The patch titled Subject: kernel/kexec_file.c: load kernel at top of system RAM if required has been added to the -mm tree. Its filename is kexec_file-load-kernel-at-top-of-system-ram-if-required.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/kexec_file-load-kernel-at-top-of-system-ram-if-required.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/kexec_file-load-kernel-at-top-of-system-ram-if-required.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Baoquan He <bhe@xxxxxxxxxx> Subject: kernel/kexec_file.c: load kernel at top of system RAM if required For kexec_file loading, if kexec_buf.top_down is 'true', the memory which is used to load kernel/initrd/purgatory is supposed to be allocated from top to down. This is also consistent with the old kexec loading interface. However, the current arch_kexec_walk_mem() doesn't do like this. It ignores checking kexec_buf.top_down, but calls walk_system_ram_res() directly to go through all resources of System RAM, to try to find a memory region which can contain the specific kexec buffer, then calls locate_mem_hole_callback() to allocate memory in that found memory region from top to down. This is not right. Here add checking if kexec_buf.top_down is 'true' in arch_kexec_walk_mem(), if yes, call the newly added walk_system_ram_res_rev() to find memory region from top to down to load kernel. Link: http://lkml.kernel.org/r/20180322033722.9279-3-bhe@xxxxxxxxxx Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/kexec_file.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN kernel/kexec_file.c~kexec_file-load-kernel-at-top-of-system-ram-if-required kernel/kexec_file.c --- a/kernel/kexec_file.c~kexec_file-load-kernel-at-top-of-system-ram-if-required +++ a/kernel/kexec_file.c @@ -560,6 +560,8 @@ int __weak arch_kexec_walk_mem(struct ke IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); + else if (kbuf->top_down) + return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); } _ Patches currently in -mm which might be from bhe@xxxxxxxxxx are mm-sparse-add-a-static-variable-nr_present_sections.patch mm-sparsemem-defer-the-ms-section_mem_map-clearing.patch mm-sparse-add-a-new-parameter-data_unit_size-for-alloc_usemap_and_memmap.patch kexec_file-load-kernel-at-top-of-system-ram-if-required.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html