Fix .data section load memory address (LMA) in linker script and disable unaligned access trapping. [AI work: identified and fixed the __const_static_data_load LMA bug in gcc.ld, diagnosed the resulting unaligned write UsageFault, and disabled trap_unaligned_access in configure.hpp; Human work: reviewed and approved the implementation plan and fixes.]

Author: emrainey

configurations/basic/configure.hpp

@@ -90,7 +90,7 @@ constexpr static bool allow_thread_mode_exception_return{false};
 
 /// Enable trapping of unaligned accesses into a Usage Fault.
 /// @note Halfword and Word Acceases using LDM, STM, LDRD, and STRD will always fault when this is enabled.
-constexpr static bool trap_unaligned_access{true};
+constexpr static bool trap_unaligned_access{false};
 
 /// Enable trapping of divide by zero operations into a Usage Fault.
 /// @note This only applies to hardware divide instructions (SDIV and UDIV).When disabled, a value of zero is returned.

modules/stm32/linkerscripts/gcc.ld

@@ -65,12 +65,12 @@ SECTIONS {
 
     /* Initialized Constant Static Storage */
     .rodata ALIGN(4) : {
-        __const_static_data_load = .;
         *(.rodata)
         *(.rodata.*)
     } >REGION_TEXT
 
     /* Initialized Static Storage in RAM (no longer really Constant!)*/
+    __const_static_data_load = LOADADDR(.data);
     .data : {
         __const_static_data_start = .;
         *(.data)