/*
* best effort, GUP based copy_from_user() that assumes IRQ or NMI context
*/
static unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
{
unsigned long offset, addr = (unsigned long)from;
int type = in_nmi() ? KM_NMI : KM_IRQ0;
unsigned long size, len = 0;
struct page *page;
void *map;
int ret;
do {
ret = __get_user_pages_fast(addr, 1, 0, &page);
if (!ret)
break;
offset = addr & (PAGE_SIZE - 1);
size = min(PAGE_SIZE - offset, n - len);
map = kmap_atomic(page, type);
memcpy(to, map+offset, size);
kunmap_atomic(map, type);
put_page(page);
len += size;
to += size;
addr += size;
} while (len < n);
return len;
}
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
struct mm_struct *mm = current->mm;
int nr, ret;
start &= PAGE_MASK;
nr = __get_user_pages_fast(start, nr_pages, write, pages);
ret = nr;
if (nr < nr_pages) {
pr_devel(" slow path ! nr = %d\n", nr);
/* Try to get the remaining pages with get_user_pages */
start += nr << PAGE_SHIFT;
pages += nr;
down_read(&mm->mmap_sem);
ret = get_user_pages(current, mm, start,
nr_pages - nr, write, 0, pages, NULL);
up_read(&mm->mmap_sem);
/* Have to be a bit careful with return values */
if (nr > 0) {
if (ret < 0)
ret = nr;
else
ret += nr;
}
}
return ret;
}
/*
* best effort, GUP based copy_from_user() that is NMI-safe
*/
unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
{
unsigned long offset, addr = (unsigned long)from;
unsigned long size, len = 0;
struct page *page;
void *map;
int ret;
if (__range_not_ok(from, n, TASK_SIZE))
return len;
do {
ret = __get_user_pages_fast(addr, 1, 0, &page);
if (!ret)
break;
offset = addr & (PAGE_SIZE - 1);
size = min(PAGE_SIZE - offset, n - len);
map = kmap_atomic(page);
memcpy(to, map+offset, size);
kunmap_atomic(map);
put_page(page);
len += size;
to += size;
addr += size;
} while (len < n);
return len;
}
/*
* best effort, GUP based copy_from_user() that assumes IRQ or NMI context
*/
static unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
{
unsigned long offset, addr = (unsigned long)from;
unsigned long size, len = 0;
struct page *page;
void *map;
int ret;
do {
#ifndef CONFIG_L4
ret = __get_user_pages_fast(addr, 1, 0, &page);
#else
ret = get_user_pages_fast(addr, 1, 0, &page);
#endif
if (!ret)
break;
offset = addr & (PAGE_SIZE - 1);
size = min(PAGE_SIZE - offset, n - len);
map = kmap_atomic(page);
memcpy(to, map+offset, size);
kunmap_atomic(map);
put_page(page);
len += size;
to += size;
addr += size;
} while (len < n);
return len;
}
static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
{
const int num_pages = obj->base.size >> PAGE_SHIFT;
struct mm_struct *mm = obj->userptr.mm->mm;
struct page **pvec;
struct sg_table *pages;
bool active;
int pinned;
/* If userspace should engineer that these pages are replaced in
* the vma between us binding this page into the GTT and completion
* of rendering... Their loss. If they change the mapping of their
* pages they need to create a new bo to point to the new vma.
*
* However, that still leaves open the possibility of the vma
* being copied upon fork. Which falls under the same userspace
* synchronisation issue as a regular bo, except that this time
* the process may not be expecting that a particular piece of
* memory is tied to the GPU.
*
* Fortunately, we can hook into the mmu_notifier in order to
* discard the page references prior to anything nasty happening
* to the vma (discard or cloning) which should prevent the more
* egregious cases from causing harm.
*/
if (obj->userptr.work) {
/* active flag should still be held for the pending work */
if (IS_ERR(obj->userptr.work))
return PTR_ERR(obj->userptr.work);
else
return -EAGAIN;
}
pvec = NULL;
pinned = 0;
if (mm == current->mm) {
pvec = kvmalloc_array(num_pages, sizeof(struct page *),
GFP_KERNEL |
__GFP_NORETRY |
__GFP_NOWARN);
if (pvec) /* defer to worker if malloc fails */
pinned = __get_user_pages_fast(obj->userptr.ptr,
num_pages,
!i915_gem_object_is_readonly(obj),
pvec);
}
active = false;
if (pinned < 0) {
pages = ERR_PTR(pinned);
pinned = 0;
} else if (pinned < num_pages) {
pages = __i915_gem_userptr_get_pages_schedule(obj);
active = pages == ERR_PTR(-EAGAIN);
} else {
pages = __i915_gem_userptr_alloc_pages(obj, pvec, num_pages);
active = !IS_ERR(pages);
}
if (active)
__i915_gem_userptr_set_active(obj, true);
if (IS_ERR(pages))
release_pages(pvec, pinned);
kvfree(pvec);
return PTR_ERR_OR_ZERO(pages);
}
