kernel/linux.git/drivers/misc/cxl/api.c, branch v4.14.217

cxl_getfile(): fix double-iput() on alloc_file() failures

2018-07-25T09:25:11+00:00

commit d202797f480c0e5918e7642d6716cdc62b3ab5c9 upstream. Doing iput() after path_put() is wrong. Cc: stable@vger.kernel.org Acked-by: Linus Torvalds Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

cxl: Fix driver use count

2017-08-31T04:26:49+00:00

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 Cc: stable@vger.kernel.org # v4.2+ Fixes: 7bb5d91a4dda ("cxl: Rework context lifetimes") Acked-by: Andrew Donnellan Signed-off-by: Michael Ellerman

cxl: Keep track of mm struct associated with a context

2017-04-13T13:34:29+00:00

The mm_struct corresponding to the current task is acquired each time an interrupt is raised. So to simplify the code, we only get the mm_struct when attaching an AFU context to the process. The mm_count reference is increased to ensure that the mm_struct can't be freed. The mm_struct will be released when the context is detached. A reference on mm_users is not kept to avoid a circular dependency if the process mmaps its cxl mmio and forget to unmap before exiting. The field glpid (pid of the group leader associated with the pid), of the structure cxl_context, is removed because it's no longer useful. Signed-off-by: Christophe Lombard Reviewed-by: Andrew Donnellan Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman

cxl: Drop unused header asm/pnv-pci.h

2017-01-25T02:34:23+00:00

The kernel API does not use anything from this header file. Signed-off-by: Greg Kurz Reviewed-by: Andrew Donnellan Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman

cxl: Fix coredump generation when cxl_get_fd() is used

2016-11-18T12:02:17+00:00

If a process dumps core while owning a cxl file descriptor obtained from an AFU driver (e.g. cxlflash) through the cxl_get_fd() API, the following error occurs: [ 868.027591] Unable to handle kernel paging request for data at address ... [ 868.027778] Faulting instruction address: 0xc00000000035edb0 cpu 0x8c: Vector: 300 (Data Access) at [c000003c688275e0] pc: c00000000035edb0: elf_core_dump+0xd60/0x1300 lr: c00000000035ed80: elf_core_dump+0xd30/0x1300 sp: c000003c68827860 msr: 9000000100009033 dar: c dsisr: 40000000 current = 0xc000003c68780000 paca = 0xc000000001b73200 softe: 0 irq_happened: 0x01 pid = 46725, comm = hxesurelock enter ? for help [c000003c68827a60] c00000000036948c do_coredump+0xcec/0x11e0 [c000003c68827c20] c0000000000ce9e0 get_signal+0x540/0x7b0 [c000003c68827d10] c000000000017354 do_signal+0x54/0x2b0 [c000003c68827e00] c00000000001777c do_notify_resume+0xbc/0xd0 [c000003c68827e30] c000000000009838 ret_from_except_lite+0x64/0x68 --- Exception: 300 (Data Access) at 00003fff98ad2918 The root cause is that the address_space structure for the file doesn't define a 'host' member. When cxl allocates a file descriptor, it's using the anonymous inode to back the file, but allocates a private address_space for each context. The private address_space allows to track memory allocation for each context. cxl doesn't define the 'host' member of the address space, i.e. the inode. We don't want to define it as the anonymous inode, since there's no longer a 1-to-1 relation between address_space and inode. To fix it, instead of using the anonymous inode, we introduce a simple pseudo filesystem so that cxl can allocate its own inodes. So we now have one inode for each file and address_space. The pseudo filesystem is only mounted on the first allocation of a file descriptor by cxl_get_fd(). Tested with cxlflash. Signed-off-by: Frederic Barrat Reviewed-by: Matthew R. Ochs Signed-off-by: Michael Ellerman

cxl: Fix error handling in _cxl_cx4_setup_msi_irqs()

2016-11-18T11:41:08+00:00

'cxl_dev_context_init()' returns an error pointer in case of error, not NULL. So test it with IS_ERR. Signed-off-by: Christophe JAILLET Reviewed-by: Andrew Donnellan Acked-by: Frederic Barrat Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Fix memory allocation failure test

2016-11-18T11:41:08+00:00

'cxl_context_alloc()' does not return an error pointer. It is just a shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the size parameter. So its return value should be compared with NULL. While fixing it, simplify a bit the code. Signed-off-by: Christophe JAILLET Reviewed-by: Andrew Donnellan Acked-by: Frederic Barrat Acked-by: Ian Munsie Signed-off-by: Michael Ellerman

cxl: Fix leaking pid refs in some error paths

2016-10-24T00:38:27+00:00

In some error paths in functions cxl_start_context and afu_ioctl_start_work pid references to the current & group-leader tasks can leak after they are taken. This patch fixes these error paths to release these pid references before exiting the error path. Fixes: 7b8ad495d592 ("cxl: Fix DSI misses when the context owning task exits") Cc: stable@vger.kernel.org # v4.5+ Reviewed-by: Andrew Donnellan Reported-by: Frederic Barrat Signed-off-by: Vaibhav Jain Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman

cxl: Prevent adapter reset if an active context exists

2016-10-19T09:35:39+00:00

This patch prevents resetting the cxl adapter via sysfs in presence of one or more active cxl_context on it. This protects against an unrecoverable error caused by PSL owning a dirty cache line even after reset and host tries to touch the same cache line. In case a force reset of the card is required irrespective of any active contexts, the int value -1 can be stored in the 'reset' sysfs attribute of the card. The patch introduces a new atomic_t member named contexts_num inside struct cxl that holds the number of active context attached to the card , which is checked against '0' before proceeding with the reset. To prevent against a race condition where a context is activated just after reset check is performed, the contexts_num is atomically set to '-1' after reset-check to indicate that no more contexts can be activated on the card anymore. Before activating a context we atomically test if contexts_num is non-negative and if so, increment its value by one. In case the value of contexts_num is negative then it indicates that the card is about to be reset and context activation is error-ed out at that point. Fixes: 62fa19d4b4fd ("cxl: Add ability to reset the card") Cc: stable@vger.kernel.org # v4.0+ Acked-by: Frederic Barrat Reviewed-by: Andrew Donnellan Signed-off-by: Vaibhav Jain Signed-off-by: Michael Ellerman

cxl: Add support for interrupts on the Mellanox CX4

2016-07-14T10:27:08+00:00

The Mellanox CX4 in cxl mode uses a hybrid interrupt model, where interrupts are routed from the networking hardware to the XSL using the MSIX table, and from there will be transformed back into an MSIX interrupt using the cxl style interrupts (i.e. using IVTE entries and ranges to map a PE and AFU interrupt number to an MSIX address). We want to hide the implementation details of cxl interrupts as much as possible. To this end, we use a special version of the MSI setup & teardown routines in the PHB while in cxl mode to allocate the cxl interrupts and configure the IVTE entries in the process element. This function does not configure the MSIX table - the CX4 card uses a custom format in that table and it would not be appropriate to fill that out in generic code. The rest of the functionality is similar to the "Full MSI-X mode" described in the CAIA, and this could be easily extended to support other adapters that use that mode in the future. The interrupts will be associated with the default context. If the maximum number of interrupts per context has been limited (e.g. by the mlx5 driver), it will automatically allocate additional kernel contexts to associate extra interrupts as required. These contexts will be started using the same WED that was used to start the default context. Signed-off-by: Ian Munsie Reviewed-by: Andrew Donnellan Signed-off-by: Michael Ellerman