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.
this commit adds the facilities to extract eh_frame[_header]
sections and pass it to each process.
A bump is required to `std` to extract the passed parameters.
it works with e.g. shellchat, but not vault.
still scratching my head on what's gone wrong -- it's
crashing in the pre-boot, which means something is not
mapped right for some case that wasn't caught in the
earlier testing.
Atomic operations were previously broken. RISC-V breaks atomic
operations into multiple instructions, and there is some state kept
between those instructions. This state is not visible, and is internal
to the processor.
We were ignoring this state, which resulted in inconsistencies
throughout the system. The following sequence was possible:
1. A thread loads a value, and obtains the `reservation set`
2. A context switch happens on the following instruction
3. A different thread loads the value, modifies it, and continues
4. A third thread (or a different process) loads a value and obtains the
`reservation set`
5. The original thread runs, sees the `reservation set` is held, and
updates the value, clobbering what the second thread did in #3
A workaround for this is to perform a dummy `sc` as part of the context
switch. This invalidates any atomic operations that may be pending.
Signed-off-by: Sean Cross <sean@xobs.io>
The previous patch didn't properly restore thread IDs when switching
contexts -- there were spots where we missed things, and spots where we
were double-borrowing.
Fix these corner cases.
Signed-off-by: Sean Cross <sean@xobs.io>
Note the current thread in the original process when its quantum
expires. This will allow us to clean up after ourselves when a context
switch occurs, and will help to prevent thread starvation.
Signed-off-by: Sean Cross <sean@xobs.io>
Currently, returning a Message (e.g. a Scalar1, Scalar2, or
MemoryMessage) always results in a context switch from the server to the
client. This is what makes these syscalls cheaper.
However, this results in process starvation. For example, if three
processes send a message to a server, then the server will only be able
to respond to one of those messages at a time. This works well with a
lightly-loaded system, but quickly falls apart when many threads are
running.
Keep track of which process and thread were originally switched to as
part of the `SwitchTo` call. If the Server is responding to a message
and owns the current quantum, don't immediately switch to the Client
thread.
Signed-off-by: Sean Cross <sean@xobs.io>
For some reason, the current thread becomes 0 during suspend or resume.
This causes an error during boot.
Patch this up while we figure out what's causing it.
Signed-off-by: Sean Cross <sean@xobs.io>
Unify scalar return calls so that we only have one return path rather
than three.
We can almost unify memory returning as well, but it's not quite there.
Signed-off-by: Sean Cross <sean@xobs.io>
