[PATCH 0/3] Fix Thumb-2 undef handling for mixed-arch kernels

[tixy@yxit.co.uk (Tixy)]

On Tue, 2011-08-16 at 15:14 +0100, Dave Martin wrote:
> In kernels which support v6 and v7 platforms in a single binary
> such as omap2plus_defconfig for example, undefined instruction
> exceptions taken on Thumb instructions are not processed correctly,
> because the kernel assumes at build-time that Thumb-2 won't be
> supported in userspace.
> 
> This series implements a workaround, by allowing the __und_usr
> handler to check the CPU architecture at runtime, in affected
> kernels.
> 
> Changes since RFC:
>   * Renamed the global variable to __cpu_architecture and provided
>     cpu_architecture() as in inline function in <asm/system.h>.
>     This brings back the old API, but more efficiently.
>   * Dropped all the patches required to handle the reverted API
>     change.
>   * cpu_architecture is now declared __pure, which may lead to
>     slightly more efficient code in some cases.
>   * Added BUG_ON() to cpu_architecture() so that if
>     __cpu_architecture is not set early enough, it gets noticed.
> 
> Thanks to Tixy and Nicolas Pitre for their helpful feedback which
> helped slim down this series.
> 
> Dave Martin (3):
>   ARM: Make cpu_alignment into a global variable
>   ARM: entry: Remove unnecessary masking when decoding Thumb-2
>     instructions
>   ARM: entry: Fix Thumb-2 undef handling for multi-CPU kernels
> 
>  arch/arm/include/asm/system.h |   11 +++++++++-
>  arch/arm/kernel/entry-armv.S  |   44 ++++++++++++++++++++++++++++++++++++----
>  arch/arm/kernel/setup.c       |    5 +++-
>  3 files changed, 53 insertions(+), 7 deletions(-)
> 

Looks good to me.

-- 
Tixy