1 files changed, 80 insertions, 0 deletions
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
new file mode 100644
index 000000000..5240f6aca
--- /dev/null
+++ b/arch/arm64/mm/dma-mapping.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Catalin Marinas <catalin.marinas@arm.com>
+ */
+
+#include <linux/gfp.h>
+#include <linux/cache.h>
+#include <linux/dma-map-ops.h>
+#include <linux/iommu.h>
+#include <xen/xen.h>
+
+#include <asm/cacheflush.h>
+#include <asm/xen/xen-ops.h>
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+			      enum dma_data_direction dir)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+
+	dcache_clean_poc(start, start + size);
+}
+
+void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
+			   enum dma_data_direction dir)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+
+	if (dir == DMA_TO_DEVICE)
+		return;
+
+	dcache_inval_poc(start, start + size);
+}
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
+{
+	unsigned long start = (unsigned long)page_address(page);
+
+	/*
+	 * The architecture only requires a clean to the PoC here in order to
+	 * meet the requirements of the DMA API. However, some vendors (i.e.
+	 * Qualcomm) abuse the DMA API for transferring buffers from the
+	 * non-secure to the secure world, resetting the system if a non-secure
+	 * access shows up after the buffer has been transferred:
+	 *
+	 * https://lore.kernel.org/r/20221114110329.68413-1-manivannan.sadhasivam@linaro.org
+	 *
+	 * Using clean+invalidate appears to make this issue less likely, but
+	 * the drivers themselves still need fixing as the CPU could issue a
+	 * speculative read from the buffer via the linear mapping irrespective
+	 * of the cache maintenance we use. Once the drivers are fixed, we can
+	 * relax this to a clean operation.
+	 */
+	dcache_clean_inval_poc(start, start + size);
+}
+
+#ifdef CONFIG_IOMMU_DMA
+void arch_teardown_dma_ops(struct device *dev)
+{
+	dev->dma_ops = NULL;
+}
+#endif
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+			const struct iommu_ops *iommu, bool coherent)
+{
+	int cls = cache_line_size_of_cpu();
+
+	WARN_TAINT(!coherent && cls > ARCH_DMA_MINALIGN,
+		   TAINT_CPU_OUT_OF_SPEC,
+		   "%s %s: ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (%d < %d)",
+		   dev_driver_string(dev), dev_name(dev),
+		   ARCH_DMA_MINALIGN, cls);
+
+	dev->dma_coherent = coherent;
+	if (iommu)
+		iommu_setup_dma_ops(dev, dma_base, dma_base + size - 1);
+
+	xen_setup_dma_ops(dev);
+}