From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB

---
 kernel/drivers/gpu/drm/i915/i915_mm.c |   78 ++++++++++++++++++++++++++++++++++++---
 1 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/kernel/drivers/gpu/drm/i915/i915_mm.c b/kernel/drivers/gpu/drm/i915/i915_mm.c
index e4935dd..43039dc 100644
--- a/kernel/drivers/gpu/drm/i915/i915_mm.c
+++ b/kernel/drivers/gpu/drm/i915/i915_mm.c
@@ -25,7 +25,6 @@
 #include <linux/mm.h>
 #include <linux/io-mapping.h>
 
-#include <asm/pgtable.h>
 
 #include "i915_drv.h"
 
@@ -33,16 +32,47 @@
 	struct mm_struct *mm;
 	unsigned long pfn;
 	pgprot_t prot;
+
+	struct sgt_iter sgt;
+	resource_size_t iobase;
 };
 
-static int remap_pfn(pte_t *pte, pgtable_t token,
-		     unsigned long addr, void *data)
+static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
 {
 	struct remap_pfn *r = data;
 
 	/* Special PTE are not associated with any struct page */
 	set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot)));
 	r->pfn++;
+
+	return 0;
+}
+
+#define use_dma(io) ((io) != -1)
+
+static inline unsigned long sgt_pfn(const struct remap_pfn *r)
+{
+	if (use_dma(r->iobase))
+		return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT;
+	else
+		return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT);
+}
+
+static int remap_sg(pte_t *pte, unsigned long addr, void *data)
+{
+	struct remap_pfn *r = data;
+
+	if (GEM_WARN_ON(!r->sgt.pfn))
+		return -EINVAL;
+
+	/* Special PTE are not associated with any struct page */
+	set_pte_at(r->mm, addr, pte,
+		   pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot)));
+	r->pfn++; /* track insertions in case we need to unwind later */
+
+	r->sgt.curr += PAGE_SIZE;
+	if (r->sgt.curr >= r->sgt.max)
+		r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase));
 
 	return 0;
 }
@@ -64,9 +94,8 @@
 	struct remap_pfn r;
 	int err;
 
-	GEM_BUG_ON((vma->vm_flags &
-		    (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)) !=
-		   (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP));
+#define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
+	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
 
 	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
 	r.mm = vma->vm_mm;
@@ -82,3 +111,40 @@
 
 	return 0;
 }
+
+/**
+ * remap_io_sg - remap an IO mapping to userspace
+ * @vma: user vma to map to
+ * @addr: target user address to start at
+ * @size: size of map area
+ * @sgl: Start sg entry
+ * @iobase: Use stored dma address offset by this address or pfn if -1
+ *
+ *  Note: this is only safe if the mm semaphore is held when called.
+ */
+int remap_io_sg(struct vm_area_struct *vma,
+		unsigned long addr, unsigned long size,
+		struct scatterlist *sgl, resource_size_t iobase)
+{
+	struct remap_pfn r = {
+		.mm = vma->vm_mm,
+		.prot = vma->vm_page_prot,
+		.sgt = __sgt_iter(sgl, use_dma(iobase)),
+		.iobase = iobase,
+	};
+	int err;
+
+	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
+	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
+
+	if (!use_dma(iobase))
+		flush_cache_range(vma, addr, size);
+
+	err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
+	if (unlikely(err)) {
+		zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
+		return err;
+	}
+
+	return 0;
+}

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