[PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Bharat Bhushan]

This patch have minor updates in Documentation for arm64i as
relocatable kernel.
Also this patch updates documentation for using uncompressed
image "Image" which is used for ARM64.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
---
 Documentation/kdump/kdump.txt | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 615434d..522ce13 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -112,8 +112,8 @@ There are two possible methods of using Kdump.
 2) Or use the system kernel binary itself as dump-capture kernel and there is
    no need to build a separate dump-capture kernel. This is possible
    only with the architectures which support a relocatable kernel. As
-   of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable
-   kernel.
+   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
+   relocatable kernel.
 
 Building a relocatable kernel is advantageous from the point of view that
 one does not have to build a second kernel for capturing the dump. But
@@ -361,6 +361,12 @@ to load dump-capture kernel.
    --dtb=<dtb-for-dump-capture-kernel> \
    --append="root=<root-dev> <arch-specific-options>"
 
+If you are using a uncompressed Image, then use following command
+to load dump-capture kernel.
+
+   kexec -p <dump-capture-kernel-Image> \
+   --initrd=<initrd-for-dump-capture-kernel> \
+   --append="root=<root-dev> <arch-specific-options>"
 
 Please note, that --args-linux does not need to be specified for ia64.
 It is planned to make this a no-op on that architecture, but for now
-- 
1.9.3

Re: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Baoquan He]

On 05/18/17 at 11:03am, Bharat Bhushan wrote:
> This patch have minor updates in Documentation for arm64i as
> relocatable kernel.
> Also this patch updates documentation for using uncompressed
> image "Image" which is used for ARM64.
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> ---
>  Documentation/kdump/kdump.txt | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 615434d..522ce13 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -112,8 +112,8 @@ There are two possible methods of using Kdump.
>  2) Or use the system kernel binary itself as dump-capture kernel and there is
>     no need to build a separate dump-capture kernel. This is possible
>     only with the architectures which support a relocatable kernel. As
> -   of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable
> -   kernel.
> +   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
> +   relocatable kernel.
>  
>  Building a relocatable kernel is advantageous from the point of view that
>  one does not have to build a second kernel for capturing the dump. But
> @@ -361,6 +361,12 @@ to load dump-capture kernel.
>     --dtb=<dtb-for-dump-capture-kernel> \
>     --append="root=<root-dev> <arch-specific-options>"
>  
> +If you are using a uncompressed Image, then use following command
		    ~ an
> +to load dump-capture kernel.
> +
> +   kexec -p <dump-capture-kernel-Image> \
> +   --initrd=<initrd-for-dump-capture-kernel> \
> +   --append="root=<root-dev> <arch-specific-options>"
>  
>  Please note, that --args-linux does not need to be specified for ia64.
>  It is planned to make this a no-op on that architecture, but for now
> -- 
> 1.9.3
> 

Re: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Dave Young]

Add Takahiro and Pratyush, they should be able to review the arm64 part.

On 05/18/17 at 11:03am, Bharat Bhushan wrote:
> This patch have minor updates in Documentation for arm64i as
> relocatable kernel.
> Also this patch updates documentation for using uncompressed
> image "Image" which is used for ARM64.
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> ---
>  Documentation/kdump/kdump.txt | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 615434d..522ce13 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -112,8 +112,8 @@ There are two possible methods of using Kdump.
>  2) Or use the system kernel binary itself as dump-capture kernel and there is
>     no need to build a separate dump-capture kernel. This is possible
>     only with the architectures which support a relocatable kernel. As
> -   of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable
> -   kernel.
> +   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
> +   relocatable kernel.
>  
>  Building a relocatable kernel is advantageous from the point of view that
>  one does not have to build a second kernel for capturing the dump. But
> @@ -361,6 +361,12 @@ to load dump-capture kernel.
>     --dtb=<dtb-for-dump-capture-kernel> \
>     --append="root=<root-dev> <arch-specific-options>"
>  
> +If you are using a uncompressed Image, then use following command

s/a/an

> +to load dump-capture kernel.
> +
> +   kexec -p <dump-capture-kernel-Image> \
> +   --initrd=<initrd-for-dump-capture-kernel> \
> +   --append="root=<root-dev> <arch-specific-options>"

For uncompressed Image, dtb is not necessary?

>  
>  Please note, that --args-linux does not need to be specified for ia64.
>  It is planned to make this a no-op on that architecture, but for now
> -- 
> 1.9.3
> 

Thanks
Dave

RE: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Bharat Bhushan]

> -----Original Message-----
> From: Dave Young [mailto:dyoung@redhat.com]
> Sent: Thursday, May 18, 2017 11:29 AM
> To: Bharat Bhushan <bharat.bhushan@nxp.com>
> Cc: bhe@redhat.com; vgoyal@redhat.com; corbet@lwn.net;
> kexec@lists.infradead.org; linux-doc@vger.kernel.org; linux-
> kernel@vger.kernel.org; takahiro.akashi@linaro.org; panand@redhat.com
> Subject: Re: [PATCH] kexec/kdump: Minor Documentation updates for
> arm64 and Image
> 
> Add Takahiro and Pratyush, they should be able to review the arm64 part.
> 
> On 05/18/17 at 11:03am, Bharat Bhushan wrote:
> > This patch have minor updates in Documentation for arm64i as
> > relocatable kernel.
> > Also this patch updates documentation for using uncompressed image
> > "Image" which is used for ARM64.
> >
> > Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> > ---
> >  Documentation/kdump/kdump.txt | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/kdump/kdump.txt
> > b/Documentation/kdump/kdump.txt index 615434d..522ce13 100644
> > --- a/Documentation/kdump/kdump.txt
> > +++ b/Documentation/kdump/kdump.txt
> > @@ -112,8 +112,8 @@ There are two possible methods of using Kdump.
> >  2) Or use the system kernel binary itself as dump-capture kernel and there
> is
> >     no need to build a separate dump-capture kernel. This is possible
> >     only with the architectures which support a relocatable kernel. As
> > -   of today, i386, x86_64, ppc64, ia64 and arm architectures support
> relocatable
> > -   kernel.
> > +   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
> > +   relocatable kernel.
> >
> >  Building a relocatable kernel is advantageous from the point of view
> > that  one does not have to build a second kernel for capturing the
> > dump. But @@ -361,6 +361,12 @@ to load dump-capture kernel.
> >     --dtb=<dtb-for-dump-capture-kernel> \
> >     --append="root=<root-dev> <arch-specific-options>"
> >
> > +If you are using a uncompressed Image, then use following command
> 
> s/a/an
> 
> > +to load dump-capture kernel.
> > +
> > +   kexec -p <dump-capture-kernel-Image> \
> > +   --initrd=<initrd-for-dump-capture-kernel> \
> > +   --append="root=<root-dev> <arch-specific-options>"
> 
> For uncompressed Image, dtb is not necessary?

Yes dtb is not necessary, it works for me without giving dtb.

Thanks
-Bharat

> 
> >
> >  Please note, that --args-linux does not need to be specified for ia64.
> >  It is planned to make this a no-op on that architecture, but for now
> > --
> > 1.9.3
> >
> 
> Thanks
> Dave

Re: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[AKASHI Takahiro]

On Thu, May 18, 2017 at 01:59:14PM +0800, Dave Young wrote:
> Add Takahiro and Pratyush, they should be able to review the arm64 part.
> 
> On 05/18/17 at 11:03am, Bharat Bhushan wrote:
> > This patch have minor updates in Documentation for arm64i as
> > relocatable kernel.
> > Also this patch updates documentation for using uncompressed
> > image "Image" which is used for ARM64.
> > 
> > Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> > ---
> >  Documentation/kdump/kdump.txt | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> > index 615434d..522ce13 100644
> > --- a/Documentation/kdump/kdump.txt
> > +++ b/Documentation/kdump/kdump.txt
> > @@ -112,8 +112,8 @@ There are two possible methods of using Kdump.
> >  2) Or use the system kernel binary itself as dump-capture kernel and there is
> >     no need to build a separate dump-capture kernel. This is possible
> >     only with the architectures which support a relocatable kernel. As
> > -   of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable
> > -   kernel.
> > +   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
> > +   relocatable kernel.
> >  
> >  Building a relocatable kernel is advantageous from the point of view that
> >  one does not have to build a second kernel for capturing the dump. But
> > @@ -361,6 +361,12 @@ to load dump-capture kernel.
> >     --dtb=<dtb-for-dump-capture-kernel> \
> >     --append="root=<root-dev> <arch-specific-options>"
> >  
> > +If you are using a uncompressed Image, then use following command
> 
> s/a/an
> 
> > +to load dump-capture kernel.
> > +
> > +   kexec -p <dump-capture-kernel-Image> \
> > +   --initrd=<initrd-for-dump-capture-kernel> \
> > +   --append="root=<root-dev> <arch-specific-options>"
> 
> For uncompressed Image, dtb is not necessary?

Just for clarification, dtb is optional for both vmlinux and Image
on arm64. (This means you can specify it if you want.)
But this is also true for initrd and append(command line) to some extent.

More precisely, whether these parameters are optional or not will
depend on architectures, not formats, I believe.

Thanks,
-Takahiro AKASHI

> >  
> >  Please note, that --args-linux does not need to be specified for ia64.
> >  It is planned to make this a no-op on that architecture, but for now
> > -- 
> > 1.9.3
> > 
> 
> Thanks
> Dave

Re: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Pratyush Anand]

On Friday 19 May 2017 09:15 AM, AKASHI Takahiro wrote:
>>> +to load dump-capture kernel.
>>> +
>>> +   kexec -p <dump-capture-kernel-Image> \
>>> +   --initrd=<initrd-for-dump-capture-kernel> \
>>> +   --append="root=<root-dev> <arch-specific-options>"
>> For uncompressed Image, dtb is not necessary?
> Just for clarification, dtb is optional for both vmlinux and Image
> on arm64. (This means you can specify it if you want.)
> But this is also true for initrd and append(command line) to some extent.

Yes, I agree.
>
> More precisely, whether these parameters are optional or not will
> depend on architectures, not formats, I believe.

May be not architecture, rather a distro environment.

For example, we should be able to work without --initrd for any arch if kernel 
has been compiled by configuring CONFG_INITRAMFS_SOURCE.

~Pratyush

RE: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Bharat Bhushan]

> -----Original Message-----
> From: Pratyush Anand [mailto:panand@redhat.com]
> Sent: Monday, May 22, 2017 12:09 PM
> To: AKASHI Takahiro <takahiro.akashi@linaro.org>; Dave Young
> <dyoung@redhat.com>; Bharat Bhushan <bharat.bhushan@nxp.com>;
> bhe@redhat.com; vgoyal@redhat.com; corbet@lwn.net;
> kexec@lists.infradead.org; linux-doc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH] kexec/kdump: Minor Documentation updates for
> arm64 and Image
> 
> 
> 
> On Friday 19 May 2017 09:15 AM, AKASHI Takahiro wrote:
> >>> +to load dump-capture kernel.
> >>> +
> >>> +   kexec -p <dump-capture-kernel-Image> \
> >>> +   --initrd=<initrd-for-dump-capture-kernel> \
> >>> +   --append="root=<root-dev> <arch-specific-options>"
> >> For uncompressed Image, dtb is not necessary?
> > Just for clarification, dtb is optional for both vmlinux and Image on
> > arm64. (This means you can specify it if you want.) But this is also
> > true for initrd and append(command line) to some extent.
> 
> Yes, I agree.

Should I mention "-dtb" also for "Image"?

Also do we need to mention that it is optional somewhere in this document? I do not see "optional" is mentioned for other parameters and architecture.

Does this looks ok:

	" -dtb=<optional-dtb-for-dump-capture-kernel> \"

Thanks
-Bharat

> >
> > More precisely, whether these parameters are optional or not will
> > depend on architectures, not formats, I believe.
> 
> May be not architecture, rather a distro environment.
> 
> For example, we should be able to work without --initrd for any arch if kernel
> has been compiled by configuring CONFG_INITRAMFS_SOURCE.
> 
> ~Pratyush

Re: [PATCH] kexec/kdump: Minor Documentation updates for arm64 and Image

[Pratyush Anand]

On Monday 22 May 2017 12:19 PM, Bharat Bhushan wrote:
>> On Friday 19 May 2017 09:15 AM, AKASHI Takahiro wrote:
>>>>> +to load dump-capture kernel.
>>>>> +
>>>>> +   kexec -p <dump-capture-kernel-Image> \
>>>>> +   --initrd=<initrd-for-dump-capture-kernel> \
>>>>> +   --append="root=<root-dev> <arch-specific-options>"
>>>> For uncompressed Image, dtb is not necessary?
>>> Just for clarification, dtb is optional for both vmlinux and Image on
>>> arm64. (This means you can specify it if you want.) But this is also
>>> true for initrd and append(command line) to some extent.
>>
>> Yes, I agree.
>
> Should I mention "-dtb" also for "Image"?

No,I think it is fine.

This documentation is representing a typical use case and so above changes is 
OK for me. I think,your v2 is fine.

~Pratyush

>
> Also do we need to mention that it is optional somewhere in this document? I do not see "optional" is mentioned for other parameters and architecture.
>
> Does this looks ok:
>
> 	" -dtb=<optional-dtb-for-dump-capture-kernel> \"
>
> Thanks
> -Bharat
>
>>>
>>> More precisely, whether these parameters are optional or not will
>>> depend on architectures, not formats, I believe.
>>
>> May be not architecture, rather a distro environment.
>>
>> For example, we should be able to work without --initrd for any arch if kernel
>> has been compiled by configuring CONFG_INITRAMFS_SOURCE.
>>
>> ~Pratyush
>