Messages in this thread | | | From | Thiago Jung Bauermann <> | Subject | Re: [PATCH v4 09/12] ppc64/kexec_file: setup backup region for kdump kernel | Date | Thu, 23 Jul 2020 21:28:55 -0300 |
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Hari Bathini <hbathini@linux.ibm.com> writes:
> Though kdump kernel boots from loaded address, the first 64K bytes > of it is copied down to real 0. So, setup a backup region to copy > the first 64K bytes of crashed kernel, in purgatory, before booting > into kdump kernel. Also, update reserve map with backup region and > crashed kernel's memory to avoid kdump kernel from accidentially > using that memory. > > Reported-by: kernel test robot <lkp@intel.com> > [lkp: In v1, purgatory() declaration was missing] > Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Just one minor comment below:
> @@ -1047,13 +1120,26 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, > goto out; > } > > - /* Ensure we don't touch crashed kernel's memory */ > - ret = fdt_add_mem_rsv(fdt, 0, crashk_res.start); > + /* > + * Ensure we don't touch crashed kernel's memory except the > + * first 64K of RAM, which will be backed up. > + */ > + ret = fdt_add_mem_rsv(fdt, BACKUP_SRC_SIZE,
I know BACKUP_SRC_START is 0, but please forgive my pedantry when I say that I think it's clearer if the start address above is changed to BACKUP_SRC_START + BACKUP_SRC_SIZE...
> + crashk_res.start - BACKUP_SRC_SIZE); > if (ret) { > pr_err("Error reserving crash memory: %s\n", > fdt_strerror(ret)); > goto out; > } > + > + /* Ensure backup region is not used by kdump/capture kernel */ > + ret = fdt_add_mem_rsv(fdt, image->arch.backup_start, > + BACKUP_SRC_SIZE); > + if (ret) { > + pr_err("Error reserving memory for backup: %s\n", > + fdt_strerror(ret)); > + goto out; > + } > } > > out:
-- Thiago Jung Bauermann IBM Linux Technology Center
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