[PATCH] powerpc: add `cur_cpu_spec` symbol to vmcoreinfo

[Sachin Sant]

> On 14-Sep-2023, at 6:52 PM, Michael Ellerman <mpe at ellerman.id.au> wrote:
> 
> Sachin Sant <sachinp at linux.ibm.com> writes:
>>> On 11-Sep-2023, at 2:44 PM, Aditya Gupta <adityag at linux.ibm.com> wrote:
>>> 
>>> Presently, while reading a vmcore, makedumpfile uses
>>> `cur_cpu_spec.mmu_features` to decide whether the crashed system had
>>> RADIX MMU or not.
>>> 
>>> Currently, makedumpfile fails to get the `cur_cpu_spec` symbol (unless
>>> a vmlinux is passed with the `-x` flag to makedumpfile), and hence
>>> assigns offsets and shifts (such as pgd_offset_l4) incorrecly considering
>>> MMU to be hash MMU.
>>> 
>>> Add `cur_cpu_spec` symbol and offset of `mmu_features` in the
>>> `cpu_spec` struct, to VMCOREINFO, so that the symbol address and offset
>>> is accessible to makedumpfile, without needing the vmlinux file
>>> 
>>> Signed-off-by: Aditya Gupta <adityag at linux.ibm.com>
>>> ---
>> 
>> Thanks for the patch. With this patch applied (along with makedumpfile changes)
>> I am able to capture vmcore against a kernel which contains commit 8dc9a0ad0c3e
> 
> I can't find that commit? Was just wondering if it should be referenced
> in the commit message.
> 

My bad, I copied that commit id from the email when I first reported this issue
against linux-next.

The commit should be 
368a0590d954: (powerpc/book3s64/vmemmap: switch radix to use a
different vmemmap handling function)