Added detection of case when no unwind tables are available

2.0.x
etagle 7 years ago
parent b210bdf032
commit c3b23974bd

@ -114,7 +114,9 @@ static void TXDec(uint32_t v) {
// Dump a backtrace entry
static void backtrace_dump_fn(int idx, const backtrace_t* bte, void* ctx) {
TX('#'); TXDec(idx); TX(' '); TX(bte->name); TX(" @ ");TXHex((uint32_t)bte->address); TX('\n');
TX('#'); TXDec(idx); TX(' ');
TX(bte->name); TX('@');TXHex((uint32_t)bte->function); TX('+'); TXDec((uint32_t)bte->address - (uint32_t)bte->function);
TX(" PC:");TXHex((uint32_t)bte->address); TX('\n');
}
/**
@ -176,6 +178,19 @@ void HardFault_HandlerC(unsigned long *hardfault_args, unsigned long cause) {
btf.pc = ((unsigned long)hardfault_args[6]);
backtrace_dump(&btf, backtrace_dump_fn, nullptr);
// Disable all NVIC interrupts
NVIC->ICER[0] = 0xFFFFFFFF;
NVIC->ICER[1] = 0xFFFFFFFF;
// Relocate VTOR table to default position
SCB->VTOR = 0;
// Disable USB
otg_disable();
// Restart watchdog
WDT_Restart(WDT);
// Reset controller
NVIC_SystemReset();
while(1) { WDT_Restart(WDT); }

@ -6,9 +6,9 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This library was modified and adapted to be used in Marlin 3D printer
* firmware as backtracer for exceptions for debugging purposes in 2018
* by Eduardo José Tagle.
* This library was modified, some bugs fixed, stack address validated
* and adapted to be used in Marlin 3D printer firmware as backtracer
* for exceptions for debugging purposes in 2018 by Eduardo José Tagle.
*/
#ifdef ARDUINO_ARCH_SAM
@ -43,10 +43,30 @@ void __aeabi_unwind_cpp_pr2(void) {};
extern const int _sstack;
extern const int _estack;
/* Validate stack pointer */
/* These symbols point to the start and end of the code section */
extern const int _sfixed;
extern const int _efixed;
/* These symbols point to the start and end of initialized data (could be SRAM functions!) */
extern const int _srelocate;
extern const int _erelocate;
/* Validate stack pointer (SP): It must be in the stack area */
static inline __attribute__((always_inline)) int validate_sp(const void* sp) {
if ((uint32_t)sp < (uint32_t)&_sstack || (uint32_t)sp > (uint32_t)&_estack)
return -1;
// SP must point into the allocated stack area
if ((uint32_t)sp >= (uint32_t)&_sstack && (uint32_t)sp <= (uint32_t)&_estack)
return 0;
return -1;
}
/* Validate code pointer (PC): It must be either in TEXT or in SRAM */
static inline __attribute__((always_inline)) int validate_pc(const void* pc) {
// PC must point into the text (CODE) area
if ((uint32_t)pc >= (uint32_t)&_sfixed && (uint32_t)pc <= (uint32_t)&_efixed)
return 0;
// Or into the SRAM function area
if ((uint32_t)pc >= (uint32_t)&_srelocate && (uint32_t)pc <= (uint32_t)&_erelocate)
return 0;
return 0;
}
@ -103,11 +123,11 @@ static int unwind_control_block_init(unwind_control_block_t *ucb, const uint32_t
memset(ucb, 0, sizeof(unwind_control_block_t));
ucb->current = instructions;
/* Is the a short unwind description */
/* Is a short unwind description */
if ((*instructions & 0xff000000) == 0x80000000) {
ucb->remaining = 3;
ucb->byte = 2;
/* Is the a long unwind description */
/* Is a long unwind description */
} else if ((*instructions & 0xff000000) == 0x81000000) {
ucb->remaining = ((*instructions & 0x00ff0000) >> 14) + 2;
ucb->byte = 1;
@ -115,12 +135,10 @@ static int unwind_control_block_init(unwind_control_block_t *ucb, const uint32_t
return -1;
/* Initialize the virtual register set */
if (frame) {
ucb->vrs[7] = frame->fp;
ucb->vrs[13] = frame->sp;
ucb->vrs[14] = frame->lr;
ucb->vrs[15] = 0;
}
ucb->vrs[7] = frame->fp;
ucb->vrs[13] = frame->sp;
ucb->vrs[14] = frame->lr;
ucb->vrs[15] = 0;
/* All good */
return 0;
@ -136,46 +154,49 @@ static int unwind_execute_instruction(unwind_control_block_t *ucb) {
/* Consume all instruction byte */
while ((instruction = unwind_get_next_byte(ucb)) != -1) {
if ((instruction & 0xc0) == 0x00) {
if ((instruction & 0xc0) == 0x00) { // ARM_EXIDX_CMD_DATA_POP
/* vsp = vsp + (xxxxxx << 2) + 4 */
ucb->vrs[13] += ((instruction & 0x3f) << 2) + 4;
} else if ((instruction & 0xc0) == 0x40) {
} else
if ((instruction & 0xc0) == 0x40) { // ARM_EXIDX_CMD_DATA_PUSH
/* vsp = vsp - (xxxxxx << 2) - 4 */
ucb->vrs[13] -= ((instruction & 0x3f) << 2) - 4;
} else if ((instruction & 0xf0) == 0x80) {
} else
if ((instruction & 0xf0) == 0x80) {
/* pop under mask {r15-r12},{r11-r4} or refuse to unwind */
instruction = instruction << 8 | unwind_get_next_byte(ucb);
/* Check for refuse to unwind */
if (instruction == 0x8000)
if (instruction == 0x8000) // ARM_EXIDX_CMD_REFUSED
return 0;
/* Pop registers using mask */
/* Pop registers using mask */ // ARM_EXIDX_CMD_REG_POP
vsp = (uint32_t *)ucb->vrs[13];
mask = instruction & 0xfff;
reg = 4;
while (mask != 0) {
if ((mask & 0x001) != 0) {
while (mask) {
if ((mask & 1) != 0) {
if (validate_sp(vsp))
return -1;
ucb->vrs[reg] = *vsp++;
}
mask = mask >> 1;
mask >>= 1;
++reg;
}
/* Patch up the vrs sp if it was in the mask */
if ((mask & (1 << (13 - 4))) != 0)
if ((instruction & (1 << (13 - 4))) != 0)
ucb->vrs[13] = (uint32_t)vsp;
} else if ((instruction & 0xf0) == 0x90 && instruction != 0x9d && instruction != 0x9f) {
} else
if ((instruction & 0xf0) == 0x90 && // ARM_EXIDX_CMD_REG_TO_SP
instruction != 0x9d &&
instruction != 0x9f) {
/* vsp = r[nnnn] */
ucb->vrs[13] = ucb->vrs[instruction & 0x0f];
} else if ((instruction & 0xf0) == 0xa0) {
} else
if ((instruction & 0xf0) == 0xa0) { // ARM_EXIDX_CMD_REG_POP
/* pop r4-r[4+nnn] or pop r4-r[4+nnn], r14*/
vsp = (uint32_t *)ucb->vrs[13];
@ -185,7 +206,7 @@ static int unwind_execute_instruction(unwind_control_block_t *ucb) {
ucb->vrs[reg] = *vsp++;
}
if (instruction & 0x80) {
if (instruction & 0x08) { // ARM_EXIDX_CMD_REG_POP
if (validate_sp(vsp))
return -1;
ucb->vrs[14] = *vsp++;
@ -193,7 +214,8 @@ static int unwind_execute_instruction(unwind_control_block_t *ucb) {
ucb->vrs[13] = (uint32_t)vsp;
} else if (instruction == 0xb0) {
} else
if (instruction == 0xb0) { // ARM_EXIDX_CMD_FINISH
/* finished */
if (ucb->vrs[15] == 0)
ucb->vrs[15] = ucb->vrs[14];
@ -201,28 +223,34 @@ static int unwind_execute_instruction(unwind_control_block_t *ucb) {
/* All done unwinding */
return 0;
} else if (instruction == 0xb1) {
} else
if (instruction == 0xb1) { // ARM_EXIDX_CMD_REG_POP
/* pop register under mask {r3,r2,r1,r0} */
vsp = (uint32_t *)ucb->vrs[13];
mask = unwind_get_next_byte(ucb);
reg = 0;
while (mask != 0) {
if ((mask & 0x01) != 0) {
while (mask) {
if ((mask & 1) != 0) {
if (validate_sp(vsp))
return -1;
ucb->vrs[reg] = *vsp++;
}
mask = mask >> 1;
mask >>= 1;
++reg;
}
ucb->vrs[13] = (uint32_t)vsp;
} else if (instruction == 0xb2) {
} else
if (instruction == 0xb2) { // ARM_EXIDX_CMD_DATA_POP
/* vps = vsp + 0x204 + (uleb128 << 2) */
ucb->vrs[13] += 0x204 + (unwind_get_next_byte(ucb) << 2);
} else if (instruction == 0xb3 || instruction == 0xc8 || instruction == 0xc9) {
} else
if (instruction == 0xb3 || // ARM_EXIDX_CMD_VFP_POP
instruction == 0xc8 ||
instruction == 0xc9) {
/* pop VFP double-precision registers */
vsp = (uint32_t *)ucb->vrs[13];
@ -243,7 +271,10 @@ static int unwind_execute_instruction(unwind_control_block_t *ucb) {
ucb->vrs[13] = (uint32_t)vsp;
} else if ((instruction & 0xf8) == 0xb8 || (instruction & 0xf8) == 0xd0) {
} else
if ((instruction & 0xf8) == 0xb8 ||
(instruction & 0xf8) == 0xd0) {
/* Pop VFP double precision registers D[8]-D[8+nnn] */
ucb->vrs[14] = 0x80 | (instruction & 0x07);
@ -296,7 +327,7 @@ static int unwind_frame(backtrace_frame_t *frame) {
if (unwind_control_block_init(&ucb, instructions, frame) < 0)
return -1;
/* Execute the unwind instructions TODO range check the stack pointer */
/* Execute the unwind instructions */
while ((execution_result = unwind_execute_instruction(&ucb)) > 0);
if (execution_result == -1)
return -1;
@ -332,8 +363,7 @@ static int unwind_frame(backtrace_frame_t *frame) {
stack -= 2;
/* If there was a VFP exception (0xffffffe1), the PC is located another 18 words down */
if ((ucb.vrs[15] & 0xf0) == 0xe0)
{
if ((ucb.vrs[15] & 0xf0) == 0xe0) {
stack -= 18;
}
}
@ -366,47 +396,146 @@ static int unwind_frame(backtrace_frame_t *frame) {
return 1;
}
// Detect if function names are available
static int __attribute__ ((noinline)) has_function_names(void) {
uint32_t flag_word = ((uint32_t*)&has_function_names)[-1];
return ((flag_word & 0xff000000) == 0xff000000) ? 1 : 0;
}
// Detect if unwind information is present or not
static int has_unwind_info(void) {
return ((char*)(&__exidx_end) - (char*)(&__exidx_start)) > 16 ? 1 : 0; // 16 because there are default entries we can´t supress
}
int backtrace_dump(backtrace_frame_t *frame, backtrace_dump_fn_t dump_entry, void* ctx )
{
backtrace_t entry;
int count = 1;
/* Unwind all frames */
do {
if (frame->pc == 0) {
/* Reached __exidx_end. */
entry.name = "<reached end of unwind table>";
entry.address = 0;
entry.function = 0;
dump_entry(count, &entry, ctx);
break;
}
/* If there is no unwind information, perform a RAW try at it. Idea was taken from
* https://stackoverflow.com/questions/3398664/how-to-get-a-call-stack-backtrace-deeply-embedded-no-library-support
*
* And requires code to be compiled with the following flags:
* -mtpcs-frame -mtpcs-leaf-frame -fno-omit-frame-pointer
* With these options, the Stack pointer is automatically
* pushed to the stack at the beginning of each function.
*/
if (!has_unwind_info()) {
/*
* We basically iterate through the current stack finding the
* following combination of values:
* - <Frame Address>
* - <Link Address>
* This combination will occur for each function in the call stack
*/
uint32_t previous_frame_address = (uint32_t)frame->sp;
uint32_t* stack_pointer = (uint32_t*)frame->sp;
// loop following stack frames
while (1) {
// Validate stack address
if (validate_sp(stack_pointer))
break;
// Attempt to obtain next stack pointer
// The link address should come immediately after
const uint32_t possible_frame_address = *stack_pointer;
const uint32_t possible_link_address = *(stack_pointer+1);
// Next check that the frame addresss (i.e. stack pointer for the function)
// and Link address are within an acceptable range
if(possible_frame_address > previous_frame_address &&
validate_sp((const void *)possible_frame_address) == 0 &&
(possible_link_address & 1) != 0 && // in THUMB mode the address will be odd
validate_pc((const void *)possible_link_address) == 0) {
// We found two acceptable values.
entry.name = "unknown";
entry.address = (void*)possible_link_address;
entry.function = 0;
// If there are function names, try to solve name
if (has_function_names()) {
// Lets find the function name, if possible
// Align address to 4 bytes
uint32_t* pf = (uint32_t*) (((uint32_t)possible_link_address) & (-4));
// Scan backwards until we find the function name
while(validate_pc(pf-1) == 0) {
// Get name descriptor value
uint32_t v = pf[-1];
// Check if name descriptor is valid and name is terminated in 0.
if ((v & 0xffffff00) == 0xff000000 &&
(v & 0xff) > 1) {
// Assume the name was found!
entry.name = ((const char*)pf) - 4 - (v & 0xff);
entry.function = (void*)pf;
break;
}
// Go backwards to the previous word
--pf;
}
}
dump_entry(count, &entry, ctx);
++count;
if (frame->pc == 0x00000001) {
/* Reached .cantunwind instruction. */
entry.name = "<reached .cantunwind>";
entry.address = 0;
entry.function = 0;
dump_entry(count, &entry, ctx);
break;
// Update the book-keeping registers for the next search
previous_frame_address = possible_frame_address;
stack_pointer = (uint32_t*)(possible_frame_address + 4);
} else {
// Keep iterating through the stack until we find an acceptable combination
++stack_pointer;
}
}
/* Find the unwind index of the current frame pc */
const unwind_index_t *index = unwind_search_index(__exidx_start, __exidx_end, frame->pc);
} else {
/* Otherwise, unwind information is present. Use it to unwind frames */
do {
if (frame->pc == 0) {
/* Reached __exidx_end. */
entry.name = "<reached end of unwind table>";
entry.address = 0;
entry.function = 0;
dump_entry(count, &entry, ctx);
break;
}
/* Clear last bit (Thumb indicator) */
frame->pc &= 0xfffffffeU;
if (frame->pc == 0x00000001) {
/* Reached .cantunwind instruction. */
entry.name = "<reached .cantunwind>";
entry.address = 0;
entry.function = 0;
dump_entry(count, &entry, ctx);
break;
}
/* Generate the backtrace information */
entry.address = (void *)frame->pc;
entry.function = (void *)prel31_to_addr(&index->addr_offset);
entry.name = unwind_get_function_name(entry.function);
dump_entry(count, &entry, ctx);
/* Find the unwind index of the current frame pc */
const unwind_index_t *index = unwind_search_index(__exidx_start, __exidx_end, frame->pc);
/* Next backtrace frame */
++count;
/* Clear last bit (Thumb indicator) */
frame->pc &= 0xfffffffeU;
} while (unwind_frame(frame) == 1);
/* Generate the backtrace information */
entry.address = (void *)frame->pc;
entry.function = (void *)prel31_to_addr(&index->addr_offset);
entry.name = unwind_get_function_name(entry.function);
dump_entry(count, &entry, ctx);
/* Next backtrace frame */
++count;
} while (unwind_frame(frame) == 1);
}
/* All done */
return count;

@ -97,6 +97,18 @@ lib_deps = ${common.lib_deps}
lib_ignore = c1921b4
src_filter = ${common.default_src_filter}
monitor_baud = 250000
[env:DUE_debug]
# Used when WATCHDOG_RESET_MANUAL is enabled
platform = atmelsam
framework = arduino
board = due
build_flags = ${common.build_flags}
-funwind-tables
-mpoke-function-name
lib_deps = ${common.lib_deps}
lib_ignore = c1921b4
src_filter = ${common.default_src_filter}
monitor_baud = 250000
#
# NXP LPC1768 ARM Cortex-M3

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