stm32/boards: Add common_basic.ld for a board to have a single section.

ports/stm32/boards/common_basic.ld

+/* Memory layout for basic configuration:
+
+    FLASH       .isr_vector
+    FLASH       .text
+    FLASH       .data
+
+    RAM         .data
+    RAM         .bss
+    RAM         .heap
+    RAM         .stack
+*/
+
+ENTRY(Reset_Handler)
+
+/* define output sections */
+SECTIONS
+{
+    /* The startup code goes first into FLASH */
+    .isr_vector :
+    {
+        . = ALIGN(4);
+        KEEP(*(.isr_vector)) /* Startup code */
+
+        . = ALIGN(4);
+    } >FLASH
+
+    /* The program code and other data goes into FLASH */
+    .text :
+    {
+        . = ALIGN(4);
+        *(.text*)          /* .text* sections (code) */
+        *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+    /*  *(.glue_7)   */    /* glue arm to thumb code */
+    /*  *(.glue_7t)  */    /* glue thumb to arm code */
+
+        . = ALIGN(4);
+        _etext = .;        /* define a global symbol at end of code */
+    } >FLASH
+
+    /* used by the startup to initialize data */
+    _sidata = LOADADDR(.data);
+
+    /* This is the initialized data section
+    The program executes knowing that the data is in the RAM
+    but the loader puts the initial values in the FLASH (inidata).
+    It is one task of the startup to copy the initial values from FLASH to RAM. */
+    .data :
+    {
+        . = ALIGN(4);
+        _sdata = .;        /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
+        *(.data*)          /* .data* sections */
+
+        . = ALIGN(4);
+        _edata = .;        /* define a global symbol at data end; used by startup code in order to initialise the .data section in RAM */
+    } >RAM AT> FLASH
+
+    /* Uninitialized data section */
+    .bss :
+    {
+        . = ALIGN(4);
+        _sbss = .;         /* define a global symbol at bss start; used by startup code */
+        *(.bss*)
+        *(COMMON)
+
+        . = ALIGN(4);
+        _ebss = .;         /* define a global symbol at bss end; used by startup code and GC */
+    } >RAM
+
+    /* this is to define the start of the heap, and make sure we have a minimum size */
+    .heap :
+    {
+        . = ALIGN(4);
+        . = . + _minimum_heap_size;
+        . = ALIGN(4);
+    } >RAM
+
+    /* this just checks there is enough RAM for the stack */
+    .stack :
+    {
+        . = ALIGN(4);
+        . = . + _minimum_stack_size;
+        . = ALIGN(4);
+    } >RAM
+
+    .ARM.attributes 0 : { *(.ARM.attributes) }
+}