While trying to address the common patters in our
linker scripts I made a sketch of a minimal linker script.
As this will be the basis for my continued effort to create
a set of defines that can be used by all architectues I would like
to receive some feedback.
/*
* Helper macros to support writing architecture specific
* linker scripts.
*
* A minimal linker scripts has following content:
*
* OUTPUT_FORMAT(...)
* OUTPUT_ARCH(...)
* ENTRY(...)
* SECTIONS
* {
* . = START;
* __init_begin = .;
* HEAD_SECTION
* INIT_TEXT_SECTION(PAGE_SIZE)
* INIT_DATA_SECTION(...)
* PERCPU(PAGE_SIZE)
* __init_end = .;
*
* _stext = .;
* TEXT_SECTION = 0
* _etext = .;
*
* _sdata = .;
* RO_DATA_SECTION(PAGE_SIZE)
* RW_DATA_SECTION(...)
* _edata = .;
*
* EXCEPTION_TABLE(...)
* NOTES
*
* __bss_start = .;
* BSS_SECTION(0, 0)
* __bss_stop = .;
* _end = .;
*
* /DISCARD/ : {
* EXIT_TEXT
* EXIT_DATA
* *(.exitcall.exit)
* }
* STABS_DEBUG
* DWARF_DEBUG
* }
*
* [__init_begin, __init_end] is the init section that may be freed after init
* [_stext, _etext] is the text section
* [_sdata, _edata] is the data section
*
* Some of the included output section include their own set of constants.
* Examples are: [__initramfs_start, __initramfs_end] for initramfs and
* [__nosave_begin, __nosave_end] for the nosave data
*/
There is one majot issue in the minimal script I need to address.
All symbols are absolute (__init_begin, _stext etc) - I need to find a nice
way to make them non-absolute.
For now I and more interested in comments on the structure and the coverage
of the symbols.
I strikes me that [_stext, _etext] do not cover text in the init section.
And does [_sdata, _edata] cover RO_DATA?
What abut the order of the sections - are they significant for any archtecture?
I have used an order used by some of the embedded targets that allows
a maximum of code to reside inisde [__init_begin, __init_end].
Comments appreciated!
Sam
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