From: Christoph Hellwig <hch@lst.de>
Date: Fri, 21 Feb 2020 15:55:43 -0800
Subject: dma-direct: make uncached_kernel_address more general
Git-commit: fa7e2247c5729f990c7456fe09f3af99c8f2571b
Patch-mainline: v5.7-rc1
References: bsc#1175713

Rename the symbol to arch_dma_set_uncached, and pass a size to it as
well as allow an error return.  That will allow reusing this hook for
in-place pagetable remapping.

As the in-place remap doesn't always require an explicit cache flush,
also detangle ARCH_HAS_DMA_PREP_COHERENT from ARCH_HAS_DMA_SET_UNCACHED.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 arch/Kconfig                    |    8 ++++----
 arch/mips/Kconfig               |    3 ++-
 arch/mips/mm/dma-noncoherent.c  |    2 +-
 arch/nios2/Kconfig              |    3 ++-
 arch/nios2/mm/dma-mapping.c     |    2 +-
 include/linux/dma-noncoherent.h |    2 +-
 kernel/dma/direct.c             |   10 ++++++----
 7 files changed, 17 insertions(+), 13 deletions(-)

--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -248,11 +248,11 @@ config ARCH_HAS_SET_DIRECT_MAP
 	bool
 
 #
-# Select if arch has an uncached kernel segment and provides the
-# uncached_kernel_address symbol to use it
+# Select if the architecture provides the arch_dma_set_uncached symbol to
+# either provide an uncached segement alias for a DMA allocation, or
+# to remap the page tables in place.
 #
-config ARCH_HAS_UNCACHED_SEGMENT
-	select ARCH_HAS_DMA_PREP_COHERENT
+config ARCH_HAS_DMA_SET_UNCACHED
 	bool
 
 # Select if arch init_task must go in the __init_task_data section
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1120,8 +1120,9 @@ config DMA_PERDEV_COHERENT
 config DMA_NONCOHERENT
 	bool
 	select ARCH_HAS_DMA_WRITE_COMBINE
+	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_HAS_UNCACHED_SEGMENT
+	select ARCH_HAS_DMA_SET_UNCACHED
 	select DMA_NONCOHERENT_MMAP
 	select DMA_NONCOHERENT_CACHE_SYNC
 	select NEED_DMA_MAP_STATE
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -49,7 +49,7 @@ void arch_dma_prep_coherent(struct page
 	dma_cache_wback_inv((unsigned long)page_address(page), size);
 }
 
-void *uncached_kernel_address(void *addr)
+void *arch_dma_set_uncached(void *addr, size_t size)
 {
 	return (void *)(__pa(addr) + UNCAC_BASE);
 }
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -2,9 +2,10 @@
 config NIOS2
 	def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
-	select ARCH_HAS_UNCACHED_SEGMENT
+	select ARCH_HAS_DMA_SET_UNCACHED
 	select ARCH_NO_SWAP
 	select TIMER_OF
 	select GENERIC_ATOMIC64
--- a/arch/nios2/mm/dma-mapping.c
+++ b/arch/nios2/mm/dma-mapping.c
@@ -67,7 +67,7 @@ void arch_dma_prep_coherent(struct page
 	flush_dcache_range(start, start + size);
 }
 
-void *uncached_kernel_address(void *ptr)
+void *arch_dma_set_uncached(void *ptr, size_t size)
 {
 	unsigned long addr = (unsigned long)ptr;
 
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -108,6 +108,6 @@ static inline void arch_dma_prep_coheren
 }
 #endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */
 
-void *uncached_kernel_address(void *addr);
+void *arch_dma_set_uncached(void *addr, size_t size);
 
 #endif /* _LINUX_DMA_NONCOHERENT_H */
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -180,10 +180,12 @@ void *dma_direct_alloc_pages(struct devi
 
 	memset(ret, 0, size);
 
-	if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+	if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    dma_alloc_need_uncached(dev, attrs)) {
 		arch_dma_prep_coherent(page, size);
-		ret = uncached_kernel_address(ret);
+		ret = arch_dma_set_uncached(ret, size);
+		if (IS_ERR(ret))
+			goto out_free_pages;
 	}
 done:
 	if (force_dma_unencrypted(dev))
@@ -224,7 +226,7 @@ void dma_direct_free_pages(struct device
 void *dma_direct_alloc(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
-	if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
 	    dma_alloc_need_uncached(dev, attrs))
 		return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
@@ -234,7 +236,7 @@ void *dma_direct_alloc(struct device *de
 void dma_direct_free(struct device *dev, size_t size,
 		void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
 {
-	if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
 	    dma_alloc_need_uncached(dev, attrs))
 		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);