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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"
- #define LOAD_MASK 0x00f00fu
- #define L8UI_MATCH 0x000002u
- #define L16UI_MATCH 0x001002u
- #define L16SI_MATCH 0x009002u
- static exception_handler_fn load_store_handler;
- void load_non_32_wide_handler (struct exception_frame *ef, uint32_t cause)
- {
- /* If this is not EXCCAUSE_LOAD_STORE_ERROR you're doing it wrong! */
- (void)cause;
- uint32_t epc1 = ef->epc;
- uint32_t excvaddr;
- uint32_t insn;
- asm (
- "rsr %0, EXCVADDR;" /* read out the faulting address */
- "movi a4, ~3;" /* prepare a mask for the EPC */
- "and a4, a4, %2;" /* apply mask for 32bit aligned base */
- "l32i a5, a4, 0;" /* load part 1 */
- "l32i a6, a4, 4;" /* load part 2 */
- "ssa8l %2;" /* set up shift register for src op */
- "src %1, a6, a5;" /* right shift to get faulting instruction */
- :"=r"(excvaddr), "=r"(insn)
- :"r"(epc1)
- :"a4", "a5", "a6"
- );
- uint32_t valmask = 0;
- uint32_t what = insn & LOAD_MASK;
- if (what == L8UI_MATCH)
- valmask = 0xffu;
- else if (what == L16UI_MATCH || what == L16SI_MATCH)
- valmask = 0xffffu;
- else
- {
- die:
- /* Turns out we couldn't fix this, so try and chain to the handler
- * that was set by the SDK. If none then trigger a system break instead
- * and hang if the break doesn't get handled. This is effectively
- * what would happen if the default handler was installed. */
- if (load_store_handler) {
- load_store_handler(ef, cause);
- }
- asm ("break 1, 1");
- while (1) {}
- }
- /* Load, shift and mask down to correct size */
- uint32_t val = (*(uint32_t *)(excvaddr & ~0x3));
- val >>= (excvaddr & 0x3) * 8;
- val &= valmask;
- /* Sign-extend for L16SI, if applicable */
- if (what == L16SI_MATCH && (val & 0x8000))
- val |= 0xffff0000;
- int regno = (insn & 0x0000f0u) >> 4;
- if (regno == 1)
- goto die; /* we can't support loading into a1, just die */
- else if (regno != 0)
- --regno; /* account for skipped a1 in exception_frame */
- ef->a_reg[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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