1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
new file mode 100644
index 000000000000..43c7acbdc79d
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/shmem_fs.h>
+
+#include "gem/i915_gem_object.h"
+#include "shmem_utils.h"
+
+struct file *shmem_create_from_data(const char *name, void *data, size_t len)
+{
+	struct file *file;
+	int err;
+
+	file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
+	if (IS_ERR(file))
+		return file;
+
+	err = shmem_write(file, 0, data, len);
+	if (err) {
+		fput(file);
+		return ERR_PTR(err);
+	}
+
+	return file;
+}
+
+struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
+{
+	struct file *file;
+	void *ptr;
+
+	if (obj->ops == &i915_gem_shmem_ops) {
+		file = obj->base.filp;
+		atomic_long_inc(&file->f_count);
+		return file;
+	}
+
+	ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
+	if (IS_ERR(ptr))
+		return ERR_CAST(ptr);
+
+	file = shmem_create_from_data("", ptr, obj->base.size);
+	i915_gem_object_unpin_map(obj);
+
+	return file;
+}
+
+static size_t shmem_npte(struct file *file)
+{
+	return file->f_mapping->host->i_size >> PAGE_SHIFT;
+}
+
+static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
+{
+	unsigned long pfn;
+
+	vunmap(ptr);
+
+	for (pfn = 0; pfn < n_pte; pfn++) {
+		struct page *page;
+
+		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+						   GFP_KERNEL);
+		if (!WARN_ON(IS_ERR(page))) {
+			put_page(page);
+			put_page(page);
+		}
+	}
+}
+
+void *shmem_pin_map(struct file *file)
+{
+	const size_t n_pte = shmem_npte(file);
+	pte_t *stack[32], **ptes, **mem;
+	struct vm_struct *area;
+	unsigned long pfn;
+
+	mem = stack;
+	if (n_pte > ARRAY_SIZE(stack)) {
+		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
+		if (!mem)
+			return NULL;
+	}
+
+	area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
+	if (!area) {
+		if (mem != stack)
+			kvfree(mem);
+		return NULL;
+	}
+
+	ptes = mem;
+	for (pfn = 0; pfn < n_pte; pfn++) {
+		struct page *page;
+
+		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+						   GFP_KERNEL);
+		if (IS_ERR(page))
+			goto err_page;
+
+		**ptes++ = mk_pte(page,  PAGE_KERNEL);
+	}
+
+	if (mem != stack)
+		kvfree(mem);
+
+	mapping_set_unevictable(file->f_mapping);
+	return area->addr;
+
+err_page:
+	if (mem != stack)
+		kvfree(mem);
+
+	__shmem_unpin_map(file, area->addr, pfn);
+	return NULL;
+}
+
+void shmem_unpin_map(struct file *file, void *ptr)
+{
+	mapping_clear_unevictable(file->f_mapping);
+	__shmem_unpin_map(file, ptr, shmem_npte(file));
+}
+
+static int __shmem_rw(struct file *file, loff_t off,
+		      void *ptr, size_t len,
+		      bool write)
+{
+	unsigned long pfn;
+
+	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
+		unsigned int this =
+			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
+		struct page *page;
+		void *vaddr;
+
+		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+						   GFP_KERNEL);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		vaddr = kmap(page);
+		if (write)
+			memcpy(vaddr + offset_in_page(off), ptr, this);
+		else
+			memcpy(ptr, vaddr + offset_in_page(off), this);
+		kunmap(page);
+		put_page(page);
+
+		len -= this;
+		ptr += this;
+		off = 0;
+	}
+
+	return 0;
+}
+
+int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
+{
+	return __shmem_rw(file, off, dst, len, false);
+}
+
+int shmem_write(struct file *file, loff_t off, void *src, size_t len)
+{
+	return __shmem_rw(file, off, src, len, true);
+}
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "st_shmem_utils.c"
+#endif