#define old_itimerspec32	compat_itimerspec
-#define ns_to_old_timeval32	ns_to_compat_timeval
-#define get_old_itimerspec32	get_compat_itimerspec64
-#define put_old_itimerspec32	put_compat_itimerspec64
-#define get_old_timespec32	compat_get_timespec64
-#define put_old_timespec32	compat_put_timespec64
+#define compat_time_t		old_time32_t
+#define compat_timeval		old_timeval32
+#define compat_timespec		old_timespec32
+#define compat_itimerspec	old_itimerspec32
+#define ns_to_compat_timeval	ns_to_old_timeval32
+#define get_compat_itimerspec64	get_old_itimerspec32
+#define put_compat_itimerspec64	put_old_itimerspec32
+#define compat_get_timespec64	get_old_timespec32
+#define compat_put_timespec64	put_old_timespec32
 
 #endif