target/linux/bcm27xx/patches-6.1/950-0738-pps-Compatibility-hack-should-be-X86-specific.patch

   1 From 138d22ae4abf49d9694a4398857fb4be5114f103 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Mon, 22 May 2023 14:22:55 +0100
   4 Subject: [PATCH] pps: Compatibility hack should be X86-specific
   5
   6 As of [1], using PPS_FETCH on a 64-bit ARM kernel with a 32-bit userland
   7 is broken, returning a timeout. This is because the requested 4-byte
   8 alignment for struct pps_ktime_compat (illegal on arm64) results in the
   9 timeout flags field being uninitialised.
  10
  11 Make the hack specific to X86_64 builds with CONFIG_COMPAT defined.
  12
  13 [1] commit c2a49fe8eeef ("pps: fix padding issue with PPS_FETCH for
  14     ioctl_compat")
  15
  16 See: https://github.com/raspberrypi/linux/issues/5430
  17 Fixes: c2a49fe8eeef ("pps: fix padding issue with PPS_FETCH for ioctl_compat")
  18 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  19 ---
  20  drivers/pps/pps.c | 6 ++++--
  21  1 file changed, 4 insertions(+), 2 deletions(-)
  22
  23 --- a/drivers/pps/pps.c
  24 +++ b/drivers/pps/pps.c
  25 @@ -249,12 +249,13 @@ static long pps_cdev_ioctl(struct file *
  26  static long pps_cdev_compat_ioctl(struct file *file,
  27                 unsigned int cmd, unsigned long arg)
  28  {
  29 -       struct pps_device *pps = file->private_data;
  30 -       void __user *uarg = (void __user *) arg;
  31
  32         cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *));
  33
  34 +#ifdef CONFIG_X86_64
  35         if (cmd == PPS_FETCH) {
  36 +               struct pps_device *pps = file->private_data;
  37 +               void __user *uarg = (void __user *) arg;
  38                 struct pps_fdata_compat compat;
  39                 struct pps_fdata fdata;
  40                 int err;
  41 @@ -289,6 +290,7 @@ static long pps_cdev_compat_ioctl(struct
  42                 return copy_to_user(uarg, &compat,
  43                                 sizeof(struct pps_fdata_compat)) ? -EFAULT : 0;
  44         }
  45 +#endif
  46
  47         return pps_cdev_ioctl(file, cmd, arg);
  48  }