kernel/linux.git/drivers/misc/cxl/native.c, branch linux-4.3.y

cxl: Fix number of allocated pages in SPA

2015-10-07T05:44:46+00:00

The scheduled process area is currently allocated before assigning the correct maximum processes to the AFU, which will mean we only ever allocate a fixed number of pages for the scheduled process area. This will limit us to 958 processes with 2 x 64K pages. If we try to use more processes than that we'd probably overrun the buffer and corrupt memory or crash. AFUs that require three or more interrupts per process will not be affected as they are already limited to less processes than that, but we could hit it on an AFU that requires 0, 1 or 2 interrupts per process, or when using 4K pages. This patch moves the initialisation of the num_procs to before the SPA allocation so that enough pages will be allocated for the number of processes that the AFU supports. Signed-off-by: Christophe Lombard Signed-off-by: Ian Munsie Cc: # 3.18+ Signed-off-by: Michael Ellerman

cxl: Allocate and release the SPA with the AFU

2015-08-14T11:32:04+00:00

Previously the SPA was allocated and freed upon entering and leaving AFU-directed mode. This causes some issues for error recovery - contexts hold a pointer inside the SPA, and they may persist after the AFU has been detached. We would ideally like to allocate the SPA when the AFU is allocated, and release it until the AFU is released. However, we don't know how big the SPA needs to be until we read the AFU descriptor. Therefore, restructure the code: - Allocate the SPA only once, on the first attach. - Release the SPA only when the entire AFU is being released (not detached). Guard the release with a NULL check, so we don't free if it was never allocated (e.g. dedicated mode) Acked-by: Cyril Bur Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

cxl: Drop commands if the PCI channel is not in normal state

2015-08-14T11:32:03+00:00

If the PCI channel has gone down, don't attempt to poke the hardware. We need to guard every time cxl_whatever_(read|write) is called. This is because a call to those functions will dereference an offset into an mmio register, and the mmio mappings get invalidated in the EEH teardown. Check in the read/write functions in the header. We give them the same semantics as usual PCI operations: - a write to a channel that is down is ignored. - a read from a channel that is down returns all fs. Also, we try to access the MMIO space of a vPHB device as part of the PCI disable path. Because that's a read that bypasses most of our usual checks, we handle it explicitly. As far as user visible warnings go: - Check link state in file ops, return -EIO if down. - Be reasonably quiet if there's an error in a teardown path, or when we already know the hardware is going down. - Throw a big WARN if someone tries to start a CXL operation while the card is down. This gives a useful stacktrace for debugging whatever is doing that. Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

cxl: Don't ignore add_process_element() result when attaching context

2015-08-06T05:10:19+00:00

Currently when attaching a context in dedicated mode, we ignore the result of add_process_element(), which could potentially fail. If add_process_element() returns an error, pass it back to the caller. Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

cxl: use more common format specifier

2015-07-13T00:10:54+00:00

A precision of 16 (%.16llx) has the same effect as a field width of 16 along with passing the 0 flag (%016llx), but the latter is much more common in the kernel tree. Update cxl to use that. Signed-off-by: Rasmus Villemoes Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Move include file cxl.h -> cxl-base.h

2015-06-03T03:27:19+00:00

This moves the current include file from cxl.h -> cxl-base.h. This current include file is used only to pass information between the base driver that needs to be built into the kernel and the cxl module. This is to make way for a new include/misc/cxl.h which will contain just the kernel API for other driver to use Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Configure PSL for kernel contexts and merge code

2015-06-03T03:27:19+00:00

This updates AFU directed and dedicated modes for contexts attached to the kernel. The SR (similar to the MSR in the core) calculation is getting quite complex and is duplicated in AFU directed and dedicated modes. This patch also merges this SR calculation for these modes. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Export some symbols

2015-06-03T03:27:18+00:00

Export some symbols which will soon be used elsewhere in this driver. Now they are global we rename them so to avoid collisions. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: cxl_afu_reset() -> __cxl_afu_reset()

2015-06-03T03:27:18+00:00

Rename cxl_afu_reset() to __cxl_afu_reset() to we can reuse this function name in the API. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Add tracepoints

2015-01-22T06:31:51+00:00

This patch adds tracepoints throughout the cxl driver, which can provide insight into: - Context lifetimes - Commands sent to the PSL and AFU and their completion status - Segment and page table misses and their resolution - PSL and AFU interrupts - slbia calls from the powerpc copro_fault code These tracepoints are mostly intended to aid in debugging (particularly for new AFU designs), and may be useful standalone or in conjunction with hardware traces collected by the PSL (read out via the trace interface in debugfs) and AFUs. Signed-off-by: Ian Munsie Signed-off-by: Michael Ellerman