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pps: Compatibility hack should be X86-specific

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As of [1], using PPS_FETCH on a 64-bit ARM kernel with a 32-bit userland
is broken, returning a timeout. This is because the requested 4-byte
alignment for struct pps_ktime_compat (illegal on arm64) results in the
timeout flags field being uninitialised.

Make the hack specific to X86_64 builds with CONFIG_COMPAT defined.

[1] commit c2a49fe8ee ("pps: fix padding issue with PPS_FETCH for
    ioctl_compat")

See: https://github.com/raspberrypi/linux/issues/5430
Fixes: c2a49fe8ee ("pps: fix padding issue with PPS_FETCH for ioctl_compat")
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
This commit is contained in:
Phil Elwell
2023-05-22 14:22:55 +01:00
committed by Dom Cobley
parent 759b8a0a02
commit c8320e3349
1 changed files with 4 additions and 2 deletions
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6
drivers/pps/pps.c
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@@ -254,12 +254,13 @@ static long pps_cdev_ioctl(struct file *file,
static long pps_cdev_compat_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
struct pps_device *pps = file->private_data;
void __user *uarg = (void __user *) arg;
cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *));
#ifdef CONFIG_X86_64
if (cmd == PPS_FETCH) {
struct pps_device *pps = file->private_data;
void __user *uarg = (void __user *) arg;
struct pps_fdata_compat compat;
struct pps_fdata fdata;
int err;
@@ -296,6 +297,7 @@ static long pps_cdev_compat_ioctl(struct file *file,
return copy_to_user(uarg, &compat,
sizeof(struct pps_fdata_compat)) ? -EFAULT : 0;
}
#endif
return pps_cdev_ioctl(file, cmd, arg);
}