On 30/06/20 9:00 am, piliu wrote: > > > On 06/29/2020 01:55 PM, Hari Bathini wrote: >> >> >> On 28/06/20 7:44 am, piliu wrote: >>> Hi Hari, >> >> Hi Pingfan, >> >>> >>> After a quick through for this series, I have a few question/comment on >>> this patch for the time being. Pls see comment inline. >>> >>> On 06/27/2020 03:05 AM, Hari Bathini wrote: >>>> crashkernel region could have an overlap with special memory regions >>>> like opal, rtas, tce-table & such. These regions are referred to as >>>> exclude memory ranges. Setup this ranges during image probe in order >>>> to avoid them while finding the buffer for different kdump segments. >> >> [...] >> >>>> + /* >>>> + * Use the locate_mem_hole logic in kexec_add_buffer() for regular >>>> + * kexec_file_load syscall >>>> + */ >>>> + if (kbuf->image->type != KEXEC_TYPE_CRASH) >>>> + return 0; >>> Can the ranges overlap [crashk_res.start, crashk_res.end]? Otherwise >>> there is no requirement for @exclude_ranges. >> >> The ranges like rtas, opal are loaded by f/w. They almost always overlap with >> crashkernel region. So, @exclude_ranges is required to support kdump. > f/w passes rtas/opal as service, then must f/w mark these ranges as > fdt_reserved_mem in order to make kernel aware not to use these ranges? It does. Actually, reserve_map + reserved-ranges are reserved as soon as memblock allocator is ready but not before crashkernel reservation. Check early_reserve_mem() call in kernel/prom.c > Otherwise kernel memory allocation besides kdump can also overwrite > these ranges.> > Hmm, revisiting reserve_crashkernel(). It seems not to take any reserved > memory into consider except kernel text. Could it work based on memblock > allocator? So, kdump could possibly overwrite these regions which is why an exclude range list is needed. Same thing was done in kexec-tools as well. Thanks Hari _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
