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Re: [Patch ARM] Add support for bare-metal cpu initialization on A profile cores.
- From: Ye Joey <joey dot ye dot cc at gmail dot com>
- To: Ramana Radhakrishnan <ramrad01 at arm dot com>
- Cc: newlib at sourceware dot org
- Date: Mon, 23 Sep 2013 11:12:52 +0800
- Subject: Re: [Patch ARM] Add support for bare-metal cpu initialization on A profile cores.
- Authentication-results: sourceware.org; auth=none
- References: <523AFD69 dot 8060701 at arm dot com>
This patch breaks combined build for Cortex-M, i.e., configured with
combine/src/libgloss/arm/cpu-init/rdimon-aem.S:84: Error: thumb
conditional instruction should be in IT block -- `moveq r4,#0'
I think when configured for M-profile, it shouldn't build rdimon-aem.S at all.
On Thu, Sep 19, 2013 at 9:34 PM, Ramana Radhakrishnan <email@example.com> wrote:
> Increasingly we've found the need for a start-up routine required
> for bare-metal applications that need to initialize the mmu and the caches
> for use during hardware bring-up and/or for bare-metal testing on ARM's
> propreitary models as well as allow for semi-hosting to happen at the same
> time. This has been found to be useful in a number of situations and this is
> just the initial patch set required for this to work on A profile CPUs. I
> would recommend that this not be used for earlier cores without testing.
> The way this is implemented is by adding a new weak function called
> _rdimon_init_hook that deals with this initialization. I expect this to work
> on newer hardware because our testing involves testing with the AEM models
> that model the newer hardware but I don't have access to any such hardware
> to test this right now.
> The SMP enable bit in the ACTLR is enabled only for A15 and A7 but not for
> any other cores as this is needed only on those cores. We use this
> internally for some of our GCC test runs on our fast models, we've tried it
> in the past to run some simple applications on bare-metal A7 and A15 boards.
> This necessitates the use of a new specs file aprofile-ve.specs which I've
> added and provided as an example. I have tested this on an AEM model but am
> confident that this will work just fine on a bare-metal board connected via
> D-Stream or anything that implements the standard Angel API.
> If people want to use a different base address for the text section and / or
> for the vectors page in the cpu init code this is available by doing
> --defsym _rdimon_vector_base=FOO or -Ttext_section=BAR . The specs file only
> eases the use for this.
> Tested with an arm-eabi bare-metal GCC multilib build across architecture
> variants, Thumbness and fpu abi variants using the new specs file in my
> baremetal build script and tested with --specs=aprofile-ve.specs passed by
> default in my site.exp - tested on AEM VE model internally .
> Ok to apply ?
> <DATE> Matthew Gretton-Dann <firstname.lastname@example.org>
> Ramana Radhakrishnan <email@example.com>
> Greta Yorsh <firstname.lastname@example.org>
> * arm/Makefile.in: Add support for cpu-init directory and add
> * arm/configure.in: Likewise.
> * arm/configure: Regenerate.
> * arm/cpu-init: New directory.
> * arm/cpu-init/Makefile.in: New file.
> * arm/cpu-init/rdimon-aem.S: Likewise.
> * arm/crt0.S: Call _rdimon_init_hook
> * arm/elf-aprofile-ve.specs: New file.