Commit 534a6687 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

drm/i915: use vmap in i915_gem_object_map 



i915_gem_object_map implements fairly low-level vmap functionality in a
driver.  Split it into two helpers, one for remapping kernel memory which
can use vmap, and one for I/O memory that uses vmap_pfn.

The only practical difference is that alloc_vm_area prefeaults the vmalloc
area PTEs, which doesn't seem to be required here for the kernel memory
case (and could be added to vmap using a flag if actually required).

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002122204.1534411-9-hch@lst.de


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 46ce3a62

drivers/gpu/drm/i915/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ config DRM_I915 
	select CRC32

	select SND_HDA_I915 if SND_HDA_CORE

	select CEC_CORE if CEC_NOTIFIER

	select VMAP_PFN

	help

	  Choose this option if you have a system that has "Intel Graphics

	  Media Accelerator" or "HD Graphics" integrated graphics,

drivers/gpu/drm/i915/gem/i915_gem_pages.c

+59 −68
Original line number Diff line number Diff line
@@ -232,34 +232,21 @@ unlock: 
	return err;

}



static inline pte_t iomap_pte(resource_size_t base,

			      dma_addr_t offset,

			      pgprot_t prot)

{

	return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot));

}



/* The 'mapping' part of i915_gem_object_pin_map() below */

static void *i915_gem_object_map(struct drm_i915_gem_object *obj,

static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj,

		enum i915_map_type type)

{

	unsigned long n_pte = obj->base.size >> PAGE_SHIFT;

	struct sg_table *sgt = obj->mm.pages;

	pte_t *stack[32], **mem;

	struct vm_struct *area;

	unsigned long n_pages = obj->base.size >> PAGE_SHIFT, i;

	struct page *stack[32], **pages = stack, *page;

	struct sgt_iter iter;

	pgprot_t pgprot;

	void *vaddr;



	if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC)

		return NULL;



	if (GEM_WARN_ON(type == I915_MAP_WC &&

			!static_cpu_has(X86_FEATURE_PAT)))

		return NULL;



	/* A single page can always be kmapped */

	if (n_pte == 1 && type == I915_MAP_WB) {

		struct page *page = sg_page(sgt->sgl);



	switch (type) {

	default:

		MISSING_CASE(type);

		fallthrough;	/* to use PAGE_KERNEL anyway */

	case I915_MAP_WB:

		/*

		 * On 32b, highmem using a finite set of indirect PTE (i.e.

		 * vmap) to provide virtual mappings of the high pages.
@@ -277,30 +264,8 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, 
		 * So if the page is beyond the 32b boundary, make an explicit

		 * vmap.

		 */

		if (!PageHighMem(page))

			return page_address(page);

	}



	mem = stack;

	if (n_pte > ARRAY_SIZE(stack)) {

		/* Too big for stack -- allocate temporary array instead */

		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);

		if (!mem)

			return NULL;

	}



	area = alloc_vm_area(obj->base.size, mem);

	if (!area) {

		if (mem != stack)

			kvfree(mem);

		return NULL;

	}



	switch (type) {

	default:

		MISSING_CASE(type);

		fallthrough;	/* to use PAGE_KERNEL anyway */

	case I915_MAP_WB:

		if (n_pages == 1 && !PageHighMem(sg_page(obj->mm.pages->sgl)))

			return page_address(sg_page(obj->mm.pages->sgl));

		pgprot = PAGE_KERNEL;

		break;

	case I915_MAP_WC:
@@ -308,30 +273,50 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, 
		break;

	}



	if (i915_gem_object_has_struct_page(obj)) {

		struct sgt_iter iter;

		struct page *page;

		pte_t **ptes = mem;

	if (n_pages > ARRAY_SIZE(stack)) {

		/* Too big for stack -- allocate temporary array instead */

		pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);

		if (!pages)

			return NULL;

	}



		for_each_sgt_page(page, iter, sgt)

			**ptes++ = mk_pte(page, pgprot);

	} else {

		resource_size_t iomap;

	i = 0;

	for_each_sgt_page(page, iter, obj->mm.pages)

		pages[i++] = page;

	vaddr = vmap(pages, n_pages, 0, pgprot);

	if (pages != stack)

		kvfree(pages);

	return vaddr;

}



static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj,

		enum i915_map_type type)

{

	resource_size_t iomap = obj->mm.region->iomap.base -

		obj->mm.region->region.start;

	unsigned long n_pfn = obj->base.size >> PAGE_SHIFT;

	unsigned long stack[32], *pfns = stack, i;

	struct sgt_iter iter;

		pte_t **ptes = mem;

	dma_addr_t addr;

	void *vaddr;



		iomap = obj->mm.region->iomap.base;

		iomap -= obj->mm.region->region.start;

	if (type != I915_MAP_WC)

		return NULL;



		for_each_sgt_daddr(addr, iter, sgt)

			**ptes++ = iomap_pte(iomap, addr, pgprot);

	if (n_pfn > ARRAY_SIZE(stack)) {

		/* Too big for stack -- allocate temporary array instead */

		pfns = kvmalloc_array(n_pfn, sizeof(*pfns), GFP_KERNEL);

		if (!pfns)

			return NULL;

	}



	if (mem != stack)

		kvfree(mem);



	return area->addr;

	i = 0;

	for_each_sgt_daddr(addr, iter, obj->mm.pages)

		pfns[i++] = (iomap + addr) >> PAGE_SHIFT;

	vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO));

	if (pfns != stack)

		kvfree(pfns);

	return vaddr;

}



/* get, pin, and map the pages of the object into kernel space */
@@ -383,7 +368,13 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, 
	}



	if (!ptr) {

		ptr = i915_gem_object_map(obj, type);

		if (GEM_WARN_ON(type == I915_MAP_WC &&

				!static_cpu_has(X86_FEATURE_PAT)))

			ptr = NULL;

		else if (i915_gem_object_has_struct_page(obj))

			ptr = i915_gem_object_map_page(obj, type);

		else

			ptr = i915_gem_object_map_pfn(obj, type);

		if (!ptr) {

			err = -ENOMEM;

			goto err_unpin;

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