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.
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.
Allocate and initialize a thread-local block for each thread at the
top of the stack.
Set the tls base when switching to a new thread.
Add tdata/tbss linker instructions to cortex_m and risc-v scripts.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
v2:
Squash fixes
v3:
Replace tabs with spaces
v4:
Add tbss to fe310 linker script
Disable the newlib-nano stubs code when picolibc is in use
Signed-off-by: Keith Packard <keithp@keithp.com>
---
v2:
Squash fixes in
v3:
call stdio_init in _PICOLIBC_ mode to initialize uart
v3:
Remove call to stdio_init from nanostubs_init, always
call from cpu_init.
Picolibc makes atexit state per-thread instead of global, so we can't
register destructors with atexit in a non-thread context as we won't
have any TLS space initialized.
Signed-off-by: Keith Packard <keithp@keithp.com>
- Add libstdcpp feature to indicate a platform is providing a libstdc++
implementation ready for use
- The existing cpp feature now only indicates a working C++ toolchain without
libstdc++. (E.g. still useful for the Arduino compatibility layer.)
- Added libstdcpp as required feature were needed
- Added some documentation on C++ on RIOT
Other archs use `_sheap` and `_eheap` to mark the start and end of
the heap.
fe310 uses `_heap_start` and `_heap_end`, so platform independent
code that wants to make use of this will needlessly fail.
For compatibility with common code, name them the same on fe310.
As the comment above cpu_switch_context_exit notes:
sched_active_thread is not valid when cpu_switch_context_exit() is called.
Unfortunately, thread_yield(), which is called directly by
cpu_switch_context_exit(), uses sched_active_thread possibly resulting
in a null pointer dereference.
Solution: Trigger a software interrupt to perform a context switch and
let sched_run() determine the next valid thread from there.
Rational: the periph_common module is required by (most) other periph drivers
and also during startup of the CPU/MCU to run periph_init. The latter is only
required if other periph drivers are used, hence periph_common should be a
depency of periph_* modules and *not* of the CPU/MCU. This PR fixes that
by making periph_common a depency of periph_* and removing the explicit
include in the CPU/MCU implementation.
It is the role of boards based on 'cpu/fe310' to give the configuration
for the rtc/rtt.
The fe310/periph/rtc implementation depends on having periph/rtt configured
by the board so depends on the board 'providing' the periph_rtt feature
and declaring the required macros.
It should not simply depend of the 'periph_rtt' module as this does not
enforce having a configuration for the module in the board.
In practice, when compiling, it would result in undefined 'RTT' symbols,
instead of the build system detecting it.
Added HiFive1 to BOARD_INSUFFICIENT_MEMORY list for examples and tests that are too big to fit
build: fixed missing syscall and cpuid failures
Added missing syscall stubs for nanostubs and fixed compile error with cpuid periph
build: fixed whitespace error
build: add hifive1 to more BOARD_INSUFFICIENT_MEMORY
doc: fixed doxygen warnings
Addressed Doxygen warnings in source file comments
doc: more doxygen fixes
doc: even more doxygen fixes
doc: more changes
build: fix pedantic and rdci_simple build failures
make: exclude lua
