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

[Sourabh Jain]

Hello Hari,


On 04/11/24 15:50, Hari Bathini wrote:
>
>
> 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 at linux.ibm.com>

Thanks for Ack.


- Sourabh Jain

>
>> Cc: Mahesh Salgaonkar <mahesh at linux.ibm.com>
>> Cc: Hari Bathini <hbathini at linux.ibm.com>
>> Cc: Michael Ellerman <mpe at ellerman.id.au>
>> Signed-off-by: Sourabh Jain <sourabhjain at 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;
>