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Diffstat (limited to 'include/linker_lists.h')
| -rw-r--r-- | include/linker_lists.h | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/include/linker_lists.h b/include/linker_lists.h new file mode 100644 index 0000000..d775d04 --- /dev/null +++ b/include/linker_lists.h @@ -0,0 +1,261 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * include/linker_lists.h + * + * Implementation of linker-generated arrays + * + * Copyright (C) 2012 Marek Vasut <marex@denx.de> + */ + +#ifndef __LINKER_LISTS_H__ +#define __LINKER_LISTS_H__ + +#include <linux/compiler.h> + +/* + * There is no use in including this from ASM files. + * So just don't define anything when included from ASM. + */ + +#if !defined(__ASSEMBLY__) + +/** + * llsym() - Access a linker-generated array entry + * @_type: Data type of the entry + * @_name: Name of the entry + * @_list: name of the list. Should contain only characters allowed + * in a C variable name! + */ +#define llsym(_type, _name, _list) \ + ((_type *)&_u_boot_list_2_##_list##_2_##_name) + +/** + * ll_entry_declare() - Declare linker-generated array entry + * @_type: Data type of the entry + * @_name: Name of the entry + * @_list: name of the list. Should contain only characters allowed + * in a C variable name! + * + * This macro declares a variable that is placed into a linker-generated + * array. This is a basic building block for more advanced use of linker- + * generated arrays. The user is expected to build their own macro wrapper + * around this one. + * + * A variable declared using this macro must be compile-time initialized. + * + * Special precaution must be made when using this macro: + * + * 1) The _type must not contain the "static" keyword, otherwise the + * entry is generated and can be iterated but is listed in the map + * file and cannot be retrieved by name. + * + * 2) In case a section is declared that contains some array elements AND + * a subsection of this section is declared and contains some elements, + * it is imperative that the elements are of the same type. + * + * 3) In case an outer section is declared that contains some array elements + * AND an inner subsection of this section is declared and contains some + * elements, then when traversing the outer section, even the elements of + * the inner sections are present in the array. + * + * Example: + * + * :: + * + * ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub) = { + * .x = 3, + * .y = 4, + * }; + */ +#define ll_entry_declare(_type, _name, _list) \ + _type _u_boot_list_2_##_list##_2_##_name __aligned(4) \ + __attribute__((unused, \ + section(".u_boot_list_2_"#_list"_2_"#_name))) + +/** + * ll_entry_declare_list() - Declare a list of link-generated array entries + * @_type: Data type of each entry + * @_name: Name of the entry + * @_list: name of the list. Should contain only characters allowed + * in a C variable name! + * + * This is like ll_entry_declare() but creates multiple entries. It should + * be assigned to an array. + * + * :: + * + * ll_entry_declare_list(struct my_sub_cmd, my_sub_cmd, cmd_sub) = { + * { .x = 3, .y = 4 }, + * { .x = 8, .y = 2 }, + * { .x = 1, .y = 7 } + * }; + */ +#define ll_entry_declare_list(_type, _name, _list) \ + _type _u_boot_list_2_##_list##_2_##_name[] __aligned(4) \ + __attribute__((unused, \ + section(".u_boot_list_2_"#_list"_2_"#_name))) + +/* + * We need a 0-byte-size type for iterator symbols, and the compiler + * does not allow defining objects of C type 'void'. Using an empty + * struct is allowed by the compiler, but causes gcc versions 4.4 and + * below to complain about aliasing. Therefore we use the next best + * thing: zero-sized arrays, which are both 0-byte-size and exempt from + * aliasing warnings. + */ + +/** + * ll_entry_start() - Point to first entry of linker-generated array + * @_type: Data type of the entry + * @_list: Name of the list in which this entry is placed + * + * This function returns ``(_type *)`` pointer to the very first entry of a + * linker-generated array placed into subsection of .u_boot_list section + * specified by _list argument. + * + * Since this macro defines an array start symbol, its leftmost index + * must be 2 and its rightmost index must be 1. + * + * Example: + * + * :: + * + * struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub); + */ +#define ll_entry_start(_type, _list) \ +({ \ + static char start[0] __aligned(4) __attribute__((unused, \ + section(".u_boot_list_2_"#_list"_1"))); \ + (_type *)&start; \ +}) + +/** + * ll_entry_end() - Point after last entry of linker-generated array + * @_type: Data type of the entry + * @_list: Name of the list in which this entry is placed + * (with underscores instead of dots) + * + * This function returns ``(_type *)`` pointer after the very last entry of + * a linker-generated array placed into subsection of .u_boot_list + * section specified by _list argument. + * + * Since this macro defines an array end symbol, its leftmost index + * must be 2 and its rightmost index must be 3. + * + * Example: + * + * :: + * + * struct my_sub_cmd *msc = ll_entry_end(struct my_sub_cmd, cmd_sub); + */ +#define ll_entry_end(_type, _list) \ +({ \ + static char end[0] __aligned(4) __attribute__((unused, \ + section(".u_boot_list_2_"#_list"_3"))); \ + (_type *)&end; \ +}) +/** + * ll_entry_count() - Return the number of elements in linker-generated array + * @_type: Data type of the entry + * @_list: Name of the list of which the number of elements is computed + * + * This function returns the number of elements of a linker-generated array + * placed into subsection of .u_boot_list section specified by _list + * argument. The result is of an unsigned int type. + * + * Example: + * + * :: + * + * int i; + * const unsigned int count = ll_entry_count(struct my_sub_cmd, cmd_sub); + * struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub); + * for (i = 0; i < count; i++, msc++) + * printf("Entry %i, x=%i y=%i\n", i, msc->x, msc->y); + */ +#define ll_entry_count(_type, _list) \ + ({ \ + _type *start = ll_entry_start(_type, _list); \ + _type *end = ll_entry_end(_type, _list); \ + unsigned int _ll_result = end - start; \ + _ll_result; \ + }) + +/** + * ll_entry_get() - Retrieve entry from linker-generated array by name + * @_type: Data type of the entry + * @_name: Name of the entry + * @_list: Name of the list in which this entry is placed + * + * This function returns a pointer to a particular entry in linker-generated + * array identified by the subsection of u_boot_list where the entry resides + * and it's name. + * + * Example: + * + * :: + * + * ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub) = { + * .x = 3, + * .y = 4, + * }; + * ... + * struct my_sub_cmd *c = ll_entry_get(struct my_sub_cmd, my_sub_cmd, cmd_sub); + */ +#define ll_entry_get(_type, _name, _list) \ + ({ \ + extern _type _u_boot_list_2_##_list##_2_##_name; \ + _type *_ll_result = \ + &_u_boot_list_2_##_list##_2_##_name; \ + _ll_result; \ + }) + +/** + * ll_start() - Point to first entry of first linker-generated array + * @_type: Data type of the entry + * + * This function returns ``(_type *)`` pointer to the very first entry of + * the very first linker-generated array. + * + * Since this macro defines the start of the linker-generated arrays, + * its leftmost index must be 1. + * + * Example: + * + * :: + * + * struct my_sub_cmd *msc = ll_start(struct my_sub_cmd); + */ +#define ll_start(_type) \ +({ \ + static char start[0] __aligned(4) __attribute__((unused, \ + section(".u_boot_list_1"))); \ + (_type *)&start; \ +}) + +/** + * ll_end() - Point after last entry of last linker-generated array + * @_type: Data type of the entry + * + * This function returns ``(_type *)`` pointer after the very last entry of + * the very last linker-generated array. + * + * Since this macro defines the end of the linker-generated arrays, + * its leftmost index must be 3. + * + * Example: + * + * :: + * + * struct my_sub_cmd *msc = ll_end(struct my_sub_cmd); + */ +#define ll_end(_type) \ +({ \ + static char end[0] __aligned(4) __attribute__((unused, \ + section(".u_boot_list_3"))); \ + (_type *)&end; \ +}) + +#endif /* __ASSEMBLY__ */ + +#endif /* __LINKER_LISTS_H__ */ |