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
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------------------------------------------------------
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
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