Linker Scripts

Memory Layout

Compilers output generic object files containing text, rodata, data and bss sections without knowledge of target microcontrollers. Linker scripts define memory regions with explicit start addresses and length limits matching physical memory maps. Syntax directives specify where initial boot vectors reside and establish boundary symbols for C runtime stack and heap initialization.

Hardware Integration

Specialized microcontroller peripherals like Ethernet DMA controllers or crypto hardware often require buffers located at strict memory alignment boundaries. Embedded engineers modify linker scripts to allocate dedicated memory sections within fast internal tightly-coupled memory banks for time-critical interrupt routines. When security features like execute-never memory protection are enabled, linker scripts segregate executable instruction code from writeable data sections.

Misconfigured memory origin addresses cause hard faults during bootloader startup when CPU instruction fetches target unmapped bus regions.

Constraint Enforcement

Exceeding target RAM or flash capacity during compilation causes the linker utility to raise immediate memory overflow errors. Structuring linker scripts with explicit section assertion checks prevents silent overlap between heap structures and interrupt stack memory. Output map files document exact memory consumption across all physical memory blocks.