mirror of https://github.com/arendst/Tasmota.git
94 lines
3.4 KiB
C
94 lines
3.4 KiB
C
/*
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StackThunk_light.h - Allow use second stack for BearSSL calls
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Light version with reduced Stack size due to Tasmota optimizations.
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BearSSL uses a significant amount of stack space, much larger than
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the default Arduino core stack. These routines handle swapping
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between a secondary, user-allocated stack on the heap and the real
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stack.
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Copyright (C) 2021 Earle F. Philhower, III. All rights reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Modified 8 May 2015 by Hristo Gochkov (proper post and file upload handling)
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*/
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#ifndef _STACKTHUNK_LIGHT_H
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#define _STACKTHUNK__LIGHTH
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern void stack_thunk_light_add_ref();
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extern void stack_thunk_light_del_ref();
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extern void stack_thunk_light_repaint();
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extern uint32_t stack_thunk_light_get_refcnt();
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extern uint32_t stack_thunk_light_get_stack_top();
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extern uint32_t stack_thunk_light_get_stack_bot();
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extern uint32_t stack_thunk_light_get_cont_sp();
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extern uint32_t stack_thunk_light_get_max_usage();
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extern void stack_thunk_light_dump_stack();
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extern void stack_thunk_light_fatal_overflow();
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// Globals required for thunking operation
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extern uint32_t *stack_thunk_light_ptr;
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extern uint32_t *stack_thunk_light_top;
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extern uint32_t *stack_thunk_light_save;
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extern uint32_t stack_thunk_light_refcnt;
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// Thunking macro
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#define make_stack_thunk_light(fcnToThunk) \
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__asm__("\n\
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.text\n\
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.literal_position\n\
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.literal .LC_STACK_VALUE"#fcnToThunk", 0xdeadbeef\n\
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\n\
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.text\n\
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.global thunk_light_"#fcnToThunk"\n\
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.type thunk_light_"#fcnToThunk", @function\n\
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.align 4\n\
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thunk_light_"#fcnToThunk":\n\
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addi a1, a1, -16 /* Allocate space for saved registers on stack */\n\
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s32i a0, a1, 12 /* Store A0, trounced by calls */\n\
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s32i a15, a1, 8 /* Store A15 (our temporary one) */\n\
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movi a15, stack_thunk_light_save /* Store A1(SP) in temp space */\n\
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s32i a1, a15, 0\n\
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movi a15, stack_thunk_light_top /* Load A1(SP) with thunk stack */\n\
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l32i.n a1, a15, 0\n\
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call0 "#fcnToThunk" /* Do the call */\n\
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/* Check the stack canary wasn't overwritten */\n\
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movi a15, stack_thunk_light_ptr\n\
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l32i.n a15, a15, 0 /* A15 now has the pointer to stack end*/ \n\
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l32i.n a15, a15, 0 /* A15 now has contents of last stack entry */\n\
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l32r a0, .LC_STACK_VALUE"#fcnToThunk" /* A0 now has the check value */\n\
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beq a0, a15, .L1"#fcnToThunk"\n\
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call0 stack_thunk_light_fatal_overflow\n\
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.L1"#fcnToThunk":\n\
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movi a15, stack_thunk_light_save /* Restore A1(SP) */\n\
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l32i.n a1, a15, 0\n\
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l32i.n a15, a1, 8 /* Restore the saved registers */\n\
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l32i.n a0, a1, 12\n\
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addi a1, a1, 16 /* Free up stack and return to caller */\n\
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ret\n\
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.size thunk_light_"#fcnToThunk", . - thunk_light_"#fcnToThunk"\n");
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#ifdef __cplusplus
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}
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#endif
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#endif
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