Instead of always doing bytewise accesses, support 2- and 4-byte access.
Additionally, recognize when multiple 4-byte reads are required.
Note that an additional optimization may be made here in the future to
prevent having to check every address, but this is left for a future
optimization.
Signed-off-by: Sean Cross <sean@xobs.io>
Instead of remapping the page to allow the kernel to access a process'
memory, simply set the SUM bit. This makes it no longer an error for the
kernel to access userspace.
Keep setting the `W` bit when we poke, to allow for updating program
memory with breakpoints.
Signed-off-by: Sean Cross <sean@xobs.io>
Previously, we were creating a fake interrupt that was a "user software
interrupt". Update this to be a "supervisor external interrupt" to fix
hardware resume.
Signed-off-by: Sean Cross <sean@xobs.io>
Debug handling was not correct, and didn't work at all. Additionally,
interrupt masking didn't work.
Fix these problems.
Signed-off-by: Sean Cross <sean@xobs.io>
Implement the basics required to get "extended mode" working. This is
waiting on upstream to fix issues, but should allow us to attach to
processes once it works.
Signed-off-by: Sean Cross <sean@xobs.io>
When debugging an invalid process (e.g. not yet run, terminated, etc.)
return an error rather than silently continuing.
Signed-off-by: Sean Cross <sean@xobs.io>
Disable IRQs during destruction, but only if constructed with
`GdbUart::new()`. This allows characters to buffer when the GDB bridge
is destroyed while avoiding the double-free error we were getting from
creating a new UART in the IRQ handler.
Signed-off-by: Sean Cross <sean@xobs.io>
This adds a basic gdb server. Currently, it is possible to list
processes and inspect memory and threads. It is not yet possible to
actually interact with code (e.g. no breakpoints and no single
stepping).
Signed-off-by: Sean Cross <sean@xobs.io>
Add an initial reimplementation of the gdb-stub using the gdbstub
backing crate.
This supports process enumeration and basic thread investigation.
Processes will pause when the debugger is inspecting them. Memory and
registers can be investigated. Threads can be listed and selected.
It does not yet support breakpoints.
Signed-off-by: Sean Cross <sean@xobs.io>
Previously, `disable_irq()` would unconditionally mask an interrupt in
the `sim` register. However, when interrupts are disabled this register
is zero, and we really should be updating `SIM_BACKING`.
Consult the state of the interrupt handler and update the appropriate
field as necessary.
Signed-off-by: Sean Cross <sean@xobs.io>
This function never failed. Make it infallible so that it matches the
same calling convention as `enable_irq()`
Signed-off-by: Sean Cross <sean@xobs.io>
Even when the print-debug feature isn't turned on, println! macro is still able to output some critical non-debug info to the console such as panics, process crashes and violations, etc. Debugging messages are printed with klog! macro that's disabled when debug-print feature is not set.
