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Commit cf540145 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by Linus Torvalds
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alpha: make IOMMU respect the segment boundary limits 



This patch makes the IOMMU code not allocate a memory area spanning LLD's
segment boundary.

is_span_boundary() judges whether a memory area spans LLD's segment boundary.
If iommu_arena_find_pages() finds such a area, it tries to find the next
available memory area.

Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23d7e039

arch/alpha/kernel/pci_iommu.c

+34 −6
Original line number Diff line number Diff line
@@ -126,13 +126,34 @@ iommu_arena_new(struct pci_controller *hose, dma_addr_t base, 
	return iommu_arena_new_node(0, hose, base, window_size, align);

}



static inline int is_span_boundary(unsigned int index, unsigned int nr,

				   unsigned long shift,

				   unsigned long boundary_size)

{

	shift = (shift + index) & (boundary_size - 1);

	return shift + nr > boundary_size;

}



/* Must be called with the arena lock held */

static long

iommu_arena_find_pages(struct pci_iommu_arena *arena, long n, long mask)

iommu_arena_find_pages(struct device *dev, struct pci_iommu_arena *arena,

		       long n, long mask)

{

	unsigned long *ptes;

	long i, p, nent;

	int pass = 0;

	unsigned long base;

	unsigned long boundary_size;



	BUG_ON(arena->dma_base & ~PAGE_MASK);

	base = arena->dma_base >> PAGE_SHIFT;

	if (dev)

		boundary_size = ALIGN(dma_get_max_seg_size(dev) + 1, PAGE_SIZE)

			>> PAGE_SHIFT;

	else

		boundary_size = ALIGN(1UL << 32, PAGE_SIZE) >> PAGE_SHIFT;



	BUG_ON(!is_power_of_2(boundary_size));



	/* Search forward for the first mask-aligned sequence of N free ptes */

	ptes = arena->ptes;
@@ -142,6 +163,11 @@ iommu_arena_find_pages(struct pci_iommu_arena *arena, long n, long mask) 


again:

	while (i < n && p+i < nent) {

		if (!i && is_span_boundary(p, n, base, boundary_size)) {

			p = ALIGN(p + 1, mask + 1);

			goto again;

		}



		if (ptes[p+i])

			p = ALIGN(p + i + 1, mask + 1), i = 0;

		else
@@ -170,7 +196,8 @@ iommu_arena_find_pages(struct pci_iommu_arena *arena, long n, long mask) 
}



static long

iommu_arena_alloc(struct pci_iommu_arena *arena, long n, unsigned int align)

iommu_arena_alloc(struct device *dev, struct pci_iommu_arena *arena, long n,

		  unsigned int align)

{

	unsigned long flags;

	unsigned long *ptes;
@@ -181,7 +208,7 @@ iommu_arena_alloc(struct pci_iommu_arena *arena, long n, unsigned int align) 
	/* Search for N empty ptes */

	ptes = arena->ptes;

	mask = max(align, arena->align_entry) - 1;

	p = iommu_arena_find_pages(arena, n, mask);

	p = iommu_arena_find_pages(dev, arena, n, mask);

	if (p < 0) {

		spin_unlock_irqrestore(&arena->lock, flags);

		return -1;
@@ -231,6 +258,7 @@ pci_map_single_1(struct pci_dev *pdev, void *cpu_addr, size_t size, 
	unsigned long paddr;

	dma_addr_t ret;

	unsigned int align = 0;

	struct device *dev = pdev ? &pdev->dev : NULL;



	paddr = __pa(cpu_addr);
@@ -278,7 +306,7 @@ pci_map_single_1(struct pci_dev *pdev, void *cpu_addr, size_t size, 
	/* Force allocation to 64KB boundary for ISA bridges. */

	if (pdev && pdev == isa_bridge)

		align = 8;

	dma_ofs = iommu_arena_alloc(arena, npages, align);

	dma_ofs = iommu_arena_alloc(dev, arena, npages, align);

	if (dma_ofs < 0) {

		printk(KERN_WARNING "pci_map_single failed: "

		       "could not allocate dma page tables\n");
@@ -565,7 +593,7 @@ sg_fill(struct device *dev, struct scatterlist *leader, struct scatterlist *end, 


	paddr &= ~PAGE_MASK;

	npages = calc_npages(paddr + size);

	dma_ofs = iommu_arena_alloc(arena, npages, 0);

	dma_ofs = iommu_arena_alloc(dev, arena, npages, 0);

	if (dma_ofs < 0) {

		/* If we attempted a direct map above but failed, die.  */

		if (leader->dma_address == 0)
@@ -832,7 +860,7 @@ iommu_reserve(struct pci_iommu_arena *arena, long pg_count, long align_mask) 


	/* Search for N empty ptes.  */

	ptes = arena->ptes;

	p = iommu_arena_find_pages(arena, pg_count, align_mask);

	p = iommu_arena_find_pages(NULL, arena, pg_count, align_mask);

	if (p < 0) {

		spin_unlock_irqrestore(&arena->lock, flags);

		return -1;