[PATCH 5.0 038/139] intel_th: msu: Fix single mode with IOMMU

Greg Kroah-Hartman
2019-05-23T19:39:54Z

From: Alexander Shishkin <alexander.shishkin@linux.intel.com>

commit 4e0eaf239fb33ebc671303e2b736fa043462e2f4 upstream.

Currently, the pages that are allocated for the single mode of MSC are not
mapped into the device's dma space and the code is incorrectly using
*_to_phys() in place of a dma address. This fails with IOMMU enabled and
is otherwise bad practice.

Fix the single mode buffer allocation to map the pages into the device's
DMA space.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: ba82664c134e ("intel_th: Add Memory Storage Unit driver")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hwtracing/intel_th/msu.c | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)

--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -84,6 +84,7 @@ struct msc_iter {
* @reg_base: register window base address
* @thdev: intel_th_device pointer
* @win_list: list of windows in multiblock mode
+ * @single_sgt: single mode buffer
* @nr_pages: total number of pages allocated for this buffer
* @single_sz: amount of data in single mode
* @single_wrap: single mode wrap occurred
@@ -104,6 +105,7 @@ struct msc {
struct intel_th_device *thdev;

struct list_head win_list;
+ struct sg_table single_sgt;
unsigned long nr_pages;
unsigned long single_sz;
unsigned int single_wrap : 1;
@@ -617,22 +619,45 @@ static void intel_th_msc_deactivate(stru
*/
static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
{
+ unsigned long nr_pages = size >> PAGE_SHIFT;
unsigned int order = get_order(size);
struct page *page;
+ int ret;

if (!size)
return 0;

+ ret = sg_alloc_table(&msc->single_sgt, 1, GFP_KERNEL);
+ if (ret)
+ goto err_out;
+
+ ret = -ENOMEM;
page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!page)
- return -ENOMEM;
+ goto err_free_sgt;

split_page(page, order);
- msc->nr_pages = size >> PAGE_SHIFT;
+ sg_set_buf(msc->single_sgt.sgl, page_address(page), size);
+
+ ret = dma_map_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl, 1,
+ DMA_FROM_DEVICE);
+ if (ret < 0)
+ goto err_free_pages;
+
+ msc->nr_pages = nr_pages;
msc->base = page_address(page);
- msc->base_addr = page_to_phys(page);
+ msc->base_addr = sg_dma_address(msc->single_sgt.sgl);

return 0;
+
+err_free_pages:
+ __free_pages(page, order);
+
+err_free_sgt:
+ sg_free_table(&msc->single_sgt);
+
+err_out:
+ return ret;
}

/**
@@ -643,6 +668,10 @@ static void msc_buffer_contig_free(struc
{
unsigned long off;

+ dma_unmap_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl,
+ 1, DMA_FROM_DEVICE);
+ sg_free_table(&msc->single_sgt);
+
for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
struct page *page = virt_to_page(msc->base + off);