kernel/linux.git/drivers/misc/cxl, branch v4.4.171

cxl: Check if vphb exists before iterating over AFU devices

2017-12-25T13:22:08+00:00

commit 12841f87b7a8ceb3d54f171660f72a86941bfcb3 upstream. During an eeh a kernel-oops is reported if no vPHB is allocated to the AFU. This happens as during AFU init, an error in creation of vPHB is a non-fatal error. Hence afu->phb should always be checked for NULL before iterating over it for the virtual AFU pci devices. This patch fixes the kenel-oops by adding a NULL pointer check for afu->phb before it is dereferenced. Fixes: 9e8df8a21963 ("cxl: EEH support") Signed-off-by: Vaibhav Jain Acked-by: Andrew Donnellan Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

cxl: Fix driver use count

2017-10-05T07:41:47+00:00

commit 197267d0356004a31c4d6b6336598f5dff3301e1 upstream. cxl keeps a driver use count, which is used with the hash memory model on p8 to know when to upgrade local TLBIs to global and to trigger callbacks to manage the MMU for PSL8. If a process opens a context and closes without attaching or fails the attachment, the driver use count is never decremented. As a consequence, TLB invalidations remain global, even if there are no active cxl contexts. We should increment the driver use count when the process is attaching to the cxl adapter, and not on open. It's not needed before the adapter starts using the context and the use count is decremented on the detach path, so it makes more sense. It affects only the user api. The kernel api is already doing The Right Thing. Signed-off-by: Frederic Barrat Fixes: 7bb5d91a4dda ("cxl: Rework context lifetimes") Acked-by: Andrew Donnellan Signed-off-by: Michael Ellerman [ajd: backport to stable v4.4 tree] Signed-off-by: Andrew Donnellan Signed-off-by: Greg Kroah-Hartman

cxl: Fix error path on bad ioctl

2017-06-14T11:16:24+00:00

commit cec422c11caeeccae709e9942058b6b644ce434c upstream. Fix error path if we can't copy user structure on CXL_IOCTL_START_WORK ioctl. We shouldn't unlock the context status mutex as it was not locked (yet). Fixes: 0712dc7e73e5 ("cxl: Fix issues when unmapping contexts") Signed-off-by: Frederic Barrat Reviewed-by: Vaibhav Jain Reviewed-by: Andrew Donnellan Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

cxl: Enable PCI device ID for future IBM CXL adapter

2016-09-15T06:27:41+00:00

[ Upstream commit 68adb7bfd66504e97364651fb7dac3f9c8aa8561 ] Add support for future IBM Coherent Accelerator (CXL) device with ID of 0x0601. Signed-off-by: Uma Krishnan Reviewed-by: Matthew R. Ochs Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

cxl: fix build for GCC 4.6.x

2016-09-15T06:27:41+00:00

[ Upstream commit aa09545589ceeff884421d8eb38d04963190afbe ] GCC 4.6.3 does not support -Wno-unused-const-variable. Instead, use the kbuild infrastructure that checks if this options exists. Fixes: 2cd55c68c0a4 ("cxl: Fix build failure due to -Wunused-variable behaviour change") Suggested-by: Michal Marek Suggested-by: Arnd Bergmann Signed-off-by: Brian Norris Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

cxl: Fix DSI misses when the context owning task exits

2016-09-15T06:27:41+00:00

[ Upstream commit 7b8ad495d59280b634a7b546f4cdf58cf4d65f61 ] Presently when a user-space process issues CXL_IOCTL_START_WORK ioctl we store the pid of the current task_struct and use it to get pointer to the mm_struct of the process, while processing page or segment faults from the capi card. However this causes issues when the thread that had originally issued the start-work ioctl exits in which case the stored pid is no more valid and the cxl driver is unable to handle faults as the mm_struct corresponding to process is no more accessible. This patch fixes this issue by using the mm_struct of the next alive task in the thread group. This is done by iterating over all the tasks in the thread group starting from thread group leader and calling get_task_mm on each one of them. When a valid mm_struct is obtained the pid of the associated task is stored in the context replacing the exiting one for handling future faults. The patch introduces a new function named get_mem_context that checks if the current task pointed to by ctx->pid is dead? If yes it performs the steps described above. Also a new variable cxl_context.glpid is introduced which stores the pid of the thread group leader associated with the context owning task. Reported-by: Matthew R. Ochs Reported-by: Frank Haverkamp Suggested-by: Ian Munsie Signed-off-by: Vaibhav Jain Acked-by: Ian Munsie Reviewed-by: Frederic Barrat Reviewed-by: Matthew R. Ochs Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

cxl: Fix possible idr warning when contexts are released

2016-09-15T06:27:41+00:00

[ Upstream commit 1b5df59e50874b9034c0fa389cd52b65f1f93292 ] An idr warning is reported when a context is release after the capi card is unbound from the cxl driver via sysfs. Below are the steps to reproduce: 1. Create multiple afu contexts in an user-space application using libcxl. 2. Unbind capi card from cxl using command of form echo > /sys/bus/pci/drivers/cxl-pci/unbind 3. Exit/kill the application owning afu contexts. After above steps a warning message is usually seen in the kernel logs of the form "idr_remove called for id= which is not allocated." This is caused by the function cxl_release_afu which destroys the contexts_idr table. So when a context is release no entry for context pe is found in the contexts_idr table and idr code prints this warning. This patch fixes this issue by increasing & decreasing the ref-count on the afu device when a context is initialized or when its freed respectively. This prevents the afu from being released until all the afu contexts have been released. The patch introduces two new functions namely cxl_afu_get/put that manage the ref-count on the afu device. Also the patch removes code inside cxl_dev_context_init that increases ref on the afu device as its guaranteed to be alive during this function. Reported-by: Ian Munsie Signed-off-by: Vaibhav Jain Acked-by: Ian Munsie Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

cxl: Keep IRQ mappings on context teardown

2016-05-04T21:48:48+00:00

commit d6776bba44d9752f6cdf640046070e71ee4bba7b upstream. Keep IRQ mappings on context teardown. This won't leak IRQs as if we allocate the mapping again, the generic code will give the same mapping used last time. Doing this works around a race in the generic code. Masking the interrupt introduces a race which can crash the kernel or result in IRQ that is never EOIed. The lost of EOI results in all subsequent mappings to the same HW IRQ never receiving an interrupt. We've seen this race with cxl test cases which are doing heavy context startup and teardown at the same time as heavy interrupt load. A fix to the generic code is being investigated also. Signed-off-by: Michael Neuling Tested-by: Andrew Donnellan Acked-by: Ian Munsie Tested-by: Vaibhav Jain Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

cxl: Fix PSL timebase synchronization detection

2016-03-09T23:34:55+00:00

commit 923adb1646d5ba739d2a1e63ee20d60574d9da8e upstream. The PSL timebase synchronization is seemingly failing for configuration not including VIRT_CPU_ACCOUNTING_NATIVE. The driver shows the following trace in dmesg: PSL: Timebase sync: giving up! The PSL timebase register is actually syncing correctly, but the cxl driver is not detecting it. Fix is to use the proper timebase-to-time conversion. Signed-off-by: Frederic Barrat Acked-by: Michael Neuling Reviewed-by: Matthew R. Ochs Acked-by: Ian Munsie Reviewed-by: Andrew Donnellan Reviewed-by: Vaibhav Jain Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

cxl: use correct operator when writing pcie config space values

2016-03-03T23:07:17+00:00

commit 48f0f6b717e314a30be121b67e1d044f6d311d66 upstream. When writing a value to config space, cxl_pcie_write_config() calls cxl_pcie_config_info() to obtain a mask and shift value, shifts the new value accordingly, then uses the mask to combine the shifted value with the existing value at the address as part of a read-modify-write pattern. Currently, we use a logical OR operator rather than a bitwise OR operator, which means any use of this function results in an incorrect value being written. Replace the logical OR operator with a bitwise OR operator so the value is written correctly. Reported-by: Michael Ellerman Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API") Signed-off-by: Andrew Donnellan Acked-by: Ian Munsie Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman