From: Alexander Shishkin alexander.shishkin@linux.intel.com
commit 918b8646497b5dba6ae82d4a7325f01b258972b9 upstream.
Commit 4e0eaf239fb3 ("intel_th: msu: Fix single mode with IOMMU") switched the single mode code to use dma mapping pages obtained from the page allocator, but with IOMMU disabled, that may lead to using SWIOTLB bounce buffers and without additional sync'ing, produces empty trace buffers.
Fix this by using a DMA32 GFP flag to the page allocation in single mode, as the device supports full 32-bit DMA addressing.
Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Fixes: 4e0eaf239fb3 ("intel_th: msu: Fix single mode with IOMMU") Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Reported-by: Ammy Yi ammy.yi@intel.com Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20190621161930.60785-4-alexander.shishkin@linux.in... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/hwtracing/intel_th/msu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -640,7 +640,7 @@ static int msc_buffer_contig_alloc(struc goto err_out;
ret = -ENOMEM; - page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); + page = alloc_pages(GFP_KERNEL | __GFP_ZERO | GFP_DMA32, order); if (!page) goto err_free_sgt;