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/* See how various faults are reported and recovered
*/
#include "armv7m.h"
void inst_skip(uint32_t *sp);
static
volatile unsigned fault_type;
static
void check_fault(unsigned expect)
{
unsigned actual = fault_type;
puts("# Fault: ");
switch(actual) {
case 0: puts("None\n"); break;
case 1: puts("Mem\n"); break;
case 2: puts("Bus\n"); break;
case 3: puts("Usage\n"); break;
default: puthex(actual);
}
if(expect!=actual)
puts("not ");
puts("ok - ");
puthex(actual);
puts(" = ");
puthex(expect);
putc('\n');
fault_type = 0;
}
static
void set_fault(unsigned actual)
{
if(fault_type) {
puts("Secondary fault ");
puthex(actual);
putc('\n');
abort();
}
fault_type = actual;
}
static
void hard(void)
{
puts("Unexpected HardFault\n");
abort();
}
void bus(uint32_t *sp)
{
uint32_t sts, addr;
set_fault(2);
sts = in32(SCB(0xd28));
addr= in32(SCB(0xd38));
out32(SCB(0xd28), 0xff00); /* W1C */
out32(SCB(0xd38), 0);
puts("BusFault: ");
puthex(sts);
putc(' ');
if(sts&0x8000) {
puthex(addr);
putc(' ');
}
if(sts&0x1000)
puts("STKERR ");
if(sts&0x0800)
puts("UNSTKERR ");
if(sts&0x0400)
puts("IMPRECISERR ");
if(sts&0x0200)
puts("PRECISERR ");
if(sts&0x0100)
puts("IBUSERR ");
putc('\n');
if(sts&0x0200) {
/* precise faults would return to the faulting
* instruction, which would then fault again
* since we change nothing, so skip it.
*/
puts("From: ");
puthex(sp[6]);
if(sp[6]<0xfffffff0)
inst_skip(sp);
} else {
puts("From before: ");
puthex(sp[6]);
}
putc('\n');
if(sp[6]>=0xfffffff0) {
/* evil hack since we know this was a bx instruction */
sp[6] = sp[5]&~1; /* jump to LR */
}
}
static __attribute__((naked))
void bus_entry(void)
{
asm("mov r0, sp");
asm("b bus");
}
void mem(uint32_t *sp)
{
uint32_t sts, addr;
set_fault(1);
sts = in32(SCB(0xd28));
addr= in32(SCB(0xd34));
out32(SCB(0xd28), 0xff); /* W1C */
puts("MemFault: ");
puthex(sts);
putc(' ');
if(sts&0x80) {
puthex(addr);
putc(' ');
}
if(sts&0x08)
puts("MSTKERR ");
if(sts&0x04)
puts("MUNSTKERR ");
if(sts&0x02)
puts("DACCVIOL ");
if(sts&0x01)
puts("IACCVIOL ");
putc('\n');
puts("From: ");
puthex(sp[6]);
putc('\n');
if(sp[6]>=0xfffffff0) {
/* evil hack since we know this was a bx instruction */
sp[6] = sp[5]&~1; /* jump to LR */
} else {
inst_skip(sp);
}
}
static __attribute__((naked))
void mem_entry(void)
{
asm("mov r0, sp");
asm("b mem");
}
void usage(uint32_t *sp)
{
uint32_t sts;
set_fault(1);
sts = in32(SCB(0xd28));
out32(SCB(0xd28), 0xffff0000); /* W1C */
puts("UsageFault: ");
if(sts&0x2000000)
puts("DIVBYZERO ");
if(sts&0x1000000)
puts("UNALIGNED ");
if(sts&0x80000)
puts("NOCP ");
if(sts&0x40000)
puts("INVPC ");
if(sts&0x20000)
puts("INVSTATE ");
if(sts&0x10000)
puts("UNDEFINSTR ");
putc('\n');
puts("From: ");
puthex(sp[6]);
putc('\n');
if(sts&0x20000) {
abort(); /* attempt to execute ARM mode */
}
inst_skip(sp);
}
static __attribute__((naked))
void usage_entry(void)
{
asm("mov r0, sp");
asm("b usage");
}
static __attribute__((naked))
void jumpff(uint32_t x)
{
(void)x;
/* evilness
* 'blx' would fault before updating 'lr' anyway, so use 'bx'
* to be clear.
* We will return using the link register from our caller.
*/
asm("bx r0");
asm("jumpstuck: b jumpstuck");
}
void main(void)
{
run_table.bus = bus_entry;
run_table.mem = mem_entry;
run_table.usage = usage_entry;
run_table.hard = hard;
out32(SCB(0xd24), 0x70000); /* Enable Bus, Mem, and Usage Faults */
puts("# w/o MPU, hits background mapping\n");
puts("1. Cause BusFault 0xe100ffff\n");
out32((void*)0xe100fff0, 0);
check_fault(2);
puts("Back in Main\n");
puts("2. Another BusFault 0x10000000\n");
out32((void*)0x10000000, 0);
check_fault(2);
puts("Back in Main\n");
puts("3. Another BusFault 0x01000000\n");
out32((void*)0x01000000, 0);
check_fault(2);
puts("Back in Main\n");
puts("4. Another BusFault 0xfffffffe\n");
out32((void*)0xfffffffe, 0);
check_fault(2);
puts("Back in Main\n");
// this jump works, and TI has hidden so data here
// puts("5. MemFault (jump to 0x01000001)\n");
// jumpff(0x01000001);
// check_fault(1);
// puts("Back in Main\n");
puts("5. MemFault (jump to 0xfffffff9)\n");
jumpff(0xfffffff9);
check_fault(1);
puts("Back in Main\n");
puts("# Enable MPU, but not for privlaged"
" still hits background mapping\n");
enable_mpu(1,0,0);
puts("6. Cause BusFault 0xe100ffff\n");
out32((void*)0xe100ffff, 0);
check_fault(2);
puts("Back in Main\n");
puts("7. Another BusFault 0x10000000\n");
out32((void*)0x10000000, 0);
check_fault(2);
puts("Back in Main\n");
puts("8. Another BusFault 0x01000000\n");
out32((void*)0x01000000, 0);
check_fault(2);
puts("Back in Main\n");
puts("9. Another BusFault 0xfffffffe\n");
out32((void*)0xfffffffe, 0);
check_fault(2);
puts("Back in Main\n");
// this jump works, and TI has hidden so data here
// puts("5. MemFault (jump to 0x01000001)\n");
// jumpff(0x01000001);
// check_fault(1);
// puts("Back in Main\n");
puts("10. MemFault (jump to 0xfffffff9)\n");
jumpff(0xfffffff9);
check_fault(1);
puts("Back in Main\n");
// ROM region is made larger than actual rom to pass through 0x05000000
set_mpu(0, 0x00000000, 0x08000000, MPU_NORMAL|MPU_RORO);
set_mpu(1, 0x20000000, 0x00080000, MPU_NORMAL|MPU_RWRW|MPU_XN);
set_mpu(2, 0x400fe000, 0x00100000, MPU_DEVICE|MPU_RWRW|MPU_XN);
set_mpu(3, 0xe000e000, 0x00001000, MPU_DEVICE|MPU_RWRW|MPU_XN);
// Allow through access to unconnected address space
set_mpu(4, 0xe100e000, 0x00020000, MPU_DEVICE|MPU_RWRW|MPU_XN);
puts("# Enable MPU, including privlaged\n");
enable_mpu(1,1,0);
// MPU allows through, but no one is home == BusFault
puts("11. Cause BusFault 0xe100ffff\n");
out32((void*)0xe100ffff, 0);
check_fault(2);
puts("Back in Main\n");
puts("12. Another MemFault 0x10000000\n");
out32((void*)0x10000000, 0);
check_fault(1);
puts("Back in Main\n");
// MPU allows through, no one is home, but still MemFault...?
puts("13. Another MemFault 0x05000000\n");
out32((void*)0x05000000, 0);
check_fault(1);
puts("Back in Main\n");
puts("14. Another MemFault 0xfffffffe\n");
out32((void*)0xfffffffe, 0);
check_fault(1);
puts("Back in Main\n");
// this jump works, and TI has hidden so data here
// puts("5. MemFault (jump to 0x01000001)\n");
// jumpff(0x01000001);
// check_fault(1);
// puts("Back in Main\n");
puts("15. MemFault (jump to 0xfffffff9)\n");
jumpff(0xfffffff9);
check_fault(1);
puts("Back in Main\n");
}
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