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

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.deSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 46ce3a62
......@@ -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,
......
......@@ -232,34 +232,21 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
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,
enum i915_map_type type)
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;
struct sgt_iter iter;
pte_t **ptes = mem;
dma_addr_t addr;
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;
}
iomap = obj->mm.region->iomap.base;
iomap -= obj->mm.region->region.start;
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;
dma_addr_t addr;
void *vaddr;
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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