101 lines
3.0 KiB
ReStructuredText
101 lines
3.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
Linker-Generated Arrays
|
|
=======================
|
|
|
|
A linker list is constructed by grouping together linker input
|
|
sections, each containing one entry of the list. Each input section
|
|
contains a constant initialized variable which holds the entry's
|
|
content. Linker list input sections are constructed from the list
|
|
and entry names, plus a prefix which allows grouping all lists
|
|
together. Assuming _list and _entry are the list and entry names,
|
|
then the corresponding input section name is
|
|
|
|
::
|
|
|
|
.u_boot_list_ + 2_ + @_list + _2_ + @_entry
|
|
|
|
and the C variable name is
|
|
|
|
::
|
|
|
|
_u_boot_list + _2_ + @_list + _2_ + @_entry
|
|
|
|
This ensures uniqueness for both input section and C variable name.
|
|
|
|
Note that the names differ only in the first character, "." for the
|
|
section and "_" for the variable, so that the linker cannot confuse
|
|
section and symbol names. From now on, both names will be referred
|
|
to as
|
|
|
|
::
|
|
|
|
%u_boot_list_ + 2_ + @_list + _2_ + @_entry
|
|
|
|
Entry variables need never be referred to directly.
|
|
|
|
The naming scheme for input sections allows grouping all linker lists
|
|
into a single linker output section and grouping all entries for a
|
|
single list.
|
|
|
|
Note the two '_2_' constant components in the names: their presence
|
|
allows putting a start and end symbols around a list, by mapping
|
|
these symbols to sections names with components "1" (before) and
|
|
"3" (after) instead of "2" (within).
|
|
Start and end symbols for a list can generally be defined as
|
|
|
|
::
|
|
|
|
%u_boot_list_2_ + @_list + _1_...
|
|
%u_boot_list_2_ + @_list + _3_...
|
|
|
|
Start and end symbols for the whole of the linker lists area can be
|
|
defined as
|
|
|
|
::
|
|
|
|
%u_boot_list_1_...
|
|
%u_boot_list_3_...
|
|
|
|
Here is an example of the sorted sections which result from a list
|
|
"array" made up of three entries : "first", "second" and "third",
|
|
iterated at least once.
|
|
|
|
::
|
|
|
|
.u_boot_list_2_array_1
|
|
.u_boot_list_2_array_2_first
|
|
.u_boot_list_2_array_2_second
|
|
.u_boot_list_2_array_2_third
|
|
.u_boot_list_2_array_3
|
|
|
|
If lists must be divided into sublists (e.g. for iterating only on
|
|
part of a list), one can simply give the list a name of the form
|
|
'outer_2_inner', where 'outer' is the global list name and 'inner'
|
|
is the sub-list name. Iterators for the whole list should use the
|
|
global list name ("outer"); iterators for only a sub-list should use
|
|
the full sub-list name ("outer_2_inner").
|
|
|
|
Here is an example of the sections generated from a global list
|
|
named "drivers", two sub-lists named "i2c" and "pci", and iterators
|
|
defined for the whole list and each sub-list:
|
|
|
|
::
|
|
|
|
%u_boot_list_2_drivers_1
|
|
%u_boot_list_2_drivers_2_i2c_1
|
|
%u_boot_list_2_drivers_2_i2c_2_first
|
|
%u_boot_list_2_drivers_2_i2c_2_first
|
|
%u_boot_list_2_drivers_2_i2c_2_second
|
|
%u_boot_list_2_drivers_2_i2c_2_third
|
|
%u_boot_list_2_drivers_2_i2c_3
|
|
%u_boot_list_2_drivers_2_pci_1
|
|
%u_boot_list_2_drivers_2_pci_2_first
|
|
%u_boot_list_2_drivers_2_pci_2_second
|
|
%u_boot_list_2_drivers_2_pci_2_third
|
|
%u_boot_list_2_drivers_2_pci_3
|
|
%u_boot_list_2_drivers_3
|
|
|
|
.. kernel-doc:: include/linker_lists.h
|
|
:internal:
|