From: "Richard Earnshaw (lists)" <Richard.Earnshaw@arm.com>
To: Alex Coplan <alex.coplan@arm.com>
Cc: newlib@sourceware.org
Subject: Re: [PATCH] libgloss/aarch64: Add support for Armv8-R AArch64
Date: Wed, 30 Sep 2020 11:25:18 +0100 [thread overview]
Message-ID: <3afe2476-6360-fb1a-60bb-e345a731b686@arm.com> (raw)
In-Reply-To: <20200929162718.x2s3w2pfnelxkzkr@arm.com>
On 29/09/2020 17:27, Alex Coplan via Newlib wrote:
> Hi Richard,
>
> On 29/09/2020 15:06, Richard Earnshaw (lists) wrote:
>> On 18/09/2020 15:43, Alex Coplan wrote:
>>> Hello,
>>>
>>> This patch adds support for Armv8-R AArch64. We update the AArch64 CPU
>>> boot code to work on Armv8-R if __ARM_ARCH_PROFILE is set to 'R'.
>>> Armv8-R AArch64 has no EL3, so we don't set vbar_el3, and adjust the
>>> code to set up the MPU for Armv8-R.
>>>
>>> We also add a specs file for use with Armv8-R AArch64 models.
>>>
>>> Testing:
>>> * Ran AArch64 GCC testsuite using --with-arch=armv8-r together with the
>>> new specs file and boot code in an Armv8-R AArch64 model.
>>> * Ran newlib testsuite, no regressions.
>>>
>>> OK for master?
>>>
>>> Thanks,
>>> Alex
>>>
>>> ---
>>>
>>> 2020-09-18 Alex Coplan <alex.coplan@arm.com>
>>>
>>> libgloss/ChangeLog:
>>>
>>> * aarch64/Makefile.in: Install new specs file.
>>> * aarch64/cpu-init/Makefile.in: Also build boot code for Armv8-R.
>>> * aarch64/cpu-init/rdimon-aem-el3.S: Add support for Armv8-R.
>>> * aarch64/elf-aem-v8-r.specs: New.
>>>
>>
>> The main problem I see with this is that it assumes that the compiler
>> being used is *not* configured for a default CPU architecture of
>> ARMv8-r. If it is, then the normal rdimon-aem-el3.o file will in fact
>> become the same as the v8-r version, which is not really what we want.
>
> Good catch. Thanks for the review.
>
>>
>> Perhaps, rather than hacking around the __ARM_ARCH_PROFILE setting you
>> should just set things up to build the file twice, but with a different
>> conventional pre-define set each time.
>>
>> R.
>
> Sounds sensible. Is the revised patch (attached) OK?
>
> Thanks,
> Alex
>
Pushed. I've used the following as the commit message (note that newlib
doesn't use ChangeLog files anymore).
libgloss: aarch64: Add support for Armv8-R AArch64
This patch adds support for Armv8-R AArch64.
Armv8-R AArch64 has no EL3, so we don't set vbar_el3, and adjust the
code to set up the MPU for Armv8-R. So build a different flavour of the
startup code to support that.
We also add a specs file that uses this alternative startup code which
can be used with Armv8-R AArch64 models.
R.
next prev parent reply other threads:[~2020-09-30 10:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 14:43 Alex Coplan
2020-09-22 12:42 ` Kyrylo Tkachov
2020-09-29 14:06 ` Richard Earnshaw (lists)
2020-09-29 16:27 ` Alex Coplan
2020-09-30 10:25 ` Richard Earnshaw (lists) [this message]
2020-09-30 13:25 ` UNSUBSCRIBE Brian Hawley
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