this seems to help #321. At the very least, on my test unit
an image without this crashes fairly reliably, and with this,
it can complete a few tries consecutively without fail
normally we never see these failures, but, as we are seeing
flash wear-out on the CI machine the writes can take
long enough that we get some concurrent requests. As a work-around,
just automatically retry a few times before throwing the error
back to the caller.
In general, hosted mode is assumed "by default" if the target
is not Xous. This allows packages to be built cleanly on command
lines that don't know to pass a --feature flag to specify a target.
However, an explicit "hosted" flag is still retained so that we
can confirm the build system intent. This saves us from the failure
mode that we thought we were building for target A, but accidentally
ommitted the flag, and instead we've been silently building for
"hosted" mode without any warning. The main consumer of the "hosted"
flag is now just the build.rs script inside of the utralib.
suspect maybe the custom vex routine for cache flush has a subtle
issue, so fall back to first-principles read-region flush.
remove excess calls to flushing as well, turns out we effectively
duplicated the call because it was both in the core patch routine
and outside of it too.
after updating a piece of FLASH memory, there is an inherent
cache coherence issue. This is because the write happens through
a side channel that is outside of the memory model of the system:
writes happen through a CSR that feed data to pages of FLASH.
Reads happen through direct-mapped memory regions that are unaware
of write mutations.
Thus, after writing a page of memory, if you try to access it,
sometimes you'll read the old cached value instead of the new
updated value.
This patch introduces a mandatory dcache flush after every
FLASH write, so that any cached FLASH regions are re-fetched.
This will allow for e.g. xous on riscv32-imac but not a precursor
target, for example: by using feature selectors we get to have
a bigger range of targets that we support, such as for implementations
that haven't been upstreamed or have official target-triples.
The downsides are:
- patch override libraries don't absorb feature flags. so, for
example, the AES crate that is used to patch other crates won't
be aware of the target features without modifying the referencing
crates.
- features are normally meant to be additive, but target features
are mutually exclusive. The mutex is enforced by a check in
utralib that throws a panic on build if two targets are accidentally
selected at the same time.
This macro will be removed, since it is no longer necessary. Remove this
macro across the project and replace it with a standard `main()`
function.
Signed-off-by: Sean Cross <sean@xobs.io>
Add a "Later" stage, and have exactly one "Last" stage.
"Last" to suspend is the ticktimer -- this is crucial for
basically everything else to work. The other really
low level stuff that needs to work to the last minute is
now in the "Later" bin.
The init code tried to set up the ECC block to report errors by writing
into the softirq block. Correct the block so that it goes into the
spinor block instead.
Signed-off-by: Sean Cross <sean@xobs.io>
Keyboard setting is "the one and only" exception to user settings
that are saved without encryption. This is because you need your
keyboard layout to be set in order for you to type your password.
Thus, this needed a bit of a special-case to handle its storage record.
We decided to lop off 1 page from the loader and have it store
the keyboard layout code.
Let's hope we can have the discipline to really just store that
one word of information and not later be like "gee wally, you have
a whoooole 4092 unused bytes of space we can cram unencrypted
user settings in, sure would be a waste to not put those use those".
Was doing disjoint loads and stores on an Atomic, really, should
be using the fetch_add, fetch_sub variants to be proper.
Didn't seem to impact anything but maybe there's a future version
of me that high fives me for doing this.
