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

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Message-ID: <afaa4192-da08-4180-a09b-2b953293ba76@ghiti.fr>
Date: Thu, 15 Aug 2024 13:01:37 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Yunhui Cui <cuiyunhui@...edance.com>, punit.agrawal@...edance.com,
 paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu,
 alexghiti@...osinc.com, chenjiahao16@...wei.com, guoren@...nel.org,
 vishal.moola@...il.com, stuart.menefy@...asip.com,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] riscv: add a warning when physical memory address
 overflows

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@...edance.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);
> +		}
>   	}
>   
>   


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

Reviewed-by: Alexandre Ghiti <alexghiti@...osinc.com>

Tested-by: Alexandre Ghiti <alexghiti@...osinc.com>

Thanks,

Alex