[PATCH] riscv: add a warning when physical memory address overflows

[Yunhui Cui]

The part of physical memory that exceeds the size of the linear mapping
will be discarded. When the system starts up normally, a warning message
will be printed to prevent confusion caused by the mismatch between the
system memory and the actual physical memory.

Signed-off-by: Yunhui Cui <cuiyunhui at bytedance.com>
---
 arch/riscv/mm/init.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 52290c9bd04bd..c93164dc51658 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -236,8 +236,12 @@ static void __init setup_bootmem(void)
 	 */
 	if (IS_ENABLED(CONFIG_64BIT)) {
 		max_mapped_addr = __pa(PAGE_OFFSET) + KERN_VIRT_SIZE;
-		memblock_cap_memory_range(phys_ram_base,
-					  max_mapped_addr - phys_ram_base);
+		if (memblock_end_of_DRAM() > max_mapped_addr) {
+			memblock_cap_memory_range(phys_ram_base,
+						  max_mapped_addr - phys_ram_base);
+			pr_warn("Physical memory overflows the linear mapping size: region above 0x%llx removed",
+				max_mapped_addr);
+		}
 	}
 
 
-- 
2.39.2