100 lines
3.4 KiB
C
100 lines
3.4 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2014 Paul Sokolovsky
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/runtime.h"
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#include "py/stackctrl.h"
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void mp_stack_ctrl_init(void) {
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// Force routine to not be inlined. Better guarantee than MP_NOINLINE for -flto.
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__asm volatile ("");
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volatile int stack_dummy;
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MP_STATE_THREAD(stack_top) = (char*)&stack_dummy;
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}
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void mp_stack_set_top(void *top) {
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MP_STATE_THREAD(stack_top) = top;
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}
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mp_uint_t mp_stack_usage(void) {
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// Assumes descending stack
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// Force routine to not be inlined. Better guarantee than MP_NOINLINE for -flto.
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__asm volatile ("");
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volatile int stack_dummy;
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return MP_STATE_THREAD(stack_top) - (char*)&stack_dummy;
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}
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#if MICROPY_STACK_CHECK
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void mp_stack_set_limit(mp_uint_t limit) {
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MP_STATE_THREAD(stack_limit) = limit;
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}
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void mp_stack_check(void) {
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if (mp_stack_usage() >= MP_STATE_THREAD(stack_limit)) {
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mp_raise_recursion_depth();
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}
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}
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#endif // MICROPY_STACK_CHECK
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#if MICROPY_MAX_STACK_USAGE
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// Fill stack space with this unusual value.
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const char MP_MAX_STACK_USAGE_SENTINEL_BYTE = 0xEE;
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// Record absolute bottom (logical limit) of stack.
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void mp_stack_set_bottom(void* stack_bottom) {
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MP_STATE_THREAD(stack_bottom) = stack_bottom;
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}
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// Return the current frame pointer. This can be used as an
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// approximation for the stack pointer of the _calling_ function.
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// This routine must not be inlined. This method is
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// architecture-independent, as opposed to using asm("sp") or similar.
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//
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// The stack_dummy approach used elsewhere in this file is not safe in
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// all cases. That value may be below the actual top of the stack.
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static void* approx_stack_pointer(void){
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__asm volatile ("");
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return __builtin_frame_address(0);
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}
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// Fill stack space down toward the stack limit with a known unusual value.
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void mp_stack_fill_with_sentinel(void) {
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// Force routine to not be inlined. Better guarantee than MP_NOINLINE for -flto.
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__asm volatile ("");
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// Start filling stack just below the current stack frame.
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// Continue until we've hit the bottom of the stack (lowest address,
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// logical "ceiling" of stack).
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char* p = (char *) approx_stack_pointer() - 1;
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while(p >= MP_STATE_THREAD(stack_bottom)) {
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*p-- = MP_MAX_STACK_USAGE_SENTINEL_BYTE;
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}
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}
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#endif // MICROPY_MAX_STACK_USAGE
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