diff options
Diffstat (limited to 'drivers/infiniband/core/ib_core_uverbs.c')
-rw-r--r-- | drivers/infiniband/core/ib_core_uverbs.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/drivers/infiniband/core/ib_core_uverbs.c b/drivers/infiniband/core/ib_core_uverbs.c new file mode 100644 index 000000000000..b74d2a2fb342 --- /dev/null +++ b/drivers/infiniband/core/ib_core_uverbs.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* + * Copyright (c) 2005 Mellanox Technologies. All rights reserved. + * Copyright 2018-2019 Amazon.com, Inc. or its affiliates. All rights reserved. + * Copyright 2019 Marvell. All rights reserved. + */ +#include <linux/xarray.h> +#include "uverbs.h" +#include "core_priv.h" + +/* + * Each time we map IO memory into user space this keeps track of the mapping. + * When the device is hot-unplugged we 'zap' the mmaps in user space to point + * to the zero page and allow the hot unplug to proceed. + * + * This is necessary for cases like PCI physical hot unplug as the actual BAR + * memory may vanish after this and access to it from userspace could MCE. + * + * RDMA drivers supporting disassociation must have their user space designed + * to cope in some way with their IO pages going to the zero page. + */ +void rdma_umap_priv_init(struct rdma_umap_priv *priv, + struct vm_area_struct *vma) +{ + struct ib_uverbs_file *ufile = vma->vm_file->private_data; + + priv->vma = vma; + vma->vm_private_data = priv; + /* vm_ops is setup in ib_uverbs_mmap() to avoid module dependencies */ + + mutex_lock(&ufile->umap_lock); + list_add(&priv->list, &ufile->umaps); + mutex_unlock(&ufile->umap_lock); +} +EXPORT_SYMBOL(rdma_umap_priv_init); + +/* + * Map IO memory into a process. This is to be called by drivers as part of + * their mmap() functions if they wish to send something like PCI-E BAR memory + * to userspace. + */ +int rdma_user_mmap_io(struct ib_ucontext *ucontext, struct vm_area_struct *vma, + unsigned long pfn, unsigned long size, pgprot_t prot) +{ + struct ib_uverbs_file *ufile = ucontext->ufile; + struct rdma_umap_priv *priv; + + if (!(vma->vm_flags & VM_SHARED)) + return -EINVAL; + + if (vma->vm_end - vma->vm_start != size) + return -EINVAL; + + /* Driver is using this wrong, must be called by ib_uverbs_mmap */ + if (WARN_ON(!vma->vm_file || + vma->vm_file->private_data != ufile)) + return -EINVAL; + lockdep_assert_held(&ufile->device->disassociate_srcu); + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + vma->vm_page_prot = prot; + if (io_remap_pfn_range(vma, vma->vm_start, pfn, size, prot)) { + kfree(priv); + return -EAGAIN; + } + + rdma_umap_priv_init(priv, vma); + return 0; +} +EXPORT_SYMBOL(rdma_user_mmap_io); |