After some research we found that the stack pointer on ARM platforms must be
at least double word aligned (See: "Procedure Call Standard for the ARM
Architecture" - 5.2.1.1). Since a 'call' on ARM will not result in a stack pointer
change (like on x86), the current behavior resulted in a 4 Byte aligned stack
only.
Follow up to #1043
Implies support for the ARMv6 architecture through 'base-hw'.
Get rid of 'base/include/drivers' expect of 'base/include/drivers/uart'.
Merge with the support for trustzone on VEA9X4 that came from
Stefan Kalkowski.
Leave board drivers in 'base/include/platform'.
Rework structure of the other drivers that were moved to
'base_hw/src/core' and those that came with the trustzone support.
Beautify further stuff in 'base_hw'.
Test 'nested_init' with 'hw_imx31' (hardware) and 'hw_panda_a2' (hardware),
'demo' and 'signal' with 'hw_pbxa9' (qemu) and 'hw_vea9x4'
(hardware, no trustzone), and 'vmm' with 'hw_vea9x4'
(hardware, with trustzone).
* Introduces Schedule_context
* Use fast-interrupts or normal interrupts
* Add mode-transition between secure/non-secure world
* Limit system resources for Genode apps due to non-secure world
This commit implements the newly introduced Vm session interface to be used
on top of TrustZone capable Armv7 CPUs. Therefore a new Schedule_context is
introduced in the kernel. Threads and Vms are both Schedule_contexts used
by the scheduler. In contrast to a thread a vm uses a different assembler
mode switch to the non-secure, virtual world, as well as another exception
is used, when the non-secure world is left. For both worlds to co-exist
the interrupt-controller needs to be configured, so that the secure (Genode)
world uses fast-interrupts only, and the non-secure world only legacy
interrupts.
The only TrustZone capable platform the base-hw kernel works on top of
is the CoreTile Express 9x4 for the Versatile Express motherboard. For a
virtual machine working properly on top some platform resources must be
reserved. Therefore there exist two flavours of this platform now, one with
the 'trustzone' spec-variable enabled, and one without. If 'trustzone' is
specified most platform resources (DDR-RAM, and most IRQs) are reserved
for the Vm and not available to the secure Genode world.
Driver definitions which are used by kernel/core in base-hw, and also by other
drivers (e.g. from the os repository) have to reside in the generic
base-repository, for instance some uart drivers. All drivers which are
interesting for one of the sites only (sp804 for timer driver, or
cortex_a9 cpu driver for base-hw) should reside in the respective repos.
Factorize cpu context out of Cortex A9 specific definitions. Moreover, there
is already a Cpu_state object containing all common ARM registers. We use
this as a base for the cpu context switching done by the base-hw kernel.
The Cpu_state class get extended by a cpu-exception field, that stores the kind
of exception raised when the corresponding context got interrupted. This
information is used not only by the base-hw kernel, but also by the TrustZone
VMM that is build currently.
