COMMONPAGESIZE)'
     This is equivalent to either
          (ALIGN(MAXPAGESIZE) + (. & (MAXPAGESIZE - 1)))
     or
          (ALIGN(MAXPAGESIZE)
           + ((. + COMMONPAGESIZE - 1) & (MAXPAGESIZE - COMMONPAGESIZE)))
     depending on whether the latter uses fewer COMMONPAGESIZE sized
     pages for the data segment (area between the result of this
     expression and 'DATA_SEGMENT_END') than the former or not.  If the
     latter form is used, it means COMMONPAGESIZE bytes of runtime
     memory will be saved at the expense of up to COMMONPAGESIZE wasted
     bytes in the on-disk file.

     This expression can only be used directly in 'SECTIONS' commands,
     not in any output section descriptions and only once in the linker
     script.  COMMONPAGESIZE should be less or equal to MAXPAGESIZE and
     should be the system page size the object wants to be optimized for
     while still running on system page sizes up to MAXPAGESIZE.  Note
     however that '-z relro' protection will not be effective if the
     system page size is larger than COMMONPAGESIZE.

     Example:
            . = DATA_SEGMENT_ALIGN(0x10000, 0x2000);

'DATA_SEGMENT_END(EXP)'
     This defines the end of data segment for 'DATA_SEGMENT_ALIGN'
     evaluation purposes.

            . = DATA_SEGMENT_END(.);

'DATA_SEGMENT_RELRO_END(OFFSET, EXP)'
     This defines the end of the 'PT_GNU_RELRO' segment when '-z relro'
     option is used.  When '-z relro' option is not present,
     'DATA_SEGMENT_RELRO_END' does nothing, otherwise
     'DATA_SEGMENT_ALIGN' is padded so that EXP + OFFSET is aligned to
     the COMMONPAGESIZE argument given to 'DATA_SEGMENT_ALIGN'.  If
     present in the linker script, it must be placed between
     'DATA_SEGMENT_ALIGN' and 'DATA_SEGMENT_END'.  Evaluates to the
     second argument plus any padding needed at the end of the
     'PT_GNU_RELRO' segment due to section alignment.

            . = DATA_SEGMENT_RELRO_END(24, .);

'DEFINED(SYMBOL)'
     Return 1 if SYMBOL is in the linker global symbol table and is
     defined before the statement using DEFINED in the script, otherwise
     return 0.  You can use this function to provide default values for
     symbols.  For example, the following script fragment shows how to
     set a global symbol 'begin' to the first location in the '.text'
     section--but if a symbol called 'begin' already existed, its value
     is preserved:

          SECTIONS { ...
            .text : {
              begin = DEFINED(begin) ? begin : . ;
              ...
            }
            ...
          }

'LENGTH(MEMORY)'
     Return the length of the memory region named MEMORY.

'LOADADDR(SECTION)'
     Return the absolute LMA of the named SECTION.  (*note Output
     Section LMA::).

'LOG2CEIL(EXP)'
     Return the binary logarithm of EXP rounded towards infinity.
     'LOG2CEIL(0)' returns 0.

'MAX(EXP1, EXP2)'
     Returns the maximum of EXP1 and EXP2.

'MIN(EXP1, EXP2)'
     Returns the minimum of EXP1 and EXP2.

'NEXT(EXP)'
     Return the next unallocated address that is a multiple of EXP.
     This function is closely related to 'ALIGN(EXP)'; unless you use
     the 'MEMORY' command to define discontinuous memory for the output
     file, the two functions are equivalent.

'ORIGIN(MEMORY)'
     Return the origin of the memory region named MEMORY.

'SEGMENT_START(SEGMENT, DEFAULT)'
     Return the base address of the named SEGMENT.  If an explicit value
     has already been given for this segment (with a command-line '-T'
     option) then that value will be returned otherwise the value will
     be DEFAULT.  At present, the '-T' command-line option can only be
     used to set the base address for the "text", "data", and "bss"
     sections, but you can use 'SEGMENT_START' with any segment name.

'SIZEOF(SECTION)'
     Return the size in bytes of the named SECTION, if that section has
     been allocated.  If the section has not been allocated when this is
     evaluated, the linker will report an error.  In the following
     example, 'symbol_1' and 'symbol_2' are assigned identical values:
          SECTIONS{ ...
            .output {
              .start = . ;
              ...
              .end = . ;
              }
            symbol_1 = .end - .start ;
            symbol_2 = SIZEOF(.output);
          ... }

'SIZEOF_HEADERS'
'sizeof_headers'
     Return the size in bytes of the output file's headers.  This is
     information which appears at the start of the output file.  You can
     use this number when setting the start address of the first
     section, if you choose, to facilitate paging.

     When producing an ELF output file, if the linker script uses the
     'SIZEOF_HEADERS' builtin function, the linker must compute the
     number of program headers before it has determined all the section
     addresses and sizes.  If the linker later discovers that it needs
     additional program headers, it will report an error 'not enough
     room for program headers'.  To avoid this error, you must avoid
     using the 'SIZEOF_HEADERS' function, or you must rework your linker
     script to avoid forcing the linker to use additional program
     headers, or you must define the program headers yourself using the
     'PHDRS' command (*note PHDRS::).