[PATCH 4.4 039/241] intel_th: msu: Fix single mode with IOMMU

[Greg Kroah-Hartman]

From: Alexander Shishkin <alexander.shish...@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.shish...@linux.intel.com>
Fixes: ba82664c134e ("intel_th: Add Memory Storage Unit driver")
Cc: sta...@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gre...@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
@@ -90,6 +90,7 @@ 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
@@ -110,6 +111,7 @@ 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;
@@ -610,22 +612,45 @@ 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;
 }
 
 /**
@@ -636,6 +661,10 @@ 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);