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

From: Alexandre Ghiti
Date: Thu Aug 15 2024 - 07:01:51 EST


Hi Yunhui,

On 14/08/2024 08:26, Yunhui Cui wrote:
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@xxxxxxxxxxxxx>
---
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);
+ }
}


A bit weird to review and test my own patch, but here it is anyway :)

Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>

Tested-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>

Thanks,

Alex