Commit 48ab6d5d authored Oct 26, 2020 by Geert Uytterhoeven Committed by Christoph Hellwig Oct 29, 2020

dma-mapping: fix 32-bit overflow with CONFIG_ARM_LPAE=n



On r8a7791/koelsch and shmobile_defconfig, PCIe probing fails with:

    rcar-pcie fe000000.pcie: Adjusted size 0x0 invalid
    rcar-pcie: probe of fe000000.pcie failed with error -22

of_dma_get_range() returns the following map:

    cpu_start 0x40000000 dma_start 0x40000000 size 0x080000000 offset 0
    cpu_start 0x00000000 dma_start 0x00000000 size 0x100000000 offset 0

If CONFIG_ARM_LPAE=n, dma_addr_t is 32-bit.  Hence when assigning
r->dma_start + r->size to dma_end, this value will be truncated to
32-bit, yielding zero when processing the second table entry.
Consequently, both dma_start and dma_end will be zero, leading to a zero
size.

Fix this by changing the dma_start and dma_end variables from dma_addr_t
to u64.

Fixes: e0d07278 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent ed8780e3

drivers/of/device.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -93,7 +93,7 @@ int of_dma_configure_id(struct device dev, struct device_node np,
		{
		const struct iommu_ops *iommu;
		const struct bus_dma_region *map = NULL;
		dma_addr_t dma_start = 0;
		u64 dma_start = 0;
		u64 mask, end, size = 0;
		bool coherent;
		int ret;
		@@ -109,10 +109,10 @@ int of_dma_configure_id(struct device dev, struct device_node np,
		return ret == -ENODEV ? 0 : ret;
		} else {
		const struct bus_dma_region *r = map;
		dma_addr_t dma_end = 0;
		u64 dma_end = 0;

		/* Determine the overall bounds of all DMA regions */
		for (dma_start = ~(dma_addr_t)0; r->size; r++) {
		for (dma_start = ~0ULL; r->size; r++) {
		/* Take lower and upper limits */
		if (r->dma_start < dma_start)
		dma_start = r->dma_start;

Admin message