kernel/linux.git - Linux kernel stable tree (mirror)

Age	Commit message (Collapse)	Author	Files	Lines
2014-12-12	cxl: Change contexts_lock to a mutex to fix sleep while atomic bug	Ian Munsie	1	-1/+1
	We had a known sleep while atomic bug if a CXL device was forcefully unbound while it was in use. This could occur as a result of EEH, or manually induced with something like this while the device was in use: echo 0000:01:00.0 > /sys/bus/pci/drivers/cxl-pci/unbind The issue was that in this code path we iterated over each context and forcefully detached it with the contexts_lock spin lock held, however the detach also needed to take the spu_mutex, and call schedule. This patch changes the contexts_lock to a mutex so that we are not in atomic context while doing the detach, thereby avoiding the sleep while atomic. Also delete the related TODO comment, which suggested an alternate solution which turned out to not be workable. Cc: stable@vger.kernel.org Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08	cxl: Driver code for powernv PCIe based cards for userspace access	Ian Munsie	1	-0/+1000
	This is the core of the cxl driver. It adds support for using cxl cards in the powernv environment only (ie POWER8 bare metal). It allows access to cxl accelerators by userspace using the /dev/cxl/afuM.N char devices. The kernel driver has no knowledge of the function implemented by the accelerator. It provides services to userspace via the /dev/cxl/afuM.N devices. When a program opens this device and runs the start work IOCTL, the accelerator will have coherent access to that processes memory using the same virtual addresses. That process may mmap the device to access any MMIO space the accelerator provides. Also, reads on the device will allow interrupts to be received. These services are further documented in a later patch in Documentation/powerpc/cxl.txt. Documentation of the cxl hardware architecture and userspace API is provided in subsequent patches. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>