circuitpython/py/nlr.c
Damien George d54208a2ff py/scheduler: Implement VM abort flag and mp_sched_vm_abort().
This is intended to be used by the very outer caller of the VM/runtime.  It
allows setting a top-level NLR handler that can be jumped to directly, in
order to forcefully abort the VM/runtime.

Enable using:

    #define MICROPY_ENABLE_VM_ABORT (1)

Set up the handler at the top level using:

    nlr_buf_t nlr;
    nlr.ret_val = NULL;
    if (nlr_push(&nlr) == 0) {
        nlr_set_abort(&nlr);
        // call into the VM/runtime
        ...
        nlr_pop();
    } else {
        if (nlr.ret_val == NULL) {
            // handle abort
            ...
        } else {
            // handle other exception that propagated to the top level
            ...
        }
    }
    nlr_set_abort(NULL);

Schedule an abort, eg from an interrupt handler, using:

    mp_sched_vm_abort();

Signed-off-by: Damien George <damien@micropython.org>
2023-03-21 18:08:57 +11:00

59 lines
2.1 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013-2017 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "py/mpstate.h"
#if !MICROPY_NLR_SETJMP
// When not using setjmp, nlr_push_tail is called from inline asm so needs special care
#if MICROPY_NLR_X86 && MICROPY_NLR_OS_WINDOWS
// On these 32-bit platforms make sure nlr_push_tail doesn't have a leading underscore
unsigned int nlr_push_tail(nlr_buf_t *nlr) asm ("nlr_push_tail");
#else
// LTO can't see inside inline asm functions so explicitly mark nlr_push_tail as used
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
#endif
#endif
unsigned int nlr_push_tail(nlr_buf_t *nlr) {
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
nlr->prev = *top;
MP_NLR_SAVE_PYSTACK(nlr);
*top = nlr;
return 0; // normal return
}
void nlr_pop(void) {
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
*top = (*top)->prev;
}
#if MICROPY_ENABLE_VM_ABORT
NORETURN void nlr_jump_abort(void) {
MP_STATE_THREAD(nlr_top) = MP_STATE_VM(nlr_abort);
nlr_jump(NULL);
}
#endif