This is a small optimization to the RISC-V trap handler. By splitting
the call to sched_run from the trap_handle call, loading the previous
thread ptr can be delayed until after it is determined that a schedule
run is required. This shaves of a few cycles during regular interrupts
that do not trigger the scheduler.
This commit reworks the trap entry to only save the callee-saved
registers when a context switch is required. the caller-saved registers
are always stored and restored to adhere to the RISC-V ABI. This saves
considerable cycles on interrupts.
Use RTC helper functions instead of libc functions.
This gives us y2038 safety by the extended epoch
and saves a good chunk of memory:
mktime():
text data bss dec hex filename
24756 232 2736 27724 6c4c testssperiph_rtc/bin/openlabs-kw41z-mini/tests_periph_rtc.elf
rtc_mktime():
text data bss dec hex filename
16348 132 2696 19176 4ae8 tests/periph_rtc/bin/openlabs-kw41z-mini/tests_periph_rtc.elf
The `_zep_params_setup()` function will modify the `argv` string passed to it.
This is a problem because that string is re-used on reboot.
The modified string is then later processed in `socket_zep_setup()`, so we have to keep
the memory around.
The `strdup()` fulfills all this and the memory is freed by `execve()` on reboot.
A proper solution would be to parse the strings in `_zep_params_setup()`.
While the hard fault handler prints the offending program counter, it
does not print information about the context triggering the hard fault.
This commit adds a line printing the thread ID and name that triggered
the hard fault. If the hard fault is triggered during an ISR, it only
prints that the hard fault happened during ISR context, not which ISR
triggered it.
The RISC-V timer should only be touched by periph/timer and must not be
initialized and enabled by the IRQ code. The current code can cause an
unhandled interrupt when the timer is not used and the mtime register
hits UINT64_MAX.
We can achieve greater accuracy for the relative timer_set()
if we don't use the generic implementation.
Use the same approach as used by atmega_common to trigger interrupts
for too small offsets.
tests/periph_timer_short_relative_set should now succeed for all intervals.
In most places, picolibc and newlib are the same, so use
the existing newlib code when compiling with picolibc.
Signed-off-by: Keith Packard <keithp@keithp.com>
