On 24/05/2023 6:19 pm, Catalin Marinas wrote:
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).
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/Kconfig | 1 +
arch/arm64/mm/init.c | 7 ++++++-
2 files changed, 7 insertions(+), 1 deletion(-)
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
We may want to give the embedded folks an easier way of turning this
off, since IIRC one of the reasons for the existing automatic behaviour
was people not wanting to have to depend on the command line. Things
with 256MB or so of RAM seem unlikely to get enough memory efficiency
back from the smaller kmem caches to pay off the SWIOTLB allocation :)
Cheers,
Robin.
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();
