Identify the Cause of the Error
- In embedded systems development, the error most likely stems from how the linker script or startup files are configured. HardFaults can occur when there's an incorrect declaration in sections of the startup files, leading to handlers being discarded.
- Inspect the map file generated during the build process. It details how functions and variables are linked. Look for the HardFault\_Handler to determine its origin and status.
Modify the Linker Script
- Locate the linker script file, often with a `.ld` or similar extension. This file dictates how different sections of code and data are aligned and managed in memory. Ensure correct linker script sections for interrupt handlers.
- Verify that the `.text` section, which typically contains executable code, is set up properly to include your fault handlers. Ensure sections like `.text.HardFault_Handler` are not mistakenly omitted or improperly ordered causing them to be discarded.
- An example section in a linker script might include:
.text :
{
*(.text*)
KEEP(*(.text.HardFault_Handler))
} > FLASH
- The `KEEP` directive ensures that specified sections are not discarded during the linker's garbage collection.
Check Startup Code
- Examine the startup code or vector table, often in `startup.s` or `startup.c`. Handlers like `HardFault_Handler` should be correctly referenced in the vector table.
- Ensure the actual function prototype and definitions match what the startup code references:
// Example of a proper handler in C/C++
extern "C" void HardFault_Handler(void)
{
while (1)
{
// Implementation-specific code, e.g., logging
}
}
Adjust Build Settings
- Review build settings or flags in your IDE or build toolchain. Ensure optimizations don't inadvertently remove unused code.
- If using GCC, options such as `-ffunction-sections` and `-fdata-sections` may help manage sections more granularly.
- Enable verbose output during linking to acquire more insight into what the linker is discarding, which can help in troubleshooting.
Inspect and Update Firmware Libraries
- Ensure any libraries or SDKs used in the project are compatible with your target hardware and configured correctly.
- Look for updates or forum posts about similar issues in the development community, as this error might be known for specific versions of firmware libraries.
Validate and Test the Configuration
- Once modifications are made, rebuild the project and test thoroughly. Consider using debugging tools to simulate or diagnose HardFault conditions.
- Utilize debugging interfaces like J-Link or OpenOCD to set breakpoints and inspect whether the HardFault\_Handler is correctly invoked.
Document and Review
- Keep thorough documentation of any changes made to startup files, linker scripts, and build settings, noting the reasons and outcomes.
- Conduct a peer review of these changes if possible, to ensure they adhere to best practices and don't introduce new issues.
