This doesn't have the potential blocking issue of the getentropy call
(which calls WASI random_get when using wasi-libc) and should therefore
be a lot faster.
For context, this is what the random_get documentation says:
> Write high-quality random data into a buffer. This function blocks
> when the implementation is unable to immediately provide sufficient
> high-quality random data. This function may execute slowly, so when
> large mounts of random data are required, it's advisable to use this
> function to seed a pseudo-random number generator, rather than to
> provide the random data directly.
This commit fixes two things:
* It changes the alignment to 16 bytes (from 4), to match max_align_t
in C.
* It manually aligns heapStart on WebAssembly, to work around a bug in
wasm-ld with --stack-first (see https://reviews.llvm.org/D106499).
This function previously returned the atomic time, that isn't affected
by system time changes but also has a time base at some arbitrary time
in the past. This makes sense for baremetal platforms (which typically
don't know the wall time) but it gives surprising results on Linux and
macOS: time.Now() usually returns a time somewhere near the start of
1970.
This commit fixes this by obtaining both time values: the monotonic time
and the wall clock time. This is also how the Go runtime implements the
time.now function.
These two heaps conflict with each other, so that if any function uses
the dlmalloc heap implementation it will eventually result in memory
corruption.
This commit fixes this by implementing all heap-related functions. This
overrides the functions that are implemented in wasi-libc. That's why
all of them are implemented (even if they just panic): to make sure no
program accidentally uses the wrong one.
This can be very useful for some purposes:
* It makes it possible to disable the UART in cases where it is not
needed or needs to be disabled to conserve power.
* It makes it possible to disable the serial output to reduce code
size, which may be important for some chips. Sometimes, a few kB can
be saved this way.
* It makes it possible to override the default, for example you might
want to use an actual UART to debug the USB-CDC implementation.
It also lowers the dependency on having machine.Serial defined, which is
often not defined when targeting a chip. Eventually, we might want to
make it possible to write `-target=nrf52` or `-target=atmega328p` for
example to target the chip itself with no board specific assumptions.
The defaults don't change. I checked this by running `make smoketest`
before and after and comparing the results.
This commit implements various process related functions like
os.Getuid() and os.Getpid(). It also implements or improves this support
in the syscall package if it isn't available yet.
The wasm build tag together with GOARCH=arm was causing problems in the
internal/cpu package. In general, I think having two architecture build
tag will only cause problems (in this case, wasm and arm) so I've
removed the wasm build tag and replaced it with tinygo.wasm.
This is similar to the tinygo.riscv build tag, which is used for older
Go versions that don't yet have RISC-V support in the standard library
(and therefore pretend to be GOARCH=arm instead).
This package provides access to an operating system resource
(cryptographic numbers) and so needs to be replaced with a TinyGo
version that does this in a different way.
I've made the following choices while adding this feature:
- I'm using the getentropy call whenever possible (most POSIX like
systems), because it is easier to use and more reliable. Linux is
the exception: it only added getentropy relatively recently.
- I've left bare-metal implementations to a future patch. This because
it's hard to reliably get cryptographically secure random numbers on
embedded devices: most devices do not have a hardware PRNG for this
purpose.
This only works with a custom bossac build from Arduino, not with the
upstream version. It avoids needing the manual "double tap" to enter
bootloader mode before flashing firmware.
Int in Go and C are two different types (hence why CGo has C.int). The
code in syscall assumed they were of the same type, which led to a bug:
https://github.com/tinygo-org/tinygo/issues/1957
While the C standard makes no guarantees on the size of int, in most
modern operating systems it is 32-bits so Go int32 would be the correct
choice.
Other chips support explicit control of pull-up vs pull-down for GPIO input. Support that with bluepill also. PinInputPullUpDown is maintained for back-compat. It is implicit pull-down.
Because arm.SVCall1 lets pointers escape, the return value of
sd_softdevice_is_enabled (passed as a pointer in a parameter) will
escape and thus this value will be heap allocated.
Use a global variable for this purpose instead to avoid the heap
allocation. This is safe as waitForEvent may only be called outside of
interrupts.
