linux/drivers/gpu/drm/ttm/ttm_bo_vm.c

/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/**************************************************************************
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#define pr_fmt(fmt) …

#include <drm/ttm/ttm_bo.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_tt.h>

#include <drm/drm_drv.h>
#include <drm/drm_managed.h>

static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo,
				struct vm_fault *vmf)
{ … }

static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
				       unsigned long page_offset)
{ … }

/**
 * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback
 * @bo: The buffer object
 * @vmf: The fault structure handed to the callback
 *
 * vm callbacks like fault() and *_mkwrite() allow for the mmap_lock to be dropped
 * during long waits, and after the wait the callback will be restarted. This
 * is to allow other threads using the same virtual memory space concurrent
 * access to map(), unmap() completely unrelated buffer objects. TTM buffer
 * object reservations sometimes wait for GPU and should therefore be
 * considered long waits. This function reserves the buffer object interruptibly
 * taking this into account. Starvation is avoided by the vm system not
 * allowing too many repeated restarts.
 * This function is intended to be used in customized fault() and _mkwrite()
 * handlers.
 *
 * Return:
 *    0 on success and the bo was reserved.
 *    VM_FAULT_RETRY if blocking wait.
 *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed.
 */
vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
			     struct vm_fault *vmf)
{ … }
EXPORT_SYMBOL(…);

/**
 * ttm_bo_vm_fault_reserved - TTM fault helper
 * @vmf: The struct vm_fault given as argument to the fault callback
 * @prot: The page protection to be used for this memory area.
 * @num_prefault: Maximum number of prefault pages. The caller may want to
 * specify this based on madvice settings and the size of the GPU object
 * backed by the memory.
 *
 * This function inserts one or more page table entries pointing to the
 * memory backing the buffer object, and then returns a return code
 * instructing the caller to retry the page access.
 *
 * Return:
 *   VM_FAULT_NOPAGE on success or pending signal
 *   VM_FAULT_SIGBUS on unspecified error
 *   VM_FAULT_OOM on out-of-memory
 *   VM_FAULT_RETRY if retryable wait
 */
vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
				    pgprot_t prot,
				    pgoff_t num_prefault)
{ … }
EXPORT_SYMBOL(…);

static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res)
{ … }

vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot)
{ … }
EXPORT_SYMBOL(…);

vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
{ … }
EXPORT_SYMBOL(…);

void ttm_bo_vm_open(struct vm_area_struct *vma)
{ … }
EXPORT_SYMBOL(…);

void ttm_bo_vm_close(struct vm_area_struct *vma)
{ … }
EXPORT_SYMBOL(…);

static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
				 unsigned long offset,
				 uint8_t *buf, int len, int write)
{ … }

int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
		     void *buf, int len, int write)
{ … }
EXPORT_SYMBOL(…);

static const struct vm_operations_struct ttm_bo_vm_ops = …;

/**
 * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
 *
 * @vma:       vma as input from the fbdev mmap method.
 * @bo:        The bo backing the address space.
 *
 * Maps a buffer object.
 */
int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
{ … }
EXPORT_SYMBOL(…);