116 lines
4.7 KiB
C
116 lines
4.7 KiB
C
/*
|
|
* 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;
|
|
}
|