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Postmortem Debugging to serial port (#20492)

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This commit is contained in:
X-Ryl669
2021-02-21 03:22:20 +01:00
committed by GitHub
parent fb8b421aac
commit 8d28853774
34 changed files with 1286 additions and 740 deletions
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33
Marlin/src/HAL/shared/HAL_MinSerial.cpp Normal file
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@ -0,0 +1,33 @@
/**
* Marlin 3D Printer Firmware
* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#include "HAL_MinSerial.h"
#if ENABLED(POSTMORTEM_DEBUGGING)
void HAL_min_serial_init_default() {}
void HAL_min_serial_out_default(char ch) { SERIAL_CHAR(ch); }
void (*HAL_min_serial_init)() = &HAL_min_serial_init_default;
void (*HAL_min_serial_out)(char) = &HAL_min_serial_out_default;
bool MinSerial::force_using_default_output = false;
#endif

79
Marlin/src/HAL/shared/HAL_MinSerial.h Normal file
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@ -0,0 +1,79 @@
/**
* Marlin 3D Printer Firmware
* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#pragma once
#include "../../core/serial.h"
#include <stdint.h>
// Serial stuff here
// Inside an exception handler, the CPU state is not safe, we can't expect the handler to resume
// and the software to continue. UART communication can't rely on later callback/interrupt as it might never happen.
// So, you need to provide some method to send one byte to the usual UART with the interrupts disabled
// By default, the method uses SERIAL_CHAR but it's 100% guaranteed to break (couldn't be worse than nothing...)7
extern void (*HAL_min_serial_init)();
extern void (*HAL_min_serial_out)(char ch);
struct MinSerial {
static bool force_using_default_output;
// Serial output
static void TX(char ch) {
if (force_using_default_output)
SERIAL_CHAR(ch);
else
HAL_min_serial_out(ch);
}
// Send String through UART
static void TX(const char* s) { while (*s) TX(*s++); }
// Send a digit through UART
static void TXDigit(uint32_t d) {
if (d < 10) TX((char)(d+'0'));
else if (d < 16) TX((char)(d+'A'-10));
else TX('?');
}
// Send Hex number through UART
static void TXHex(uint32_t v) {
TX("0x");
for (uint8_t i = 0; i < 8; i++, v <<= 4)
TXDigit((v >> 28) & 0xF);
}
// Send Decimal number through UART
static void TXDec(uint32_t v) {
if (!v) {
TX('0');
return;
}
char nbrs[14];
char *p = &nbrs[0];
while (v != 0) {
*p++ = '0' + (v % 10);
v /= 10;
}
do {
p--;
TX(*p);
} while (p != &nbrs[0]);
}
static void init() { if (!force_using_default_output) HAL_min_serial_init(); }
};

28
Marlin/src/HAL/shared/backtrace/backtrace.cpp
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@ -25,7 +25,7 @@
#include "unwinder.h"
#include "unwmemaccess.h"
#include "../../../core/serial.h"
#include "../HAL_MinSerial.h"
#include <stdarg.h>
// Dump a backtrace entry
@ -34,10 +34,12 @@ static bool UnwReportOut(void* ctx, const UnwReport* bte) {
(*p)++;
SERIAL_CHAR('#'); SERIAL_ECHO(*p); SERIAL_ECHOPGM(" : ");
SERIAL_ECHOPGM(bte->name ? bte->name : "unknown"); SERIAL_ECHOPGM("@0x"); SERIAL_PRINT(bte->function, PrintBase::Hex);
SERIAL_CHAR('+'); SERIAL_ECHO(bte->address - bte->function);
SERIAL_ECHOPGM(" PC:"); SERIAL_PRINT(bte->address, PrintBase::Hex); SERIAL_CHAR('\n');
const uint32_t a = bte->address, f = bte->function;
MinSerial::TX('#'); MinSerial::TXDec(*p); MinSerial::TX(" : ");
MinSerial::TX(bte->name?:"unknown"); MinSerial::TX('@'); MinSerial::TXHex(f);
MinSerial::TX('+'); MinSerial::TXDec(a - f);
MinSerial::TX(" PC:"); MinSerial::TXHex(a);
MinSerial::TX('\n');
return true;
}
@ -48,7 +50,7 @@ static bool UnwReportOut(void* ctx, const UnwReport* bte) {
va_start(argptr, format);
vsprintf(dest, format, argptr);
va_end(argptr);
TX(&dest[0]);
MinSerial::TX(&dest[0]);
}
#endif
@ -63,10 +65,10 @@ static const UnwindCallbacks UnwCallbacks = {
#endif
};
// Perform a backtrace to the serial port
void backtrace() {
UnwindFrame btf;
uint32_t sp = 0, lr = 0, pc = 0;
unsigned long sp = 0, lr = 0, pc = 0;
// Capture the values of the registers to perform the traceback
__asm__ __volatile__ (
@ -79,6 +81,12 @@ void backtrace() {
::
);
backtrace_ex(sp, lr, pc);
}
void backtrace_ex(unsigned long sp, unsigned long lr, unsigned long pc) {
UnwindFrame btf;
// Fill the traceback structure
btf.sp = sp;
btf.fp = btf.sp;
@ -86,7 +94,7 @@ void backtrace() {
btf.pc = pc | 1; // Force Thumb, as CORTEX only support it
// Perform a backtrace
SERIAL_ERROR_MSG("Backtrace:");
MinSerial::TX("Backtrace:");
int ctr = 0;
UnwindStart(&btf, &UnwCallbacks, &ctr);
}
@ -95,4 +103,4 @@ void backtrace() {
void backtrace() {}
#endif
#endif // __arm__ || __thumb__

3
Marlin/src/HAL/shared/backtrace/backtrace.h
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@ -23,3 +23,6 @@
// Perform a backtrace to the serial port
void backtrace();
// Perform a backtrace to the serial port
void backtrace_ex(unsigned long sp, unsigned long lr, unsigned long pc);

72
Marlin/src/HAL/shared/backtrace/unwmemaccess.cpp
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@ -41,27 +41,16 @@
#define START_FLASH_ADDR 0x00000000
#define END_FLASH_ADDR 0x00080000
#elif 0
// For STM32F103CBT6
// SRAM (0x20000000 - 0x20005000) (20kb)
// FLASH (0x00000000 - 0x00020000) (128kb)
//
#define START_SRAM_ADDR 0x20000000
#define END_SRAM_ADDR 0x20005000
#define START_FLASH_ADDR 0x00000000
#define END_FLASH_ADDR 0x00020000
#elif defined(__STM32F1__) || defined(STM32F1xx) || defined(STM32F0xx)
// For STM32F103ZET6/STM32F103VET6/STM32F0xx
// SRAM (0x20000000 - 0x20010000) (64kb)
// FLASH (0x00000000 - 0x00080000) (512kb)
// FLASH (0x08000000 - 0x08080000) (512kb)
//
#define START_SRAM_ADDR 0x20000000
#define END_SRAM_ADDR 0x20010000
#define START_FLASH_ADDR 0x00000000
#define END_FLASH_ADDR 0x00080000
#define START_FLASH_ADDR 0x08000000
#define END_FLASH_ADDR 0x08080000
#elif defined(STM32F4) || defined(STM32F4xx)
@ -142,20 +131,57 @@
#define START_FLASH_ADDR 0x00000000
#define END_FLASH_ADDR 0x00100000
#else
// Generic ARM code, that's testing if an access to the given address would cause a fault or not
// It can't guarantee an address is in RAM or Flash only, but we usually don't care
#define NVIC_FAULT_STAT 0xE000ED28 // Configurable Fault Status Reg.
#define NVIC_CFG_CTRL 0xE000ED14 // Configuration Control Register
#define NVIC_FAULT_STAT_BFARV 0x00008000 // BFAR is valid
#define NVIC_CFG_CTRL_BFHFNMIGN 0x00000100 // Ignore bus fault in NMI/fault
#define HW_REG(X) (*((volatile unsigned long *)(X)))
static bool validate_addr(uint32_t read_address) {
bool works = true;
uint32_t intDisabled = 0;
// Read current interrupt state
__asm__ __volatile__ ("MRS %[result], PRIMASK\n\t" : [result]"=r"(intDisabled) :: ); // 0 is int enabled, 1 for disabled
// Clear bus fault indicator first (write 1 to clear)
HW_REG(NVIC_FAULT_STAT) |= NVIC_FAULT_STAT_BFARV;
// Ignore bus fault interrupt
HW_REG(NVIC_CFG_CTRL) |= NVIC_CFG_CTRL_BFHFNMIGN;
// Disable interrupts if not disabled previously
if (!intDisabled) __asm__ __volatile__ ("CPSID f");
// Probe address
*(volatile uint32_t*)read_address;
// Check if a fault happened
if ((HW_REG(NVIC_FAULT_STAT) & NVIC_FAULT_STAT_BFARV) != 0)
works = false;
// Enable interrupts again if previously disabled
if (!intDisabled) __asm__ __volatile__ ("CPSIE f");
// Enable fault interrupt flag
HW_REG(NVIC_CFG_CTRL) &= ~NVIC_CFG_CTRL_BFHFNMIGN;
return works;
}
#endif
static bool validate_addr(uint32_t addr) {
#ifdef START_SRAM_ADDR
static bool validate_addr(uint32_t addr) {
// Address must be in SRAM range
if (addr >= START_SRAM_ADDR && addr < END_SRAM_ADDR)
return true;
// Address must be in SRAM range
if (addr >= START_SRAM_ADDR && addr < END_SRAM_ADDR)
return true;
// Or in FLASH range
if (addr >= START_FLASH_ADDR && addr < END_FLASH_ADDR)
return true;
// Or in FLASH range
if (addr >= START_FLASH_ADDR && addr < END_FLASH_ADDR)
return true;
return false;
}
return false;
}
#endif
bool UnwReadW(const uint32_t a, uint32_t *v) {
if (!validate_addr(a))

379
Marlin/src/HAL/shared/cpu_exception/exception_arm.cpp Normal file
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@ -0,0 +1,379 @@
/**
* Marlin 3D Printer Firmware
* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
* Copyright (c) 2020 Cyril Russo
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
/***************************************************************************
* ARM CPU Exception handler
***************************************************************************/
#if defined(__arm__) || defined(__thumb__)
/*
On ARM CPUs exception handling is quite powerful.
By default, upon a crash, the CPU enters the handlers that have a higher priority than any other interrupts,
so, in effect, no (real) interrupt can "interrupt" the handler (it's acting like if interrupts were disabled).
If the handler is not called as re-entrant (that is, if the crash is not happening inside an interrupt or an handler),
then it'll patch the return address to a dumping function (resume_from_fault) and save the crash state.
The CPU will exit the handler and, as such, re-allow the other interrupts, and jump to the dumping function.
In this function, the usual serial port (USB / HW) will be used to dump the crash (no special configuration required).
The only case where it requires hardware UART is when it's crashing in an interrupt or a crash handler.
In that case, instead of returning to the resume_from_fault function (and thus, re-enabling interrupts),
it jumps to this function directly (so with interrupts disabled), after changing the behavior of the serial output
wrapper to use the HW uart (and in effect, calling MinSerial::init which triggers a warning if you are using
a USB serial port).
In the case you have a USB serial port, this part will be disabled, and only that part (so that's the reason for
the warning).
This means that you can't have a crash report if the crash happens in an interrupt or an handler if you are using
a USB serial port since it's physically impossible.
You will get a crash report in all other cases.
*/
#include "exception_hook.h"
#include "../backtrace/backtrace.h"
#include "../HAL_MinSerial.h"
#define HW_REG(X) (*((volatile unsigned long *)(X)))
// Default function use the CPU VTOR register to get the vector table.
// Accessing the CPU VTOR register is done in assembly since it's the only way that's common to all current tool
unsigned long get_vtor() { return HW_REG(0xE000ED08); } // Even if it looks like an error, it is not an error
void * hook_get_hardfault_vector_address(unsigned vtor) { return (void*)(vtor + 0x03); }
void * hook_get_memfault_vector_address(unsigned vtor) { return (void*)(vtor + 0x04); }
void * hook_get_busfault_vector_address(unsigned vtor) { return (void*)(vtor + 0x05); }
void * hook_get_usagefault_vector_address(unsigned vtor) { return (void*)(vtor + 0x06); }
void * hook_get_reserved_vector_address(unsigned vtor) { return (void*)(vtor + 0x07); }
// Common exception frame for ARM, should work for all ARM CPU
// Described here (modified for convenience): https://interrupt.memfault.com/blog/cortex-m-fault-debug
struct __attribute__((packed)) ContextStateFrame {
uint32_t r0;
uint32_t r1;
uint32_t r2;
uint32_t r3;
uint32_t r12;
uint32_t lr;
uint32_t pc;
uint32_t xpsr;
};
struct __attribute__((packed)) ContextSavedFrame {
uint32_t R0;
uint32_t R1;
uint32_t R2;
uint32_t R3;
uint32_t R12;
uint32_t LR;
uint32_t PC;
uint32_t XPSR;
uint32_t CFSR;
uint32_t HFSR;
uint32_t DFSR;
uint32_t AFSR;
uint32_t MMAR;
uint32_t BFAR;
uint32_t ESP;
uint32_t ELR;
};
#if DISABLED(STM32F0xx)
extern "C"
__attribute__((naked)) void CommonHandler_ASM() {
__asm__ __volatile__ (
// Bit 2 of LR tells which stack pointer to use (either main or process, only main should be used anyway)
"tst lr, #4\n"
"ite eq\n"
"mrseq r0, msp\n"
"mrsne r0, psp\n"
// Save the LR in use when being interrupted
"mov r1, lr\n"
// Get the exception number from the ICSR register
"ldr r2, =0xE000ED00\n"
"ldr r2, [r2, #4]\n"
"b CommonHandler_C\n"
);
}
#else // Cortex M0 does not support conditional mov and testing with a constant, so let's have a specific handler for it
extern "C"
__attribute__((naked)) void CommonHandler_ASM() {
__asm__ __volatile__ (
".syntax unified\n"
// Save the LR in use when being interrupted
"mov r1, lr\n"
// Get the exception number from the ICSR register
"ldr r2, =0xE000ED00\n"
"ldr r2, [r2, #4]\n"
"movs r0, #4\n"
"tst r1, r0\n"
"beq _MSP\n"
"mrs r0, psp\n"
"b CommonHandler_C\n"
"_MSP:\n"
"mrs r0, msp\n"
"b CommonHandler_C\n"
);
}
#if DISABLED(DYNAMIC_VECTORTABLE) // Cortex M0 requires the handler's address to be within 32kB to the actual function to be able to branch to it
extern "C" {
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __exc_hardfault();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __exc_busfault();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __exc_usagefault();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __exc_memmanage();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __exc_nmi();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __stm32reservedexception7();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __stm32reservedexception8();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __stm32reservedexception9();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __stm32reservedexception10();
void __attribute__((naked, alias("CommonHandler_ASM"), nothrow)) __stm32reservedexception13();
}
//TODO When going off from libmaple, you'll need to replace those by the one from STM32/HAL_MinSerial.cpp
#endif
#endif
// Must be a macro to avoid creating a function frame
#define HALT_IF_DEBUGGING() \
do { \
if (HW_REG(0xE000EDF0) & _BV(0)) { \
__asm("bkpt 1"); \
} \
} while (0)
// Resume from a fault (if possible) so we can still use interrupt based code for serial output
// In that case, we will not jump back to the faulty code, but instead to a dumping code and then a
// basic loop with watchdog calling or manual resetting
static ContextSavedFrame savedFrame;
static uint8_t lastCause;
bool resume_from_fault() {
static const char* causestr[] = { "Thread", "Rsvd", "NMI", "Hard", "Mem", "Bus", "Usage", "7", "8", "9", "10", "SVC", "Dbg", "13", "PendSV", "SysTk", "IRQ" };
// Reinit the serial link (might only work if implemented in each of your boards)
MinSerial::init();
MinSerial::TX("\n\n## Software Fault detected ##\n");
MinSerial::TX("Cause: "); MinSerial::TX(causestr[min(lastCause, (uint8_t)16)]); MinSerial::TX('\n');
MinSerial::TX("R0 : "); MinSerial::TXHex(savedFrame.R0); MinSerial::TX('\n');
MinSerial::TX("R1 : "); MinSerial::TXHex(savedFrame.R1); MinSerial::TX('\n');
MinSerial::TX("R2 : "); MinSerial::TXHex(savedFrame.R2); MinSerial::TX('\n');
MinSerial::TX("R3 : "); MinSerial::TXHex(savedFrame.R3); MinSerial::TX('\n');
MinSerial::TX("R12 : "); MinSerial::TXHex(savedFrame.R12); MinSerial::TX('\n');
MinSerial::TX("LR : "); MinSerial::TXHex(savedFrame.LR); MinSerial::TX('\n');
MinSerial::TX("PC : "); MinSerial::TXHex(savedFrame.PC); MinSerial::TX('\n');
MinSerial::TX("PSR : "); MinSerial::TXHex(savedFrame.XPSR); MinSerial::TX('\n');
// Configurable Fault Status Register
// Consists of MMSR, BFSR and UFSR
MinSerial::TX("CFSR : "); MinSerial::TXHex(savedFrame.CFSR); MinSerial::TX('\n');
// Hard Fault Status Register
MinSerial::TX("HFSR : "); MinSerial::TXHex(savedFrame.HFSR); MinSerial::TX('\n');
// Debug Fault Status Register
MinSerial::TX("DFSR : "); MinSerial::TXHex(savedFrame.DFSR); MinSerial::TX('\n');
// Auxiliary Fault Status Register
MinSerial::TX("AFSR : "); MinSerial::TXHex(savedFrame.AFSR); MinSerial::TX('\n');
// Read the Fault Address Registers. These may not contain valid values.
// Check BFARVALID/MMARVALID to see if they are valid values
// MemManage Fault Address Register
MinSerial::TX("MMAR : "); MinSerial::TXHex(savedFrame.MMAR); MinSerial::TX('\n');
// Bus Fault Address Register
MinSerial::TX("BFAR : "); MinSerial::TXHex(savedFrame.BFAR); MinSerial::TX('\n');
MinSerial::TX("ExcLR: "); MinSerial::TXHex(savedFrame.ELR); MinSerial::TX('\n');
MinSerial::TX("ExcSP: "); MinSerial::TXHex(savedFrame.ESP); MinSerial::TX('\n');
// The stack pointer is pushed by 8 words upon entering an exception, so we need to revert this
backtrace_ex(savedFrame.ESP + 8*4, savedFrame.LR, savedFrame.PC);
// Call the last resort function here
hook_last_resort_func();
const uint32_t start = millis(), end = start + 100; // 100ms should be enough
// We need to wait for the serial buffers to be output but we don't know for how long
// So we'll just need to refresh the watchdog for a while and then stop for the system to reboot
uint32_t last = start;
while (PENDING(last, end)) {
watchdog_refresh();
while (millis() == last) { /* nada */ }
last = millis();
MinSerial::TX('.');
}
// Reset now by reinstantiating the bootloader's vector table
HW_REG(0xE000ED08) = 0;
// Restart watchdog
#if DISABLED(USE_WATCHDOG)
// No watchdog, let's perform ARMv7 reset instead by writing to AIRCR register with VECTKEY set to SYSRESETREQ
HW_REG(0xE000ED0C) = (HW_REG(0xE000ED0C) & 0x0000FFFF) | 0x05FA0004;
#endif
while(1) {} // Bad luck, nothing worked
}
// Make sure the compiler does not optimize the frame argument away
extern "C"
__attribute__((optimize("O0")))
void CommonHandler_C(ContextStateFrame * frame, unsigned long lr, unsigned long cause) {
// If you are using it'll stop here
HALT_IF_DEBUGGING();
// Save the state to backtrace later on (don't call memcpy here since the stack can be corrupted)
savedFrame.R0 = frame->r0;
savedFrame.R1 = frame->r1;
savedFrame.R2 = frame->r2;
savedFrame.R3 = frame->r3;
savedFrame.R12 = frame->r12;
savedFrame.LR = frame->lr;
savedFrame.PC = frame->pc;
savedFrame.XPSR= frame->xpsr;
lastCause = cause & 0x1FF;
volatile uint32_t &CFSR = HW_REG(0xE000ED28);
savedFrame.CFSR = CFSR;
savedFrame.HFSR = HW_REG(0xE000ED2C);
savedFrame.DFSR = HW_REG(0xE000ED30);
savedFrame.AFSR = HW_REG(0xE000ED3C);
savedFrame.MMAR = HW_REG(0xE000ED34);
savedFrame.BFAR = HW_REG(0xE000ED38);
savedFrame.ESP = (unsigned long)frame; // Even on return, this should not be overwritten by the CPU
savedFrame.ELR = lr;
// First check if we can resume from this exception to our own handler safely
// If we can, then we don't need to disable interrupts and the usual serial code
// can be used
//const uint32_t non_usage_fault_mask = 0x0000FFFF;
//const bool non_usage_fault_occurred = (CFSR & non_usage_fault_mask) != 0;
// the bottom 8 bits of the xpsr hold the exception number of the
// executing exception or 0 if the processor is in Thread mode
const bool faulted_from_exception = ((frame->xpsr & 0xFF) != 0);
if (!faulted_from_exception) { // Not sure about the non_usage_fault, we want to try anyway, don't we ? && !non_usage_fault_occurred)
// Try to resume to our handler here
CFSR |= CFSR; // The ARM programmer manual says you must write to 1 all fault bits to clear them so this instruction is correct
// The frame will not be valid when returning anymore, let's clean it
savedFrame.CFSR = 0;
frame->pc = (uint32_t)resume_from_fault; // Patch where to return to
frame->lr = 0xdeadbeef; // If our handler returns (it shouldn't), let's make it trigger an exception immediately
frame->xpsr = _BV(24); // Need to clean the PSR register to thumb II only
MinSerial::force_using_default_output = true;
return; // The CPU will resume in our handler hopefully, and we'll try to use default serial output
}
// Sorry, we need to emergency code here since the fault is too dangerous to recover from
MinSerial::force_using_default_output = false;
resume_from_fault();
}
void hook_cpu_exceptions() {
#if ENABLED(DYNAMIC_VECTORTABLE)
// On ARM 32bits CPU, the vector table is like this:
// 0x0C => Hardfault
// 0x10 => MemFault
// 0x14 => BusFault
// 0x18 => UsageFault
// Unfortunately, it's usually run from flash, and we can't write to flash here directly to hook our instruction
// We could set an hardware breakpoint, and hook on the fly when it's being called, but this
// is hard to get right and would probably break debugger when attached
// So instead, we'll allocate a new vector table filled with the previous value except
// for the fault we are interested in.
// Now, comes the issue to figure out what is the current vector table size
// There is nothing telling us what is the vector table as it's per-cpu vendor specific.
// BUT: we are being called at the end of the setup, so we assume the setup is done
// Thus, we can read the current vector table until we find an address that's not in flash, and it would mark the
// end of the vector table (skipping the fist entry obviously)
// The position of the program in flash is expected to be at 0x08xxx xxxx on all known platform for ARM and the
// flash size is available via register 0x1FFFF7E0 on STM32 family, but it's not the case for all ARM boards
// (accessing this register might trigger a fault if it's not implemented).
// So we'll simply mask the top 8 bits of the first handler as an hint of being in the flash or not -that's poor and will
// probably break if the flash happens to be more than 128MB, but in this case, we are not magician, we need help from outside.
unsigned long * vecAddr = (unsigned long*)get_vtor();
SERIAL_ECHO("Vector table addr: ");
SERIAL_PRINTLN(get_vtor(), HEX);
#ifdef VECTOR_TABLE_SIZE
uint32_t vec_size = VECTOR_TABLE_SIZE;
alignas(128) static unsigned long vectable[VECTOR_TABLE_SIZE] ;
#else
#ifndef IS_IN_FLASH
#define IS_IN_FLASH(X) (((unsigned long)X & 0xFF000000) == 0x08000000)
#endif
// When searching for the end of the vector table, this acts as a limit not to overcome
#ifndef VECTOR_TABLE_SENTINEL
#define VECTOR_TABLE_SENTINEL 80
#endif
// Find the vector table size
uint32_t vec_size = 1;
while (IS_IN_FLASH(vecAddr[vec_size]) && vec_size < VECTOR_TABLE_SENTINEL)
vec_size++;
// We failed to find a valid vector table size, let's abort hooking up
if (vec_size == VECTOR_TABLE_SENTINEL) return;
// Poor method that's wasting RAM here, but allocating with malloc and alignment would be worst
// 128 bytes alignement is required for writing the VTOR register
alignas(128) static unsigned long vectable[VECTOR_TABLE_SENTINEL];
SERIAL_ECHO("Detected vector table size: ");
SERIAL_PRINTLN(vec_size, HEX);
#endif
uint32_t defaultFaultHandler = vecAddr[(unsigned)7];
// Copy the current vector table into the new table
for (uint32_t i = 0; i < vec_size; i++) {
vectable[i] = vecAddr[i];
// Replace all default handler by our own handler
if (vectable[i] == defaultFaultHandler)
vectable[i] = (unsigned long)&CommonHandler_ASM;
}
// Let's hook now with our functions
vectable[(unsigned long)hook_get_hardfault_vector_address(0)] = (unsigned long)&CommonHandler_ASM;
vectable[(unsigned long)hook_get_memfault_vector_address(0)] = (unsigned long)&CommonHandler_ASM;
vectable[(unsigned long)hook_get_busfault_vector_address(0)] = (unsigned long)&CommonHandler_ASM;
vectable[(unsigned long)hook_get_usagefault_vector_address(0)] = (unsigned long)&CommonHandler_ASM;
// Finally swap with our own vector table
// This is supposed to be atomic, but let's do that with interrupt disabled
HW_REG(0xE000ED08) = (unsigned long)vectable | _BV32(29); // 29th bit is for telling the CPU the table is now in SRAM (should be present already)
SERIAL_ECHOLN("Installed fault handlers");
#endif
}
#endif // __arm__ || __thumb__

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Marlin/src/HAL/shared/cpu_exception/exception_hook.cpp Normal file
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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#include "exception_hook.h"
void * __attribute__((weak)) hook_get_hardfault_vector_address(unsigned) { return 0; }
void * __attribute__((weak)) hook_get_memfault_vector_address(unsigned) { return 0; }
void * __attribute__((weak)) hook_get_busfault_vector_address(unsigned) { return 0; }
void * __attribute__((weak)) hook_get_usagefault_vector_address(unsigned) { return 0; }
void __attribute__((weak)) hook_last_resort_func() {}

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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#pragma once
/* Here is the expected behavior of a system producing a CPU exception with this hook installed:
1. Before the system is crashed
1.1 Upon validation (not done yet in this code, but we could be using DEBUG flags here to allow/disallow hooking)
1.2 Install the hook by overwriting the vector table exception handler with the hooked function
2. Upon system crash (for example, by a dereference of a NULL pointer or anything else)
2.1 The CPU triggers its exception and jump into the vector table for the exception type
2.2 Instead of finding the default handler, it finds the updated pointer to our hook
2.3 The CPU jumps into our hook function (likely a naked function to keep all information about crash point intact)
2.4 The hook (naked) function saves the important registers (stack pointer, program counter, current mode) and jumps to a common exception handler (in C)
2.5 The common exception handler dumps the registers on the serial link and perform a backtrace around the crashing point
2.6 Once the backtrace is performed the last resort function is called (platform specific).
On some platform with a LCD screen, this might display the crash information as a QR code or as text for the
user to capture by taking a picture
2.7 The CPU is reset and/or halted by triggering a debug breakpoint if a debugger is attached */
// Hook into CPU exception interrupt table to call the backtracing code upon an exception
// Most platform will simply do nothing here, but those who can will install/overwrite the default exception handler
// with a more performant exception handler
void hook_cpu_exceptions();
// Some platform might deal without a hard fault handler, in that case, return 0 in your platform here or skip implementing it
void * __attribute__((weak)) hook_get_hardfault_vector_address(unsigned base_address);
// Some platform might deal without a memory management fault handler, in that case, return 0 in your platform here or skip implementing it
void * __attribute__((weak)) hook_get_memfault_vector_address(unsigned base_address);
// Some platform might deal without a bus fault handler, in that case, return 0 in your platform here or skip implementing it
void * __attribute__((weak)) hook_get_busfault_vector_address(unsigned base_address);
// Some platform might deal without a usage fault handler, in that case, return 0 in your platform here or skip implementing it
void * __attribute__((weak)) hook_get_usagefault_vector_address(unsigned base_address);
// Last resort function that can be called after the exception handler was called.
void __attribute__((weak)) hook_last_resort_func();