drm: Add the TTM GPU memory manager subsystem.

TTM is a GPU memory manager subsystem designed for use with GPU
devices with various memory types (On-card VRAM, AGP,
PCI apertures etc.). It's essentially a helper library that assists
the DRM driver in creating and managing persistent buffer objects.

TTM manages placement of data and CPU map setup and teardown on
data movement. It can also optionally manage synchronization of
data on a per-buffer-object level.

TTM takes care to provide an always valid virtual user-space address
to a buffer object which makes user-space sub-allocation of
big buffer objects feasible.

TTM uses a fine-grained per buffer-object locking scheme, taking
care to release all relevant locks when waiting for the GPU.
Although this implies some locking overhead, it's probably a big
win for devices with multiple command submission mechanisms, since
the lock contention will be minimal.

TTM can be used with whatever user-space interface the driver
chooses, including GEM. It's used by the upcoming Radeon KMS DRM driver
and is also the GPU memory management core of various new experimental
DRM drivers.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 635 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
new file mode 100644
index 000000000000..c27ab3a877ad
--- /dev/null
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -0,0 +1,635 @@
+/**************************************************************************
+ *
+ * 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>
+ */
+
+#include <linux/version.h>
+#include <linux/vmalloc.h>
+#include <linux/sched.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/swap.h>
+#include "ttm/ttm_module.h"
+#include "ttm/ttm_bo_driver.h"
+#include "ttm/ttm_placement.h"
+
+static int ttm_tt_swapin(struct ttm_tt *ttm);
+
+#if defined(CONFIG_X86)
+static void ttm_tt_clflush_page(struct page *page)
+{
+        uint8_t *page_virtual;
+        unsigned int i;
+
+        if (unlikely(page == NULL))
+                return;
+
+        page_virtual = kmap_atomic(page, KM_USER0);
+
+        for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
+                clflush(page_virtual + i);
+
+        kunmap_atomic(page_virtual, KM_USER0);
+}
+
+static void ttm_tt_cache_flush_clflush(struct page *pages[],
+                                       unsigned long num_pages)
+{
+        unsigned long i;
+
+        mb();
+        for (i = 0; i < num_pages; ++i)
+                ttm_tt_clflush_page(*pages++);
+        mb();
+}
+#else
+static void ttm_tt_ipi_handler(void *null)
+{
+        ;
+}
+#endif
+
+void ttm_tt_cache_flush(struct page *pages[], unsigned long num_pages)
+{
+
+#if defined(CONFIG_X86)
+        if (cpu_has_clflush) {
+                ttm_tt_cache_flush_clflush(pages, num_pages);
+                return;
+        }
+#else
+        if (on_each_cpu(ttm_tt_ipi_handler, NULL, 1) != 0)
+                printk(KERN_ERR TTM_PFX
+                       "Timed out waiting for drm cache flush.\n");
+#endif
+}
+
+/**
+ * Allocates storage for pointers to the pages that back the ttm.
+ *
+ * Uses kmalloc if possible. Otherwise falls back to vmalloc.
+ */
+static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
+{
+        unsigned long size = ttm->num_pages * sizeof(*ttm->pages);
+        ttm->pages = NULL;
+
+        if (size <= PAGE_SIZE)
+                ttm->pages = kzalloc(size, GFP_KERNEL);
+
+        if (!ttm->pages) {
+                ttm->pages = vmalloc_user(size);
+                if (ttm->pages)
+                        ttm->page_flags |= TTM_PAGE_FLAG_VMALLOC;
+        }
+}
+
+static void ttm_tt_free_page_directory(struct ttm_tt *ttm)
+{
+        if (ttm->page_flags & TTM_PAGE_FLAG_VMALLOC) {
+                vfree(ttm->pages);
+                ttm->page_flags &= ~TTM_PAGE_FLAG_VMALLOC;
+        } else {
+                kfree(ttm->pages);
+        }
+        ttm->pages = NULL;
+}
+
+static struct page *ttm_tt_alloc_page(unsigned page_flags)
+{
+        if (page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
+                return alloc_page(GFP_HIGHUSER | __GFP_ZERO);
+
+        return alloc_page(GFP_HIGHUSER);
+}
+
+static void ttm_tt_free_user_pages(struct ttm_tt *ttm)
+{
+        int write;
+        int dirty;
+        struct page *page;
+        int i;
+        struct ttm_backend *be = ttm->be;
+
+        BUG_ON(!(ttm->page_flags & TTM_PAGE_FLAG_USER));
+        write = ((ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0);
+        dirty = ((ttm->page_flags & TTM_PAGE_FLAG_USER_DIRTY) != 0);
+
+        if (be)
+                be->func->clear(be);
+
+        for (i = 0; i < ttm->num_pages; ++i) {
+                page = ttm->pages[i];
+                if (page == NULL)
+                        continue;
+
+                if (page == ttm->dummy_read_page) {
+                        BUG_ON(write);
+                        continue;
+                }
+
+                if (write && dirty && !PageReserved(page))
+                        set_page_dirty_lock(page);
+
+                ttm->pages[i] = NULL;
+                ttm_mem_global_free(ttm->bdev->mem_glob, PAGE_SIZE, false);
+                put_page(page);
+        }
+        ttm->state = tt_unpopulated;
+        ttm->first_himem_page = ttm->num_pages;
+        ttm->last_lomem_page = -1;
+}
+
+static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
+{
+        struct page *p;
+        struct ttm_bo_device *bdev = ttm->bdev;
+        struct ttm_mem_global *mem_glob = bdev->mem_glob;
+        int ret;
+
+        while (NULL == (p = ttm->pages[index])) {
+                p = ttm_tt_alloc_page(ttm->page_flags);
+
+                if (!p)
+                        return NULL;
+
+                if (PageHighMem(p)) {
+                        ret =
+                            ttm_mem_global_alloc(mem_glob, PAGE_SIZE,
+                                                 false, false, true);
+                        if (unlikely(ret != 0))
+                                goto out_err;
+                        ttm->pages[--ttm->first_himem_page] = p;
+                } else {
+                        ret =
+                            ttm_mem_global_alloc(mem_glob, PAGE_SIZE,
+                                                 false, false, false);
+                        if (unlikely(ret != 0))
+                                goto out_err;
+                        ttm->pages[++ttm->last_lomem_page] = p;
+                }
+        }
+        return p;
+out_err:
+        put_page(p);
+        return NULL;
+}
+
+struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index)
+{
+        int ret;
+
+        if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
+                ret = ttm_tt_swapin(ttm);
+                if (unlikely(ret != 0))
+                        return NULL;
+        }
+        return __ttm_tt_get_page(ttm, index);
+}
+
+int ttm_tt_populate(struct ttm_tt *ttm)
+{
+        struct page *page;
+        unsigned long i;
+        struct ttm_backend *be;
+        int ret;
+
+        if (ttm->state != tt_unpopulated)
+                return 0;
+
+        if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
+                ret = ttm_tt_swapin(ttm);
+                if (unlikely(ret != 0))
+                        return ret;
+        }
+
+        be = ttm->be;
+
+        for (i = 0; i < ttm->num_pages; ++i) {
+                page = __ttm_tt_get_page(ttm, i);
+                if (!page)
+                        return -ENOMEM;
+        }
+
+        be->func->populate(be, ttm->num_pages, ttm->pages,
+                           ttm->dummy_read_page);
+        ttm->state = tt_unbound;
+        return 0;
+}
+
+#ifdef CONFIG_X86
+static inline int ttm_tt_set_page_caching(struct page *p,
+                                          enum ttm_caching_state c_state)
+{
+        if (PageHighMem(p))
+                return 0;
+
+        switch (c_state) {
+        case tt_cached:
+                return set_pages_wb(p, 1);
+        case tt_wc:
+            return set_memory_wc((unsigned long) page_address(p), 1);
+        default:
+                return set_pages_uc(p, 1);
+        }
+}
+#else /* CONFIG_X86 */
+static inline int ttm_tt_set_page_caching(struct page *p,
+                                          enum ttm_caching_state c_state)
+{
+        return 0;
+}
+#endif /* CONFIG_X86 */
+
+/*
+ * Change caching policy for the linear kernel map
+ * for range of pages in a ttm.
+ */
+
+static int ttm_tt_set_caching(struct ttm_tt *ttm,
+                              enum ttm_caching_state c_state)
+{
+        int i, j;
+        struct page *cur_page;
+        int ret;
+
+        if (ttm->caching_state == c_state)
+                return 0;
+
+        if (c_state != tt_cached) {
+                ret = ttm_tt_populate(ttm);
+                if (unlikely(ret != 0))
+                        return ret;
+        }
+
+        if (ttm->caching_state == tt_cached)
+                ttm_tt_cache_flush(ttm->pages, ttm->num_pages);
+
+        for (i = 0; i < ttm->num_pages; ++i) {
+                cur_page = ttm->pages[i];
+                if (likely(cur_page != NULL)) {
+                        ret = ttm_tt_set_page_caching(cur_page, c_state);
+                        if (unlikely(ret != 0))
+                                goto out_err;
+                }
+        }
+
+        ttm->caching_state = c_state;
+
+        return 0;
+
+out_err:
+        for (j = 0; j < i; ++j) {
+                cur_page = ttm->pages[j];
+                if (likely(cur_page != NULL)) {
+                        (void)ttm_tt_set_page_caching(cur_page,
+                                                      ttm->caching_state);
+                }
+        }
+
+        return ret;
+}
+
+int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
+{
+        enum ttm_caching_state state;
+
+        if (placement & TTM_PL_FLAG_WC)
+                state = tt_wc;
+        else if (placement & TTM_PL_FLAG_UNCACHED)
+                state = tt_uncached;
+        else
+                state = tt_cached;
+
+        return ttm_tt_set_caching(ttm, state);
+}
+
+static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
+{
+        int i;
+        struct page *cur_page;
+        struct ttm_backend *be = ttm->be;
+
+        if (be)
+                be->func->clear(be);
+        (void)ttm_tt_set_caching(ttm, tt_cached);
+        for (i = 0; i < ttm->num_pages; ++i) {
+                cur_page = ttm->pages[i];
+                ttm->pages[i] = NULL;
+                if (cur_page) {
+                        if (page_count(cur_page) != 1)
+                                printk(KERN_ERR TTM_PFX
+                                       "Erroneous page count. "
+                                       "Leaking pages.\n");
+                        ttm_mem_global_free(ttm->bdev->mem_glob, PAGE_SIZE,
+                                            PageHighMem(cur_page));
+                        __free_page(cur_page);
+                }
+        }
+        ttm->state = tt_unpopulated;
+        ttm->first_himem_page = ttm->num_pages;
+        ttm->last_lomem_page = -1;
+}
+
+void ttm_tt_destroy(struct ttm_tt *ttm)
+{
+        struct ttm_backend *be;
+
+        if (unlikely(ttm == NULL))
+                return;
+
+        be = ttm->be;
+        if (likely(be != NULL)) {
+                be->func->destroy(be);
+                ttm->be = NULL;
+        }
+
+        if (likely(ttm->pages != NULL)) {
+                if (ttm->page_flags & TTM_PAGE_FLAG_USER)
+                        ttm_tt_free_user_pages(ttm);
+                else
+                        ttm_tt_free_alloced_pages(ttm);
+
+                ttm_tt_free_page_directory(ttm);
+        }
+
+        if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP) &&
+            ttm->swap_storage)
+                fput(ttm->swap_storage);
+
+        kfree(ttm);
+}
+
+int ttm_tt_set_user(struct ttm_tt *ttm,
+                    struct task_struct *tsk,
+                    unsigned long start, unsigned long num_pages)
+{
+        struct mm_struct *mm = tsk->mm;
+        int ret;
+        int write = (ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0;
+        struct ttm_mem_global *mem_glob = ttm->bdev->mem_glob;
+
+        BUG_ON(num_pages != ttm->num_pages);
+        BUG_ON((ttm->page_flags & TTM_PAGE_FLAG_USER) == 0);
+
+        /**
+         * Account user pages as lowmem pages for now.
+         */
+
+        ret = ttm_mem_global_alloc(mem_glob, num_pages * PAGE_SIZE,
+                                   false, false, false);
+        if (unlikely(ret != 0))
+                return ret;
+
+        down_read(&mm->mmap_sem);
+        ret = get_user_pages(tsk, mm, start, num_pages,
+                             write, 0, ttm->pages, NULL);
+        up_read(&mm->mmap_sem);
+
+        if (ret != num_pages && write) {
+                ttm_tt_free_user_pages(ttm);
+                ttm_mem_global_free(mem_glob, num_pages * PAGE_SIZE, false);
+                return -ENOMEM;
+        }
+
+        ttm->tsk = tsk;
+        ttm->start = start;
+        ttm->state = tt_unbound;
+
+        return 0;
+}
+
+struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
+                             uint32_t page_flags, struct page *dummy_read_page)
+{
+        struct ttm_bo_driver *bo_driver = bdev->driver;
+        struct ttm_tt *ttm;
+
+        if (!bo_driver)
+                return NULL;
+
+        ttm = kzalloc(sizeof(*ttm), GFP_KERNEL);
+        if (!ttm)
+                return NULL;
+
+        ttm->bdev = bdev;
+
+        ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        ttm->first_himem_page = ttm->num_pages;
+        ttm->last_lomem_page = -1;
+        ttm->caching_state = tt_cached;
+        ttm->page_flags = page_flags;
+
+        ttm->dummy_read_page = dummy_read_page;
+
+        ttm_tt_alloc_page_directory(ttm);
+        if (!ttm->pages) {
+                ttm_tt_destroy(ttm);
+                printk(KERN_ERR TTM_PFX "Failed allocating page table\n");
+                return NULL;
+        }
+        ttm->be = bo_driver->create_ttm_backend_entry(bdev);
+        if (!ttm->be) {
+                ttm_tt_destroy(ttm);
+                printk(KERN_ERR TTM_PFX "Failed creating ttm backend entry\n");
+                return NULL;
+        }
+        ttm->state = tt_unpopulated;
+        return ttm;
+}
+
+void ttm_tt_unbind(struct ttm_tt *ttm)
+{
+        int ret;
+        struct ttm_backend *be = ttm->be;
+
+        if (ttm->state == tt_bound) {
+                ret = be->func->unbind(be);
+                BUG_ON(ret);
+                ttm->state = tt_unbound;
+        }
+}
+
+int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
+{
+        int ret = 0;
+        struct ttm_backend *be;
+
+        if (!ttm)
+                return -EINVAL;
+
+        if (ttm->state == tt_bound)
+                return 0;
+
+        be = ttm->be;
+
+        ret = ttm_tt_populate(ttm);
+        if (ret)
+                return ret;
+
+        ret = be->func->bind(be, bo_mem);
+        if (ret) {
+                printk(KERN_ERR TTM_PFX "Couldn't bind backend.\n");
+                return ret;
+        }
+
+        ttm->state = tt_bound;
+
+        if (ttm->page_flags & TTM_PAGE_FLAG_USER)
+                ttm->page_flags |= TTM_PAGE_FLAG_USER_DIRTY;
+        return 0;
+}
+EXPORT_SYMBOL(ttm_tt_bind);
+
+static int ttm_tt_swapin(struct ttm_tt *ttm)
+{
+        struct address_space *swap_space;
+        struct file *swap_storage;
+        struct page *from_page;
+        struct page *to_page;
+        void *from_virtual;
+        void *to_virtual;
+        int i;
+        int ret;
+
+        if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
+                ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
+                                      ttm->num_pages);
+                if (unlikely(ret != 0))
+                        return ret;
+
+                ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
+                return 0;
+        }
+
+        swap_storage = ttm->swap_storage;
+        BUG_ON(swap_storage == NULL);
+
+        swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
+
+        for (i = 0; i < ttm->num_pages; ++i) {
+                from_page = read_mapping_page(swap_space, i, NULL);
+                if (IS_ERR(from_page))
+                        goto out_err;
+                to_page = __ttm_tt_get_page(ttm, i);
+                if (unlikely(to_page == NULL))
+                        goto out_err;
+
+                preempt_disable();
+                from_virtual = kmap_atomic(from_page, KM_USER0);
+                to_virtual = kmap_atomic(to_page, KM_USER1);
+                memcpy(to_virtual, from_virtual, PAGE_SIZE);
+                kunmap_atomic(to_virtual, KM_USER1);
+                kunmap_atomic(from_virtual, KM_USER0);
+                preempt_enable();
+                page_cache_release(from_page);
+        }
+
+        if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP))
+                fput(swap_storage);
+        ttm->swap_storage = NULL;
+        ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
+
+        return 0;
+out_err:
+        ttm_tt_free_alloced_pages(ttm);
+        return -ENOMEM;
+}
+
+int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
+{
+        struct address_space *swap_space;
+        struct file *swap_storage;
+        struct page *from_page;
+        struct page *to_page;
+        void *from_virtual;
+        void *to_virtual;
+        int i;
+
+        BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
+        BUG_ON(ttm->caching_state != tt_cached);
+
+        /*
+         * For user buffers, just unpin the pages, as there should be
+         * vma references.
+         */
+
+        if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
+                ttm_tt_free_user_pages(ttm);
+                ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
+                ttm->swap_storage = NULL;
+                return 0;
+        }
+
+        if (!persistant_swap_storage) {
+                swap_storage = shmem_file_setup("ttm swap",
+                                                ttm->num_pages << PAGE_SHIFT,
+                                                0);
+                if (unlikely(IS_ERR(swap_storage))) {
+                        printk(KERN_ERR "Failed allocating swap storage.\n");
+                        return -ENOMEM;
+                }
+        } else
+                swap_storage = persistant_swap_storage;
+
+        swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
+
+        for (i = 0; i < ttm->num_pages; ++i) {
+                from_page = ttm->pages[i];
+                if (unlikely(from_page == NULL))
+                        continue;
+                to_page = read_mapping_page(swap_space, i, NULL);
+                if (unlikely(to_page == NULL))
+                        goto out_err;
+
+                preempt_disable();
+                from_virtual = kmap_atomic(from_page, KM_USER0);
+                to_virtual = kmap_atomic(to_page, KM_USER1);
+                memcpy(to_virtual, from_virtual, PAGE_SIZE);
+                kunmap_atomic(to_virtual, KM_USER1);
+                kunmap_atomic(from_virtual, KM_USER0);
+                preempt_enable();
+                set_page_dirty(to_page);
+                mark_page_accessed(to_page);
+                page_cache_release(to_page);
+        }
+
+        ttm_tt_free_alloced_pages(ttm);
+        ttm->swap_storage = swap_storage;
+        ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
+        if (persistant_swap_storage)
+                ttm->page_flags |= TTM_PAGE_FLAG_PERSISTANT_SWAP;
+
+        return 0;
+out_err:
+        if (!persistant_swap_storage)
+                fput(swap_storage);
+
+        return -ENOMEM;
+}