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From: dyoung@redhat.com (Dave Young)
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 10:03:00 +0800	[thread overview]
Message-ID: <20161123020300.GA3481@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <54cad725-90f0-8dfe-bee6-fe1d3e02175d@redhat.com>

On 11/23/16 at 07:16am, Pratyush Anand wrote:
> 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.

If it is *unlikely* it could be better to make it as default and add a
--disable-dcache instead.

> 
> ~Pratyush
> 
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Thanks
Dave

WARNING: multiple messages have this Message-ID (diff)
From: Dave Young <dyoung@redhat.com>
To: Pratyush Anand <panand@redhat.com>
Cc: Geoff Levand <geoff@infradead.org>,
	james.morse@arm.com, kexec@lists.infradead.org,
	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 10:03:00 +0800	[thread overview]
Message-ID: <20161123020300.GA3481@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <54cad725-90f0-8dfe-bee6-fe1d3e02175d@redhat.com>

On 11/23/16 at 07:16am, Pratyush Anand wrote:
> 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.

If it is *unlikely* it could be better to make it as default and add a
--disable-dcache instead.

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

Thanks
Dave

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

  reply	other threads:[~2016-11-23  2:03 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
2016-11-23  1:46       ` Pratyush Anand
2016-11-23  2:03       ` Dave Young [this message]
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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