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Commit bb320786 authored by Dan Williams's avatar Dan Williams
Browse files

ioat: ignore reserved bits for chancnt and xfercap 



Don't trust that the reserved bits are always zero, also sanity check
the returned value.

Signed-off-by: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 4fb9b9e8

drivers/dma/ioat/dma.c

+7 −0
Original line number Diff line number Diff line
@@ -132,7 +132,14 @@ static int ioat1_enumerate_channels(struct ioatdma_device *device) 


	INIT_LIST_HEAD(&dma->channels);

	dma->chancnt = readb(device->reg_base + IOAT_CHANCNT_OFFSET);

	dma->chancnt &= 0x1f; /* bits [4:0] valid */

	if (dma->chancnt > ARRAY_SIZE(device->idx)) {

		dev_warn(dev, "(%d) exceeds max supported channels (%zu)\n",

			 dma->chancnt, ARRAY_SIZE(device->idx));

		dma->chancnt = ARRAY_SIZE(device->idx);

	}

	xfercap_scale = readb(device->reg_base + IOAT_XFERCAP_OFFSET);

	xfercap_scale &= 0x1f; /* bits [4:0] valid */

	xfercap = (xfercap_scale == 0 ? -1 : (1UL << xfercap_scale));

	dev_dbg(dev, "%s: xfercap = %d\n", __func__, xfercap);

drivers/dma/ioat/dma_v2.c

+7 −0
Original line number Diff line number Diff line
@@ -359,7 +359,14 @@ static int ioat2_enumerate_channels(struct ioatdma_device *device) 


	INIT_LIST_HEAD(&dma->channels);

	dma->chancnt = readb(device->reg_base + IOAT_CHANCNT_OFFSET);

	dma->chancnt &= 0x1f; /* bits [4:0] valid */

	if (dma->chancnt > ARRAY_SIZE(device->idx)) {

		dev_warn(dev, "(%d) exceeds max supported channels (%zu)\n",

			 dma->chancnt, ARRAY_SIZE(device->idx));

		dma->chancnt = ARRAY_SIZE(device->idx);

	}

	xfercap_log = readb(device->reg_base + IOAT_XFERCAP_OFFSET);

	xfercap_log &= 0x1f; /* bits [4:0] valid */

	if (xfercap_log == 0)

		return 0;

	dev_dbg(dev, "%s: xfercap = %d\n", __func__, 1 << xfercap_log);