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>
There were a few corner cases when it came to thread selection. Namely,
the same thread had a higher chance of repeatedly being executed.
Clean up these corner cases, and as a result get libstd tests to pass.
Signed-off-by: Sean Cross <sean@xobs.io>
Add notes on how to properly hand memory to userspace. This does not yet
work, but is committed here as a work-in-progress.
Signed-off-by: Sean Cross <sean@xobs.io>
The default mem size got shrunk down to 4 MB earlier, but there is a
lingering issue that prevents specifying virtual addresses. As a result,
pddb and others don't work.
Temporarily revert this change.
Signed-off-by: Sean Cross <sean@xobs.io>
The process search now uses iterators properly. It's still not ideal
because it needs to investigate every process, but it's better than it
was.
Signed-off-by: Sean Cross <sean@xobs.io>
