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linux-next/drivers/infiniband/sw/rxe/rxe_mmap.c
Jason Gunthorpe cb88645596 infiniband: Fix alignment of mmap cookies to support VIPT caching
When vmalloc_user is used to create memory that is supposed to be mmap'd
to user space, it is necessary for the mmap cookie (eg the offset) to be
aligned to SHMLBA.

This creates a situation where all virtual mappings of the same physical
page share the same virtual cache index and guarantees VIPT coherence.
Otherwise the cache is non-coherent and the kernel will not see writes
by userspace when reading the shared page (or vice-versa).

Reported-by: Josh Beavers <josh.beavers@gmail.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-03-24 16:50:51 -04:00

174 lines
4.6 KiB
C

/*
* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <asm/pgtable.h>
#include "rxe.h"
#include "rxe_loc.h"
#include "rxe_queue.h"
void rxe_mmap_release(struct kref *ref)
{
struct rxe_mmap_info *ip = container_of(ref,
struct rxe_mmap_info, ref);
struct rxe_dev *rxe = to_rdev(ip->context->device);
spin_lock_bh(&rxe->pending_lock);
if (!list_empty(&ip->pending_mmaps))
list_del(&ip->pending_mmaps);
spin_unlock_bh(&rxe->pending_lock);
vfree(ip->obj); /* buf */
kfree(ip);
}
/*
* open and close keep track of how many times the memory region is mapped,
* to avoid releasing it.
*/
static void rxe_vma_open(struct vm_area_struct *vma)
{
struct rxe_mmap_info *ip = vma->vm_private_data;
kref_get(&ip->ref);
}
static void rxe_vma_close(struct vm_area_struct *vma)
{
struct rxe_mmap_info *ip = vma->vm_private_data;
kref_put(&ip->ref, rxe_mmap_release);
}
static struct vm_operations_struct rxe_vm_ops = {
.open = rxe_vma_open,
.close = rxe_vma_close,
};
/**
* rxe_mmap - create a new mmap region
* @context: the IB user context of the process making the mmap() call
* @vma: the VMA to be initialized
* Return zero if the mmap is OK. Otherwise, return an errno.
*/
int rxe_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
{
struct rxe_dev *rxe = to_rdev(context->device);
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long size = vma->vm_end - vma->vm_start;
struct rxe_mmap_info *ip, *pp;
int ret;
/*
* Search the device's list of objects waiting for a mmap call.
* Normally, this list is very short since a call to create a
* CQ, QP, or SRQ is soon followed by a call to mmap().
*/
spin_lock_bh(&rxe->pending_lock);
list_for_each_entry_safe(ip, pp, &rxe->pending_mmaps, pending_mmaps) {
if (context != ip->context || (__u64)offset != ip->info.offset)
continue;
/* Don't allow a mmap larger than the object. */
if (size > ip->info.size) {
pr_err("mmap region is larger than the object!\n");
spin_unlock_bh(&rxe->pending_lock);
ret = -EINVAL;
goto done;
}
goto found_it;
}
pr_warn("unable to find pending mmap info\n");
spin_unlock_bh(&rxe->pending_lock);
ret = -EINVAL;
goto done;
found_it:
list_del_init(&ip->pending_mmaps);
spin_unlock_bh(&rxe->pending_lock);
ret = remap_vmalloc_range(vma, ip->obj, 0);
if (ret) {
pr_err("err %d from remap_vmalloc_range\n", ret);
goto done;
}
vma->vm_ops = &rxe_vm_ops;
vma->vm_private_data = ip;
rxe_vma_open(vma);
done:
return ret;
}
/*
* Allocate information for rxe_mmap
*/
struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe,
u32 size,
struct ib_ucontext *context,
void *obj)
{
struct rxe_mmap_info *ip;
ip = kmalloc(sizeof(*ip), GFP_KERNEL);
if (!ip)
return NULL;
size = PAGE_ALIGN(size);
spin_lock_bh(&rxe->mmap_offset_lock);
if (rxe->mmap_offset == 0)
rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
ip->info.offset = rxe->mmap_offset;
rxe->mmap_offset += ALIGN(size, SHMLBA);
spin_unlock_bh(&rxe->mmap_offset_lock);
INIT_LIST_HEAD(&ip->pending_mmaps);
ip->info.size = size;
ip->context = context;
ip->obj = obj;
kref_init(&ip->ref);
return ip;
}