[PATCH 1/4] kexec-tools: mips: Merge adjacent memory ranges.

[David Daney]

On 10/15/2017 11:53 PM, Simon Horman wrote:
> On Thu, Oct 12, 2017 at 02:02:25PM -0700, David Daney wrote:
>> Some kernel versions running on MIPS split the System RAM memory
>> regions reported in /proc/iomem.  This may cause loading of the kexec
>> kernel to fail if it crosses one of the splits.
>>
>> Fix by merging adjacent memory ranges that have the same type.
>>
>> Signed-off-by: David Daney <david.daney at cavium.com>
>> ---
>>   kexec/arch/mips/kexec-mips.c | 14 ++++++++++----
>>   1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/kexec/arch/mips/kexec-mips.c b/kexec/arch/mips/kexec-mips.c
>> index 2e5b700..415c2ed 100644
>> --- a/kexec/arch/mips/kexec-mips.c
>> +++ b/kexec/arch/mips/kexec-mips.c
>> @@ -60,10 +60,16 @@ int get_memory_ranges(struct memory_range **range, int *ranges,
>>   		} else {
>>   			continue;
>>   		}
>> -		memory_range[memory_ranges].start = start;
>> -		memory_range[memory_ranges].end = end;
>> -		memory_range[memory_ranges].type = type;
>> -		memory_ranges++;
>> +		if (memory_ranges > 0 &&
> 
> It seems that this will never merge the first memory range
> with subsequent ones. Is that intentional?


With the first range (index 0), no other range yet exists to merge with. 
  We can only test for merging with the second and subsequent ranges 
(indices 1 and above).  To do otherwise would cause us to read things 
from *before* the beginning of the array ...

> 
> 
>> +		    memory_range[memory_ranges - 1].end == start &&

... here.

>> +		    memory_range[memory_ranges - 1].type == type) {
>> +			memory_range[memory_ranges - 1].end = end;
>> +		} else {
>> +			memory_range[memory_ranges].start = start;
>> +			memory_range[memory_ranges].end = end;
>> +			memory_range[memory_ranges].type = type;
>> +			memory_ranges++;
>> +		}
>>   	}
>>   	fclose(fp);
>>   	*range = memory_range;
>> -- 
>> 2.9.5
>>
>>
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