[PATCH 0/4] ABI updates

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

As a result of the recent discussions about android, several issues
have been identified with existing kernels:

1. HWCAP_SWP does not properly reflect whether the SWP instruction
   should be used.  Turn HWCAP_SWP off on ARMv6+ where the exclusives
   are available.

2. SWP is unsafe when running on a SMP CPU; there is no bus locking
   between the read and write parts of the instruction execution.
   Force SWP emulation on ARMv7+ where we can disable the SWP
   instruction.

3. Reporting of alignment faults - kernel mode faults are silent due to
   the requirements of the network stack, but we can note where the
   last one occurs.

Testing reveals that at least my OMAP4430 userspace (supplied from TI)
executes lots of SWP instructions, which is something that wasn't known
before this patch.

Many systems today are not configured with SWP emulation enabled on SMP.
This means that the SWP instruction is available, but unsafe.

 arch/arm/kernel/setup.c       | 29 ++++++++++++++++++++++-------
 arch/arm/kernel/swp_emulate.c |  4 ++++
 arch/arm/mm/Kconfig           |  2 +-
 arch/arm/mm/alignment.c       |  4 +++-
 4 files changed, 30 insertions(+), 9 deletions(-)

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