Re: [PATCH] posix-clock: Explicitly handle compat ioctls

[Cyrill Gorcunov]

On Tue, Jan 21, 2025 at 11:41:24PM +0100, Thomas Weißschuh wrote:
> Pointer arguments passed to ioctls need to pass through compat_ptr() to
> work correctly on s390; as explained in Documentation/driver-api/ioctl.rst.
> Plumb the compat_ioctl callback through 'struct posix_clock_operations'
> and handle the different ioctls cmds in the new ptp_compat_ioctl().
> 
> Using compat_ptr_ioctl is not possible.
> For the commands PTP_ENABLE_PPS/PTP_ENABLE_PPS2 on s390
> it would corrupt the argument 0x80000000, aka BIT(31) to zero.
> 
> Fixes: 0606f422b453 ("posix clocks: Introduce dynamic clocks")
> Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Reviewed-by: Cyrill Gorcunov <gorcunov@xxxxxxxxx>

Thanks, Thomas!