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- /*
- * Copyright 2015 Dius Computing Pty Ltd. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * - Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the
- * distribution.
- * - Neither the name of the copyright holders nor the names of
- * its contributors may be used to endorse or promote products derived
- * from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
- * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
- * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
- * OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * @author Johny Mattsson <jmattsson@dius.com.au>
- */
- #include "user_exceptions.h"
- static exception_handler_fn load_store_handler;
- void load_non_32_wide_handler (struct exception_frame *ef, uint32_t cause)
- {
- uint32_t val, insn;
- (void)cause; /* If this is not EXCCAUSE_LOAD_STORE_ERROR you're doing it wrong! */
-
- asm (
- /*
- * Move the aligned content of the exception addr to val
- */
- "rsr a6, EXCVADDR;" /* read out the faulting address */
- "movi a5, ~3;" /* prepare a mask for the EPC */
- "and a5, a5, a6;" /* apply mask for 32bit aligned base */
- "l32i a5, a5, 0;" /* load aligned value */
- "ssa8l a6;" /* set up shift register for value */
- "srl %[val], a5;" /* shift left to align value */
- /* we are done with a6 = EXCVADDR */
- /*
- * Move the aligned instruction to insn
- */
- "movi a5, ~3;" /* prepare a mask for the insn */
- "and a6, a5, %[epc];" /* apply mask for 32bit aligned base */
- "l32i a5, a6, 0;" /* load part 1 */
- "l32i a6, a6, 4;" /* load part 2 */
- "ssa8l %[epc];" /* set up shift register for src op */
- "src %[op], a6, a5;" /* right shift to get faulting instruction */
- :[val]"=r"(val), [op]"=r"(insn)
- :[epc]"r"(ef->epc)
- :"a5", "a6"
- );
- /* These instructions have the format 0xADSBII where AB = opcode and D = dest reg */
- uint32_t regno = (insn>>4)&0x0f; /* pick out nibble D*/
- uint32_t opcode = (uint8_t) (((insn>>12)<<4)|(insn&0xf)); /* and nibbles AB */
- #define L8UI 0x02u
- #define L16UI 0x12u
- #define L16SI 0x92u
- if (opcode == L8UI) { /* L8UI */
- val = (uint8_t) val;
- } else {
- val = (uint16_t) val; /* assume L16SI or L16UI */
- if (opcode == L16SI) {
- val = (unsigned)((int)((sint16_t)val)); /* force signed 16->32 bit */
- } else if (opcode != L16UI) {
- /*
- * Anything other than L8UI, L16SI or L16UI then chain to the next handler
- * if set (typically a remote GDB break). Otherwise execute the default action
- * which is to trigger a system break and hang if the break doesn't get handled
- */
- if (load_store_handler) {
- load_store_handler(NULL, 0 /* ef , cause */);
- return;
- } else {
- asm ("break 1, 1");
- while (1) {}
- }
- }
- }
- ef->a_reg[regno ? regno-1: regno] = val; /* carry out the load */
- ef->epc += 3; /* resume at following instruction */
- }
- /**
- * The SDK's user_main function installs a debugging handler regardless
- * of whether there's a proper handler installed for EXCCAUSE_LOAD_STORE_ERROR,
- * which of course breaks everything if we allow that to go through. As such,
- * we use the linker to wrap that call and stop the SDK from shooting itself in
- * its proverbial foot. We do save the EXCCAUSE_LOAD_STORE_ERROR handler so that
- * we can chain to it above.
- */
- exception_handler_fn TEXT_SECTION_ATTR
- __wrap__xtos_set_exception_handler (uint32_t cause, exception_handler_fn fn)
- {
- if (cause != EXCCAUSE_LOAD_STORE_ERROR)
- __real__xtos_set_exception_handler (cause, fn);
- else
- load_store_handler = fn;
- }
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