From: panand@redhat.com (Pratyush Anand)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm64: Pass RAM boundary and enable-dcache flag to purgatory
Date: Wed, 23 Nov 2016 07:16:26 +0530 [thread overview]
Message-ID: <54cad725-90f0-8dfe-bee6-fe1d3e02175d@redhat.com> (raw)
In-Reply-To: <53ee2a62-7822-5457-e59f-e65e64a57019@infradead.org>
Hi Geoff,
On Wednesday 23 November 2016 12:27 AM, Geoff Levand wrote:
> Hi Pratyush,
>
> On 11/21/2016 08:32 PM, Pratyush Anand wrote:
>> When "enable-dcache" is passed to the kexec() command line, kexec-tools
>> passes this information to purgatory, which in turn enables cache during
>> sha-256 verification.
>
> What's the point of this enable-dcache option? Why not just
> always enable the cache if we can?
As I have written in changelog of patch 1/2
"We are supporting only 4K and 64K page sizes. This code will not work if a
hardware is not supporting at least one of these page sizes. Therefore,
D-cache is disabled by default and enabled only when "enable-dcache" is
passed to the kexec()."
Although this is very unlikely that a hardware will support only 16K
page sizes, however it is possible. Therefore, its better to keep it
disabled by default.
~Pratyush
WARNING: multiple messages have this Message-ID (diff)
From: Pratyush Anand <panand@redhat.com>
To: Geoff Levand <geoff@infradead.org>, kexec@lists.infradead.org
Cc: james.morse@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] arm64: Pass RAM boundary and enable-dcache flag to purgatory
Date: Wed, 23 Nov 2016 07:16:26 +0530 [thread overview]
Message-ID: <54cad725-90f0-8dfe-bee6-fe1d3e02175d@redhat.com> (raw)
In-Reply-To: <53ee2a62-7822-5457-e59f-e65e64a57019@infradead.org>
Hi Geoff,
On Wednesday 23 November 2016 12:27 AM, Geoff Levand wrote:
> Hi Pratyush,
>
> On 11/21/2016 08:32 PM, Pratyush Anand wrote:
>> When "enable-dcache" is passed to the kexec() command line, kexec-tools
>> passes this information to purgatory, which in turn enables cache during
>> sha-256 verification.
>
> What's the point of this enable-dcache option? Why not just
> always enable the cache if we can?
As I have written in changelog of patch 1/2
"We are supporting only 4K and 64K page sizes. This code will not work if a
hardware is not supporting at least one of these page sizes. Therefore,
D-cache is disabled by default and enabled only when "enable-dcache" is
passed to the kexec()."
Although this is very unlikely that a hardware will support only 16K
page sizes, however it is possible. Therefore, its better to keep it
disabled by default.
~Pratyush
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next prev parent reply other threads:[~2016-11-23 1:46 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-22 4:32 [PATCH 0/2] kexec-tools: arm64: Add dcache enabling facility Pratyush Anand
2016-11-22 4:32 ` Pratyush Anand
2016-11-22 4:32 ` [PATCH 1/2] arm64: Add enable/disable d-cache support for purgatory Pratyush Anand
2016-11-22 4:32 ` Pratyush Anand
2016-11-25 18:30 ` James Morse
2016-11-25 18:30 ` James Morse
2016-12-14 9:38 ` Pratyush Anand
2016-12-14 9:38 ` Pratyush Anand
2016-12-14 10:12 ` Pratyush Anand
2016-12-14 10:12 ` Pratyush Anand
2016-12-14 11:16 ` James Morse
2016-12-14 11:16 ` James Morse
2016-12-14 11:37 ` Mark Rutland
2016-12-14 11:37 ` Mark Rutland
2016-12-14 12:11 ` James Morse
2016-12-14 12:11 ` James Morse
2016-12-14 12:21 ` Pratyush Anand
2016-12-14 12:21 ` Pratyush Anand
2016-12-14 13:44 ` Mark Rutland
2016-12-14 13:44 ` Mark Rutland
2016-12-14 14:13 ` Pratyush Anand
2016-12-14 14:13 ` Pratyush Anand
2016-12-14 12:13 ` Pratyush Anand
2016-12-14 12:13 ` Pratyush Anand
2016-12-14 11:16 ` James Morse
2016-12-14 11:16 ` James Morse
2016-12-14 11:28 ` Mark Rutland
2016-12-14 11:28 ` Mark Rutland
2016-11-22 4:32 ` [PATCH 2/2] arm64: Pass RAM boundary and enable-dcache flag to purgatory Pratyush Anand
2016-11-22 4:32 ` Pratyush Anand
2016-11-22 18:57 ` Geoff Levand
2016-11-22 18:57 ` Geoff Levand
2016-11-23 1:46 ` Pratyush Anand [this message]
2016-11-23 1:46 ` Pratyush Anand
2016-11-23 2:03 ` Dave Young
2016-11-23 2:03 ` Dave Young
2016-11-23 2:11 ` Pratyush Anand
2016-11-23 2:11 ` Pratyush Anand
2016-11-23 8:08 ` Simon Horman
2016-11-23 8:08 ` Simon Horman
2016-11-23 8:17 ` Pratyush Anand
2016-11-23 8:17 ` Pratyush Anand
2016-11-22 18:56 ` [PATCH 0/2] kexec-tools: arm64: Add dcache enabling facility Geoff Levand
2016-11-22 18:56 ` Geoff Levand
2016-11-23 1:39 ` Pratyush Anand
2016-11-23 1:39 ` Pratyush Anand
2016-11-25 18:30 ` James Morse
2016-11-25 18:30 ` James Morse
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