[PATCH] ARM: xip: disable PATCH_PHYS_VIRT for ARCH_MULTIPLATFORM when XIP

Russell King - ARM Linux linux at armlinux.org.uk
Wed Feb 8 10:39:37 PST 2017


On Wed, Feb 08, 2017 at 06:53:14PM +0100, Geert Uytterhoeven wrote:
> The problem is that "multiplatform" may mean one of two things:
>   1. Build a single kernel that can run on multiple platforms.
>      This is tricky when enabling XIP and/or NOMMU, as the physical parameters
>      must be compatible with all platforms. But building a kernel with the
>      right parameters is the responsibility of the user.
>      I.e. don't shoot yourself in the foot.
>   2. Your platform uses the arch/arm multiplatform framework.
> 
> As everything is being migrated to 2, not allowing XIP and/or NOMMU on
> "multiplatform" is IMHO an insane limitation.

There _isn't_ a framework.  What there is are a collection of Kconfig
options that multiplatform provides you that can also be selected by
any other configuration route.

(2) really doesn't apply.

The real issue is that board stuff ends up with a "depends on MULTI_xxx"
which needs to be bypassed.  That's pretty easy to do - I've done it as
a proof of concept a few years ago when this exact same thing came up
for !MMU, and since then I've been NAKing and refusing to apply patches
that try to re-use multiplat for !MMU.

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