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| 1 | +/* |
| 2 | + StackThunk.c - Allow use second stack for BearSSL calls |
| 3 | +
|
| 4 | + BearSSL uses a significant amount of stack space, much larger than |
| 5 | + the default Arduino core stack. These routines handle swapping |
| 6 | + between a secondary, user-allocated stack on the heap and the real |
| 7 | + stack. |
| 8 | +
|
| 9 | + Copyright (c) 2017 Earle F. Philhower, III. All rights reserved. |
| 10 | +
|
| 11 | + This library is free software; you can redistribute it and/or |
| 12 | + modify it under the terms of the GNU Lesser General Public |
| 13 | + License as published by the Free Software Foundation; either |
| 14 | + version 2.1 of the License, or (at your option) any later version. |
| 15 | +
|
| 16 | + This library is distributed in the hope that it will be useful, |
| 17 | + but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 19 | + Lesser General Public License for more details. |
| 20 | +
|
| 21 | + You should have received a copy of the GNU Lesser General Public |
| 22 | + License along with this library; if not, write to the Free Software |
| 23 | + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 24 | + Modified 8 May 2015 by Hristo Gochkov (proper post and file upload handling) |
| 25 | +*/ |
| 26 | + |
| 27 | +#include <stdint.h> |
| 28 | +#include <stdlib.h> |
| 29 | +#include "StackThunk.h" |
| 30 | + |
| 31 | +uint32_t *stack_thunk_ptr = NULL; |
| 32 | +uint32_t *stack_thunk_top = NULL; |
| 33 | +uint32_t *stack_thunk_save = NULL; /* Saved A1 while in BearSSL */ |
| 34 | +uint32_t stack_thunk_refcnt = 0; |
| 35 | + |
| 36 | +#define _stackSize (5600/4) |
| 37 | +#define _stackPaint 0xdeadbeef |
| 38 | + |
| 39 | +/* Add a reference, and allocate the stack if necessary */ |
| 40 | +void stack_thunk_add_ref() |
| 41 | +{ |
| 42 | + stack_thunk_refcnt++; |
| 43 | + if (stack_thunk_refcnt == 1) { |
| 44 | + stack_thunk_ptr = (uint32_t *)malloc(_stackSize * sizeof(uint32_t)); |
| 45 | + stack_thunk_top = stack_thunk_ptr + _stackSize - 1; |
| 46 | + stack_thunk_save = NULL; |
| 47 | + stack_thunk_repaint(); |
| 48 | + } |
| 49 | +} |
| 50 | + |
| 51 | +/* Drop a reference, and free stack if no more in use */ |
| 52 | +void stack_thunk_del_ref() |
| 53 | +{ |
| 54 | + if (stack_thunk_refcnt == 0) { |
| 55 | + /* Error! */ |
| 56 | + return; |
| 57 | + } |
| 58 | + stack_thunk_refcnt--; |
| 59 | + if (!stack_thunk_refcnt) { |
| 60 | + free(stack_thunk_ptr); |
| 61 | + stack_thunk_ptr = NULL; |
| 62 | + stack_thunk_top = NULL; |
| 63 | + stack_thunk_save = NULL; |
| 64 | + } |
| 65 | +} |
| 66 | + |
| 67 | +void stack_thunk_repaint() |
| 68 | +{ |
| 69 | + for (int i=0; i < _stackSize; i++) { |
| 70 | + stack_thunk_ptr[i] = _stackPaint; |
| 71 | + } |
| 72 | +} |
| 73 | + |
| 74 | +/* Simple accessor functions used by postmortem */ |
| 75 | +uint32_t stack_thunk_get_refcnt() { |
| 76 | + return stack_thunk_refcnt; |
| 77 | +} |
| 78 | + |
| 79 | +uint32_t stack_thunk_get_stack_top() { |
| 80 | + return (uint32_t)stack_thunk_top; |
| 81 | +} |
| 82 | + |
| 83 | +uint32_t stack_thunk_get_stack_bot() { |
| 84 | + return (uint32_t)stack_thunk_ptr; |
| 85 | +} |
| 86 | + |
| 87 | +uint32_t stack_thunk_get_cont_sp() { |
| 88 | + return (uint32_t)stack_thunk_save; |
| 89 | +} |
| 90 | + |
| 91 | +/* Return the number of bytes ever used since the stack was created */ |
| 92 | +uint32_t stack_thunk_get_max_usage() |
| 93 | +{ |
| 94 | + uint32_t cnt = 0; |
| 95 | + |
| 96 | + /* No stack == no usage by definition! */ |
| 97 | + if (!stack_thunk_ptr) { |
| 98 | + return 0; |
| 99 | + } |
| 100 | + |
| 101 | + for (cnt=0; (cnt < _stackSize) && (stack_thunk_ptr[cnt] == _stackPaint); cnt++) { |
| 102 | + /* Noop, all work done in for() */ |
| 103 | + } |
| 104 | + return 4 * (_stackSize - cnt); |
| 105 | +} |
| 106 | + |
| 107 | +/* Print the stack from the first used 16-byte chunk to the top, decodable by the exception decoder */ |
| 108 | +void stack_thunk_dump_stack() |
| 109 | +{ |
| 110 | + uint32_t *pos = stack_thunk_top; |
| 111 | + while (pos < stack_thunk_ptr) { |
| 112 | + if ((pos[0] != _stackPaint) || (pos[1] != _stackPaint) || (pos[2] != _stackPaint) || (pos[3] != _stackPaint)) |
| 113 | + break; |
| 114 | + pos += 4; |
| 115 | + } |
| 116 | + ets_printf(">>>stack>>>\n"); |
| 117 | + while (pos < stack_thunk_ptr) { |
| 118 | + ets_printf("%08x: %08x %08x %08x %08x\n", pos, pos[0], pos[1], pos[2], pos[3]); |
| 119 | + pos += 4; |
| 120 | + } |
| 121 | + ets_printf("<<<stack<<<\n"); |
| 122 | +} |
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