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/* Test MPU
*/
#include "armv7m.h"
#include "testme.h"
static inline void test_equal(const char *m, uint32_t expect, uint32_t actual)
{
testEqI(expect, actual, "%s", m);
}
char __end_rom, __after_all_load;
char offlimits[1024] __attribute__((aligned(1024)));
char privonly[1024] __attribute__((aligned(1024)));
static
void try(volatile char *p)
{
uint32_t tval = 0;
testDiag("Try %x", (uint32_t)p);
__asm__ ("mov %r0, #'X'; ldr %r0, [%r1]" : "+r"(tval) : "r"(p) :);
testDiag("Got %x", tval);
}
#define EXPECT_NO_FAULT 1
#define EXPECT_MEMFAULT 2
#define EXPECT_TAKEN_MEMFAULT 3
#define EXPECT_HARDFAULT 10
#define EXPECT_TAKEN_HARDFAULT 11
static volatile unsigned expect_fault = EXPECT_NO_FAULT;
static
void checkfault(unsigned v)
{
testEqI(v, expect_fault, "fault state");
}
void hard(uint32_t *sp)
{
testDiag("In HardFault handler");
if(expect_fault==EXPECT_HARDFAULT) {
sp = get_src_stack(sp);
inst_skip(sp);
testDiag("Trying access offlimits inside HardFault handler");
try(offlimits);
expect_fault = EXPECT_TAKEN_HARDFAULT;
return;
}
testDiag("Unexpected HardFault!!");
abort();
}
static __attribute__((naked))
void hard_entry(void)
{
asm("mov r0, sp");
asm("b hard");
}
void mem(uint32_t *sp)
{
uint32_t addr;
sp = get_src_stack(sp);
inst_skip(sp);
addr = in32((void*)0xe000ed34);
testDiag("In MemFault, Addr 0x%x, from 0x%x", addr, sp[6]);
switch(expect_fault) {
case EXPECT_MEMFAULT:
expect_fault = EXPECT_TAKEN_MEMFAULT;
break;
case EXPECT_NO_FAULT:
testDiag("Unexpected MemFault!!");
abort();
default:
testDiag("Unexpected state 0x%x", expect_fault);
abort();
}
}
static __attribute__((naked))
void mem_entry(void)
{
asm("mov r0, sp");
asm("b mem");
}
static inline
void drop_priv(void)
{
uint32_t val;
__asm__ ("mrs %0, CONTROL" : "=r"(val) ::);
val |= 1;
__asm__ ("msr CONTROL, %0" :: "r"(val) :);
}
void svc(void *sp)
{
int num;
sp = get_src_stack(sp);
num = get_svc(sp);
if(num<0) {
testDiag("SVC but not looking at an SVC insn??\n");
abort();
} else {
testDiag("SVC 0x%x", num);
}
switch(num) {
case 1: /* restore privlage */
{
uint32_t val;
__asm__ ("mrs %0, CONTROL" : "=r"(val) ::);
val &= ~1;
__asm__ ("msr CONTROL, %0" :: "r"(val) :);
}
break;
case 2:
abort();
default:
testDiag("Unknown SVC request value");
abort();
}
}
static __attribute__((naked))
void svc_entry(void)
{
asm("mov r0, sp");
asm("b svc");
}
void main(void)
{
run_table.hard = &hard_entry;
run_table.svc = &svc_entry;
run_table.mem = &mem_entry;
testInit(6);
asm("cpsid if");
out32(SCB(0xd24), 1<<16); // enable MemFault with SHCSR
testDiag("In Main");
expect_fault = EXPECT_NO_FAULT;
/* priority of entries is highest to lowest (0 checked last) */
set_mpu(0, 0x00000000, (uint32_t)&__end_rom, MPU_NORMAL|MPU_RORO);
set_mpu(1, 0x20000000, 0x00080000, MPU_NORMAL|MPU_RWRW|MPU_XN);
set_mpu(2, 0x4000c000, 0x00001000, MPU_DEVICE|MPU_RWRW|MPU_XN);
set_mpu(3, 0xe000e000, 0x00001000, MPU_DEVICE|MPU_RWRW|MPU_XN);
/* disable all access to offlimits[] */
set_mpu(4, (uint32_t)offlimits, sizeof(offlimits),
MPU_XN|MPU_NORMAL|MPU_NANA);
/* disable unpriv access to privonly[] */
set_mpu(5, (uint32_t)privonly, sizeof(privonly),
MPU_XN|MPU_NORMAL|MPU_RONA);
testDiag("Access offlimits with MPU disabled (should not fault)");
try(offlimits);
checkfault(EXPECT_NO_FAULT);
testDiag("Enable MPU");
enable_mpu(1,1,0);
asm("cpsie if");
expect_fault = EXPECT_MEMFAULT;
testDiag("Access offlimits with MPU enabled (should fault)");
try(offlimits);
checkfault(EXPECT_TAKEN_MEMFAULT);
testDiag("In Main");
expect_fault = EXPECT_NO_FAULT;
testDiag("Access privonly (should not fault)");
try(privonly);
checkfault(EXPECT_NO_FAULT);
testDiag("drop_priv");
expect_fault = EXPECT_MEMFAULT;
drop_priv();
testDiag("Access privonly as user (should fault)");
try(privonly);
checkfault(EXPECT_TAKEN_MEMFAULT);
testDiag("Back in Main, regaining privilege");
asm("svc 1");
expect_fault = EXPECT_NO_FAULT;
testDiag("Access privonly as priv (should not fault)");
try(privonly);
checkfault(EXPECT_NO_FAULT);
asm("cpsid i");
testDiag("Check escalation of MemManage to HardFault");
expect_fault = EXPECT_HARDFAULT;
try(offlimits);
checkfault(EXPECT_TAKEN_HARDFAULT);
#if 0
/* don't try to test unrecoverable errors */
testDiag("Enable MPU w/ HFNMIENA");
enable_mpu(1,1,1);
testDiag("fault to hardfault (will escalate to unrecoverable)");
expect_fault = EXPECT_HARDFAULT;
try(offlimits);
testDiag("Shouldn't be here!");
#endif
testDiag("Done.");
}
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