On 10/02/22 9:40 pm, Matthew Auld wrote:
> On 27/01/2022 14:11, Arunpravin wrote:
>> - Make drm_buddy_alloc a single function to handle
>> range allocation and non-range allocation demands
>>
>> - Implemented a new function alloc_range() which allocates
>> the requested power-of-two block comply with range limitations
>>
>> - Moved order computation and memory alignment logic from
>> i915 driver to drm buddy
>>
>> v2:
>> merged below changes to keep the build unbroken
>> - drm_buddy_alloc_range() becomes obsolete and may be removed
>> - enable ttm range allocation (fpfn / lpfn) support in i915 driver
>> - apply enhanced drm_buddy_alloc() function to i915 driver
>>
>> v3(Matthew Auld):
>> - Fix alignment issues and remove unnecessary list_empty check
>> - add more validation checks for input arguments
>> - make alloc_range() block allocations as bottom-up
>> - optimize order computation logic
>> - replace uint64_t with u64, which is preferred in the kernel
>>
>> v4(Matthew Auld):
>> - keep drm_buddy_alloc_range() function implementation for generic
>> actual range allocations
>> - keep alloc_range() implementation for end bias allocations
>>
>> v5(Matthew Auld):
>> - modify drm_buddy_alloc() passing argument place->lpfn to lpfn
>> as place->lpfn will currently always be zero for i915
>>
>> v6(Matthew Auld):
>> - fixup potential uaf - If we are unlucky and can't allocate
>> enough memory when splitting blocks, where we temporarily
>> end up with the given block and its buddy on the respective
>> free list, then we need to ensure we delete both blocks,
>> and no just the buddy, before potentially freeing them
>>
>> - fix warnings reported by kernel test robot <lkp@xxxxxxxxx>
>>
>> v7(Matthew Auld):
>> - revert fixup potential uaf
>> - keep __alloc_range() add node to the list logic same as
>> drm_buddy_alloc_blocks() by having a temporary list variable
>> - at drm_buddy_alloc_blocks() keep i915 range_overflows macro
>> and add a new check for end variable
>>
>> v8:
>> - fix warnings reported by kernel test robot <lkp@xxxxxxxxx>
>>
>> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@xxxxxxx>
>> ---
>> drivers/gpu/drm/drm_buddy.c | 315 +++++++++++++-----
>> drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 67 ++--
>> drivers/gpu/drm/i915/i915_ttm_buddy_manager.h | 2 +
>> include/drm/drm_buddy.h | 13 +-
>> 4 files changed, 280 insertions(+), 117 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
>> index d60878bc9c20..cfc160a1ef1a 100644
>> --- a/drivers/gpu/drm/drm_buddy.c
>> +++ b/drivers/gpu/drm/drm_buddy.c
>> @@ -282,23 +282,97 @@ void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects)
>> }
>> EXPORT_SYMBOL(drm_buddy_free_list);
>>
>> -/**
>> - * drm_buddy_alloc_blocks - allocate power-of-two blocks
>> - *
>> - * @mm: DRM buddy manager to allocate from
>> - * @order: size of the allocation
>> - *
>> - * The order value here translates to:
>> - *
>> - * 0 = 2^0 * mm->chunk_size
>> - * 1 = 2^1 * mm->chunk_size
>> - * 2 = 2^2 * mm->chunk_size
>> - *
>> - * Returns:
>> - * allocated ptr to the &drm_buddy_block on success
>> - */
>> -struct drm_buddy_block *
>> -drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order)
>> +static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
>> +{
>> + return s1 <= e2 && e1 >= s2;
>> +}
>> +
>> +static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
>> +{
>> + return s1 <= s2 && e1 >= e2;
>> +}
>> +
>> +static struct drm_buddy_block *
>> +alloc_range_bias(struct drm_buddy *mm,
>> + u64 start, u64 end,
>> + unsigned int order)
>> +{
>> + struct drm_buddy_block *block;
>> + struct drm_buddy_block *buddy;
>> + LIST_HEAD(dfs);
>> + int err;
>> + int i;
>> +
>> + end = end - 1;
>> +
>> + for (i = 0; i < mm->n_roots; ++i)
>> + list_add_tail(&mm->roots[i]->tmp_link, &dfs);
>> +
>> + do {
>> + u64 block_start;
>> + u64 block_end;
>> +
>> + block = list_first_entry_or_null(&dfs,
>> + struct drm_buddy_block,
>> + tmp_link);
>> + if (!block)
>> + break;
>> +
>> + list_del(&block->tmp_link);
>> +
>> + if (drm_buddy_block_order(block) < order)
>> + continue;
>> +
>> + block_start = drm_buddy_block_offset(block);
>> + block_end = block_start + drm_buddy_block_size(mm, block) - 1;
>> +
>> + if (!overlaps(start, end, block_start, block_end))
>> + continue;
>> +
>> + if (drm_buddy_block_is_allocated(block))
>> + continue;
>> +
>> + if (contains(start, end, block_start, block_end) &&
>> + order == drm_buddy_block_order(block)) {
>> + /*
>> + * Find the free block within the range.
>> + */
>> + if (drm_buddy_block_is_free(block))
>> + return block;
>> +
>> + continue;
>> + }
>> +
>> + if (!drm_buddy_block_is_split(block)) {
>> + err = split_block(mm, block);
>> + if (unlikely(err))
>> + goto err_undo;
>> + }
>> +
>> + list_add(&block->right->tmp_link, &dfs);
>> + list_add(&block->left->tmp_link, &dfs);
>> + } while (1);
>> +
>> + return ERR_PTR(-ENOSPC);
>> +
>> +err_undo:
>> + /*
>> + * We really don't want to leave around a bunch of split blocks, since
>> + * bigger is better, so make sure we merge everything back before we
>> + * free the allocated blocks.
>> + */
>> + buddy = get_buddy(block);
>> + if (buddy &&
>> + (drm_buddy_block_is_free(block) &&
>> + drm_buddy_block_is_free(buddy)))
>> + __drm_buddy_free(mm, block);
>> + return ERR_PTR(err);
>> +}
>> +
>> +static struct drm_buddy_block *
>> +alloc_from_freelist(struct drm_buddy *mm,
>> + unsigned int order,
>> + unsigned long flags)
>> {
>> struct drm_buddy_block *block = NULL;
>> unsigned int i;
>> @@ -320,78 +394,29 @@ drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order)
>> while (i != order) {
>> err = split_block(mm, block);
>> if (unlikely(err))
>> - goto out_free;
>> + goto err_undo;
>>
>> - /* Go low */
>> - block = block->left;
>> + block = block->right;
>> i--;
>> }
>> -
>> - mark_allocated(block);
>> - mm->avail -= drm_buddy_block_size(mm, block);
>> - kmemleak_update_trace(block);
>> return block;
>>
>> -out_free:
>> +err_undo:
>> if (i != order)
>> __drm_buddy_free(mm, block);
>> return ERR_PTR(err);
>> }
>> -EXPORT_SYMBOL(drm_buddy_alloc_blocks);
>> -
>> -static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
>> -{
>> - return s1 <= e2 && e1 >= s2;
>> -}
>>
>> -static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
>> -{
>> - return s1 <= s2 && e1 >= e2;
>> -}
>> -
>> -/**
>> - * drm_buddy_alloc_range - allocate range
>> - *
>> - * @mm: DRM buddy manager to allocate from
>> - * @blocks: output list head to add allocated blocks
>> - * @start: start of the allowed range for this block
>> - * @size: size of the allocation
>> - *
>> - * Intended for pre-allocating portions of the address space, for example to
>> - * reserve a block for the initial framebuffer or similar, hence the expectation
>> - * here is that drm_buddy_alloc_blocks() is still the main vehicle for
>> - * allocations, so if that's not the case then the drm_mm range allocator is
>> - * probably a much better fit, and so you should probably go use that instead.
>> - *
>> - * Note that it's safe to chain together multiple alloc_ranges
>> - * with the same blocks list
>> - *
>> - * Returns:
>> - * 0 on success, error code on failure.
>> - */
>> -int drm_buddy_alloc_range(struct drm_buddy *mm,
>> - struct list_head *blocks,
>> - u64 start, u64 size)
>> +static int __alloc_range(struct drm_buddy *mm,
>> + struct list_head *dfs,
>> + u64 start, u64 size,
>> + struct list_head *blocks)
>> {
>> struct drm_buddy_block *block;
>> struct drm_buddy_block *buddy;
>> LIST_HEAD(allocated);
>> - LIST_HEAD(dfs);
>> u64 end;
>> int err;
>> - int i;
>> -
>> - if (size < mm->chunk_size)
>> - return -EINVAL;
>> -
>> - if (!IS_ALIGNED(size | start, mm->chunk_size))
>> - return -EINVAL;
>> -
>> - if (range_overflows(start, size, mm->size))
>> - return -EINVAL;
>> -
>> - for (i = 0; i < mm->n_roots; ++i)
>> - list_add_tail(&mm->roots[i]->tmp_link, &dfs);
>>
>> end = start + size - 1;
>>
>> @@ -399,7 +424,7 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>> u64 block_start;
>> u64 block_end;
>>
>> - block = list_first_entry_or_null(&dfs,
>> + block = list_first_entry_or_null(dfs,
>> struct drm_buddy_block,
>> tmp_link);
>> if (!block)
>> @@ -436,8 +461,8 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>> goto err_undo;
>> }
>>
>> - list_add(&block->right->tmp_link, &dfs);
>> - list_add(&block->left->tmp_link, &dfs);
>> + list_add(&block->right->tmp_link, dfs);
>> + list_add(&block->left->tmp_link, dfs);
>> } while (1);
>>
>> list_splice_tail(&allocated, blocks);
>> @@ -459,7 +484,143 @@ int drm_buddy_alloc_range(struct drm_buddy *mm,
>> drm_buddy_free_list(mm, &allocated);
>> return err;
>> }
>> -EXPORT_SYMBOL(drm_buddy_alloc_range);
>> +
>> +/**
>> + * __drm_buddy_alloc_range - actual range allocation
>> + *
>> + * @mm: DRM buddy manager to allocate from
>> + * @start: start of the allowed range for this block
>> + * @size: size of the allocation
>> + * @blocks: output list head to add allocated blocks
>
> I guess no need to add kernel-doc for static functions.
>
>> + *
>> + * Intended for pre-allocating portions of the address space, for example to
>> + * reserve a block for the initial framebuffer or similar
>> + *
>> + * Note that it's safe to chain together multiple alloc_ranges
>> + * with the same blocks list
>> + *
>> + * Returns:
>> + * 0 on success, error code on failure.
>> + */
>> +static int __drm_buddy_alloc_range(struct drm_buddy *mm,
>> + u64 start,
>> + u64 size,
>> + struct list_head *blocks)
>> +{
>> + LIST_HEAD(dfs);
>> + int i;
>> +
>> + for (i = 0; i < mm->n_roots; ++i)
>> + list_add_tail(&mm->roots[i]->tmp_link, &dfs);
>> +
>> + return __alloc_range(mm, &dfs, start, size, blocks);
>> +}
>> +
>> +/**
>> + * drm_buddy_alloc_blocks - allocate power-of-two blocks
>> + *
>> + * @mm: DRM buddy manager to allocate from
>> + * @start: start of the allowed range for this block
>> + * @end: end of the allowed range for this block
>> + * @size: size of the allocation
>> + * @min_page_size: alignment of the allocation
>> + * @blocks: output list head to add allocated blocks
>> + * @flags: DRM_BUDDY_*_ALLOCATION flags
>> + *
>> + * alloc_range_bias() called on range limitations, which traverses
>> + * the tree and returns the desired block.
>> + *
>> + * alloc_from_freelist() called when *no* range restrictions
>> + * are enforced, which picks the block from the freelist.
>> + *
>> + * blocks are allocated in order, the order value here translates to:
>> + *
>> + * 0 = 2^0 * mm->chunk_size
>> + * 1 = 2^1 * mm->chunk_size
>> + * 2 = 2^2 * mm->chunk_size
>
> The order stuff here can be dropped I think, since this is now just 'size'.
>
>> + *
>> + * Returns:
>> + * 0 on success, error code on failure.
>> + */
>> +int drm_buddy_alloc_blocks(struct drm_buddy *mm,
>> + u64 start, u64 end, u64 size,
>> + u64 min_page_size,
>> + struct list_head *blocks,
>> + unsigned long flags)
>> +{
>> + struct drm_buddy_block *block = NULL;
>> + unsigned int min_order, order;
>> + unsigned long pages;
>> + LIST_HEAD(allocated);
>> + int err;
>> +
>> + if (size < mm->chunk_size)
>> + return -EINVAL;
>> +
>> + if (min_page_size < mm->chunk_size)
>> + return -EINVAL;
>> +
>> + if (!is_power_of_2(min_page_size))
>> + return -EINVAL;
>> +
>> + if (!IS_ALIGNED(start | end | size, mm->chunk_size))
>> + return -EINVAL;
>> +
>> + if (end > mm->size)
>> + return -EINVAL;
>> +
>> + if (range_overflows(start, size, mm->size))
>> + return -EINVAL;
>> +
>> + /* Actual range allocation */
>> + if (start + size == end)
>> + return __drm_buddy_alloc_range(mm, start, size, blocks);
>> +
>> + pages = size >> ilog2(mm->chunk_size);
>> + order = fls(pages) - 1;
>> + min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
>> +
>> + do {
>> + order = min(order, (unsigned int)fls(pages) - 1);
>> + BUG_ON(order > mm->max_order);
>> + BUG_ON(order < min_order);
>> +
>> + do {
>> + if (flags & DRM_BUDDY_RANGE_ALLOCATION)
>
> Do we need an explicit flag for this? Can we not just check:
>
> if (start || end < size)
amdgpu failed to load as some requirements are not met with the above
condition,
if we keep (start || end != size), amdgpu loads successfully.
>
> We already implicitly determine the "actual range allocation" above. So
> that would just leave the TODPOWN flag
ok, now we have only the TOPDOWN flag
#define DRM_BUDDY_TOPDOWN_ALLOCATION (1 << 0)
>
> Otherwise,
> Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
>
>> + /* Allocate traversing within the range */
>> + block = alloc_range_bias(mm, start, end, order);
>> + else
>> + /* Allocate from freelist */
>> + block = alloc_from_freelist(mm, order, flags);
>> +
>> + if (!IS_ERR(block))
>> + break;
>> +
>> + if (order-- == min_order) {
>> + err = -ENOSPC;
>> + goto err_free;
>> + }
>> + } while (1);
>> +
>> + mark_allocated(block);
>> + mm->avail -= drm_buddy_block_size(mm, block);
>> + kmemleak_update_trace(block);
>> + list_add_tail(&block->link, &allocated);
>> +
>> + pages -= BIT(order);
>> +
>> + if (!pages)
>> + break;
>> + } while (1);
>> +
>> + list_splice_tail(&allocated, blocks);
>> + return 0;
>> +
>> +err_free:
>> + drm_buddy_free_list(mm, &allocated);
>> + return err;
>> +}
>> +EXPORT_SYMBOL(drm_buddy_alloc_blocks);
>>
>> /**
>> * drm_buddy_block_print - print block information
>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> index 247714bab044..a328a38fab07 100644
>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> @@ -36,13 +36,14 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>> struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
>> struct i915_ttm_buddy_resource *bman_res;
>> struct drm_buddy *mm = &bman->mm;
>> - unsigned long n_pages;
>> - unsigned int min_order;
>> + unsigned long n_pages, lpfn;
>> u64 min_page_size;
>> u64 size;
>> int err;
>>
>> - GEM_BUG_ON(place->fpfn || place->lpfn);
>> + lpfn = place->lpfn;
>> + if (!lpfn)
>> + lpfn = man->size;
>>
>> bman_res = kzalloc(sizeof(*bman_res), GFP_KERNEL);
>> if (!bman_res)
>> @@ -52,6 +53,9 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>> INIT_LIST_HEAD(&bman_res->blocks);
>> bman_res->mm = mm;
>>
>> + if (place->fpfn || lpfn != man->size)
>> + bman_res->flags |= DRM_BUDDY_RANGE_ALLOCATION;
>> +
>> GEM_BUG_ON(!bman_res->base.num_pages);
>> size = bman_res->base.num_pages << PAGE_SHIFT;
>>
>> @@ -60,10 +64,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>> min_page_size = bo->page_alignment << PAGE_SHIFT;
>>
>> GEM_BUG_ON(min_page_size < mm->chunk_size);
>> - min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
>> +
>> if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
>> + unsigned long pages;
>> +
>> size = roundup_pow_of_two(size);
>> - min_order = ilog2(size) - ilog2(mm->chunk_size);
>> + min_page_size = size;
>> +
>> + pages = size >> ilog2(mm->chunk_size);
>> + if (pages > lpfn)
>> + lpfn = pages;
>> }
>>
>> if (size > mm->size) {
>> @@ -73,34 +83,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>
>> n_pages = size >> ilog2(mm->chunk_size);
>>
>> - do {
>> - struct drm_buddy_block *block;
>> - unsigned int order;
>> -
>> - order = fls(n_pages) - 1;
>> - GEM_BUG_ON(order > mm->max_order);
>> - GEM_BUG_ON(order < min_order);
>> -
>> - do {
>> - mutex_lock(&bman->lock);
>> - block = drm_buddy_alloc_blocks(mm, order);
>> - mutex_unlock(&bman->lock);
>> - if (!IS_ERR(block))
>> - break;
>> -
>> - if (order-- == min_order) {
>> - err = -ENOSPC;
>> - goto err_free_blocks;
>> - }
>> - } while (1);
>> -
>> - n_pages -= BIT(order);
>> -
>> - list_add_tail(&block->link, &bman_res->blocks);
>> -
>> - if (!n_pages)
>> - break;
>> - } while (1);
>> + mutex_lock(&bman->lock);
>> + err = drm_buddy_alloc_blocks(mm, (u64)place->fpfn << PAGE_SHIFT,
>> + (u64)lpfn << PAGE_SHIFT,
>> + (u64)n_pages << PAGE_SHIFT,
>> + min_page_size,
>> + &bman_res->blocks,
>> + bman_res->flags);
>> + mutex_unlock(&bman->lock);
>> + if (unlikely(err))
>> + goto err_free_blocks;
>>
>> *res = &bman_res->base;
>> return 0;
>> @@ -268,10 +260,17 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
>> {
>> struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
>> struct drm_buddy *mm = &bman->mm;
>> + unsigned long flags = 0;
>> int ret;
>>
>> + flags |= DRM_BUDDY_RANGE_ALLOCATION;
>> +
>> mutex_lock(&bman->lock);
>> - ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size);
>> + ret = drm_buddy_alloc_blocks(mm, start,
>> + start + size,
>> + size, mm->chunk_size,
>> + &bman->reserved,
>> + flags);
>> mutex_unlock(&bman->lock);
>>
>> return ret;
>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> index 312077941411..72c90b432e87 100644
>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> @@ -20,6 +20,7 @@ struct drm_buddy;
>> *
>> * @base: struct ttm_resource base class we extend
>> * @blocks: the list of struct i915_buddy_block for this resource/allocation
>> + * @flags: DRM_BUDDY_*_ALLOCATION flags
>> * @mm: the struct i915_buddy_mm for this resource
>> *
>> * Extends the struct ttm_resource to manage an address space allocation with
>> @@ -28,6 +29,7 @@ struct drm_buddy;
>> struct i915_ttm_buddy_resource {
>> struct ttm_resource base;
>> struct list_head blocks;
>> + unsigned long flags;
>> struct drm_buddy *mm;
>> };
>>
>> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
>> index f524db152413..54f25a372f27 100644
>> --- a/include/drm/drm_buddy.h
>> +++ b/include/drm/drm_buddy.h
>> @@ -22,6 +22,8 @@
>> start__ >= max__ || size__ > max__ - start__; \
>> })
>>
>> +#define DRM_BUDDY_RANGE_ALLOCATION (1 << 0)
>> +
>> struct drm_buddy_block {
>> #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
>> #define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10)
>> @@ -131,12 +133,11 @@ int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
>>
>> void drm_buddy_fini(struct drm_buddy *mm);
>>
>> -struct drm_buddy_block *
>> -drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order);
>> -
>> -int drm_buddy_alloc_range(struct drm_buddy *mm,
>> - struct list_head *blocks,
>> - u64 start, u64 size);
>> +int drm_buddy_alloc_blocks(struct drm_buddy *mm,
>> + u64 start, u64 end, u64 size,
>> + u64 min_page_size,
>> + struct list_head *blocks,
>> + unsigned long flags);
>>
>> void drm_buddy_free_block(struct drm_buddy *mm, struct drm_buddy_block *block);
>>
>>
>> base-commit: 627e2885b51ab503a98aa89f0a0bd68416c731fc
