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, 103 insertions, 29 deletions

diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 8a12a7538d63..cd9bbb546846 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -50,6 +50,29 @@ static DEFINE_MUTEX(register_mutex);
 #define rmidi_dbg(rmidi, fmt, args...) \
 	dev_dbg(&(rmidi)->dev, fmt, ##args)
 
+struct snd_rawmidi_status32 {
+	s32 stream;
+	s32 tstamp_sec;			/* Timestamp */
+	s32 tstamp_nsec;
+	u32 avail;			/* available bytes */
+	u32 xruns;			/* count of overruns since last status (in bytes) */
+	unsigned char reserved[16];	/* reserved for future use */
+};
+
+#define SNDRV_RAWMIDI_IOCTL_STATUS32	_IOWR('W', 0x20, struct snd_rawmidi_status32)
+
+struct snd_rawmidi_status64 {
+	int stream;
+	u8 rsvd[4];			/* alignment */
+	s64 tstamp_sec;			/* Timestamp */
+	s64 tstamp_nsec;
+	size_t avail;			/* available bytes */
+	size_t xruns;			/* count of overruns since last status (in bytes) */
+	unsigned char reserved[16];	/* reserved for future use */
+};
+
+#define SNDRV_RAWMIDI_IOCTL_STATUS64	_IOWR('W', 0x20, struct snd_rawmidi_status64)
+
 static struct snd_rawmidi *snd_rawmidi_search(struct snd_card *card, int device)
 {
 	struct snd_rawmidi *rawmidi;
@@ -677,7 +700,7 @@ int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream,
 EXPORT_SYMBOL(snd_rawmidi_input_params);
 
 static int snd_rawmidi_output_status(struct snd_rawmidi_substream *substream,
-				     struct snd_rawmidi_status *status)
+				     struct snd_rawmidi_status64 *status)
 {
 	struct snd_rawmidi_runtime *runtime = substream->runtime;
 
@@ -690,7 +713,7 @@ static int snd_rawmidi_output_status(struct snd_rawmidi_substream *substream,
 }
 
 static int snd_rawmidi_input_status(struct snd_rawmidi_substream *substream,
-				    struct snd_rawmidi_status *status)
+				    struct snd_rawmidi_status64 *status)
 {
 	struct snd_rawmidi_runtime *runtime = substream->runtime;
 
@@ -704,6 +727,80 @@ static int snd_rawmidi_input_status(struct snd_rawmidi_substream *substream,
 	return 0;
 }
 
+static int snd_rawmidi_ioctl_status32(struct snd_rawmidi_file *rfile,
+				      struct snd_rawmidi_status32 __user *argp)
+{
+	int err = 0;
+	struct snd_rawmidi_status32 __user *status = argp;
+	struct snd_rawmidi_status32 status32;
+	struct snd_rawmidi_status64 status64;
+
+	if (copy_from_user(&status32, argp,
+			   sizeof(struct snd_rawmidi_status32)))
+		return -EFAULT;
+
+	switch (status32.stream) {
+	case SNDRV_RAWMIDI_STREAM_OUTPUT:
+		if (rfile->output == NULL)
+			return -EINVAL;
+		err = snd_rawmidi_output_status(rfile->output, &status64);
+		break;
+	case SNDRV_RAWMIDI_STREAM_INPUT:
+		if (rfile->input == NULL)
+			return -EINVAL;
+		err = snd_rawmidi_input_status(rfile->input, &status64);
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (err < 0)
+		return err;
+
+	status32 = (struct snd_rawmidi_status32) {
+		.stream = status64.stream,
+		.tstamp_sec = status64.tstamp_sec,
+		.tstamp_nsec = status64.tstamp_nsec,
+		.avail = status64.avail,
+		.xruns = status64.xruns,
+	};
+
+	if (copy_to_user(status, &status32, sizeof(*status)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int snd_rawmidi_ioctl_status64(struct snd_rawmidi_file *rfile,
+				      struct snd_rawmidi_status64 __user *argp)
+{
+	int err = 0;
+	struct snd_rawmidi_status64 status;
+
+	if (copy_from_user(&status, argp, sizeof(struct snd_rawmidi_status64)))
+		return -EFAULT;
+
+	switch (status.stream) {
+	case SNDRV_RAWMIDI_STREAM_OUTPUT:
+		if (rfile->output == NULL)
+			return -EINVAL;
+		err = snd_rawmidi_output_status(rfile->output, &status);
+		break;
+	case SNDRV_RAWMIDI_STREAM_INPUT:
+		if (rfile->input == NULL)
+			return -EINVAL;
+		err = snd_rawmidi_input_status(rfile->input, &status);
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (err < 0)
+		return err;
+	if (copy_to_user(argp, &status,
+			 sizeof(struct snd_rawmidi_status64)))
+		return -EFAULT;
+	return 0;
+}
+
 static long snd_rawmidi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct snd_rawmidi_file *rfile;
@@ -750,33 +847,10 @@ static long snd_rawmidi_ioctl(struct file *file, unsigned int cmd, unsigned long
 			return -EINVAL;
 		}
 	}
-	case SNDRV_RAWMIDI_IOCTL_STATUS:
-	{
-		int err = 0;
-		struct snd_rawmidi_status status;
-
-		if (copy_from_user(&status, argp, sizeof(struct snd_rawmidi_status)))
-			return -EFAULT;
-		switch (status.stream) {
-		case SNDRV_RAWMIDI_STREAM_OUTPUT:
-			if (rfile->output == NULL)
-				return -EINVAL;
-			err = snd_rawmidi_output_status(rfile->output, &status);
-			break;
-		case SNDRV_RAWMIDI_STREAM_INPUT:
-			if (rfile->input == NULL)
-				return -EINVAL;
-			err = snd_rawmidi_input_status(rfile->input, &status);
-			break;
-		default:
-			return -EINVAL;
-		}
-		if (err < 0)
-			return err;
-		if (copy_to_user(argp, &status, sizeof(struct snd_rawmidi_status)))
-			return -EFAULT;
-		return 0;
-	}
+	case SNDRV_RAWMIDI_IOCTL_STATUS32:
+		return snd_rawmidi_ioctl_status32(rfile, argp);
+	case SNDRV_RAWMIDI_IOCTL_STATUS64:
+		return snd_rawmidi_ioctl_status64(rfile, argp);
 	case SNDRV_RAWMIDI_IOCTL_DROP:
 	{
 		int val;