On 16/07/20 7:52 am, Thiago Jung Bauermann wrote:
>
> Hari Bathini <hbath...@linux.ibm.com> writes:
>
>> /**
>> + * get_crash_memory_ranges - Get crash memory ranges. This list includes
>> + * first/crashing kernel's memory regions that
>> + * would be exported via an elfcore.
>> + * @mem_ranges: Range list to add the memory ranges to.
>> + *
>> + * Returns 0 on success, negative errno on error.
>> + */
>> +static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
>> +{
>> + struct memblock_region *reg;
>> + struct crash_mem *tmem;
>> + int ret;
>> +
>> + for_each_memblock(memory, reg) {
>> + u64 base, size;
>> +
>> + base = (u64)reg->base;
>> + size = (u64)reg->size;
>> +
>> + /* Skip backup memory region, which needs a separate entry */
>> + if (base == BACKUP_SRC_START) {
>> + if (size > BACKUP_SRC_SIZE) {
>> + base = BACKUP_SRC_END + 1;
>> + size -= BACKUP_SRC_SIZE;
>> + } else
>> + continue;
>> + }
>> +
>> + ret = add_mem_range(mem_ranges, base, size);
>> + if (ret)
>> + goto out;
>> +
>> + /* Try merging adjacent ranges before reallocation attempt */
>> + if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
>> + sort_memory_ranges(*mem_ranges, true);
>> + }
>> +
>> + /* Reallocate memory ranges if there is no space to split ranges */
>> + tmem = *mem_ranges;
>> + if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
>> + tmem = realloc_mem_ranges(mem_ranges);
>> + if (!tmem)
>> + goto out;
>> + }
>> +
>> + /* Exclude crashkernel region */
>> + ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
>> + if (ret)
>> + goto out;
>> +
>> + ret = add_rtas_mem_range(mem_ranges);
>> + if (ret)
>> + goto out;
>> +
>> + ret = add_opal_mem_range(mem_ranges);
>> + if (ret)
>> + goto out;
>
> Maybe I'm confused, but don't you add the RTAS and OPAL regions as
> usable memory for the crashkernel? In that case they shouldn't show up
> in the core file.
kexec-tools does the same thing. I am not endorsing it but I was trying to stay
in parity to avoid breaking any userspace tools/commands. But as you rightly
pointed, this is NOT right. The right thing to do, to get the rtas/opal data at
the time of crash, is to have a backup region for them just like we have for
the first 64K memory. I was hoping to do that later.
Will check how userspace tools respond to dropping these regions. If that makes
the tools unhappy, will retain the regions with a FIXME. Sorry about the
confusion.
Thanks
Hari
