On Sat, 26 Mar 2011, Tixy wrote:
I.e. does CONFIG_THUMB2_KERNEL imply ARMv7 or newer? I assume this is the intent as arch/arm/Kconfig has
depends on CPU_V7 && !CPU_V6 && !CPU_V6K && EXPERIMENTAL
and there are no hits for the string "v6t" in the source tree
If you look at the log for commit 6e6fc998b8 which introduced that dependency, you'll find:
|commit 6e6fc998b8c127fe06b9350a1f16e41bfe4f109d |Author: Dave Martin dave.martin@linaro.org |Date: Mon Dec 13 21:53:53 2010 +0100 | | ARM: 6533/1: Thumb-2: Make CONFIG_THUMB2_KERNEL depend on !CPU_V6 | | This makes sense, because Thumb-2 code can't execute on plain | ARMv6 processors. | | This will avoid accidentally configuring a broken kernel where the | config otherwise would allow multiple architecture versions to | coexist in the same kernel. | | Not adding !CPU_V5 etc., because the chance of anyone trying to | put v5 and v7 in the same kernel is low, and I'm not aware of | any mach which can do this. These could be added later if it | matters. | | Note that the rules may need to be refined if support for the | ARM1156J(F)-S processor is later added to the kernel, since this | processor supports the rare ARMv6T2 extensions, which add support | for Thumb-2 and a few other ARMv7 features. | | Signed-off-by: Dave Martin dave.martin@linaro.org | Acked-by: Catalin Marinas catalin.marinas@arm.com | Acked-by: Nicolas Pitre nicolas.pitre@linaro.org | Acked-by: Santosh Shilimkar santosh.shilimkar@ti.com | Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk
So for now we don't support ARMv6T2. However this would still be a good idea to add some comments next to the code that may rely on this presumption.
Nicolas