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// 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);
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