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

cxl: fix leak of ctx->mapping when releasing kernel API contexts

2015-10-01T01:50:12+00:00

When a context is created via the kernel API, ctx->mapping is allocated within the kernel and thus needs to be freed when the context is freed. reclaim_ctx() attempts to do this for contexts with the ctx->kernelapi flag set, but afu_release() (which can be called from the kernel API through cxl_fd_release()) sets ctx->mapping to NULL before calling cxl_context_free() to free the context. Add a check to afu_release() so that the mappings in contexts created via the kernel API are left alone so reclaim_ctx() can free them. 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: Add alternate MMIO error handling

2015-08-18T09:34:43+00:00

userspace programs using cxl currently have to use two strategies for dealing with MMIO errors simultaneously. They have to check every read for a return of all Fs in case the adapter has gone away and the kernel has not yet noticed, and they have to deal with SIGBUS in case the kernel has already noticed, invalidated the mapping and marked the context as failed. In order to simplify things, this patch adds an alternative approach where the kernel will return a page filled with Fs instead of delivering a SIGBUS. This allows userspace to only need to deal with one of these two error paths, and is intended for use in libraries that use cxl transparently and may not be able to safely install a signal handler. This approach will only work if certain constraints are met. Namely, if the application is both reading and writing to an address in the problem state area it cannot assume that a non-FF read is OK, as it may just be reading out a value it has previously written. Further - since only one page is used per context a write to a given offset would be visible when reading the same offset from a different page in the mapping (this only applies within a single context, not between contexts). An application could deal with this by e.g. making sure it also reads from a read-only offset after any reads to a read/write offset. Due to these constraints, this functionality must be explicitly requested by userspace when starting the context by passing in the CXL_START_WORK_ERR_FF flag. Signed-off-by: Ian Munsie Acked-by: Michael Neuling 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: sparse: Make declarations static

2015-08-12T04:49:09+00:00

A few declarations were identified by sparse as needing to be static: drivers/misc/cxl/irq.c:408:6: warning: symbol 'afu_irq_name_free' was not declared. Should it be static? drivers/misc/cxl/irq.c:467:6: warning: symbol 'afu_register_hwirqs' was not declared. Should it be static? drivers/misc/cxl/file.c:254:6: warning: symbol 'afu_compat_ioctl' was not declared. Should it be static? drivers/misc/cxl/file.c:399:30: warning: symbol 'afu_master_fops' was not declared. Should it be static? Make them static. Signed-off-by: Daniel Axtens Acked-by: Michael Neuling Signed-off-by: Michael Ellerman

cxl: Export file ops for use by API

2015-06-03T03:27:20+00:00

The cxl kernel API will allow drivers other than cxl to export a file descriptor which has the same userspace API. These file descriptors will be able to be used against libcxl. This exports those file ops for use by other drivers. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Rework context lifetimes

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

This reworks contexts lifetimes a bit to enable the kernel API where we may want to reuse contexts. Here we will want to start and stop contexts without freeing them. Start context does the get pid & ctx so stop context will need to do the puts. Here we move put pid & ctx to the detach context path which will become part of the stop context path. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Add cookie parameter to afu_release_irqs()

2015-06-03T03:27:17+00:00

Add cookie parameter to afu_release_irqs() so that we can pass in a different cookie than the context structure. This will be useful for other kernel drivers that want to call this but get their own cookie back in the interrupt handler. Update all existing call sites. Signed-off-by: Michael Neuling Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Implement an ioctl to fetch afu card-id, offset-id and mode

2015-06-03T03:27:15+00:00

Given a file descriptor on an afu device, libcxl currently uses the major/minor number obtained from fstat on the fd to construct path to the afu's sysfs directory. However it is possible that rather than using one of the device in /dev/cxl, a kernel driver creates its own device which export generic cxl interface to the userspace. This causes problems with libcxl as it tries to use a wrong major/minor number to construct the sysfs path and fail. So this patch introduces a new ioctl called CXL_IOCTL_GET_AFU_ID on the afu file descriptor to fetch the cxl_afu_id struct that holds the card/offset-id and mode information. These info is then used by libcxl to construct the correct path to the afu sysfs directory. Testing: - Build against pseries be/le configs - Testing with corresponding libcxl changes to verify that it constructs right sysfs path to the afu. Signed-off-by: Vaibhav Jain Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

Merge tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

2015-02-12T02:15:38+00:00

Pull powerpc updates from Michael Ellerman: - Update of all defconfigs - Addition of a bunch of config options to modernise our defconfigs - Some PS3 updates from Geoff - Optimised memcmp for 64 bit from Anton - Fix for kprobes that allows 'perf probe' to work from Naveen - Several cxl updates from Ian & Ryan - Expanded support for the '24x7' PMU from Cody & Sukadev - Freescale updates from Scott: "Highlights include 8xx optimizations, some more work on datapath device tree content, e300 machine check support, t1040 corenet error reporting, and various cleanups and fixes" * tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (102 commits) cxl: Add missing return statement after handling AFU errror cxl: Fail AFU initialisation if an invalid configuration record is found cxl: Export optional AFU configuration record in sysfs powerpc/mm: Warn on flushing tlb page in kernel context powerpc/powernv: Add OPAL soft-poweroff routine powerpc/perf/hv-24x7: Document sysfs event description entries powerpc/perf/hv-gpci: add the remaining gpci requests powerpc/perf/{hv-gpci, hv-common}: generate requests with counters annotated powerpc/perf/hv-24x7: parse catalog and populate sysfs with events perf: define EVENT_DEFINE_RANGE_FORMAT_LITE helper perf: add PMU_EVENT_ATTR_STRING() helper perf: provide sysfs_show for struct perf_pmu_events_attr powerpc/kernel: Avoid initializing device-tree pointer twice powerpc: Remove old compile time disabled syscall tracing code powerpc/kernel: Make syscall_exit a local label cxl: Fix device_node reference counting powerpc/mm: bail out early when flushing TLB page powerpc: defconfigs: add MTD_SPI_NOR (new dependency for M25P80) perf/powerpc: reset event hw state when adding it to the PMU powerpc/qe: Use strlcpy() ...

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