BMC/Intel-BMC/linux.git/drivers/misc/cxl/context.c, branch dev-4.6

cxl: Poll for outstanding IRQs when detaching a context

2016-04-27T02:04:48+00:00

When detaching contexts, we may still have interrupts in the system which are yet to be delivered to any CPU and be acked in the PSL. This can result in a subsequent unrelated process getting an spurious IRQ or an interrupt for a non-existent context. This polls the PSL to ensure that the PSL is clear of IRQs for the detached context, before removing the context from the idr. Signed-off-by: Michael Neuling Tested-by: Andrew Donnellan Acked-by: Ian Munsie Tested-by: Vaibhav Jain Signed-off-by: Michael Ellerman

cxl: Adapter failure handling

2016-03-09T12:40:00+00:00

Check the AFU state whenever an API is called. The hypervisor may issue a reset of the adapter when it detects a fault. When it happens, it launches an error recovery which will either move the AFU to a permanent failure state, or in the disabled state. If the AFU is found to be disabled, detach all existing contexts from it before issuing a AFU reset to re-enable it. Before detaching contexts, notify any kernel driver through the EEH callbacks of the AFU pci device. Co-authored-by: Frederic Barrat Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Manoj Kumar Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Add guest-specific code

2016-03-09T12:36:52+00:00

The new of.c file contains code to parse the device tree to find out about cxl adapters and AFUs. guest.c implements the guest-specific callbacks for the backend API. The process element ID is not known until the context is attached, so we have to separate the context ID assigned by the cxl driver from the process element ID visible to the user applications. In bare-metal, the 2 IDs match. Co-authored-by: Frederic Barrat Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Manoj Kumar Acked-by: Ian Munsie [mpe: Fix SMP=n build, fix PSERIES=n build, minor whitespace fixes] Signed-off-by: Michael Ellerman

cxl: Separate bare-metal fields in adapter and AFU data structures

2016-03-09T02:05:54+00:00

Introduce sub-structures containing the bare-metal specific fields in the structures describing the adapter (struct cxl) and AFU (struct cxl_afu). Update all their references. Co-authored-by: Frederic Barrat Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Manoj Kumar Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Isolate a few bare-metal-specific calls

2016-03-09T02:05:47+00:00

A few functions are mostly common between bare-metal and guest and just need minor tuning. To avoid crowding the backend API, introduce a few 'if' based on the CPU being in HV mode. Co-authored-by: Christophe Lombard Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Manoj Kumar Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Introduce implementation-specific API

2016-03-09T02:05:43+00:00

The backend API (in cxl.h) lists some low-level functions whose implementation is different on bare-metal and in a guest. Each environment implements its own functions, and the common code uses them through function pointers, defined in cxl_backend_ops Co-authored-by: Christophe Lombard Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Manoj Kumar Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Fix DSI misses when the context owning task exits

2016-01-05T05:28:25+00:00

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

cxl: Fix possible idr warning when contexts are released

2015-11-24T03:21:27+00:00

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

cxl: fix leak of ctx->irq_bitmap when releasing context via kernel API

2015-10-01T01:49:32+00:00

At present, ctx->irq_bitmap is freed in afu_release_irqs(), which is called from afu_release() via cxl_context_detach(). Move the freeing of ctx->irq_bitmap from afu_release_irqs() to reclaim_ctx() (called through cxl_context_free()) so it's freed when releasing a context via the kernel API (cxl_release_context()) or the userspace API (afu_release()). Reported-by: Matthew R. Ochs Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API") Signed-off-by: Andrew Donnellan Acked-by: Ian Munsie Reviewed-by: Matthew R. Ochs Signed-off-by: Michael Ellerman

cxl: Fix force unmapping mmaps of contexts allocated through the kernel api

2015-08-30T08:47:26+00:00

The cxl user api uses the address_space associated with the file when we need to force unmap all cxl mmap regions (e.g. on eeh, driver detach, etc). Currently, contexts allocated through the kernel api do not do this and instead skip the mmap invalidation, potentially allowing them to poke at the hardware after such an event, which may cause all sorts of trouble. This patch allocates an address_space for cxl contexts allocated through the kernel api so that the same invalidate path will for these contexts as well. We don't use the anonymous inode's address_space, as doing so could invalidate any mmaps of completely unrelated drivers using anonymous file descriptors. This patch also introduces a kernelapi flag, so we know when freeing the context if the address_space was allocated by us and needs to be freed. Signed-off-by: Ian Munsie Signed-off-by: Michael Ellerman