Re: [PATCH 2/2] fadump: reserve param area if below boot_mem_top

[Hari Bathini <hbathini@linux.ibm.com>]

On 04/11/24 2:05 pm, Sourabh Jain wrote:
> The param area is a memory region where the kernel places additional
> command-line arguments for fadump kernel. Currently, the param memory
> area is reserved in fadump kernel if it is above boot_mem_top. However,
> it should be reserved if it is below boot_mem_top because the fadump
> kernel already reserves memory from boot_mem_top to the end of DRAM.
> 
> Currently, there is no impact from not reserving param memory if it is
> below boot_mem_top, as it is not used after the early boot phase of the
> fadump kernel. However, if this changes in the future, it could lead t
> issues in the fadump kernel.
> 

Looks good to me.

Acked-by: Hari Bathini <hbathini@linux.ibm.com>

> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
> Cc: Hari Bathini <hbathini@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
> ---
>   arch/powerpc/kernel/fadump.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 4a3f80f42118..35a8a107e16b 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -143,7 +143,7 @@ void __init fadump_append_bootargs(void)
>   	if (!fw_dump.dump_active || !fw_dump.param_area_supported || !fw_dump.param_area)
>   		return;
>   
> -	if (fw_dump.param_area >= fw_dump.boot_mem_top) {
> +	if (fw_dump.param_area < fw_dump.boot_mem_top) {
>   		if (memblock_reserve(fw_dump.param_area, COMMAND_LINE_SIZE)) {
>   			pr_warn("WARNING: Can't use additional parameters area!\n");
>   			fw_dump.param_area = 0;