disable FB

hc

2024-01-04 1543e317f1da31b75942316931e8f491a8920811

 kernel/drivers/gpu/drm/i915/i915_mm.c
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@@ -25,7 +25,6 @@
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 #include <linux/mm.h>
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 #include <linux/io-mapping.h>
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27
 
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-#include <asm/pgtable.h>
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 #include "i915_drv.h"
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..
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@@ -33,16 +32,47 @@
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 	struct mm_struct *mm;
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 	unsigned long pfn;
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 	pgprot_t prot;
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+
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+	struct sgt_iter sgt;
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+	resource_size_t iobase;
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 };
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-static int remap_pfn(pte_t *pte, pgtable_t token,
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-		     unsigned long addr, void *data)
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+static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
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 {
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 	struct remap_pfn *r = data;
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 	/* Special PTE are not associated with any struct page */
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 	set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot)));
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 	r->pfn++;
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+
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+	return 0;
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+}
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+
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+#define use_dma(io) ((io) != -1)
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+
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+static inline unsigned long sgt_pfn(const struct remap_pfn *r)
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+{
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+	if (use_dma(r->iobase))
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+		return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT;
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+	else
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+		return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT);
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+}
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+
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+static int remap_sg(pte_t *pte, unsigned long addr, void *data)
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+{
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+	struct remap_pfn *r = data;
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+
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+	if (GEM_WARN_ON(!r->sgt.pfn))
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+		return -EINVAL;
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+
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+	/* Special PTE are not associated with any struct page */
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+	set_pte_at(r->mm, addr, pte,
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+		   pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot)));
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+	r->pfn++; /* track insertions in case we need to unwind later */
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+
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+	r->sgt.curr += PAGE_SIZE;
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+	if (r->sgt.curr >= r->sgt.max)
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+		r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase));
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 	return 0;
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 }
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@@ -64,9 +94,8 @@
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 	struct remap_pfn r;
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 	int err;
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-	GEM_BUG_ON((vma->vm_flags &
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-		    (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)) !=
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-		   (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP));
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+#define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
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+	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
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 	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
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 	r.mm = vma->vm_mm;
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@@ -82,3 +111,40 @@
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111
 
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 	return 0;
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 }
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+
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+/**
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+ * remap_io_sg - remap an IO mapping to userspace
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+ * @vma: user vma to map to
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+ * @addr: target user address to start at
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+ * @size: size of map area
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+ * @sgl: Start sg entry
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+ * @iobase: Use stored dma address offset by this address or pfn if -1
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+ *
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+ *  Note: this is only safe if the mm semaphore is held when called.
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+ */
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+int remap_io_sg(struct vm_area_struct *vma,
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+		unsigned long addr, unsigned long size,
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+		struct scatterlist *sgl, resource_size_t iobase)
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+{
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+	struct remap_pfn r = {
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+		.mm = vma->vm_mm,
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+		.prot = vma->vm_page_prot,
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+		.sgt = __sgt_iter(sgl, use_dma(iobase)),
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+		.iobase = iobase,
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+	};
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+	int err;
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+
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+	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
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+	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
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+
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+	if (!use_dma(iobase))
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+		flush_cache_range(vma, addr, size);
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+
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+	err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
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+	if (unlikely(err)) {
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+		zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
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+		return err;
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+	}
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+
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+	return 0;
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+}