drm/i915: Create page table allocators

As we move toward dynamic page table allocation, it becomes much easier
to manage our data structures if break do things less coarsely by
breaking up all of our actions into individual tasks.  This makes the
code easier to write, read, and verify.

Aside from the dissection of the allocation functions, the patch
statically allocates the page table structures without a page directory.
This remains the same for all platforms,

The patch itself should not have much functional difference. The primary
noticeable difference is the fact that page tables are no longer
allocated, but rather statically declared as part of the page directory.
This has non-zero overhead, but things gain additional complexity as a
result.

This patch exists for a few reasons:
1. Splitting out the functions allows easily combining GEN6 and GEN8
code. Page tables have no difference based on GEN8. As we'll see in a
future patch when we add the DMA mappings to the allocations, it
requires only one small change to make work, and error handling should
just fall into place.

2. Unless we always want to allocate all page tables under a given PDE,
we'll have to eventually break this up into an array of pointers (or
pointer to pointer).

3. Having the discrete functions is easier to review, and understand.
All allocations and frees now take place in just a couple of locations.
Reviewing, and catching leaks should be easy.

4. Less important: the GFP flags are confined to one location, which
makes playing around with such things trivial.

v2: Updated commit message to explain why this patch exists

v3: For lrc, s/pdp.page_directory[i].daddr/pdp.page_directory[i]->daddr/

v4: Renamed free_pt/pd_single functions to unmap_and_free_pt/pd (Daniel)

v5: Added additional safety checks in gen8 clear/free/unmap.

v6: Use WARN_ON and return -EINVAL in alloc_pt_range (Mika).

v7: Make err_out loop symmetrical to the way we allocate in
alloc_pt_range. Also s/page_tables/page_table and correct commit
message (Mika)

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Michel Thierry <michel.thierry@intel.com> (v3+)
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -279,6 +279,98 @@ static gen6_gtt_pte_t iris_pte_encode(dma_addr_t addr,
 	return pte;
 }
 
+static void unmap_and_free_pt(struct i915_page_table_entry *pt)
+{
+	if (WARN_ON(!pt->page))
+		return;
+	__free_page(pt->page);
+	kfree(pt);
+}
+
+static struct i915_page_table_entry *alloc_pt_single(void)
+{
+	struct i915_page_table_entry *pt;
+
+	pt = kzalloc(sizeof(*pt), GFP_KERNEL);
+	if (!pt)
+		return ERR_PTR(-ENOMEM);
+
+	pt->page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!pt->page) {
+		kfree(pt);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return pt;
+}
+
+/**
+ * alloc_pt_range() - Allocate a multiple page tables
+ * @pd:		The page directory which will have at least @count entries
+ *		available to point to the allocated page tables.
+ * @pde:	First page directory entry for which we are allocating.
+ * @count:	Number of pages to allocate.
+ *
+ * Allocates multiple page table pages and sets the appropriate entries in the
+ * page table structure within the page directory. Function cleans up after
+ * itself on any failures.
+ *
+ * Return: 0 if allocation succeeded.
+ */
+static int alloc_pt_range(struct i915_page_directory_entry *pd, uint16_t pde, size_t count)
+{
+	int i, ret;
+
+	/* 512 is the max page tables per page_directory on any platform. */
+	if (WARN_ON(pde + count > GEN6_PPGTT_PD_ENTRIES))
+		return -EINVAL;
+
+	for (i = pde; i < pde + count; i++) {
+		struct i915_page_table_entry *pt = alloc_pt_single();
+
+		if (IS_ERR(pt)) {
+			ret = PTR_ERR(pt);
+			goto err_out;
+		}
+		WARN(pd->page_table[i],
+		     "Leaking page directory entry %d (%pa)\n",
+		     i, pd->page_table[i]);
+		pd->page_table[i] = pt;
+	}
+
+	return 0;
+
+err_out:
+	while (i-- > pde)
+		unmap_and_free_pt(pd->page_table[i]);
+	return ret;
+}
+
+static void unmap_and_free_pd(struct i915_page_directory_entry *pd)
+{
+	if (pd->page) {
+		__free_page(pd->page);
+		kfree(pd);
+	}
+}
+
+static struct i915_page_directory_entry *alloc_pd_single(void)
+{
+	struct i915_page_directory_entry *pd;
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return ERR_PTR(-ENOMEM);
+
+	pd->page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!pd->page) {
+		kfree(pd);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return pd;
+}
+
 /* Broadwell Page Directory Pointer Descriptors */
 static int gen8_write_pdp(struct intel_engine_cs *ring, unsigned entry,
 			   uint64_t val)
@@ -311,7 +403,7 @@ static int gen8_mm_switch(struct i915_hw_ppgtt *ppgtt,
 	int used_pd = ppgtt->num_pd_entries / GEN8_PDES_PER_PAGE;
 
 	for (i = used_pd - 1; i >= 0; i--) {
-		dma_addr_t addr = ppgtt->pdp.page_directory[i].daddr;
+		dma_addr_t addr = ppgtt->pdp.page_directory[i]->daddr;
 		ret = gen8_write_pdp(ring, i, addr);
 		if (ret)
 			return ret;
@@ -338,8 +430,24 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
 				      I915_CACHE_LLC, use_scratch);
 
 	while (num_entries) {
-		struct i915_page_directory_entry *pd = &ppgtt->pdp.page_directory[pdpe];
-		struct page *page_table = pd->page_table[pde].page;
+		struct i915_page_directory_entry *pd;
+		struct i915_page_table_entry *pt;
+		struct page *page_table;
+
+		if (WARN_ON(!ppgtt->pdp.page_directory[pdpe]))
+			continue;
+
+		pd = ppgtt->pdp.page_directory[pdpe];
+
+		if (WARN_ON(!pd->page_table[pde]))
+			continue;
+
+		pt = pd->page_table[pde];
+
+		if (WARN_ON(!pt->page))
+			continue;
+
+		page_table = pt->page;
 
 		last_pte = pte + num_entries;
 		if (last_pte > GEN8_PTES_PER_PAGE)
@@ -384,8 +492,9 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
 			break;
 
 		if (pt_vaddr == NULL) {
-			struct i915_page_directory_entry *pd = &ppgtt->pdp.page_directory[pdpe];
-			struct page *page_table = pd->page_table[pde].page;
+			struct i915_page_directory_entry *pd = ppgtt->pdp.page_directory[pdpe];
+			struct i915_page_table_entry *pt = pd->page_table[pde];
+			struct page *page_table = pt->page;
 
 			pt_vaddr = kmap_atomic(page_table);
 		}
@@ -416,19 +525,16 @@ static void gen8_free_page_tables(struct i915_page_directory_entry *pd)
 {
 	int i;
 
-	if (pd->page_table == NULL)
+	if (!pd->page)
 		return;
 
-	for (i = 0; i < GEN8_PDES_PER_PAGE; i++)
-		if (pd->page_table[i].page)
-			__free_page(pd->page_table[i].page);
-}
+	for (i = 0; i < GEN8_PDES_PER_PAGE; i++) {
+		if (WARN_ON(!pd->page_table[i]))
+			continue;
 
-static void gen8_free_page_directory(struct i915_page_directory_entry *pd)
-{
-	gen8_free_page_tables(pd);
-	kfree(pd->page_table);
-	__free_page(pd->page);
+		unmap_and_free_pt(pd->page_table[i]);
+		pd->page_table[i] = NULL;
+	}
 }
 
 static void gen8_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
@@ -436,7 +542,11 @@ static void gen8_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
 	int i;
 
 	for (i = 0; i < ppgtt->num_pd_pages; i++) {
-		gen8_free_page_directory(&ppgtt->pdp.page_directory[i]);
+		if (WARN_ON(!ppgtt->pdp.page_directory[i]))
+			continue;
+
+		gen8_free_page_tables(ppgtt->pdp.page_directory[i]);
+		unmap_and_free_pd(ppgtt->pdp.page_directory[i]);
 	}
 }
 
@@ -448,14 +558,23 @@ static void gen8_ppgtt_unmap_pages(struct i915_hw_ppgtt *ppgtt)
 	for (i = 0; i < ppgtt->num_pd_pages; i++) {
 		/* TODO: In the future we'll support sparse mappings, so this
 		 * will have to change. */
-		if (!ppgtt->pdp.page_directory[i].daddr)
+		if (!ppgtt->pdp.page_directory[i]->daddr)
 			continue;
 
-		pci_unmap_page(hwdev, ppgtt->pdp.page_directory[i].daddr, PAGE_SIZE,
+		pci_unmap_page(hwdev, ppgtt->pdp.page_directory[i]->daddr, PAGE_SIZE,
 			       PCI_DMA_BIDIRECTIONAL);
 
 		for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
-			dma_addr_t addr = ppgtt->pdp.page_directory[i].page_table[j].daddr;
+			struct i915_page_directory_entry *pd = ppgtt->pdp.page_directory[i];
+			struct i915_page_table_entry *pt;
+			dma_addr_t addr;
+
+			if (WARN_ON(!pd->page_table[j]))
+				continue;
+
+			pt = pd->page_table[j];
+			addr = pt->daddr;
+
 			if (addr)
 				pci_unmap_page(hwdev, addr, PAGE_SIZE,
 					       PCI_DMA_BIDIRECTIONAL);
@@ -474,25 +593,20 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
 
 static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt)
 {
-	int i, j;
+	int i, ret;
 
 	for (i = 0; i < ppgtt->num_pd_pages; i++) {
-		struct i915_page_directory_entry *pd = &ppgtt->pdp.page_directory[i];
-		for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
-			struct i915_page_table_entry *pt = &pd->page_table[j];
-
-			pt->page = alloc_page(GFP_KERNEL | __GFP_ZERO);
-			if (!pt->page)
+		ret = alloc_pt_range(ppgtt->pdp.page_directory[i],
+				     0, GEN8_PDES_PER_PAGE);
+		if (ret)
 			goto unwind_out;
-
-		}
 	}
 
 	return 0;
 
 unwind_out:
 	while (i--)
-		gen8_free_page_tables(&ppgtt->pdp.page_directory[i]);
+		gen8_free_page_tables(ppgtt->pdp.page_directory[i]);
 
 	return -ENOMEM;
 }
@@ -503,19 +617,9 @@ static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
 	int i;
 
 	for (i = 0; i < max_pdp; i++) {
-		struct i915_page_table_entry *pt;
-
-		pt = kcalloc(GEN8_PDES_PER_PAGE, sizeof(*pt), GFP_KERNEL);
-		if (!pt)
+		ppgtt->pdp.page_directory[i] = alloc_pd_single();
+		if (IS_ERR(ppgtt->pdp.page_directory[i]))
 			goto unwind_out;
-
-		ppgtt->pdp.page_directory[i].page = alloc_page(GFP_KERNEL);
-		if (!ppgtt->pdp.page_directory[i].page) {
-			kfree(pt);
-			goto unwind_out;
-		}
-
-		ppgtt->pdp.page_directory[i].page_table = pt;
 	}
 
 	ppgtt->num_pd_pages = max_pdp;
@@ -524,10 +628,8 @@ static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
 	return 0;
 
 unwind_out:
-	while (i--) {
-		kfree(ppgtt->pdp.page_directory[i].page_table);
-		__free_page(ppgtt->pdp.page_directory[i].page);
-	}
+	while (i--)
+		unmap_and_free_pd(ppgtt->pdp.page_directory[i]);
 
 	return -ENOMEM;
 }
@@ -561,14 +663,14 @@ static int gen8_ppgtt_setup_page_directories(struct i915_hw_ppgtt *ppgtt,
 	int ret;
 
 	pd_addr = pci_map_page(ppgtt->base.dev->pdev,
-			       ppgtt->pdp.page_directory[pd].page, 0,
+			       ppgtt->pdp.page_directory[pd]->page, 0,
 			       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 
 	ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pd_addr);
 	if (ret)
 		return ret;
 
-	ppgtt->pdp.page_directory[pd].daddr = pd_addr;
+	ppgtt->pdp.page_directory[pd]->daddr = pd_addr;
 
 	return 0;
 }
@@ -578,8 +680,8 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
 					const int pt)
 {
 	dma_addr_t pt_addr;
-	struct i915_page_directory_entry *pdir = &ppgtt->pdp.page_directory[pd];
-	struct i915_page_table_entry *ptab = &pdir->page_table[pt];
+	struct i915_page_directory_entry *pdir = ppgtt->pdp.page_directory[pd];
+	struct i915_page_table_entry *ptab = pdir->page_table[pt];
 	struct page *p = ptab->page;
 	int ret;
 
@@ -642,10 +744,12 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 	 * will never need to touch the PDEs again.
 	 */
 	for (i = 0; i < max_pdp; i++) {
+		struct i915_page_directory_entry *pd = ppgtt->pdp.page_directory[i];
 		gen8_ppgtt_pde_t *pd_vaddr;
-		pd_vaddr = kmap_atomic(ppgtt->pdp.page_directory[i].page);
+		pd_vaddr = kmap_atomic(ppgtt->pdp.page_directory[i]->page);
 		for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
-			dma_addr_t addr = ppgtt->pdp.page_directory[i].page_table[j].daddr;
+			struct i915_page_table_entry *pt = pd->page_table[j];
+			dma_addr_t addr = pt->daddr;
 			pd_vaddr[j] = gen8_pde_encode(ppgtt->base.dev, addr,
 						      I915_CACHE_LLC);
 		}
@@ -696,7 +800,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
 	for (pde = 0; pde < ppgtt->num_pd_entries; pde++) {
 		u32 expected;
 		gen6_gtt_pte_t *pt_vaddr;
-		dma_addr_t pt_addr = ppgtt->pd.page_table[pde].daddr;
+		dma_addr_t pt_addr = ppgtt->pd.page_table[pde]->daddr;
 		pd_entry = readl(pd_addr + pde);
 		expected = (GEN6_PDE_ADDR_ENCODE(pt_addr) | GEN6_PDE_VALID);
 
@@ -707,7 +811,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
 				   expected);
 		seq_printf(m, "\tPDE: %x\n", pd_entry);
 
-		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[pde].page);
+		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[pde]->page);
 		for (pte = 0; pte < I915_PPGTT_PT_ENTRIES; pte+=4) {
 			unsigned long va =
 				(pde * PAGE_SIZE * I915_PPGTT_PT_ENTRIES) +
@@ -746,7 +850,7 @@ static void gen6_write_pdes(struct i915_hw_ppgtt *ppgtt)
 	for (i = 0; i < ppgtt->num_pd_entries; i++) {
 		dma_addr_t pt_addr;
 
-		pt_addr = ppgtt->pd.page_table[i].daddr;
+		pt_addr = ppgtt->pd.page_table[i]->daddr;
 		pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
 		pd_entry |= GEN6_PDE_VALID;
 
@@ -922,7 +1026,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
 		if (last_pte > I915_PPGTT_PT_ENTRIES)
 			last_pte = I915_PPGTT_PT_ENTRIES;
 
-		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt].page);
+		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->page);
 
 		for (i = first_pte; i < last_pte; i++)
 			pt_vaddr[i] = scratch_pte;
@@ -951,7 +1055,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
 	pt_vaddr = NULL;
 	for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
 		if (pt_vaddr == NULL)
-			pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt].page);
+			pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->page);
 
 		pt_vaddr[act_pte] =
 			vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
@@ -974,7 +1078,7 @@ static void gen6_ppgtt_unmap_pages(struct i915_hw_ppgtt *ppgtt)
 
 	for (i = 0; i < ppgtt->num_pd_entries; i++)
 		pci_unmap_page(ppgtt->base.dev->pdev,
-			       ppgtt->pd.page_table[i].daddr,
+			       ppgtt->pd.page_table[i]->daddr,
 			       4096, PCI_DMA_BIDIRECTIONAL);
 }
 
@@ -983,9 +1087,9 @@ static void gen6_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
 	int i;
 
 	for (i = 0; i < ppgtt->num_pd_entries; i++)
-		if (ppgtt->pd.page_table[i].page)
-			__free_page(ppgtt->pd.page_table[i].page);
-	kfree(ppgtt->pd.page_table);
+		unmap_and_free_pt(ppgtt->pd.page_table[i]);
+
+	unmap_and_free_pd(&ppgtt->pd);
 }
 
 static void gen6_ppgtt_cleanup(struct i915_address_space *vm)
@@ -1040,28 +1144,6 @@ static int gen6_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt)
 	return 0;
 }
 
-static int gen6_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt)
-{
-	struct i915_page_table_entry *pt;
-	int i;
-
-	pt = kcalloc(ppgtt->num_pd_entries, sizeof(*pt), GFP_KERNEL);
-	if (!pt)
-		return -ENOMEM;
-
-	ppgtt->pd.page_table = pt;
-
-	for (i = 0; i < ppgtt->num_pd_entries; i++) {
-		pt[i].page = alloc_page(GFP_KERNEL);
-		if (!pt->page) {
-			gen6_ppgtt_free(ppgtt);
-			return -ENOMEM;
-		}
-	}
-
-	return 0;
-}
-
 static int gen6_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt)
 {
 	int ret;
@@ -1070,7 +1152,7 @@ static int gen6_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt)
 	if (ret)
 		return ret;
 
-	ret = gen6_ppgtt_allocate_page_tables(ppgtt);
+	ret = alloc_pt_range(&ppgtt->pd, 0, ppgtt->num_pd_entries);
 	if (ret) {
 		drm_mm_remove_node(&ppgtt->node);
 		return ret;
@@ -1088,7 +1170,7 @@ static int gen6_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt)
 		struct page *page;
 		dma_addr_t pt_addr;
 
-		page = ppgtt->pd.page_table[i].page;
+		page = ppgtt->pd.page_table[i]->page;
 		pt_addr = pci_map_page(dev->pdev, page, 0, 4096,
 				       PCI_DMA_BIDIRECTIONAL);
 
@@ -1097,7 +1179,7 @@ static int gen6_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt)
 			return -EIO;
 		}
 
-		ppgtt->pd.page_table[i].daddr = pt_addr;
+		ppgtt->pd.page_table[i]->daddr = pt_addr;
 	}
 
 	return 0;

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -199,12 +199,12 @@ struct i915_page_directory_entry {
 		dma_addr_t daddr;
 	};
 
-	struct i915_page_table_entry *page_table;
+	struct i915_page_table_entry *page_table[GEN6_PPGTT_PD_ENTRIES]; /* PDEs */
 };
 
 struct i915_page_directory_pointer_entry {
 	/* struct page *page; */
-	struct i915_page_directory_entry page_directory[GEN8_LEGACY_PDPES];
+	struct i915_page_directory_entry *page_directory[GEN8_LEGACY_PDPES];
 };
 
 struct i915_address_space {

drivers/gpu/drm/i915/intel_lrc.c

@@ -1772,14 +1772,14 @@ populate_lr_context(struct intel_context *ctx, struct drm_i915_gem_object *ctx_o
 	reg_state[CTX_PDP1_LDW] = GEN8_RING_PDP_LDW(ring, 1);
 	reg_state[CTX_PDP0_UDW] = GEN8_RING_PDP_UDW(ring, 0);
 	reg_state[CTX_PDP0_LDW] = GEN8_RING_PDP_LDW(ring, 0);
-	reg_state[CTX_PDP3_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[3].daddr);
-	reg_state[CTX_PDP3_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[3].daddr);
-	reg_state[CTX_PDP2_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[2].daddr);
-	reg_state[CTX_PDP2_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[2].daddr);
-	reg_state[CTX_PDP1_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[1].daddr);
-	reg_state[CTX_PDP1_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[1].daddr);
-	reg_state[CTX_PDP0_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[0].daddr);
-	reg_state[CTX_PDP0_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[0].daddr);
+	reg_state[CTX_PDP3_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[3]->daddr);
+	reg_state[CTX_PDP3_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[3]->daddr);
+	reg_state[CTX_PDP2_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[2]->daddr);
+	reg_state[CTX_PDP2_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[2]->daddr);
+	reg_state[CTX_PDP1_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[1]->daddr);
+	reg_state[CTX_PDP1_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[1]->daddr);
+	reg_state[CTX_PDP0_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[0]->daddr);
+	reg_state[CTX_PDP0_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[0]->daddr);
 	if (ring->id == RCS) {
 		reg_state[CTX_LRI_HEADER_2] = MI_LOAD_REGISTER_IMM(1);
 		reg_state[CTX_R_PWR_CLK_STATE] = GEN8_R_PWR_CLK_STATE;