arm64: Limit the CMA buffer to 32-bit if ZONE_DMA
When the CMA buffer is allocated, it is too early to know whether
devices will require ZONE_DMA memory. This patch limits the CMA buffer
to (DMA_BIT_MASK(32) + 1) if CONFIG_ZONE_DMA is enabled.
In addition, it computes the dma_to_phys(DMA_BIT_MASK(32)) before the
increment (no current functional change).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 091d428d..f43db8a 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -71,7 +71,7 @@
/* 4GB maximum for 32-bit only capable devices */
if (IS_ENABLED(CONFIG_ZONE_DMA)) {
unsigned long max_dma_phys =
- (unsigned long)dma_to_phys(NULL, DMA_BIT_MASK(32) + 1);
+ (unsigned long)(dma_to_phys(NULL, DMA_BIT_MASK(32)) + 1);
max_dma = max(min, min(max, max_dma_phys >> PAGE_SHIFT));
zone_size[ZONE_DMA] = max_dma - min;
}
@@ -126,6 +126,8 @@
void __init arm64_memblock_init(void)
{
+ phys_addr_t dma_phys_limit = 0;
+
/* Register the kernel text, kernel data and initrd with memblock */
memblock_reserve(__pa(_text), _end - _text);
#ifdef CONFIG_BLK_DEV_INITRD
@@ -141,7 +143,11 @@
memblock_reserve(__pa(idmap_pg_dir), IDMAP_DIR_SIZE);
early_init_fdt_scan_reserved_mem();
- dma_contiguous_reserve(0);
+
+ /* 4GB maximum for 32-bit only capable devices */
+ if (IS_ENABLED(CONFIG_ZONE_DMA))
+ dma_phys_limit = dma_to_phys(NULL, DMA_BIT_MASK(32)) + 1;
+ dma_contiguous_reserve(dma_phys_limit);
memblock_allow_resize();
memblock_dump_all();