This patch implements a simple, lightweight form of protection domains
using a pluggable framework. Currently, the following plugin is
available:
- Flat memory model with paging.
The overall goal of a protection domain implementation within this
framework is to define a set of resources that should be accessible to
each protection domain and to prevent that protection domain from
accessing other resources. The details of each implementation of
protection domains may differ substantially, but they should all be
guided by the principle of least privilege. However, that idealized
principle is balanced against the practical objectives of limiting the
number of relatively time-consuming context switches and minimizing
changes to existing code.
For additional information, please refer to cpu/x86/mm/README.md.
This patch also causes the C compiler to be used as the default linker
and assembler.
This patch permits interrupts to be generated by both the I2C and GPIO
controllers for simultaneously-executing applications. The controllers
share a single interrupt pin, INTC. Prior to this patch,
quarkX1000_gpio_init() routed INTA to PIRQC and IRQ 10 (due to an
incorrect assumption that INTA is connected to the GPIO controller),
and quarkX1000_i2c_init() routed INTC to PIRQC and IRQ 9. The I2C
controller initialization is a prerequisite for GPIO initialization,
so the final configuration was that INTA and INTC were both routed to
PIRQC and IRQ 10. Thus, only the GPIO ISR was being invoked, even if
the I2C controller was actually responsible for the interrupt.
This patch refactors the I2C and GPIO ISR setup and handler code so
that the shared portions are combined in
cpu/x86/drivers/legacy_pc/shared-isr.[ch]. The I2C and GPIO drivers
communicate their interrupt information to the shared component by
placing structures in a specific section of the binary.
