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From: Michael Ellerman <mpe@ellerman.id.au>
To: Hari Bathini <hbathini@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Pingfan Liu <piliu@redhat.com>,
	Kexec-ml <kexec@lists.infradead.org>,
	Mimi Zohar <zohar@linux.ibm.com>,
	Nayna Jain <nayna@linux.ibm.com>, Petr Tesarik <ptesarik@suse.cz>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Sourabh Jain <sourabhjain@linux.ibm.com>,
	lkml <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Eric Biederman <ebiederm@xmission.com>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Dave Young <dyoung@redhat.com>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [RESEND PATCH v5 07/11] ppc64/kexec_file: enable early kernel's OPAL calls
Date: Wed, 29 Jul 2020 11:15:12 +1000	[thread overview]
Message-ID: <87v9i75dgf.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <23baef6a-6ddc-572a-82c5-21a7fa441485@linux.ibm.com>

Hari Bathini <hbathini@linux.ibm.com> writes:
> On 28/07/20 7:16 pm, Michael Ellerman wrote:
>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>> Kernel built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled expects r8 & r9
>>> to be filled with OPAL base & entry addresses respectively. Setting
>>> these registers allows the kernel to perform OPAL calls before the
>>> device tree is parsed.
>> 
>> I'm not convinced we want to do this.
>> 
>> If we do it becomes part of the kexec ABI and we have to honour it into
>> the future.
>> 
>> And in practice there are no non-development kernels built with OPAL early
>> debugging enabled, so it's not clear it actually helps anyone other than
>> developers.
>> 
>
> Hmmm.. kexec-tools does it since commit d58ad564852c ("kexec/ppc64
> Enable early kernel's OPAL calls") for kexec_load syscall. So, we would
> be breaking kexec ABI either way, I guess.

Ugh, OK.

> Let me put this patch at the end of the series in the respin to let you
> decide whether to have it or not..

Thanks.

cheers

WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <mpe@ellerman.id.au>
To: Hari Bathini <hbathini@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Pingfan Liu <piliu@redhat.com>,
	Kexec-ml <kexec@lists.infradead.org>,
	Nayna Jain <nayna@linux.ibm.com>, Petr Tesarik <ptesarik@suse.cz>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Mimi Zohar <zohar@linux.ibm.com>,
	lkml <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Sourabh Jain <sourabhjain@linux.ibm.com>,
	Vivek Goyal <vgoyal@redhat.com>, Dave Young <dyoung@redhat.com>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Eric Biederman <ebiederm@xmission.com>
Subject: Re: [RESEND PATCH v5 07/11] ppc64/kexec_file: enable early kernel's OPAL calls
Date: Wed, 29 Jul 2020 11:15:12 +1000	[thread overview]
Message-ID: <87v9i75dgf.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <23baef6a-6ddc-572a-82c5-21a7fa441485@linux.ibm.com>

Hari Bathini <hbathini@linux.ibm.com> writes:
> On 28/07/20 7:16 pm, Michael Ellerman wrote:
>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>> Kernel built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled expects r8 & r9
>>> to be filled with OPAL base & entry addresses respectively. Setting
>>> these registers allows the kernel to perform OPAL calls before the
>>> device tree is parsed.
>> 
>> I'm not convinced we want to do this.
>> 
>> If we do it becomes part of the kexec ABI and we have to honour it into
>> the future.
>> 
>> And in practice there are no non-development kernels built with OPAL early
>> debugging enabled, so it's not clear it actually helps anyone other than
>> developers.
>> 
>
> Hmmm.. kexec-tools does it since commit d58ad564852c ("kexec/ppc64
> Enable early kernel's OPAL calls") for kexec_load syscall. So, we would
> be breaking kexec ABI either way, I guess.

Ugh, OK.

> Let me put this patch at the end of the series in the respin to let you
> decide whether to have it or not..

Thanks.

cheers

WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <mpe@ellerman.id.au>
To: Hari Bathini <hbathini@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Pingfan Liu <piliu@redhat.com>,
	Kexec-ml <kexec@lists.infradead.org>,
	Nayna Jain <nayna@linux.ibm.com>, Petr Tesarik <ptesarik@suse.cz>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Mimi Zohar <zohar@linux.ibm.com>,
	lkml <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Sourabh Jain <sourabhjain@linux.ibm.com>,
	Vivek Goyal <vgoyal@redhat.com>, Dave Young <dyoung@redhat.com>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Eric Biederman <ebiederm@xmission.com>
Subject: Re: [RESEND PATCH v5 07/11] ppc64/kexec_file: enable early kernel's OPAL calls
Date: Wed, 29 Jul 2020 11:15:12 +1000	[thread overview]
Message-ID: <87v9i75dgf.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <23baef6a-6ddc-572a-82c5-21a7fa441485@linux.ibm.com>

Hari Bathini <hbathini@linux.ibm.com> writes:
> On 28/07/20 7:16 pm, Michael Ellerman wrote:
>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>> Kernel built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled expects r8 & r9
>>> to be filled with OPAL base & entry addresses respectively. Setting
>>> these registers allows the kernel to perform OPAL calls before the
>>> device tree is parsed.
>> 
>> I'm not convinced we want to do this.
>> 
>> If we do it becomes part of the kexec ABI and we have to honour it into
>> the future.
>> 
>> And in practice there are no non-development kernels built with OPAL early
>> debugging enabled, so it's not clear it actually helps anyone other than
>> developers.
>> 
>
> Hmmm.. kexec-tools does it since commit d58ad564852c ("kexec/ppc64
> Enable early kernel's OPAL calls") for kexec_load syscall. So, we would
> be breaking kexec ABI either way, I guess.

Ugh, OK.

> Let me put this patch at the end of the series in the respin to let you
> decide whether to have it or not..

Thanks.

cheers

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2020-07-29  1:15 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-26 19:36 [RESEND PATCH v5 00/11] ppc64: enable kdump support for kexec_file_load syscall Hari Bathini
2020-07-26 19:36 ` Hari Bathini
2020-07-26 19:36 ` Hari Bathini
2020-07-26 19:36 ` [RESEND PATCH v5 01/11] kexec_file: allow archs to handle special regions while locating memory hole Hari Bathini
2020-07-26 19:36   ` Hari Bathini
2020-07-26 19:36   ` Hari Bathini
2020-07-26 19:36 ` [RESEND PATCH v5 02/11] powerpc/kexec_file: mark PPC64 specific code Hari Bathini
2020-07-26 19:36   ` Hari Bathini
2020-07-26 19:36   ` Hari Bathini
2020-07-26 19:37 ` [RESEND PATCH v5 03/11] powerpc/kexec_file: add helper functions for getting memory ranges Hari Bathini
2020-07-26 19:37   ` Hari Bathini
2020-07-26 19:37   ` Hari Bathini
2020-07-28 12:58   ` Michael Ellerman
2020-07-28 12:58     ` Michael Ellerman
2020-07-28 12:58     ` Michael Ellerman
2020-07-26 19:38 ` [RESEND PATCH v5 04/11] ppc64/kexec_file: avoid stomping memory used by special regions Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-26 19:38 ` [RESEND PATCH v5 05/11] powerpc/drmem: make lmb walk a bit more flexible Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-26 19:38 ` [RESEND PATCH v5 06/11] ppc64/kexec_file: restrict memory usage of kdump kernel Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-26 19:38   ` Hari Bathini
2020-07-28  2:10   ` Thiago Jung Bauermann
2020-07-28  2:10     ` Thiago Jung Bauermann
2020-07-28  2:10     ` Thiago Jung Bauermann
2020-07-28 13:44   ` Michael Ellerman
2020-07-28 13:44     ` Michael Ellerman
2020-07-28 13:44     ` Michael Ellerman
2020-07-28 19:34     ` Hari Bathini
2020-07-28 19:34       ` Hari Bathini
2020-07-28 19:34       ` Hari Bathini
2020-07-30  0:36   ` kernel test robot
2020-07-26 19:39 ` [RESEND PATCH v5 07/11] ppc64/kexec_file: enable early kernel's OPAL calls Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-28  2:17   ` Thiago Jung Bauermann
2020-07-28  2:17     ` Thiago Jung Bauermann
2020-07-28  2:17     ` Thiago Jung Bauermann
2020-07-28 13:46   ` Michael Ellerman
2020-07-28 13:46     ` Michael Ellerman
2020-07-28 13:46     ` Michael Ellerman
2020-07-28 19:24     ` Hari Bathini
2020-07-28 19:24       ` Hari Bathini
2020-07-28 19:24       ` Hari Bathini
2020-07-29  1:15       ` Michael Ellerman [this message]
2020-07-29  1:15         ` Michael Ellerman
2020-07-29  1:15         ` Michael Ellerman
2020-07-26 19:39 ` [RESEND PATCH v5 08/11] ppc64/kexec_file: setup backup region for kdump kernel Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-28  2:37   ` Thiago Jung Bauermann
2020-07-28  2:37     ` Thiago Jung Bauermann
2020-07-28  2:37     ` Thiago Jung Bauermann
2020-07-28 14:11   ` Michael Ellerman
2020-07-28 14:11     ` Michael Ellerman
2020-07-28 14:11     ` Michael Ellerman
2020-07-26 19:39 ` [RESEND PATCH v5 09/11] ppc64/kexec_file: prepare elfcore header for crashing kernel Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-26 19:39   ` Hari Bathini
2020-07-26 19:40 ` [RESEND PATCH v5 10/11] ppc64/kexec_file: add appropriate regions for memory reserve map Hari Bathini
2020-07-26 19:40   ` Hari Bathini
2020-07-26 19:40   ` Hari Bathini
2020-07-26 19:40 ` [RESEND PATCH v5 11/11] ppc64/kexec_file: fix kexec load failure with lack of memory hole Hari Bathini
2020-07-26 19:40   ` Hari Bathini
2020-07-26 19:40   ` Hari Bathini
2020-07-28  2:32 ` [RESEND PATCH v5 00/11] ppc64: enable kdump support for kexec_file_load syscall piliu
2020-07-28  2:32   ` piliu
2020-07-28  2:32   ` piliu
2020-07-30  6:05   ` Hari Bathini
2020-07-30  6:05     ` Hari Bathini
2020-07-30  6:05     ` Hari Bathini

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