suspect-devices/circuitpython/supervisor/stub/safe_mode.c, branch 6.2.xCircuitPython - a Python implementation for teaching coding with microcontrollershttps://git.suspectdevices.com/suspect-devices/circuitpython/atom?h=6.2.x2021-03-15T13:57:36+00:00run code formatting script2021-03-15T13:57:36+00:00microDev70126934+microDev1@users.noreply.github.com2021-03-15T13:57:36+00:00urn:sha1:a52eb88031620a81521b937f2a0651dbac2bb350Add some NORETURN attributes2020-09-28T23:55:56+00:00Jeff Eplerjepler@gmail.com2020-09-24T16:20:32+00:00urn:sha1:726dcdb60aa84b5070e5484a19e896abdaffeb93
I have a function where it should be impossible to reach the end, so I put in a safe-mode reset at the bottom:
```
int find_unused_slot(void) {
// precondition: you already verified that a slot was available
for (int i=0; i<NUM_SLOTS; i++) {
if( slot_free(i)) {
return i;
}
}
safe_mode_reset(MICROPY_FATAL_ERROR);
}
```
However, the compiler still gave a diagnostic, because safe_mode_reset was not declared NORETURN.
So I started by teaching the compiler that reset_into_safe_mode never returned. This leads at least one level deeper due to reset_cpu needing to be a NORETURN function. Each port is a little different in this area. I also marked reset_to_bootloader as NORETURN.
Additional notes:
* stm32's reset_to_bootloader was not implemented, but now does a bare reset. Most stm32s are not fitted with uf2 bootloaders anyway.
* ditto cxd56
* esp32s2 did not implement reset_cpu at all. I used esp_restart(). (not tested)
* litex did not implement reset_cpu at all. I used reboot_ctrl_write. But notably this is what reset_to_bootloader already did, so one or the other must be incorrect (not tested). reboot_ctrl_write cannot be declared NORETURN, as it returns unless the special value 0xac is written), so a new unreachable forever-loop is added.
* cxd56's reset is via a boardctl() call which can't generically be declared NORETURN, so a new unreacahble "for(;;)" forever-loop is added.
* In several places, NVIC_SystemReset is redeclared with NORETURN applied. This is accepted just fine by gcc. I chose this as preferable to editing the multiple copies of CMSIS headers where it is normally declared.
* the stub safe_mode reset simply aborts. This is used in mpy-cross.
supervisor: stub: make unimplemented safe_mode loop forever2020-09-24T21:57:20+00:00Jeff Eplerjepler@gmail.com2020-09-24T21:57:10+00:00urn:sha1:6bcbe51f7fcfaca6ee3ee40b4ce64fd791725e8fStub out safe mode for mpy-cross2019-03-12T18:18:30+00:00Scott Shawcroftscott@tannewt.org2019-03-09T00:20:38+00:00urn:sha1:d6b2199f3614a5fe2d4da4163ca901ac1e567f5f