// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2018 Noralf Trønnes
*/
#include <linux/dma-buf.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#ifdef CONFIG_X86
#include <asm/set_memory.h>
#endif
#include <drm/drm.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_prime.h>
#include <drm/drm_print.h>
MODULE_IMPORT_NS(DMA_BUF);
/**
* DOC: overview
*
* This library provides helpers for GEM objects backed by shmem buffers
* allocated using anonymous pageable memory.
*
* Functions that operate on the GEM object receive struct &drm_gem_shmem_object.
* For GEM callback helpers in struct &drm_gem_object functions, see likewise
* named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps
* drm_gem_shmem_vmap()). These helpers perform the necessary type conversion.
*/
static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
.free = drm_gem_shmem_object_free,
.print_info = drm_gem_shmem_object_print_info,
.pin = drm_gem_shmem_object_pin,
.unpin = drm_gem_shmem_object_unpin,
.get_sg_table = drm_gem_shmem_object_get_sg_table,
.vmap = drm_gem_shmem_object_vmap,
.vunmap = drm_gem_shmem_object_vunmap,
.mmap = drm_gem_shmem_object_mmap,
.vm_ops = &drm_gem_shmem_vm_ops,
};
static struct drm_gem_shmem_object *
__drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
{
struct drm_gem_shmem_object *shmem;
struct drm_gem_object *obj;
int ret = 0;
size = PAGE_ALIGN(size);
if (dev->driver->gem_create_object) {
obj = dev->driver->gem_create_object(dev, size);
if (IS_ERR(obj))
return ERR_CAST(obj);
shmem = to_drm_gem_shmem_obj(obj);
} else {
shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
if (!shmem)
return ERR_PTR(-ENOMEM);
obj = &shmem->base;
}
if (!obj->funcs)
obj->funcs = &drm_gem_shmem_funcs;
if (private) {
drm_gem_private_object_init(dev, obj, size);
shmem->map_wc = false; /* dma-buf mappings use always writecombine */
} else {
ret = drm_gem_object_init(dev, obj, size);
}
if (ret) {
drm_gem_private_object_fini(obj);
goto err_free;
}
ret = drm_gem_create_mmap_offset(obj);
if (ret)
goto err_release;
INIT_LIST_HEAD(&shmem->madv_list);
if (!private) {
/*
* Our buffers are kept pinned, so allocating them
* from the MOVABLE zone is a really bad idea, and
* conflicts with CMA. See comments above new_inode()
* why this is required _and_ expected if you're
* going to pin these pages.
*/
mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
__GFP_RETRY_MAYFAIL | __GFP_NOWARN);
}
return shmem;
err_release:
drm_gem_object_release(obj);
err_free:
kfree(obj);
return ERR_PTR(ret);
}
/**
* drm_gem_shmem_create - Allocate an object with the given size
* @dev: DRM device
* @size: Size of the object to allocate
*
* This function creates a shmem GEM object.
*
* Returns:
* A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
* error code on failure.
*/
struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
{
return __drm_gem_shmem_create(dev, size, false);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
/**
* drm_gem_shmem_free - Free resources associated with a shmem GEM object
* @shmem: shmem GEM object to free
*
* This function cleans up the GEM object state and frees the memory used to
* store the object itself.
*/
void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
if (obj->import_attach) {
drm_prime_gem_destroy(obj, shmem->sgt);
} else {
dma_resv_lock(shmem->base.resv, NULL);
drm_WARN_ON(obj->dev, shmem->vmap_use_count);
if (shmem->sgt) {
dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
DMA_BIDIRECTIONAL, 0);
sg_free_table(shmem->sgt);
kfree(shmem->sgt);
}
if (shmem->pages)
drm_gem_shmem_put_pages(shmem);
drm_WARN_ON(obj->dev, shmem->pages_use_count);
dma_resv_unlock(shmem->base.resv);
}
drm_gem_object_release(obj);
kfree(shmem);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
struct page **pages;
dma_resv_assert_held(shmem->base.resv);
if (shmem->pages_use_count++ > 0)
return 0;
pages = drm_gem_get_pages(obj);
if (IS_ERR(pages)) {
drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
PTR_ERR(pages));
shmem->pages_use_count = 0;
return PTR_ERR(pages);
}
/*
* TODO: Allocating WC pages which are correctly flushed is only
* supported on x86. Ideal solution would be a GFP_WC flag, which also
* ttm_pool.c could use.
*/
#ifdef CONFIG_X86
if (shmem->map_wc)
set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
#endif
shmem->pages = pages;
return 0;
}
/*
* drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
* @shmem: shmem GEM object
*
* This function decreases the use count and puts the backing pages when use drops to zero.
*/
void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
dma_resv_assert_held(shmem->base.resv);
if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
return;
if (--shmem->pages_use_count > 0)
return;
#ifdef CONFIG_X86
if (shmem->map_wc)
set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
#endif
drm_gem_put_pages(obj, shmem->pages,
shmem->pages_mark_dirty_on_put,
shmem->pages_mark_accessed_on_put);
shmem->pages = NULL;
}
EXPORT_SYMBOL(drm_gem_shmem_put_pages);
int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
{
int ret;
dma_resv_assert_held(shmem->base.resv);
drm_WARN_ON(shmem->base.dev, shmem->base.import_attach);
ret = drm_gem_shmem_get_pages(shmem);
return ret;
}
EXPORT_SYMBOL(drm_gem_shmem_pin_locked);
void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
{
dma_resv_assert_held(shmem->base.resv);
drm_gem_shmem_put_pages(shmem);
}
EXPORT_SYMBOL(drm_gem_shmem_unpin_locked);
/**
* drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
* @shmem: shmem GEM object
*
* This function makes sure the backing pages are pinned in memory while the
* buffer is exported.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
int ret;
drm_WARN_ON(obj->dev, obj->import_attach);
ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
if (ret)
return ret;
ret = drm_gem_shmem_pin_locked(shmem);
dma_resv_unlock(shmem->base.resv);
return ret;
}
EXPORT_SYMBOL(drm_gem_shmem_pin);
/**
* drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
* @shmem: shmem GEM object
*
* This function removes the requirement that the backing pages are pinned in
* memory.
*/
void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
drm_WARN_ON(obj->dev, obj->import_attach);
dma_resv_lock(shmem->base.resv, NULL);
drm_gem_shmem_unpin_locked(shmem);
dma_resv_unlock(shmem->base.resv);
}
EXPORT_SYMBOL(drm_gem_shmem_unpin);
/*
* drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
* @shmem: shmem GEM object
* @map: Returns the kernel virtual address of the SHMEM GEM object's backing
* store.
*
* This function makes sure that a contiguous kernel virtual address mapping
* exists for the buffer backing the shmem GEM object. It hides the differences
* between dma-buf imported and natively allocated objects.
*
* Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
struct iosys_map *map)
{
struct drm_gem_object *obj = &shmem->base;
int ret = 0;
if (obj->import_attach) {
ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
if (!ret) {
if (drm_WARN_ON(obj->dev, map->is_iomem)) {
dma_buf_vunmap(obj->import_attach->dmabuf, map);
return -EIO;
}
}
} else {
pgprot_t prot = PAGE_KERNEL;
dma_resv_assert_held(shmem->base.resv);
if (shmem->vmap_use_count++ > 0) {
iosys_map_set_vaddr(map, shmem->vaddr);
return 0;
}
ret = drm_gem_shmem_get_pages(shmem);
if (ret)
goto err_zero_use;
if (shmem->map_wc)
prot = pgprot_writecombine(prot);
shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
VM_MAP, prot);
if (!shmem->vaddr)
ret = -ENOMEM;
else
iosys_map_set_vaddr(map, shmem->vaddr);
}
if (ret) {
drm_dbg_kms(obj->dev, "Failed to vmap pages, error %d\n", ret);
goto err_put_pages;
}
return 0;
err_put_pages:
if (!obj->import_attach)
drm_gem_shmem_put_pages(shmem);
err_zero_use:
shmem->vmap_use_count = 0;
return ret;
}
EXPORT_SYMBOL(drm_gem_shmem_vmap);
/*
* drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
* @shmem: shmem GEM object
* @map: Kernel virtual address where the SHMEM GEM object was mapped
*
* This function cleans up a kernel virtual address mapping acquired by
* drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
* zero.
*
* This function hides the differences between dma-buf imported and natively
* allocated objects.
*/
void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
struct iosys_map *map)
{
struct drm_gem_object *obj = &shmem->base;
if (obj->import_attach) {
dma_buf_vunmap(obj->import_attach->dmabuf, map);
} else {
dma_resv_assert_held(shmem->base.resv);
if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))
return;
if (--shmem->vmap_use_count > 0)
return;
vunmap(shmem->vaddr);
drm_gem_shmem_put_pages(shmem);
}
shmem->vaddr = NULL;
}
EXPORT_SYMBOL(drm_gem_shmem_vunmap);
static int
drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
struct drm_device *dev, size_t size,
uint32_t *handle)
{
struct drm_gem_shmem_object *shmem;
int ret;
shmem = drm_gem_shmem_create(dev, size);
if (IS_ERR(shmem))
return PTR_ERR(shmem);
/*
* Allocate an id of idr table where the obj is registered
* and handle has the id what user can see.
*/
ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
/* drop reference from allocate - handle holds it now. */
drm_gem_object_put(&shmem->base);
return ret;
}
/* Update madvise status, returns true if not purged, else
* false or -errno.
*/
int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
{
dma_resv_assert_held(shmem->base.resv);
if (shmem->madv >= 0)
shmem->madv = madv;
madv = shmem->madv;
return (madv >= 0);
}
EXPORT_SYMBOL(drm_gem_shmem_madvise);
void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
struct drm_device *dev = obj->dev;
dma_resv_assert_held(shmem->base.resv);
drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem));
dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
sg_free_table(shmem->sgt);
kfree(shmem->sgt);
shmem->sgt = NULL;
drm_gem_shmem_put_pages(shmem);
shmem->madv = -1;
drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
drm_gem_free_mmap_offset(obj);
/* Our goal here is to return as much of the memory as
* is possible back to the system as we are called from OOM.
* To do this we must instruct the shmfs to drop all of its
* backing pages, *now*.
*/
shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
}
EXPORT_SYMBOL(drm_gem_shmem_purge);
/**
* drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
* @file: DRM file structure to create the dumb buffer for
* @dev: DRM device
* @args: IOCTL data
*
* This function computes the pitch of the dumb buffer and rounds it up to an
* integer number of bytes per pixel. Drivers for hardware that doesn't have
* any additional restrictions on the pitch can directly use this function as
* their &drm_driver.dumb_create callback.
*
* For hardware with additional restrictions, drivers can adjust the fields
* set up by userspace before calling into this function.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
struct drm_mode_create_dumb *args)
{
u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
if (!args->pitch || !args->size) {
args->pitch = min_pitch;
args->size = PAGE_ALIGN(args->pitch * args->height);
} else {
/* ensure sane minimum values */
if (args->pitch < min_pitch)
args->pitch = min_pitch;
if (args->size < args->pitch * args->height)
args->size = PAGE_ALIGN(args->pitch * args->height);
}
return drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct drm_gem_object *obj = vma->vm_private_data;
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
loff_t num_pages = obj->size >> PAGE_SHIFT;
vm_fault_t ret;
struct page *page;
pgoff_t page_offset;
/* We don't use vmf->pgoff since that has the fake offset */
page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
dma_resv_lock(shmem->base.resv, NULL);
if (page_offset >= num_pages ||
drm_WARN_ON_ONCE(obj->dev, !shmem->pages) ||
shmem->madv < 0) {
ret = VM_FAULT_SIGBUS;
} else {
page = shmem->pages[page_offset];
ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
}
dma_resv_unlock(shmem->base.resv);
return ret;
}
static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
{
struct drm_gem_object *obj = vma->vm_private_data;
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
drm_WARN_ON(obj->dev, obj->import_attach);
dma_resv_lock(shmem->base.resv, NULL);
/*
* We should have already pinned the pages when the buffer was first
* mmap'd, vm_open() just grabs an additional reference for the new
* mm the vma is getting copied into (ie. on fork()).
*/
if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
shmem->pages_use_count++;
dma_resv_unlock(shmem->base.resv);
drm_gem_vm_open(vma);
}
static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
{
struct drm_gem_object *obj = vma->vm_private_data;
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
dma_resv_lock(shmem->base.resv, NULL);
drm_gem_shmem_put_pages(shmem);
dma_resv_unlock(shmem->base.resv);
drm_gem_vm_close(vma);
}
const struct vm_operations_struct drm_gem_shmem_vm_ops = {
.fault = drm_gem_shmem_fault,
.open = drm_gem_shmem_vm_open,
.close = drm_gem_shmem_vm_close,
};
EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
/**
* drm_gem_shmem_mmap - Memory-map a shmem GEM object
* @shmem: shmem GEM object
* @vma: VMA for the area to be mapped
*
* This function implements an augmented version of the GEM DRM file mmap
* operation for shmem objects.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma)
{
struct drm_gem_object *obj = &shmem->base;
int ret;
if (obj->import_attach) {
/* Reset both vm_ops and vm_private_data, so we don't end up with
* vm_ops pointing to our implementation if the dma-buf backend
* doesn't set those fields.
*/
vma->vm_private_data = NULL;
vma->vm_ops = NULL;
ret = dma_buf_mmap(obj->dma_buf, vma, 0);
/* Drop the reference drm_gem_mmap_obj() acquired.*/
if (!ret)
drm_gem_object_put(obj);
return ret;
}
if (is_cow_mapping(vma->vm_flags))
return -EINVAL;
dma_resv_lock(shmem->base.resv, NULL);
ret = drm_gem_shmem_get_pages(shmem);
dma_resv_unlock(shmem->base.resv);
if (ret)
return ret;
vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
if (shmem->map_wc)
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
return 0;
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
/**
* drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
* @shmem: shmem GEM object
* @p: DRM printer
* @indent: Tab indentation level
*/
void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
struct drm_printer *p, unsigned int indent)
{
if (shmem->base.import_attach)
return;
drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
}
EXPORT_SYMBOL(drm_gem_shmem_print_info);
/**
* drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
* pages for a shmem GEM object
* @shmem: shmem GEM object
*
* This function exports a scatter/gather table suitable for PRIME usage by
* calling the standard DMA mapping API.
*
* Drivers who need to acquire an scatter/gather table for objects need to call
* drm_gem_shmem_get_pages_sgt() instead.
*
* Returns:
* A pointer to the scatter/gather table of pinned pages or error pointer on failure.
*/
struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
drm_WARN_ON(obj->dev, obj->import_attach);
return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_object *shmem)
{
struct drm_gem_object *obj = &shmem->base;
int ret;
struct sg_table *sgt;
if (shmem->sgt)
return shmem->sgt;
drm_WARN_ON(obj->dev, obj->import_attach);
ret = drm_gem_shmem_get_pages(shmem);
if (ret)
return ERR_PTR(ret);
sgt = drm_gem_shmem_get_sg_table(shmem);
if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto err_put_pages;
}
/* Map the pages for use by the h/w. */
ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
if (ret)
goto err_free_sgt;
shmem->sgt = sgt;
return sgt;
err_free_sgt:
sg_free_table(sgt);
kfree(sgt);
err_put_pages:
drm_gem_shmem_put_pages(shmem);
return ERR_PTR(ret);
}
/**
* drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
* scatter/gather table for a shmem GEM object.
* @shmem: shmem GEM object
*
* This function returns a scatter/gather table suitable for driver usage. If
* the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
* table created.
*
* This is the main function for drivers to get at backing storage, and it hides
* and difference between dma-buf imported and natively allocated objects.
* drm_gem_shmem_get_sg_table() should not be directly called by drivers.
*
* Returns:
* A pointer to the scatter/gather table of pinned pages or errno on failure.
*/
struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
{
int ret;
struct sg_table *sgt;
ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
if (ret)
return ERR_PTR(ret);
sgt = drm_gem_shmem_get_pages_sgt_locked(shmem);
dma_resv_unlock(shmem->base.resv);
return sgt;
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
/**
* drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
* another driver's scatter/gather table of pinned pages
* @dev: Device to import into
* @attach: DMA-BUF attachment
* @sgt: Scatter/gather table of pinned pages
*
* This function imports a scatter/gather table exported via DMA-BUF by
* another driver. Drivers that use the shmem helpers should set this as their
* &drm_driver.gem_prime_import_sg_table callback.
*
* Returns:
* A pointer to a newly created GEM object or an ERR_PTR-encoded negative
* error code on failure.
*/
struct drm_gem_object *
drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sgt)
{
size_t size = PAGE_ALIGN(attach->dmabuf->size);
struct drm_gem_shmem_object *shmem;
shmem = __drm_gem_shmem_create(dev, size, true);
if (IS_ERR(shmem))
return ERR_CAST(shmem);
shmem->sgt = sgt;
drm_dbg_prime(dev, "size = %zu\n", size);
return &shmem->base;
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
MODULE_IMPORT_NS(DMA_BUF);
MODULE_LICENSE("GPL v2");
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