arm64: enable ARCH_WANT_KMALLOC_DMA_BOUNCE for arm64

With the DMA bouncing of unaligned kmalloc() buffers now in place, enable
it for arm64 to allow the kmalloc-{8,16,32,48,96} caches.  In addition,
always create the swiotlb buffer even when the end of RAM is within the
32-bit physical address range (the swiotlb buffer can still be disabled on
the kernel command line).

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>
Tested-by: Isaac J. Manjarres <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Jerry Snitselaar <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Lars-Peter Clausen <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Saravana Kannan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

2 files changed, 7 insertions, 1 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1201d25a8a4..af42871431c0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -120,6 +120,7 @@ config ARM64
 	select CRC32
 	select DCACHE_WORD_ACCESS
 	select DYNAMIC_FTRACE if FUNCTION_TRACER
+	select DMA_BOUNCE_UNALIGNED_KMALLOC
 	select DMA_DIRECT_REMAP
 	select EDAC_SUPPORT
 	select FRAME_POINTER
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 66e70ca47680..3ac2e9d79ce4 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -442,7 +442,12 @@ void __init bootmem_init(void)
  */
 void __init mem_init(void)
 {
-	swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE);
+	bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit);
+
+	if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC))
+		swiotlb = true;
+
+	swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
 
 	/* this will put all unused low memory onto the freelists */
 	memblock_free_all();