diff options
| -rw-r--r-- | arch/arm64/mm/init.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 5710129b8033..eb76ac6d87c0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -116,8 +116,14 @@ static void __init arch_reserve_crashkernel(void) static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit) { - if (zone_limit == PHYS_ADDR_MAX) - zone_limit = U32_MAX; + /** + * Information we get from firmware (e.g. DT dma-ranges) describe DMA + * bus constraints. Devices using DMA might have their own limitations. + * Some of them rely on DMA zone in low 32-bit memory. Keep low RAM + * DMA zone on platforms that have RAM there. + */ + if (memblock_start_of_DRAM() < U32_MAX) + zone_limit = min(zone_limit, U32_MAX); return min(zone_limit, memblock_end_of_DRAM() - 1) + 1; } |