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* cxl: remove vma linked list walkMatthew Wilcox (Oracle)2022-06-271-30/+15
| | | | | | | | | | | | | | | | | | | Use the VMA iterator instead. This requires a little restructuring of the surrounding code to hoist the mm to the caller. That turns cxl_prefault_one() into a trivial function, so call cxl_fault_segment() directly. Link: https://lkml.kernel.org/r/20220504011345.662299-22-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20220621204632.3370049-38-Liam.Howlett@oracle.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Howells <dhowells@redhat.com> Cc: SeongJae Park <sj@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* cxl: don't manipulate the mm.mm_users field directlyLaurent Dufour2021-03-241-1/+1
| | | | | | | | | | | It is better to rely on the API provided by the MM layer instead of directly manipulating the mm_users field. Acked-by: Frederic Barrat <fbarrat@linux.ibm.com> Acked-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Link: https://lore.kernel.org/r/20210310174405.51044-1-ldufour@linux.ibm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* mmap locking API: use coccinelle to convert mmap_sem rwsem call sitesMichel Lespinasse2020-06-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner2019-05-301-5/+1
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/mm/hash64: Map all the kernel regions in the same 0xc rangeAneesh Kumar K.V2019-04-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch maps vmalloc, IO and vmemap regions in the 0xc address range instead of the current 0xd and 0xf range. This brings the mapping closer to radix translation mode. With hash 64K page size each of this region is 512TB whereas with 4K config we are limited by the max page table range of 64TB and hence there regions are of 16TB size. The kernel mapping is now: On 4K hash kernel_region_map_size = 16TB kernel vmalloc start = 0xc000100000000000 kernel IO start = 0xc000200000000000 kernel vmemmap start = 0xc000300000000000 64K hash, 64K radix and 4k radix: kernel_region_map_size = 512TB kernel vmalloc start = 0xc008000000000000 kernel IO start = 0xc00a000000000000 kernel vmemmap start = 0xc00c000000000000 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2018-08-171-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge updates from Andrew Morton: - a few misc things - a few Y2038 fixes - ntfs fixes - arch/sh tweaks - ocfs2 updates - most of MM * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (111 commits) mm/hmm.c: remove unused variables align_start and align_end fs/userfaultfd.c: remove redundant pointer uwq mm, vmacache: hash addresses based on pmd mm/list_lru: introduce list_lru_shrink_walk_irq() mm/list_lru.c: pass struct list_lru_node* as an argument to __list_lru_walk_one() mm/list_lru.c: move locking from __list_lru_walk_one() to its caller mm/list_lru.c: use list_lru_walk_one() in list_lru_walk_node() mm, swap: make CONFIG_THP_SWAP depend on CONFIG_SWAP mm/sparse: delete old sparse_init and enable new one mm/sparse: add new sparse_init_nid() and sparse_init() mm/sparse: move buffer init/fini to the common place mm/sparse: use the new sparse buffer functions in non-vmemmap mm/sparse: abstract sparse buffer allocations mm/hugetlb.c: don't zero 1GiB bootmem pages mm, page_alloc: double zone's batchsize mm/oom_kill.c: document oom_lock mm/hugetlb: remove gigantic page support for HIGHMEM mm, oom: remove sleep from under oom_lock kernel/dma: remove unsupported gfp_mask parameter from dma_alloc_from_contiguous() mm/cma: remove unsupported gfp_mask parameter from cma_alloc() ...
| * mm: convert return type of handle_mm_fault() caller to vm_fault_tSouptick Joarder2018-08-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t") In this patch all the caller of handle_mm_fault() are changed to return vm_fault_t type. Link: http://lkml.kernel.org/r/20180617084810.GA6730@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Tony Luck <tony.luck@intel.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: James Hogan <jhogan@kernel.org> Cc: Ley Foon Tan <lftan@altera.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: David S. Miller <davem@davemloft.net> Cc: Richard Weinberger <richard@nod.at> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | misc: cxl: changed asterisk positionParth Y Shah2018-08-081-1/+1
|/ | | | | | | Resolved <"foo* bar" should be "foo *bar"> error Signed-off-by: Parth Y Shah <sparth1292@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add support for POWER9 DD2Christophe Lombard2017-10-061-13/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The PSL initialization sequence has been updated to DD2. This patch adapts to the changes, retaining compatibility with DD1. The patch includes some changes to DD1 fix-ups as well. Tests performed on some of the old/new hardware. The function is_page_fault(), for POWER9, lists the Translation Checkout Responses where the page fault will be handled by copro_handle_mm_fault(). This list is too restrictive and not necessary. This patches removes this restriction and all page faults, whatever the reason, will be handled. In this case, the interruption is always acknowledged. The following features will be added soon: - phb reset when switching to capi mode. - cxllib update to support new functions. Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Reviewed-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/mm/cxl: Add barrier when setting mm cpumaskAneesh Kumar K.V2017-08-311-2/+12
| | | | | | | | | | | | | | | | | | | We need to add memory barrier so that the page table walk doesn't happen before the cpumask is set and made visible to the other cpus. We need to use a sync here instead of lwsync because lwsync is not sufficient for store/load ordering. We also need to add an if (mm) check so that we do the right thing when called with a kernel context. For kernel context, we have mm = NULL. W.r.t kernel address we can skip setting the mm cpumask. Fixes: 0f4bc0932e ("powerpc/mm/cxl: Add the fault handling cpu to mm cpumask") Cc: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/mm/cxl: Add the fault handling cpu to mm cpumaskAneesh Kumar K.V2017-08-171-0/+6
| | | | | | | | | | | | | | | We use mm cpumask for serializing against lockless page table walk. Anybody who is doing a lockless page table walk is expected to disable irq and only cpus in mm cpumask is expected do the lockless walk. This ensure that a THP split can send IPI to only cpus in the mm cpumask, to make sure there are no parallel lockless page table walk. Add the CAPI fault handling cpu to the mm cpumask so that we can do the lockless page table walk while inserting hash page table entries. Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Export library to support IBM XSLChristophe Lombard2017-07-031-10/+19
| | | | | | | | | | | | | | | | | | This patch exports a in-kernel 'library' API which can be called by other drivers to help interacting with an IBM XSL on a POWER9 system. The XSL (Translation Service Layer) is a stripped down version of the PSL (Power Service Layer) used in some cards such as the Mellanox CX5. Like the PSL, it implements the CAIA architecture, but has a number of differences, mostly in it's implementation dependent registers. The XSL also uses a special DMA cxl mode, which uses a slightly different init sequence for the CAPP and PHB. Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fixes for Coherent Accelerator Interface Architecture 2.0Christophe Lombard2017-06-231-8/+15
| | | | | | | | | | | | | | | | | | | | | | A previous set of patches "cxl: Add support for Coherent Accelerator Interface Architecture 2.0" has introduced a new support for the CAPI cards. These patches have been tested on Simulation environment and quite a bit of them have been tested on real hardware. This patch brings new fixes after a series of tests carried out on new equipment: - Add POWER9 definition. - Re-enable any masked interrupts when the AFU is not activated after resetting the AFU. - Remove the api cxl_is_psl8/9 which is no longer useful. - Do not dump CAPI1 registers. - Rewrite cxl_is_page_fault() function. - Do not register slb callack on P9. Fixes: f24be42aab37 ("cxl: Add psl9 specific code") Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add psl9 specific codeChristophe Lombard2017-04-131-21/+43
| | | | | | | | | | | | | | | | | | | | | The new Coherent Accelerator Interface Architecture, level 2, for the IBM POWER9 brings new content and features: - POWER9 Service Layer - Registers - Radix mode - Process element entry - Dedicated-Shared Process Programming Model - Translation Fault Handling - CAPP - Memory Context ID If a valid mm_struct is found the memory context id is used for each transaction associated with the process handle. The PSL uses the context ID to find the corresponding process element. Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> [mpe: Fixup comment formatting, unsplit long strings] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Keep track of mm struct associated with a contextChristophe Lombard2017-04-131-70/+6
| | | | | | | | | | | | | | | | | 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 <clombard@linux.vnet.ibm.com> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | <linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/mm.h> We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/mm.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. The APIs that are going to be moved first are: mm_alloc() __mmdrop() mmdrop() mmdrop_async_fn() mmdrop_async() mmget_not_zero() mmput() mmput_async() get_task_mm() mm_access() mm_release() Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGEDAneesh Kumar K.V2016-05-011-1/+3
| | | | | | | | | | | | | | | | | | | | | _PAGE_PRIVILEGED means the page can be accessed only by the kernel. This is done to keep pte bits similar to PowerISA 3.0 Radix PTE format. User pages are now marked by clearing _PAGE_PRIVILEGED bit. Previously we allowed the kernel to have a privileged page in the lower address range (USER_REGION). With this patch such access is denied. We also prevent a kernel access to a non-privileged page in higher address range (ie, REGION_ID != 0). Both the above access scenarios should never happen. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/mm: Use _PAGE_READ to indicate Read accessAneesh Kumar K.V2016-05-011-2/+2
| | | | | | | | | | | | | | | | | | | | This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also removes the dependency on _PAGE_USER for implying read only. Few things to note here is that, we have read implied with write and execute permission. Hence we should always find _PAGE_READ set on hash pte fault. We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on marking a prot none pte _PAGE_WRITE. (For more details look at b191f9b106ea "mm: numa: preserve PTE write permissions across a NUMA hinting fault") Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix DAR check & use REGION_ID instead of opencodingAneesh Kumar K.V2016-04-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | The current code will set _PAGE_USER to the access flags for any fault address, because the ~ operation will be true for all address we take a fault on. But setting _PAGE_USER also means that the fault will be handled only if the page table have _PAGE_USER set. Hence there is no security hole with the current code. Now if it is an user space access, then the change in this patch really don't have an impact because we have (!ctx->kernel) set true and we take the if condition true. Now kernel context created fault on an address in the kernel range will result in a fault loop because we will not insert the hash pte due to access and pte permission mismatch. This patch fix the above issue. Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards for userspace access") Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Isolate a few bare-metal-specific callsFrederic Barrat2016-03-091-8/+11
| | | | | | | | | | | | | 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 <clombard@linux.vnet.ibm.com> Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Introduce implementation-specific APIFrederic Barrat2016-03-091-3/+3
| | | | | | | | | | | | | | 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 <clombard@linux.vnet.ibm.com> Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix DSI misses when the context owning task exitsVaibhav Jain2016-01-051-34/+95
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <mrochs@linux.vnet.ibm.com> Reported-by: Frank Haverkamp <HAVERKAM@de.ibm.com> Suggested-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Only check pid for userspace contextsMichael Neuling2015-06-031-15/+19
| | | | | | | | | We only need to check the pid attached to this context for userspace contexts. Kernel contexts can skip this check. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add tracepointsIan Munsie2015-01-221-0/+5
| | | | | | | | | | | | | | | | | | | 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 <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Early return from cxl_handle_fault for a shut down contextIan Munsie2014-12-291-0/+6
| | | | | | | | | If a context is being detached and we get a translation fault for it there is little point getting it's mm and handling the fault, so just respond with an address error and return earlier. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/mm: don't do tlbie for updatepp request with NO HPTE faultAneesh Kumar K.V2014-12-051-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | upatepp can get called for a nohpte fault when we find from the linux page table that the translation was hashed before. In that case we are sure that there is no existing translation, hence we could avoid doing tlbie. We could possibly race with a parallel fault filling the TLB. But that should be ok because updatepp is only ever relaxing permissions. We also look at linux pte permission bits when filling hash pte permission bits. We also hold the linux pte busy bits while inserting/updating a hashpte entry, hence a paralle update of linux pte is not possible. On the other hand mprotect involves ptep_modify_prot_start which cause a hpte invalidate and not updatepp. Performance number: We use randbox_access_bench written by Anton. Kernel with THP disabled and smaller hash page table size. 86.60% random_access_b [kernel.kallsyms] [k] .native_hpte_updatepp 2.10% random_access_b random_access_bench [.] doit 1.99% random_access_b [kernel.kallsyms] [k] .do_raw_spin_lock 1.85% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 1.26% random_access_b [kernel.kallsyms] [k] .native_flush_hash_range 1.18% random_access_b [kernel.kallsyms] [k] .__delay 0.69% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 0.37% random_access_b [kernel.kallsyms] [k] .clear_user_page 0.34% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 0.32% random_access_b [kernel.kallsyms] [k] fast_exception_return 0.30% random_access_b [kernel.kallsyms] [k] .hash_page_mm With Fix: 27.54% random_access_b random_access_bench [.] doit 22.90% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 5.76% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 5.20% random_access_b [kernel.kallsyms] [k] fast_exception_return 5.12% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 4.80% random_access_b [kernel.kallsyms] [k] .hash_page_mm 3.31% random_access_b [kernel.kallsyms] [k] data_access_common 1.84% random_access_b [kernel.kallsyms] [k] .trace_hardirqs_on_caller Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix PSL error due to duplicate segment table entriesIan Munsie2014-10-281-6/+22
| | | | | | | | | | | | | | | | | | | | In certain circumstances the PSL (Power Service Layer, which provides translation services for CXL hardware) can send an interrupt for a segment miss that the kernel has already handled. This can happen if multiple translations for the same segment are queued in the PSL before the kernel has restarted the first translation. The CXL driver does not expect this situation and does not check if a segment had already been handled. This could cause a duplicate segment table entry which in turn caused a PSL error taking down the card. This patch fixes the issue by checking for existing entries in the segment table that match the segment we are trying to insert, so as to avoid inserting duplicate entries. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Refactor cxl_load_segment() and find_free_sste()Ian Munsie2014-10-281-16/+18
| | | | | | | | | This moves the segment table hash calculation from cxl_load_segment() into find_free_sste() since that is the only place it is actually used. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Disable secondary hash in segment tableIan Munsie2014-10-281-22/+8
| | | | | | | | | | | | | | | | | | | This patch simplifies the process of finding a free segment table entry by disabling the secondary hash. This reduces the number of possible entries in the segment table for a given address from 16 to 8. Due to the large segment sizes we use it is extremely unlikely that the secondary hash would ever have been used in practice, so this should not have any negative impacts and may even improve performance due to the reduced number of comparisons that software & hardware need to perform. This patch clears the SC bit in the hardware's state register (CXL_PSL_SR_An) to disable the secondary hash in the hardware since we can no longer fill out entries using it. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Driver code for powernv PCIe based cards for userspace accessIan Munsie2014-10-081-0/+291
This is the core of the cxl driver. It adds support for using cxl cards in the powernv environment only (ie POWER8 bare metal). It allows access to cxl accelerators by userspace using the /dev/cxl/afuM.N char devices. The kernel driver has no knowledge of the function implemented by the accelerator. It provides services to userspace via the /dev/cxl/afuM.N devices. When a program opens this device and runs the start work IOCTL, the accelerator will have coherent access to that processes memory using the same virtual addresses. That process may mmap the device to access any MMIO space the accelerator provides. Also, reads on the device will allow interrupts to be received. These services are further documented in a later patch in Documentation/powerpc/cxl.txt. Documentation of the cxl hardware architecture and userspace API is provided in subsequent patches. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>