From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Tue, 21 Oct 2014 19:03:57 +0200 Subject: [Buildroot] [PATCH 03/31] arch/arm: add blind options to know the ARM architecture In-Reply-To: <20141019215528.GD12247@free.fr> References: <1413749285-1108-1-git-send-email-thomas.petazzoni@free-electrons.com> <1413749285-1108-4-git-send-email-thomas.petazzoni@free-electrons.com> <20141019215528.GD12247@free.fr> Message-ID: <20141021190357.6982847e@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Yann E. MORIN, On Sun, 19 Oct 2014 23:55:28 +0200, Yann E. MORIN wrote: > > diff --git a/arch/Config.in.arm b/arch/Config.in.arm > > index 201ff1d..d2ba924 100644 > > --- a/arch/Config.in.arm > > +++ b/arch/Config.in.arm > > @@ -37,6 +37,27 @@ config BR2_ARM_CPU_HAS_THUMB > > config BR2_ARM_CPU_HAS_THUMB2 > > bool > > Indirectly related to your patch: HAS_THUMB2 should select HAS_THUMB, > since Thumb-2 is a superset of Thumb. Right. > Then, you could just have (for example) BR2_ARM_CPU_ARMV4 and ditch > BR2_ARM_CPU_ARMV4T since it can be reconstructed from BR2_ARM_CPU_ARMV4 > && HAS_THUMB. > > The reasonning is that few package actually require knowing the exact > variant, but rather the instruction set generation. Thus knowing about > armv4t is equivalent to knowing about armv4 for most. Those few that > actuallt require the Thumb isns would need to use the HAS_THUMB option, > which very purpose is just that, telling whether thumb is supported or > not (or HAS_THUMB2 for Thumb-2). > > As for the J version, I wonder if we need to introduce a HAS_JAZELLE > option. For armv6zk (Wikpedia refer to it as armv6kz), I also doubt we > need to introduce a HAS_TRUSTZONE option either. Agreed with all of that. > For armv7a, I think we > can just use armv7, since we will probably never support the R and M > profiles in Buildroot. But not with that one: I now have a Cortex-M platform, and I hope to do something with it at some point. And since Cortex-M platforms don't have a MMU, it's significant difference between ARMv7-A and ARMv7-M. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com