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TeensyDebug
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Fix stack, stepping

pull/2/head
Fernando Trias 4 years ago
parent
a862ba6c6a
commit
8437d32b42
3 changed files with 74 additions and 34 deletions
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  1. 97
      TeensyDebug.cpp
  2. 2
      TeensyDebug.h
  3. 9
      gdbstub.cpp

97
TeensyDebug.cpp
View File

@ -69,6 +69,17 @@ https://web.eecs.umich.edu/~prabal/teaching/eecs373-f10/readings/ARMv7-M_ARM.pdf
#define ADDRESS_MASK 0xFFFFFFFE
#define ADDRESS_MASK2 0xFFFFFFFC
#define CPU_FLAG_FPCA 2
#ifdef __MK20DX256__
#define ISR_STACK_SIZE 8
#endif
#ifdef __IMXRT1062__
// reserve space for 8 register, 16 floats, float stat and spacer
#define ISR_STACK_SIZE (8+18)
#endif
/***********************************************
*
* Breakpoint setup
@ -91,7 +102,7 @@ int swdebug_clearBreakpoint(void *p) {
sw_breakpoint_addr[i] = 0;
uint16_t *memory = (uint16_t*)addr;
*memory = sw_breakpoint_code[i];
// Serial.print("restore ");Serial.print(addr, HEX);Serial.print("=");Serial.println(*memory, HEX);
Serial.print("clear bkpt; restore ");Serial.print(addr, HEX);Serial.print("=");Serial.println(*memory, HEX);
return 0;
}
}
@ -105,7 +116,7 @@ int swdebug_setBreakpoint(void *p) {
sw_breakpoint_addr[i] = (void*)addr;
uint16_t *memory = (uint16_t*)addr;
sw_breakpoint_code[i] = *memory;
// Serial.print("overwrite ");Serial.print(addr, HEX);Serial.print(" from ");Serial.println(*memory, HEX);
Serial.print("set brkt; overwrite ");Serial.print(addr, HEX);Serial.print(" from ");Serial.println(*memory, HEX);
*memory = 0xdf10; // SVC 10
return 0;
}
@ -462,19 +473,38 @@ uint32_t getRegisterNum(int x) {
return 0;
}
int countBits(int x) {
return
((x & (1<<0)) >> 0) +
((x & (1<<1)) >> 1) +
((x & (1<<2)) >> 2) +
((x & (1<<3)) >> 3) +
((x & (1<<4)) >> 4) +
((x & (1<<5)) >> 5) +
((x & (1<<6)) >> 6) +
((x & (1<<7)) >> 7);
}
void *instructionReturn(void *p) {
uint16_t inst = *(uint16_t*)p;
uint16_t prefix = inst >> 8;
// mov pc, Rx
// Serial.print("ret? prefix ");Serial.println(prefix);
if (prefix == 0b01000110 && ((inst & 0b111) == 0b111)) {
uint32_t reg = getRegisterNum((inst >> 3) & 0b111);
// Serial.print("mov pc ");Serial.println(reg);
return (void*)reg;
}
if (prefix == 0b10111101) { // pop {Rxxx, pc}
int regs = countBits(inst & 0xFF);
uint32_t *memory = (uint32_t*)save_registers.sp;
return (void*)memory[0];
// Serial.print("pop pc instr ");Serial.println(inst, HEX);
// Serial.print("regs ");Serial.println(regs);
// Serial.print("pop pc at ");Serial.println(memory[regs], HEX);
return (void*)memory[regs];
}
if (inst == 0x4770) { // bx lr
// Serial.print("bx lr=");Serial.println(save_registers.lr);
return (void*)save_registers.lr;
}
return 0;
@ -483,26 +513,24 @@ void *instructionReturn(void *p) {
void *instructionBranch(void *p, int *bx) {
*bx = 0;
uint16_t inst = *(uint16_t*)p;
// B conditional
if ((inst & 0xF000) == 0xD000) {
int8_t offset = inst & 0xFF;
return (void*)(save_registers.pc + offset);
// BX or BLX
if ((inst & 0xFF00) == 0x4700) {
int reg = (inst >> 3) & 0b1111;
uint32_t addr = getRegisterNum(reg);
*bx = 1;
// Serial.print("BX ");Serial.println(addr, HEX);
return (void*)(addr);
}
// B
else if ((inst & 0xF800) == 0xC000) {
if ((inst & 0xF800) == 0xC000) {
int16_t offset = inst & 0x7F;
if (offset & 0x400) { // sign extend negative number
offset |= 0xF800;
}
// Serial.print("B ");Serial.println(save_registers.pc + offset, HEX);
return (void*)(save_registers.pc + offset);
}
// BX or BLX
else if ((inst & 0xFF00) == 0x4700) {
int reg = (inst >> 3) & 0b1111;
uint32_t addr = getRegisterNum(reg);
*bx = 1;
return (void*)(addr);
}
// BL prefix
else if ((inst & 0xF800) == 0xF000) {
int offset1 = inst & 0x3F;
@ -513,8 +541,14 @@ void *instructionBranch(void *p, int *bx) {
offset |= 0xFFFE0000;
}
offset <<= 1;
// Serial.print("offset ");Serial.println(offset, HEX);
return (void*)(save_registers.pc + offset + 2);
// Serial.print("BL prefix ");Serial.println(save_registers.pc + offset + 4, HEX);
return (void*)(save_registers.pc + offset + 4);
}
// B conditional
else if ((inst & 0xF000) == 0xD000) {
int8_t offset = inst & 0xFF;
// Serial.print("B cond ");Serial.println(save_registers.pc + offset, HEX);
return (void*)(save_registers.pc + offset);
}
return 0;
}
@ -601,8 +635,9 @@ void debug_monitor() {
}
// Adjust original SP to before the interrupt call to remove ISR's stack entries
// so GDB has correct stack frame
save_registers.sp += 20;
// so GDB has correct stack. The actual stack pointer will get restored
// to this value when the interrupt returns.
save_registers.sp += ISR_STACK_SIZE * 4;
if (callback) {
callback();
@ -613,18 +648,19 @@ void debug_monitor() {
debug_id = 0;
// if we need to reset the original, do so
if (debugreset) {
debug_setBreakpoint((void*)debugreset, 1);
debugreset = 0;
}
if (debugstep) {
// break at next instruction
setBreakPointNext(breakaddr, nextaddr);
debugstep = 0;
// the original breakpoint needs to be put back after next break
// debugreset = breakaddr;
}
// if we need to reset the original, do so
if (debugreset) {
debug_setBreakpoint((void*)debugreset, 1);
debugreset = 0;
}
}
#define SAVE_STACK \
@ -708,8 +744,11 @@ void (*original_svc_isr)() = NULL;
*/
__attribute__((noinline, naked))
void debug_call_isr() {
__disable_irq();
asm volatile(SAVE_STACK);
asm volatile(SAVE_REGISTERS);
__enable_irq();
asm volatile("push {lr}");
NVIC_CLEAR_PENDING(IRQ_SOFTWARE);
// Are we in debug mode? If not, just jump to original ISR
@ -718,6 +757,7 @@ void debug_call_isr() {
// asm volatile("ldr r0, =original_software_isr");
// asm volatile("ldr r0, [r0]");
// asm volatile("mov pc, r0");
asm volatile("pop {lr}");
asm volatile("mov pc, %0" : : "r" (original_software_isr));
}
return;
@ -727,7 +767,6 @@ void debug_call_isr() {
while(1) { yield(); }
}
asm volatile("push {lr}");
debug_monitor(); // process the debug event
debugenabled = 0;
// Serial.print("restore regs=");Serial.println(debugrestore);
@ -735,7 +774,9 @@ void debug_call_isr() {
if (debugrestore) {
debugrestore = 0;
asm volatile("pop {r12}");
__disable_irq();
asm volatile(RESTORE_REGISTERS);
__enable_irq();
asm volatile("mov lr, r12");
asm volatile("bx lr");
}
@ -829,7 +870,7 @@ uint32_t debug_getRegister(const char *reg) {
}
}
else if (reg[1] == '1') { // r10-r12
switch(reg[1]) {
switch(reg[2]) {
case '0': return save_registers.r10;
case '1': return save_registers.r11;
case '2': return save_registers.r12;
@ -862,7 +903,7 @@ int debug_setRegister(const char *reg, uint32_t value) {
}
}
else if (reg[1] == '1') { // r10-r12
switch(reg[1]) {
switch(reg[2]) {
case '0': save_registers.r10 = value; return 1;
case '1': save_registers.r11 = value; return 1;
case '2': save_registers.r12 = value; return 1;

2
TeensyDebug.h
View File

@ -30,7 +30,7 @@
#ifdef __IMXRT1062__
#define RAM_START ((void*)0x00000020)
#define RAM_END ((void*)0x5FFFFFFF)
#define RAM_END ((void*)0x20280000)
#endif

9
gdbstub.cpp
View File

@ -58,8 +58,6 @@
* devInit() is not standard. It must be called at initialization.
*
*/
// #include <HardwareSerial.h>
// #define dev Serial1
Stream *dev = NULL;
@ -404,7 +402,7 @@ char *append32(char *p, uint32_t n) {
* with a "Assertion `get_frame_type (frame) == DUMMY_FRAME' failed."
* I think the reason is because GDB changes SP by subtracting 4 before
* calling the function. Unfortunately, this library doesn't support
* GDB changing SP. So I just hardcode subtracting 4 from SP and this
* GDB changing SP. So I just hardcode subtracting 8 from SP and this
* seems to fool GDB.
*
* Newer versions of GDB choose a different breakpoint location. Instead
@ -431,7 +429,8 @@ int process_g(const char *cmd, char *result) {
uint32_t sp = debug.getRegister("sp");
if ((pc|1) == (uint32_t)&fake_breakpoint) {
pc = MAP_DUMMY_BREAKPOINT;
sp -= 4;
sp -= 8;
Serial.print("Fake breakpoing sp=");Serial.println(sp, HEX);
}
result = append32(result, debug.getRegister("r0"));
@ -568,7 +567,7 @@ int process_m(const char *cmd, char *result) {
// Serial.print("read at ");Serial.println(addr, HEX);
if (isValidAddress(addr) == 0) {
if (isValidAddress(addr+sz-1) == 0) {
strcpy(result, "E01");
return 0;
}

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