This commit implements the body of SELFOUR-499. The API exposes the x86 DR0-7
and ARM coprocessor 14 features to userspace by virtualizing them as context-
switched registers in the TCB. Implemented as TCB invocations. This feature is
only built when CONFIG_HARDWARE_DEBUG_API is selected.
* Add low-level support routines for setting, unsetting, getting, enabling
and disabling breakpoints.
* Add support for single-stepping as well.
^ Single-stepping is not supported on ARMv6 since the hardware
doesn't have support.
^ ARM implements single-stepping as instruction breakpoints
configured to fault on every instruction -- this is achieved through
the "mismatch" mode, which is only supported from ARMv7 onwards.
* Also support explicit software break requests, a la "BKPT" and "INT $3".
* New invocations:
* seL4_TCB_SetBreakpoint().
* seL4_TCB_GetBreakpoint().
* seL4_TCB_UnsetBreakpoint().
* seL4_TCB_ConfigureSingleStepping().
* New constants:
^ Event types:
^ seL4_InstructionBreakpoint.
^ seL4_DataBreakpoint.
^ seL4_SoftwareBreakRequest.
^ Access types:
^ seL4_BreakOnRead.
^ seL4_BreakOnWrite.
^ seL4_BreakOnReadWrite.
^ Exports:
^ seL4_NumHWBreakpoints.
^ seL4_NumExclusiveBreakpoints.
^ seL4_NumExclusiveWatchpoints.
^ seL4_NumDualFunctionMonitors.
^ seL4_FirstBreakpoint.
^ seL4_FirstWatchpoint.
^ seL4_FirstDualFunctionMonitor.
See documentation in the seL4 API manual.
