Merge tag 'y2038-alsa-v8-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground into for-next

ALSA: Fix year 2038 issue for sound subsystem

This is a series I worked on with Baolin in 2017 and 2018, but we
never quite managed to finish up the last pieces. During the
ALSA developer meetup at ELC-E 2018 in Edinburgh, a decision was
made to go with this approach for keeping best compatibility
with existing source code, and then I failed to follow up by
resending the patches.

Now I have patches for all remaining time_t uses in the kernel,
so it's absolutely time to revisit them. I have done more
review of the patches myself and found a couple of minor issues
that I have fixed up, otherwise the series is still the same as
before.

Conceptually, the idea of these patches is:

- 64-bit applications should see no changes at all, neither
  compile-time nor run-time.

- 32-bit code compiled with a 64-bit time_t currently
  does not work with ALSA, and requires kernel changes and/or
  sound/asound.h changes

- Most 32-bit code using these interfaces will work correctly
  on a modified kernel, with or without the uapi header changes.

- 32-bit code using SNDRV_TIMER_IOCTL_TREAD requires the
  updated header file for 64-bit time_t support

- 32-bit i386 user space with 64-bit time_t is broken for
  SNDRV_PCM_IOCTL_STATUS, SNDRV_RAWMIDI_IOCTL_STATUS and
  SNDRV_PCM_IOCTL_SYNC_PTR because of i386 alignment. This is also
  addressed by the updated uapi header.

- PCM mmap is currently supported on native x86 kernels
  (both 32-bit and 64-bit) but not for compat mode. This series breaks
  the 32-bit native mmap support for 32-bit time_t, but instead allows
  it for 64-bit time_t on both native and compat kernels. This seems to
  be the best trade-off, as mmap support is optional already, and most
  32-bit code runs in compat mode anyway.

- I've tried to avoid breaking compilation of 32-bit code
  as much as possible. Anything that does break however is likely code
  that is already broken on 64-bit time_t and needs source changes to
  fix them.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git y2038-alsa-v8
[2] https://lore.kernel.org/lkml/CAK8P3a2Os66+iwQYf97qh05W2JP8rmWao8zmKoHiXqVHvyYAJA@mail.gmail.com/T/#m6519cb07cfda08adf1dedea6596bb98892b4d5dc

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Changes since v7: (Arnd):
 - Fix a typo found by Ben Hutchings

Changes since v6: (Arnd):
 - Add a patch to update the API versions
 - Hide a timespec reference in #ifndef __KERNEL__ to remove the
   last reference to time_t
 - Use a more readable way to do padding and describe it in the
   changelog
 - Rebase to linux-5.5-rc1, changing include/sound/soc-component.h
   and sound/drivers/aloop.c as needed.

Changes since v5 (Arnd):
 - Rebased to linux-5.4-rc4
 - Updated to completely remove timespec and time_t references from alsa
 - found and fixed a few bugs

Changes since v4 (Baolin):
 - Add patch 5 to change trigger_tstamp member of struct snd_pcm_runtime.
 - Add patch 8 to change internal timespec.
 - Add more explanation in commit message.
 - Use ktime_get_real_ts64() in patch 6.
 - Split common code out into a separate function in patch 6.
 - Fix tu->tread bug in patch 6 and remove #if __BITS_PER_LONG == 64 macro.

Changes since v3:
 - Move struct snd_pcm_status32 to pcm.h file.
 - Modify comments and commit message.
 - Add new patch2 ~ patch6.

Changes since v2:
 - Renamed all structures to make clear.
 - Remove CONFIG_X86_X32 macro and introduced new compat_snd_pcm_status64_x86_32.

Changes since v1:
 - Add one macro for struct snd_pcm_status_32 which only active in 32bits kernel.
 - Convert pcm_compat.c to use struct snd_pcm_status_64.
 - Convert pcm_native.c to use struct snd_pcm_status_64.

1 files changed, 9 insertions, 53 deletions

diff --git a/sound/core/timer_compat.c b/sound/core/timer_compat.c
index bb6be484dfd3..0103d16f6f9f 100644
--- a/sound/core/timer_compat.c
+++ b/sound/core/timer_compat.c
@@ -69,54 +69,11 @@ static int snd_timer_user_info_compat(struct file *file,
 	return 0;
 }
 
-struct snd_timer_status32 {
-	struct compat_timespec tstamp;
-	u32 resolution;
-	u32 lost;
-	u32 overrun;
-	u32 queue;
-	unsigned char reserved[64];
-};
-
-static int snd_timer_user_status_compat(struct file *file,
-					struct snd_timer_status32 __user *_status)
-{
-	struct snd_timer_user *tu;
-	struct snd_timer_status32 status;
-	
-	tu = file->private_data;
-	if (!tu->timeri)
-		return -EBADFD;
-	memset(&status, 0, sizeof(status));
-	status.tstamp.tv_sec = tu->tstamp.tv_sec;
-	status.tstamp.tv_nsec = tu->tstamp.tv_nsec;
-	status.resolution = snd_timer_resolution(tu->timeri);
-	status.lost = tu->timeri->lost;
-	status.overrun = tu->overrun;
-	spin_lock_irq(&tu->qlock);
-	status.queue = tu->qused;
-	spin_unlock_irq(&tu->qlock);
-	if (copy_to_user(_status, &status, sizeof(status)))
-		return -EFAULT;
-	return 0;
-}
-
-#ifdef CONFIG_X86_X32
-/* X32 ABI has the same struct as x86-64 */
-#define snd_timer_user_status_x32(file, s) \
-	snd_timer_user_status(file, s)
-#endif /* CONFIG_X86_X32 */
-
-/*
- */
-
 enum {
 	SNDRV_TIMER_IOCTL_GPARAMS32 = _IOW('T', 0x04, struct snd_timer_gparams32),
 	SNDRV_TIMER_IOCTL_INFO32 = _IOR('T', 0x11, struct snd_timer_info32),
-	SNDRV_TIMER_IOCTL_STATUS32 = _IOW('T', 0x14, struct snd_timer_status32),
-#ifdef CONFIG_X86_X32
-	SNDRV_TIMER_IOCTL_STATUS_X32 = _IOW('T', 0x14, struct snd_timer_status),
-#endif /* CONFIG_X86_X32 */
+	SNDRV_TIMER_IOCTL_STATUS_COMPAT32 = _IOW('T', 0x14, struct snd_timer_status32),
+	SNDRV_TIMER_IOCTL_STATUS_COMPAT64 = _IOW('T', 0x14, struct snd_timer_status64),
 };
 
 static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
@@ -126,7 +83,8 @@ static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
 
 	switch (cmd) {
 	case SNDRV_TIMER_IOCTL_PVERSION:
-	case SNDRV_TIMER_IOCTL_TREAD:
+	case SNDRV_TIMER_IOCTL_TREAD_OLD:
+	case SNDRV_TIMER_IOCTL_TREAD64:
 	case SNDRV_TIMER_IOCTL_GINFO:
 	case SNDRV_TIMER_IOCTL_GSTATUS:
 	case SNDRV_TIMER_IOCTL_SELECT:
@@ -140,17 +98,15 @@ static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
 	case SNDRV_TIMER_IOCTL_PAUSE:
 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
-		return __snd_timer_user_ioctl(file, cmd, (unsigned long)argp);
+		return __snd_timer_user_ioctl(file, cmd, (unsigned long)argp, true);
 	case SNDRV_TIMER_IOCTL_GPARAMS32:
 		return snd_timer_user_gparams_compat(file, argp);
 	case SNDRV_TIMER_IOCTL_INFO32:
 		return snd_timer_user_info_compat(file, argp);
-	case SNDRV_TIMER_IOCTL_STATUS32:
-		return snd_timer_user_status_compat(file, argp);
-#ifdef CONFIG_X86_X32
-	case SNDRV_TIMER_IOCTL_STATUS_X32:
-		return snd_timer_user_status_x32(file, argp);
-#endif /* CONFIG_X86_X32 */
+	case SNDRV_TIMER_IOCTL_STATUS_COMPAT32:
+		return snd_timer_user_status32(file, argp);
+	case SNDRV_TIMER_IOCTL_STATUS_COMPAT64:
+		return snd_timer_user_status64(file, argp);
 	}
 	return -ENOIOCTLCMD;
 }