- we don't need a general memset call -- just a zero page call
- use native rust semantics to embody the call. some alignment checking is
done on the arguments on the way in and out that seem worth it
- the unrolled loop doesn't pay off because we're at the limit of
write bandwidth on the CPU at this point. we would need write-back
caches to gain more performance through unrolling.
@xobs found a scheduler bug that would trigger a runnable process
search every time a scalar message returned. This fixes the problem,
causing the quantum to go back to the caller as intended.
Improves performance on the syscall by about 40%.
Fix a segfault that occurred when using ReplyAndReceiveNext on hosted
mode. This now properly passes memory messages back to the client.
Signed-off-by: Sean Cross <sean@xobs.io>
Implement `ReplyAndReceiveNext` as a syscall. This will reply to a
message, pull the next message out of the queue, and then re-queue the
server to run. This should make servers much more responsive.
This patch has been tested on both hosted and native modes.
Signed-off-by: Sean Cross <sean@xobs.io>
I've added a `platform` module to store all platform specific code, (not
architecture specific) as some platforms will require custom drivers, e.g.
for debug output and for the random number generation code. The platform
code is in charge of mapping any peripherals needed to work, also to
initialize any other parts of the kernel that require drivers, for example
the debug shell.
Signed-off-by: Jean-Pierre De Jesus DIAZ <me@jeandudey.tech>
- strip out gdb-stub. Per xobs, the feature never worked, and it
depends upon a branch of a git repo which is not allowed by crates.io
Since the feature hasn't been developed, and crates.io will not
allow even an optional feature that points to a git repo, the feature
was stripped out.
- rename "kernel" to "xous-kernel", so that we can live in a crates.io
package namespace that is specific to Xous.
still have to figure out the riscv package issue.
this will help speed up performance profiling as we can
resolve the physical address of the performance buffer allocated
in RAM and use a USB command to read it out, instead of streaming
it over serial.
Instead of passing a constructed mutable ref from the pagetable entry,
pass a raw pointer and use `read_volatile()` / `write_volatile(x)` on
this pointer.
This should remove a little bit of UB from the kernel.
Signed-off-by: Sean Cross <sean@xobs.io>
Previously, the kernel would dutifully try to map memory that was in the
kernel space. It did this by investigating the kernel memory offset,
which immediately causes a double-fault.
Check to make sure a userspace process is not trying to map kernel
memory before checking the valid page.
Signed-off-by: Sean Cross <sean@xobs.io>
Implement the syscall to adjust a process' limit. Currently this
only supports adjusting the heap maximum and the heap size.
In order to adjust a limit, you must first present the current limit.
This can be obtained by requesting a bogus value. The current limit is
returned as part of the result.
Signed-off-by: Sean Cross <sean@xobs.io>
Return the heap size and offset when decreasing the heap. Additionally,
return the heap size when increasing the heap by 0 bytes.
Signed-off-by: Sean Cross <sean@xobs.io>
this contains a dependency to `failure` two levels down that has a critical
vulnerability. Unfortunately no new versions of debug-here have been
published in a while. It's no longer used, so just stripping it out
altogether.
Hosted mode spawns processes very differently, and this difference was
not reflected after changes were made to native mode.
Signed-off-by: Sean Cross <sean@xobs.io>
Unmap the pages from the child process after we're done setting them up.
This ensures they're not still aliased by our process, despite being
marked as "owned" by the other process.
Signed-off-by: Sean Cross <sean@xobs.io>
Implement a functioning CreateProcess syscall on riscv. This call
creates a server in the child process, and connects the server to the
parent. The parent can communicate with the child process using this
server.
The Server ID is passed as four `u32` values to the entrypoint function.
This can be reassembled into something that can then be passed to the
`ReceiveMessage` syscall.
Signed-off-by: Sean Cross <sean@xobs.io>
We now us `ProcessStartup` as the return type. This builds in tset
mode, hosted mode, and RISC-V mode.
Process Startup is still not implemented for RISC-V mode.
Signed-off-by: Sean Cross <sean@xobs.io>
Turns out we didn't end up needing this capability, so, commenting it
out because it is a shy too powerful and is like packing a live
mortar shell in a storage unit: eventually, someone is going to
get hurt, even though it seems mostly harmless at the moment.
Code just commented out in case we need this feature in the future,
but, the main reason it was asked for (the PDDB) was accomplished
without it.
