mei_device lifetime was managed by devm procedure of parent device.
But such memory is freed on device_del.
Mei_device object is used by client object that may be alive after
parent device is removed.
It may lead to use-after-free if discrete graphics driver unloads
mei_gsc auxiliary device while user-space holds open handle to mei
character device.
Connect mei_device structure lifteme to mei class device lifetime
by adding mei_device free to class device remove callback.
Move exising parent device pointer to separate field in mei_device
to avoid misuse.
Allocate character device dynamically and allow to control its own
lifetime as it may outlive mei_device structure while character
device closes after parent device is removed from the system.
Leave power management on parent device as we overwrite pci runtime
pm procedure and user-space is expecting it there.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14201
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20250826125617.1166546-1-alexander.usyskin@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix kernel-doc warnings in dma-ring.c:
dma-ring.c:130: warning: No description found for return value of 'mei_dma_copy_from'
dma-ring.c:150: warning: No description found for return value of 'mei_dma_copy_to'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20231012024845.29169-4-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use unified version of the copyright notice in the files
Update copyright years according the year the files
were touched, except this patch and SPDX conversions.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement a circular buffer on allocated system memory. Read and write
indices are stored on the control block which is also shared between the
device and the host.
Two new functions are exported from the DMA module: mei_dma_ring_write,
and mei_dma_ring_empty_slots. The former simply copy a packet on the TX
DMA circular buffer and later, returns the number of empty slots on the
TX DMA circular buffer.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement circular buffer protocol over receive dma
buffer. Add extension to the mei message header that holds
length of the buffer on the dma buffer.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DMA ring control block contains write and read
indices for host and device circular buffers.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allocate DMA ring buffers from managed coherent memory.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
