Re: [PATCH 4/4] kdump: update Documentation about crashkernel on arm64
From: Chen Zhou
Date: Wed May 15 2019 - 23:26:03 EST
On 2019/5/15 13:16, Bhupesh Sharma wrote:
> On 05/07/2019 09:20 AM, Chen Zhou wrote:
>> Now we support crashkernel=X,[high,low] on arm64, update the
>> Signed-off-by: Chen Zhou <chenzhou10@xxxxxxxxxx>
>> Documentation/admin-guide/kernel-parameters.txt | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 268b10a..03a08aa 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -705,7 +705,7 @@
>> memory region [offset, offset + size] for that kernel
>> image. If '@offset' is omitted, then a suitable offset
>> is selected automatically.
>> - [KNL, x86_64] select a region under 4G first, and
>> + [KNL, x86_64, arm64] select a region under 4G first, and
>> fall back to reserve region above 4G when '@offset'
>> hasn't been specified.
>> See Documentation/kdump/kdump.txt for further details.
>> @@ -718,14 +718,14 @@
>> Documentation/kdump/kdump.txt for an example.
>> - [KNL, x86_64] range could be above 4G. Allow kernel
>> + [KNL, x86_64, arm64] range could be above 4G. Allow kernel
>> to allocate physical memory region from top, so could
>> be above 4G if system have more than 4G ram installed.
>> Otherwise memory region will be allocated below 4G, if
>> It will be ignored if crashkernel=X is specified.
>> - [KNL, x86_64] range under 4G. When crashkernel=X,high
>> + [KNL, x86_64, arm64] range under 4G. When crashkernel=X,high
>> is passed, kernel could allocate physical memory region
>> above 4G, that cause second kernel crash on system
>> that require some amount of low memory, e.g. swiotlb
> IMO, it is a good time to update 'Documentation/kdump/kdump.txt' with this patchset itself for both x86_64 and arm64, where we still specify only the old format for 'crashkernel' boot-argument:
> Section: Boot into System Kernel
> On arm64, use "crashkernel=Y[@X]". Note that the start address of
> the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
> We can update this to add the new crashkernel=size[KMG],low or crashkernel=size[KMG],high format as well.
Sure, we can also update here.