blob: 4212b8c91dd425d4c94e53ba5e8d2b01410e03d4 [file] [log] [blame]
/* 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) "[TTM] " 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)
{
long err = 0;
/*
* Quick non-stalling check for idle.
*/
if (dma_resv_test_signaled(bo->base.resv, DMA_RESV_USAGE_KERNEL))
return 0;
/*
* If possible, avoid waiting for GPU with mmap_lock
* held. We only do this if the fault allows retry and this
* is the first attempt.
*/
if (fault_flag_allow_retry_first(vmf->flags)) {
if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
return VM_FAULT_RETRY;
ttm_bo_get(bo);
mmap_read_unlock(vmf->vma->vm_mm);
(void)dma_resv_wait_timeout(bo->base.resv,
DMA_RESV_USAGE_KERNEL, true,
MAX_SCHEDULE_TIMEOUT);
dma_resv_unlock(bo->base.resv);
ttm_bo_put(bo);
return VM_FAULT_RETRY;
}
/*
* Ordinary wait.
*/
err = dma_resv_wait_timeout(bo->base.resv, DMA_RESV_USAGE_KERNEL, true,
MAX_SCHEDULE_TIMEOUT);
if (unlikely(err < 0)) {
return (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS :
VM_FAULT_NOPAGE;
}
return 0;
}
static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
unsigned long page_offset)
{
struct ttm_device *bdev = bo->bdev;
if (bdev->funcs->io_mem_pfn)
return bdev->funcs->io_mem_pfn(bo, page_offset);
return (bo->resource->bus.offset >> PAGE_SHIFT) + 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)
{
/*
* Work around locking order reversal in fault / nopfn
* between mmap_lock and bo_reserve: Perform a trylock operation
* for reserve, and if it fails, retry the fault after waiting
* for the buffer to become unreserved.
*/
if (unlikely(!dma_resv_trylock(bo->base.resv))) {
/*
* If the fault allows retry and this is the first
* fault attempt, we try to release the mmap_lock
* before waiting
*/
if (fault_flag_allow_retry_first(vmf->flags)) {
if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
ttm_bo_get(bo);
mmap_read_unlock(vmf->vma->vm_mm);
if (!dma_resv_lock_interruptible(bo->base.resv,
NULL))
dma_resv_unlock(bo->base.resv);
ttm_bo_put(bo);
}
return VM_FAULT_RETRY;
}
if (dma_resv_lock_interruptible(bo->base.resv, NULL))
return VM_FAULT_NOPAGE;
}
/*
* Refuse to fault imported pages. This should be handled
* (if at all) by redirecting mmap to the exporter.
*/
if (bo->ttm && (bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
if (!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)) {
dma_resv_unlock(bo->base.resv);
return VM_FAULT_SIGBUS;
}
}
return 0;
}
EXPORT_SYMBOL(ttm_bo_vm_reserve);
/**
* 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)
{
struct vm_area_struct *vma = vmf->vma;
struct ttm_buffer_object *bo = vma->vm_private_data;
struct ttm_device *bdev = bo->bdev;
unsigned long page_offset;
unsigned long page_last;
unsigned long pfn;
struct ttm_tt *ttm = NULL;
struct page *page;
int err;
pgoff_t i;
vm_fault_t ret = VM_FAULT_NOPAGE;
unsigned long address = vmf->address;
/*
* Wait for buffer data in transit, due to a pipelined
* move.
*/
ret = ttm_bo_vm_fault_idle(bo, vmf);
if (unlikely(ret != 0))
return ret;
err = ttm_mem_io_reserve(bdev, bo->resource);
if (unlikely(err != 0))
return VM_FAULT_SIGBUS;
page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node);
page_last = vma_pages(vma) + vma->vm_pgoff -
drm_vma_node_start(&bo->base.vma_node);
if (unlikely(page_offset >= PFN_UP(bo->base.size)))
return VM_FAULT_SIGBUS;
prot = ttm_io_prot(bo, bo->resource, prot);
if (!bo->resource->bus.is_iomem) {
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = false,
.force_alloc = true
};
ttm = bo->ttm;
err = ttm_tt_populate(bdev, bo->ttm, &ctx);
if (err) {
if (err == -EINTR || err == -ERESTARTSYS ||
err == -EAGAIN)
return VM_FAULT_NOPAGE;
pr_debug("TTM fault hit %pe.\n", ERR_PTR(err));
return VM_FAULT_SIGBUS;
}
} else {
/* Iomem should not be marked encrypted */
prot = pgprot_decrypted(prot);
}
/*
* Speculatively prefault a number of pages. Only error on
* first page.
*/
for (i = 0; i < num_prefault; ++i) {
if (bo->resource->bus.is_iomem) {
pfn = ttm_bo_io_mem_pfn(bo, page_offset);
} else {
page = ttm->pages[page_offset];
if (unlikely(!page && i == 0)) {
return VM_FAULT_OOM;
} else if (unlikely(!page)) {
break;
}
pfn = page_to_pfn(page);
}
/*
* Note that the value of @prot at this point may differ from
* the value of @vma->vm_page_prot in the caching- and
* encryption bits. This is because the exact location of the
* data may not be known at mmap() time and may also change
* at arbitrary times while the data is mmap'ed.
* See vmf_insert_pfn_prot() for a discussion.
*/
ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
/* Never error on prefaulted PTEs */
if (unlikely((ret & VM_FAULT_ERROR))) {
if (i == 0)
return VM_FAULT_NOPAGE;
else
break;
}
address += PAGE_SIZE;
if (unlikely(++page_offset >= page_last))
break;
}
return ret;
}
EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res)
{
struct page *dummy_page = (struct page *)res;
__free_page(dummy_page);
}
vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot)
{
struct vm_area_struct *vma = vmf->vma;
struct ttm_buffer_object *bo = vma->vm_private_data;
struct drm_device *ddev = bo->base.dev;
vm_fault_t ret = VM_FAULT_NOPAGE;
unsigned long address;
unsigned long pfn;
struct page *page;
/* Allocate new dummy page to map all the VA range in this VMA to it*/
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page)
return VM_FAULT_OOM;
/* Set the page to be freed using drmm release action */
if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page))
return VM_FAULT_OOM;
pfn = page_to_pfn(page);
/* Prefault the entire VMA range right away to avoid further faults */
for (address = vma->vm_start; address < vma->vm_end;
address += PAGE_SIZE)
ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
return ret;
}
EXPORT_SYMBOL(ttm_bo_vm_dummy_page);
vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
pgprot_t prot;
struct ttm_buffer_object *bo = vma->vm_private_data;
struct drm_device *ddev = bo->base.dev;
vm_fault_t ret;
int idx;
ret = ttm_bo_vm_reserve(bo, vmf);
if (ret)
return ret;
prot = vma->vm_page_prot;
if (drm_dev_enter(ddev, &idx)) {
ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT);
drm_dev_exit(idx);
} else {
ret = ttm_bo_vm_dummy_page(vmf, prot);
}
if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
return ret;
dma_resv_unlock(bo->base.resv);
return ret;
}
EXPORT_SYMBOL(ttm_bo_vm_fault);
void ttm_bo_vm_open(struct vm_area_struct *vma)
{
struct ttm_buffer_object *bo = vma->vm_private_data;
WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
ttm_bo_get(bo);
}
EXPORT_SYMBOL(ttm_bo_vm_open);
void ttm_bo_vm_close(struct vm_area_struct *vma)
{
struct ttm_buffer_object *bo = vma->vm_private_data;
ttm_bo_put(bo);
vma->vm_private_data = NULL;
}
EXPORT_SYMBOL(ttm_bo_vm_close);
static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
unsigned long offset,
uint8_t *buf, int len, int write)
{
unsigned long page = offset >> PAGE_SHIFT;
unsigned long bytes_left = len;
int ret;
/* Copy a page at a time, that way no extra virtual address
* mapping is needed
*/
offset -= page << PAGE_SHIFT;
do {
unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
struct ttm_bo_kmap_obj map;
void *ptr;
bool is_iomem;
ret = ttm_bo_kmap(bo, page, 1, &map);
if (ret)
return ret;
ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
WARN_ON_ONCE(is_iomem);
if (write)
memcpy(ptr, buf, bytes);
else
memcpy(buf, ptr, bytes);
ttm_bo_kunmap(&map);
page++;
buf += bytes;
bytes_left -= bytes;
offset = 0;
} while (bytes_left);
return len;
}
int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
void *buf, int len, int write)
{
struct ttm_buffer_object *bo = vma->vm_private_data;
unsigned long offset = (addr) - vma->vm_start +
((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
<< PAGE_SHIFT);
int ret;
if (len < 1 || (offset + len) > bo->base.size)
return -EIO;
ret = ttm_bo_reserve(bo, true, false, NULL);
if (ret)
return ret;
switch (bo->resource->mem_type) {
case TTM_PL_SYSTEM:
fallthrough;
case TTM_PL_TT:
ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
break;
default:
if (bo->bdev->funcs->access_memory)
ret = bo->bdev->funcs->access_memory(
bo, offset, buf, len, write);
else
ret = -EIO;
}
ttm_bo_unreserve(bo);
return ret;
}
EXPORT_SYMBOL(ttm_bo_vm_access);
static const struct vm_operations_struct ttm_bo_vm_ops = {
.fault = ttm_bo_vm_fault,
.open = ttm_bo_vm_open,
.close = ttm_bo_vm_close,
.access = ttm_bo_vm_access,
};
/**
* 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)
{
/* Enforce no COW since would have really strange behavior with it. */
if (is_cow_mapping(vma->vm_flags))
return -EINVAL;
ttm_bo_get(bo);
/*
* Drivers may want to override the vm_ops field. Otherwise we
* use TTM's default callbacks.
*/
if (!vma->vm_ops)
vma->vm_ops = &ttm_bo_vm_ops;
/*
* Note: We're transferring the bo reference to
* vma->vm_private_data here.
*/
vma->vm_private_data = bo;
vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTEXPAND | VM_DONTDUMP);
return 0;
}
EXPORT_SYMBOL(ttm_bo_mmap_obj);