From: Santosh Shilimkar <santosh.shilimkar@ti.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
linux-mips <linux-mips@linux-mips.org>,
Aurelien Jacquiot <a-jacquiot@ti.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Max Filippov <jcmvbkbc@gmail.com>,
Paul Mackerras <paulus@samba.org>,
Jonas Bonn <jonas@southpole.se>,
Russell King <linux@arm.linux.org.uk>,
<linux-c6x-dev@linux-c6x.org>,
the arch/x86 maintainers <x86@kernel.org>,
"arm@kernel.org" <arm@kernel.org>,
Rob Herring <robherring2@gmail.com>,
Grant Likely <grant.likely@linaro.org>,
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>,
<linux-xtensa@linux-xtensa.org>,
James Hogan <james.hogan@imgtec.com>,
devicetree-discuss <devicetree-discuss@lists.ozlabs.org>,
Rob Herring <rob.herring@calxeda.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Chris Zankel <chris@zankel.net>,
Vineet Gupta <vgupta@synopsys.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ralf Baechle <ralf@linux-mips.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] of: Specify initrd location using 64-bit
Date: Mon, 1 Jul 2013 09:58:35 -0400 [thread overview]
Message-ID: <51D18B0B.1060906@ti.com> (raw)
In-Reply-To: <CAMuHMdV6YM3-hASqjxkguEukZjnjK80gBjDNiabxjfQtC=c8ag@mail.gmail.com>
On Monday 01 July 2013 03:59 AM, Geert Uytterhoeven wrote:
> On Mon, Jul 1, 2013 at 9:48 AM, Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
>> On 06/29/2013 01:43 AM, Santosh Shilimkar wrote:
>>> Apart from waste of 32bit, what is the other concern you
>>> have ?
>>
>> You pass a u64 as a physical address which is represented in other
>> parts of the kernel (for a good reason) by phys_addr_t.
>>
>>> I really want to converge on this patch because it
>>> has been a open ended discussion for quite some time. Does
>>> that really break any thing on x86 or your concern is more
>>> from semantics of the physical address.
>> You want to have your code in so you can continue with your work, that
>> is okay. The other two arguments why u64 here is a good thing was "due
>> to what I said earlier" and "+1" and I don't have the time to look
>> that up.
>>
>> There should be no problems on x86 if this goes in as it is now.
>>
>> But think about this: What happens if you boot your ARM device without
>> PAE and your initrd is in the upper region? If you are lucky the kernel
>> looks at a different place where it also has a read permission, notices
>> nothing sane is there, writes a message and continues. And if it is not
>> allowed to read? It is clearly the user's fault for booting a non-PAE
>> kernel.
>
> That's actual the original reason: DT has it as 64 bit, and passes it to a
> 32 bit kernel when running in 32 bit mode without PAE.
>
Thanks all for comments and useful discussion. I will resubmit the
patch with update to fix the printk warnings reported by Vineet and
James post the $subject change.
Am assuming the patch will go via Grant Likely's tree.
Regards,
Santosh
WARNING: multiple messages have this Message-ID (diff)
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
linux-mips <linux-mips@linux-mips.org>,
Aurelien Jacquiot <a-jacquiot@ti.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Max Filippov <jcmvbkbc@gmail.com>,
Paul Mackerras <paulus@samba.org>,
Jonas Bonn <jonas@southpole.se>,
Russell King <linux@arm.linux.org.uk>,
linux-c6x-dev@linux-c6x.org,
the arch/x86 maintainers <x86@kernel.org>,
"arm@kernel.org" <arm@kernel.org>,
Rob Herring <robherring2@gmail.com>,
Grant Likely <grant.likely@linaro.org>,
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>,
linux-xtensa@linux-xtensa.org,
James Hogan <james.hogan@imgtec.com>,
devicetree-discuss <devicetree-discuss@lists.ozlabs.org>,
Rob Herring <rob.herring@calxeda.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Chris Zankel <chris@zankel.net>,
Vineet Gupta <vgupta@synopsys.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ralf Baechle <ralf@linux-mips.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] of: Specify initrd location using 64-bit
Date: Mon, 1 Jul 2013 09:58:35 -0400 [thread overview]
Message-ID: <51D18B0B.1060906@ti.com> (raw)
Message-ID: <20130701135835.5Lso_A1KFoGgP3IdWChiw9VLVy_RY2-8IqZ9qbfcKAY@z> (raw)
In-Reply-To: <CAMuHMdV6YM3-hASqjxkguEukZjnjK80gBjDNiabxjfQtC=c8ag@mail.gmail.com>
On Monday 01 July 2013 03:59 AM, Geert Uytterhoeven wrote:
> On Mon, Jul 1, 2013 at 9:48 AM, Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
>> On 06/29/2013 01:43 AM, Santosh Shilimkar wrote:
>>> Apart from waste of 32bit, what is the other concern you
>>> have ?
>>
>> You pass a u64 as a physical address which is represented in other
>> parts of the kernel (for a good reason) by phys_addr_t.
>>
>>> I really want to converge on this patch because it
>>> has been a open ended discussion for quite some time. Does
>>> that really break any thing on x86 or your concern is more
>>> from semantics of the physical address.
>> You want to have your code in so you can continue with your work, that
>> is okay. The other two arguments why u64 here is a good thing was "due
>> to what I said earlier" and "+1" and I don't have the time to look
>> that up.
>>
>> There should be no problems on x86 if this goes in as it is now.
>>
>> But think about this: What happens if you boot your ARM device without
>> PAE and your initrd is in the upper region? If you are lucky the kernel
>> looks at a different place where it also has a read permission, notices
>> nothing sane is there, writes a message and continues. And if it is not
>> allowed to read? It is clearly the user's fault for booting a non-PAE
>> kernel.
>
> That's actual the original reason: DT has it as 64 bit, and passes it to a
> 32 bit kernel when running in 32 bit mode without PAE.
>
Thanks all for comments and useful discussion. I will resubmit the
patch with update to fix the printk warnings reported by Vineet and
James post the $subject change.
Am assuming the patch will go via Grant Likely's tree.
Regards,
Santosh
next prev parent reply other threads:[~2013-07-01 13:59 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-21 0:52 [PATCH] of: Specify initrd location using 64-bit Santosh Shilimkar
2013-06-21 0:52 ` Santosh Shilimkar
2013-06-21 4:39 ` Vineet Gupta
2013-06-21 4:39 ` Vineet Gupta
2013-06-21 8:23 ` James Hogan
2013-06-21 8:23 ` James Hogan
2013-06-21 17:12 ` Santosh Shilimkar
2013-06-21 17:12 ` Santosh Shilimkar
2013-06-21 9:04 ` Sebastian Andrzej Siewior
2013-06-21 17:20 ` Santosh Shilimkar
2013-06-21 17:20 ` Santosh Shilimkar
2013-06-27 20:54 ` Rob Herring
2013-06-28 7:54 ` Sebastian Andrzej Siewior
2013-06-28 9:59 ` Grant Likely
2013-06-28 9:59 ` Grant Likely
2013-06-28 13:49 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-28 13:49 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-28 23:43 ` Santosh Shilimkar
2013-06-28 23:43 ` Santosh Shilimkar
2013-06-29 8:34 ` Geert Uytterhoeven
2013-06-29 8:34 ` Geert Uytterhoeven
2013-07-01 7:48 ` Sebastian Andrzej Siewior
2013-07-01 7:48 ` Sebastian Andrzej Siewior
2013-07-01 7:59 ` Geert Uytterhoeven
2013-07-01 7:59 ` Geert Uytterhoeven
2013-07-01 8:09 ` Sebastian Andrzej Siewior
2013-07-01 8:09 ` Sebastian Andrzej Siewior
2013-07-01 13:58 ` Santosh Shilimkar [this message]
2013-07-01 13:58 ` Santosh Shilimkar
-- strict thread matches above, loose matches on Subject: below --
2012-09-12 16:05 [PATCH] of: specify " Cyril Chemparathy
2012-09-12 16:05 ` Cyril Chemparathy
2012-09-12 16:16 ` Geert Uytterhoeven
2012-09-12 18:02 ` Cyril Chemparathy
2012-09-12 18:02 ` Cyril Chemparathy
2012-09-12 19:58 ` Sebastian Andrzej Siewior
2012-09-12 22:08 ` Rob Herring
2012-09-13 6:47 ` Sebastian Andrzej Siewior
2012-09-13 21:02 ` Rob Herring
2012-09-12 20:23 ` Rob Herring
2012-09-12 20:31 ` Nicolas Pitre
2012-09-12 20:56 ` Rob Herring
2012-09-12 23:45 ` Cyril Chemparathy
2012-09-12 23:45 ` Cyril Chemparathy
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