[PATCH 11/28] dma-mapping: add (back) arch_dma_mark_clean for ia64

From: Christoph Hellwig
Date: Wed Aug 19 2020 - 03:05:55 EST


Add back a hook to optimize dcache flushing after reading executable
code using DMA. This gets ia64 out of the business of pretending to
be dma incoherent just for this optimization.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/ia64/Kconfig | 3 +--
arch/ia64/kernel/dma-mapping.c | 14 +-------------
arch/ia64/mm/init.c | 3 +--
include/linux/dma-direct.h | 3 +++
include/linux/dma-noncoherent.h | 8 ++++++++
kernel/dma/Kconfig | 6 ++++++
kernel/dma/direct.c | 3 +++
7 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 5b4ec80bf5863a..513ba0c5d33610 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -8,6 +8,7 @@ menu "Processor type and features"

config IA64
bool
+ select ARCH_HAS_DMA_MARK_CLEAN
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
select ACPI
@@ -32,8 +33,6 @@ config IA64
select TTY
select HAVE_ARCH_TRACEHOOK
select HAVE_VIRT_CPU_ACCOUNTING
- select DMA_NONCOHERENT_MMAP
- select ARCH_HAS_SYNC_DMA_FOR_CPU
select VIRT_TO_BUS
select GENERIC_IRQ_PROBE
select GENERIC_PENDING_IRQ if SMP
diff --git a/arch/ia64/kernel/dma-mapping.c b/arch/ia64/kernel/dma-mapping.c
index 09ef9ce9988d1f..f640ed6fe1d576 100644
--- a/arch/ia64/kernel/dma-mapping.c
+++ b/arch/ia64/kernel/dma-mapping.c
@@ -1,5 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
-#include <linux/dma-direct.h>
+#include <linux/dma-mapping.h>
#include <linux/export.h>

/* Set this to 1 if there is a HW IOMMU in the system */
@@ -7,15 +7,3 @@ int iommu_detected __read_mostly;

const struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);
-
-void *arch_dma_alloc(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
-{
- return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
-}
-
-void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
- dma_addr_t dma_addr, unsigned long attrs)
-{
- dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
-}
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 0b3fb4c7af2920..02e5aa08294ee0 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -73,8 +73,7 @@ __ia64_sync_icache_dcache (pte_t pte)
* DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
* flush them when they get mapped into an executable vm-area.
*/
-void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
- enum dma_data_direction dir)
+void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
{
unsigned long pfn = PHYS_PFN(paddr);

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 5a3ce2a2479437..738485b3578062 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -153,6 +153,9 @@ static inline void dma_direct_sync_single_for_cpu(struct device *dev,

if (unlikely(is_swiotlb_buffer(paddr)))
swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
+
+ if (dir == DMA_FROM_DEVICE)
+ arch_dma_mark_clean(paddr, size);
}

static inline dma_addr_t dma_direct_map_page(struct device *dev,
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
index ca09a4e07d2d3d..b9bc6c557ea46f 100644
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -108,6 +108,14 @@ static inline void arch_dma_prep_coherent(struct page *page, size_t size)
}
#endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */

+#ifdef CONFIG_ARCH_HAS_DMA_MARK_CLEAN
+void arch_dma_mark_clean(phys_addr_t paddr, size_t size);
+#else
+static inline void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
+{
+}
+#endif /* ARCH_HAS_DMA_MARK_CLEAN */
+
void *arch_dma_set_uncached(void *addr, size_t size);
void arch_dma_clear_uncached(void *addr, size_t size);

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 847a9d1fa6343d..6cf7f7947ae797 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -43,6 +43,12 @@ config ARCH_HAS_DMA_SET_MASK
config ARCH_HAS_DMA_WRITE_COMBINE
bool

+#
+# Select if the architectures provides the arch_dma_mark_clean hook
+#
+config ARCH_HAS_DMA_MARK_CLEAN
+ bool
+
config DMA_DECLARE_COHERENT
bool

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index bb0041e9965975..1123e767f4315f 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -340,6 +340,9 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
if (unlikely(is_swiotlb_buffer(paddr)))
swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
SYNC_FOR_CPU);
+
+ if (dir == DMA_FROM_DEVICE)
+ arch_dma_mark_clean(paddr, sg->length);
}

if (!dev_is_dma_coherent(dev))
--
2.28.0