Merge tag 'y2038-drivers-for-v5.6-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 updates from Arnd Bergmann:
 "Core, driver and file system changes

  These are updates to device drivers and file systems that for some
  reason or another were not included in the kernel in the previous
  y2038 series.

  I've gone through all users of time_t again to make sure the kernel is
  in a long-term maintainable state, replacing all remaining references
  to time_t with safe alternatives.

  Some related parts of the series were picked up into the nfsd, xfs,
  alsa and v4l2 trees. A final set of patches in linux-mm removes the
  now unused time_t/timeval/timespec types and helper functions after
  all five branches are merged for linux-5.6, ensuring that no new users
  get merged.

  As a result, linux-5.6, or my backport of the patches to 5.4 [1],
  should be the first release that can serve as a base for a 32-bit
  system designed to run beyond year 2038, with a few remaining caveats:

   - All user space must be compiled with a 64-bit time_t, which will be
     supported in the coming musl-1.2 and glibc-2.32 releases, along
     with installed kernel headers from linux-5.6 or higher.

   - Applications that use the system call interfaces directly need to
     be ported to use the time64 syscalls added in linux-5.1 in place of
     the existing system calls. This impacts most users of futex() and
     seccomp() as well as programming languages that have their own
     runtime environment not based on libc.

   - Applications that use a private copy of kernel uapi header files or
     their contents may need to update to the linux-5.6 version, in
     particular for sound/asound.h, xfs/xfs_fs.h, linux/input.h,
     linux/elfcore.h, linux/sockios.h, linux/timex.h and
     linux/can/bcm.h.

   - A few remaining interfaces cannot be changed to pass a 64-bit
     time_t in a compatible way, so they must be configured to use
     CLOCK_MONOTONIC times or (with a y2106 problem) unsigned 32-bit
     timestamps. Most importantly this impacts all users of 'struct
     input_event'.

   - All y2038 problems that are present on 64-bit machines also apply
     to 32-bit machines. In particular this affects file systems with
     on-disk timestamps using signed 32-bit seconds: ext4 with
     ext3-style small inodes, ext2, xfs (to be fixed soon) and ufs"

[1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/log/?h=y2038-endgame

* tag 'y2038-drivers-for-v5.6-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (21 commits)
  Revert "drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC"
  y2038: sh: remove timeval/timespec usage from headers
  y2038: sparc: remove use of struct timex
  y2038: rename itimerval to __kernel_old_itimerval
  y2038: remove obsolete jiffies conversion functions
  nfs: fscache: use timespec64 in inode auxdata
  nfs: fix timstamp debug prints
  nfs: use time64_t internally
  sunrpc: convert to time64_t for expiry
  drm/etnaviv: avoid deprecated timespec
  drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC
  drm/msm: avoid using 'timespec'
  hfs/hfsplus: use 64-bit inode timestamps
  hostfs: pass 64-bit timestamps to/from user space
  packet: clarify timestamp overflow
  tsacct: add 64-bit btime field
  acct: stop using get_seconds()
  um: ubd: use 64-bit time_t where possible
  xtensa: ISS: avoid struct timeval
  dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD
  ...

4 files changed, 23 insertions, 66 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 81f9831a7859..11ff4a596d6b 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -416,6 +416,7 @@ static void fill_ac(acct_t *ac)
 {
 	struct pacct_struct *pacct = &current->signal->pacct;
 	u64 elapsed, run_time;
+	time64_t btime;
 	struct tty_struct *tty;
 
 	/*
@@ -448,7 +449,8 @@ static void fill_ac(acct_t *ac)
 	}
 #endif
 	do_div(elapsed, AHZ);
-	ac->ac_btime = get_seconds() - elapsed;
+	btime = ktime_get_real_seconds() - elapsed;
+	ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
 #if ACCT_VERSION==2
 	ac->ac_ahz = AHZ;
 #endif
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 9e59c9ea92aa..ca4e6d57d68b 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -97,20 +97,20 @@ static int do_getitimer(int which, struct itimerspec64 *value)
 	return 0;
 }
 
-static int put_itimerval(struct itimerval __user *o,
+static int put_itimerval(struct __kernel_old_itimerval __user *o,
 			 const struct itimerspec64 *i)
 {
-	struct itimerval v;
+	struct __kernel_old_itimerval v;
 
 	v.it_interval.tv_sec = i->it_interval.tv_sec;
 	v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC;
 	v.it_value.tv_sec = i->it_value.tv_sec;
 	v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC;
-	return copy_to_user(o, &v, sizeof(struct itimerval)) ? -EFAULT : 0;
+	return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0;
 }
 
 
-SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
+SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value)
 {
 	struct itimerspec64 get_buffer;
 	int error = do_getitimer(which, &get_buffer);
@@ -314,11 +314,11 @@ SYSCALL_DEFINE1(alarm, unsigned int, seconds)
 
 #endif
 
-static int get_itimerval(struct itimerspec64 *o, const struct itimerval __user *i)
+static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i)
 {
-	struct itimerval v;
+	struct __kernel_old_itimerval v;
 
-	if (copy_from_user(&v, i, sizeof(struct itimerval)))
+	if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval)))
 		return -EFAULT;
 
 	/* Validate the timevals in value. */
@@ -333,8 +333,8 @@ static int get_itimerval(struct itimerspec64 *o, const struct itimerval __user *
 	return 0;
 }
 
-SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
-		struct itimerval __user *, ovalue)
+SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value,
+		struct __kernel_old_itimerval __user *, ovalue)
 {
 	struct itimerspec64 set_buffer, get_buffer;
 	int error;
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 704ccd9451b0..cdd7386115ff 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -626,10 +626,12 @@ EXPORT_SYMBOL(__usecs_to_jiffies);
  * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
  * value to a scaled second value.
  */
-static unsigned long
-__timespec64_to_jiffies(u64 sec, long nsec)
+
+unsigned long
+timespec64_to_jiffies(const struct timespec64 *value)
 {
-	nsec = nsec + TICK_NSEC - 1;
+	u64 sec = value->tv_sec;
+	long nsec = value->tv_nsec + TICK_NSEC - 1;
 
 	if (sec >= MAX_SEC_IN_JIFFIES){
 		sec = MAX_SEC_IN_JIFFIES;
@@ -640,18 +642,6 @@ __timespec64_to_jiffies(u64 sec, long nsec)
 		 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
 
 }
-
-static unsigned long
-__timespec_to_jiffies(unsigned long sec, long nsec)
-{
-	return __timespec64_to_jiffies((u64)sec, nsec);
-}
-
-unsigned long
-timespec64_to_jiffies(const struct timespec64 *value)
-{
-	return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
-}
 EXPORT_SYMBOL(timespec64_to_jiffies);
 
 void
@@ -669,44 +659,6 @@ jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
 EXPORT_SYMBOL(jiffies_to_timespec64);
 
 /*
- * We could use a similar algorithm to timespec_to_jiffies (with a
- * different multiplier for usec instead of nsec). But this has a
- * problem with rounding: we can't exactly add TICK_NSEC - 1 to the
- * usec value, since it's not necessarily integral.
- *
- * We could instead round in the intermediate scaled representation
- * (i.e. in units of 1/2^(large scale) jiffies) but that's also
- * perilous: the scaling introduces a small positive error, which
- * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
- * units to the intermediate before shifting) leads to accidental
- * overflow and overestimates.
- *
- * At the cost of one additional multiplication by a constant, just
- * use the timespec implementation.
- */
-unsigned long
-timeval_to_jiffies(const struct timeval *value)
-{
-	return __timespec_to_jiffies(value->tv_sec,
-				     value->tv_usec * NSEC_PER_USEC);
-}
-EXPORT_SYMBOL(timeval_to_jiffies);
-
-void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
-{
-	/*
-	 * Convert jiffies to nanoseconds and separate with
-	 * one divide.
-	 */
-	u32 rem;
-
-	value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
-				    NSEC_PER_SEC, &rem);
-	value->tv_usec = rem / NSEC_PER_USEC;
-}
-EXPORT_SYMBOL(jiffies_to_timeval);
-
-/*
  * Convert jiffies/jiffies_64 to clock_t and back.
  */
 clock_t jiffies_to_clock_t(unsigned long x)
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 7be3e7530841..257ffb993ea2 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -24,6 +24,7 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 	const struct cred *tcred;
 	u64 utime, stime, utimescaled, stimescaled;
 	u64 delta;
+	time64_t btime;
 
 	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
 
@@ -32,9 +33,11 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 	/* Convert to micro seconds */
 	do_div(delta, NSEC_PER_USEC);
 	stats->ac_etime = delta;
-	/* Convert to seconds for btime */
-	do_div(delta, USEC_PER_SEC);
-	stats->ac_btime = get_seconds() - delta;
+	/* Convert to seconds for btime (note y2106 limit) */
+	btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC);
+	stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
+	stats->ac_btime64 = btime;
+
 	if (thread_group_leader(tsk)) {
 		stats->ac_exitcode = tsk->exit_code;
 		if (tsk->flags & PF_FORKNOEXEC)