[PATCH] powerpc/fadump: set an upper limit for boot memory size

[Hari Bathini]

Hi Michael,


On Friday 17 February 2017 11:54 AM, Michael Ellerman wrote:
> Hari Bathini <hbathini at linux.vnet.ibm.com> writes:
>
>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>> index de7d39a..d5107f4 100644
>> --- a/arch/powerpc/kernel/fadump.c
>> +++ b/arch/powerpc/kernel/fadump.c
>> @@ -222,6 +222,18 @@ static inline unsigned long fadump_calculate_reserve_size(void)
>>   				&size, &base);
>>   	if (ret == 0 && size > 0) {
>>   		fw_dump.reserve_bootvar = (unsigned long)size;
>> +		/*
>> +		 * Adjust if the boot memory size specified is above
>> +		 * the upper limit.
>> +		 */
>> +		if (fw_dump.reserve_bootvar >
>> +		    (memblock_end_of_DRAM() / MAX_BOOT_MEM_RATIO)) {
> Using memblock_end_of_DRAM() doesn't take into account the fact that you
> might have holes in your memory layout.
>
> Possibly on PowerVM that never happens, but I don't think we should
> write the code to assume that, if possible.
>

I think memblock_phys_mem_size() can fill in..

In the same file, memblock_end_of_DRAM() is also used when nothing
is specified through cmdline. Let me also change that and respin..

Thanks
Hari