[people/ms/u-boot.git] / include / linker_lists.h

/*
 * include/linker_lists.h
 *
 * Implementation of linker-generated arrays
 *
 * Copyright (C) 2012 Marek Vasut <marex@denx.de>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#ifndef __LINKER_LISTS_H__
#define __LINKER_LISTS_H__

/*
 * There is no use in including this from ASM files, but that happens
 * anyway, e.g. PPC kgdb.S includes command.h which incluse us.
 * So just don't define anything when included from ASM.
 */

#if !defined(__ASSEMBLY__)

/**
 * A linker list is constructed by grouping together linker input
 * sections, each containning 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
 * setion 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
 */

/**
 * 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.
 *
 * 4) 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, 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)))

/**
 * 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 LG-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_entry_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__ */
Commit	Line	Data
42ebaae3 MV	1	/*
	2	* include/linker_lists.h
	3	*
	4	* Implementation of linker-generated arrays
	5	*
	6	* Copyright (C) 2012 Marek Vasut <marex@denx.de>
	7	*
1a459660	8	* SPDX-License-Identifier: GPL-2.0+
42ebaae3	9	*/
ef123c52	10
babb4440 MY	11	#ifndef __LINKER_LISTS_H__
	12	#define __LINKER_LISTS_H__
	13
ef123c52 AA	14	/*
	15	* There is no use in including this from ASM files, but that happens
	16	* anyway, e.g. PPC kgdb.S includes command.h which incluse us.
	17	* So just don't define anything when included from ASM.
	18	*/
	19
	20	#if !defined(__ASSEMBLY__)
	21
	22	/**
	23	* A linker list is constructed by grouping together linker input
	24	* sections, each containning one entry of the list. Each input section
	25	* contains a constant initialized variable which holds the entry's
	26	* content. Linker list input sections are constructed from the list
	27	* and entry names, plus a prefix which allows grouping all lists
	28	* together. Assuming _list and _entry are the list and entry names,
	29	* then the corresponding input section name is
	30	*
	31	* _u_boot_list + _2_ + @_list + _2_ + @_entry
	32	*
	33	* and the C variable name is
	34	*
	35	* .u_boot_list_ + 2_ + @_list + _2_ + @_entry
	36	*
	37	* This ensures uniqueness for both input section and C variable name.
	38	*
	39	* Note that the names differ only in the first character, "." for the
	40	* setion and "_" for the variable, so that the linker cannot confuse
	41	* section and symbol names. From now on, both names will be referred
	42	* to as
	43	*
	44	* %u_boot_list_ + 2_ + @_list + _2_ + @_entry
	45	*
	46	* Entry variables need never be referred to directly.
	47	*
	48	* The naming scheme for input sections allows grouping all linker lists
	49	* into a single linker output section and grouping all entries for a
	50	* single list.
	51	*
	52	* Note the two '_2_' constant components in the names: their presence
	53	* allows putting a start and end symbols around a list, by mapping
	54	* these symbols to sections names with components "1" (before) and
	55	* "3" (after) instead of "2" (within).
	56	* Start and end symbols for a list can generally be defined as
	57	*
	58	* %u_boot_list_2_ + @_list + _1_...
	59	* %u_boot_list_2_ + @_list + _3_...
	60	*
	61	* Start and end symbols for the whole of the linker lists area can be
	62	* defined as
	63	*
	64	* %u_boot_list_1_...
	65	* %u_boot_list_3_...
	66	*
	67	* Here is an example of the sorted sections which result from a list
	68	* "array" made up of three entries : "first", "second" and "third",
	69	* iterated at least once.
	70	*
	71	* .u_boot_list_2_array_1
	72	* .u_boot_list_2_array_2_first
	73	* .u_boot_list_2_array_2_second
	74	* .u_boot_list_2_array_2_third
	75	* .u_boot_list_2_array_3
	76	*
	77	* If lists must be divided into sublists (e.g. for iterating only on
78	* part of a list), one can simply give the list a name of the form
79	* 'outer_2_inner', where 'outer' is the global list name and 'inner'
80	* is the sub-list name. Iterators for the whole list should use the
81	* global list name ("outer"); iterators for only a sub-list should use
82	* the full sub-list name ("outer_2_inner").
83	*
84	* Here is an example of the sections generated from a global list
85	* named "drivers", two sub-lists named "i2c" and "pci", and iterators
86	* defined for the whole list and each sub-list:
87	*
88	* %u_boot_list_2_drivers_1
89	* %u_boot_list_2_drivers_2_i2c_1
90	* %u_boot_list_2_drivers_2_i2c_2_first
91	* %u_boot_list_2_drivers_2_i2c_2_first
92	* %u_boot_list_2_drivers_2_i2c_2_second
93	* %u_boot_list_2_drivers_2_i2c_2_third
94	* %u_boot_list_2_drivers_2_i2c_3
95	* %u_boot_list_2_drivers_2_pci_1
96	* %u_boot_list_2_drivers_2_pci_2_first
97	* %u_boot_list_2_drivers_2_pci_2_second
98	* %u_boot_list_2_drivers_2_pci_2_third
99	* %u_boot_list_2_drivers_2_pci_3
100	* %u_boot_list_2_drivers_3
101	*/
102
42ebaae3 MV	103	/**
	104	* ll_entry_declare() - Declare linker-generated array entry
	105	* @_type: Data type of the entry
	106	* @_name: Name of the entry
ef123c52 AA	107	* @_list: name of the list. Should contain only characters allowed
ef123c52 AA	108	* in a C variable name!
42ebaae3 MV	109	*
	110	* This macro declares a variable that is placed into a linker-generated
	111	* array. This is a basic building block for more advanced use of linker-
	112	* generated arrays. The user is expected to build their own macro wrapper
	113	* around this one.
	114	*
ef123c52	115	* A variable declared using this macro must be compile-time initialized.
42ebaae3 MV	116	*
42ebaae3 MV	117	* Special precaution must be made when using this macro:
42ebaae3	118	*
ef123c52 AA	119	* 1) The _type must not contain the "static" keyword, otherwise the
	120	* entry is generated and can be iterated but is listed in the map
	121	* file and cannot be retrieved by name.
42ebaae3	122	*
ef123c52 AA	123	* 2) In case a section is declared that contains some array elements AND
	124	* a subsection of this section is declared and contains some elements,
	125	* it is imperative that the elements are of the same type.
42ebaae3 MV	126	*
42ebaae3 MV	127	* 4) In case an outer section is declared that contains some array elements
ef123c52	128	* AND an inner subsection of this section is declared and contains some
42ebaae3 MV	129	* elements, then when traversing the outer section, even the elements of
	130	* the inner sections are present in the array.
	131	*
	132	* Example:
	133	* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub, cmd.sub) = {
	134	* .x = 3,
	135	* .y = 4,
	136	* };
	137	*/
ef123c52 AA	138	#define ll_entry_declare(_type, _name, _list) \
	139	_type _u_boot_list_2_##_list##_2_##_name __aligned(4) \
	140	__attribute__((unused, \
	141	section(".u_boot_list_2_"#_list"_2_"#_name)))
	142
	143	/**
	144	* We need a 0-byte-size type for iterator symbols, and the compiler
	145	* does not allow defining objects of C type 'void'. Using an empty
	146	* struct is allowed by the compiler, but causes gcc versions 4.4 and
	147	* below to complain about aliasing. Therefore we use the next best
	148	* thing: zero-sized arrays, which are both 0-byte-size and exempt from
	149	* aliasing warnings.
	150	*/
42ebaae3 MV	151
	152	/**
	153	* ll_entry_start() - Point to first entry of linker-generated array
	154	* @_type: Data type of the entry
ef123c52	155	* @_list: Name of the list in which this entry is placed
42ebaae3 MV	156	*
	157	* This function returns (_type *) pointer to the very first entry of a
	158	* linker-generated array placed into subsection of .u_boot_list section
ef123c52 AA	159	* specified by _list argument.
	160	*
	161	* Since this macro defines an array start symbol, its leftmost index
	162	* must be 2 and its rightmost index must be 1.
42ebaae3 MV	163	*
	164	* Example:
	165	* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
	166	*/
ef123c52 AA	167	#define ll_entry_start(_type, _list) \
	168	({ \
	169	static char start[0] __aligned(4) __attribute__((unused, \
	170	section(".u_boot_list_2_"#_list"_1"))); \
	171	(_type *)&start; \
	172	})
42ebaae3 MV	173
42ebaae3 MV	174	/**
ef123c52	175	* ll_entry_end() - Point after last entry of linker-generated array
42ebaae3	176	* @_type: Data type of the entry
ef123c52	177	* @_list: Name of the list in which this entry is placed
42ebaae3 MV	178	* (with underscores instead of dots)
42ebaae3 MV	179	*
ef123c52 AA	180	* This function returns (_type *) pointer after the very last entry of
	181	* a linker-generated array placed into subsection of .u_boot_list
	182	* section specified by _list argument.
	183	*
	184	* Since this macro defines an array end symbol, its leftmost index
	185	* must be 2 and its rightmost index must be 3.
	186	*
	187	* Example:
	188	* struct my_sub_cmd *msc = ll_entry_end(struct my_sub_cmd, cmd_sub);
	189	*/
	190	#define ll_entry_end(_type, _list) \
	191	({ \
	192	static char end[0] __aligned(4) __attribute__((unused, \
	193	section(".u_boot_list_2_"#_list"_3"))); \
	194	(_type *)&end; \
	195	})
	196	/**
	197	* ll_entry_count() - Return the number of elements in linker-generated array
	198	* @_type: Data type of the entry
	199	* @_list: Name of the list of which the number of elements is computed
	200	*
42ebaae3	201	* This function returns the number of elements of a linker-generated array
ef123c52	202	* placed into subsection of .u_boot_list section specified by _list
42ebaae3 MV	203	* argument. The result is of an unsigned int type.
	204	*
	205	* Example:
	206	* int i;
	207	* const unsigned int count = ll_entry_count(struct my_sub_cmd, cmd_sub);
	208	* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
	209	* for (i = 0; i < count; i++, msc++)
	210	* printf("Entry %i, x=%i y=%i\n", i, msc->x, msc->y);
	211	*/
ef123c52	212	#define ll_entry_count(_type, _list) \
42ebaae3	213	({ \
ef123c52 AA	214	_type *start = ll_entry_start(_type, _list); \
	215	_type *end = ll_entry_end(_type, _list); \
	216	unsigned int _ll_result = end - start; \
42ebaae3 MV	217	_ll_result; \
	218	})
	219
42ebaae3 MV	220	/**
	221	* ll_entry_get() - Retrieve entry from linker-generated array by name
	222	* @_type: Data type of the entry
	223	* @_name: Name of the entry
ef123c52	224	* @_list: Name of the list in which this entry is placed
42ebaae3 MV	225	*
	226	* This function returns a pointer to a particular entry in LG-array
	227	* identified by the subsection of u_boot_list where the entry resides
	228	* and it's name.
	229	*
	230	* Example:
af41d6b4	231	* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub) = {
42ebaae3 MV	232	* .x = 3,
	233	* .y = 4,
	234	* };
	235	* ...
	236	* struct my_sub_cmd *c = ll_entry_get(struct my_sub_cmd, my_sub_cmd, cmd_sub);
	237	*/
ef123c52	238	#define ll_entry_get(_type, _name, _list) \
42ebaae3	239	({ \
ef123c52 AA	240	extern _type _u_boot_list_2_##_list##_2_##_name; \
	241	_type *_ll_result = \
	242	&_u_boot_list_2_##_list##_2_##_name; \
42ebaae3 MV	243	_ll_result; \
	244	})
	245
ef123c52 AA	246	/**
	247	* ll_start() - Point to first entry of first linker-generated array
	248	* @_type: Data type of the entry
	249	*
	250	* This function returns (_type *) pointer to the very first entry of
	251	* the very first linker-generated array.
	252	*
	253	* Since this macro defines the start of the linker-generated arrays,
	254	* its leftmost index must be 1.
	255	*
	256	* Example:
	257	* struct my_sub_cmd *msc = ll_start(struct my_sub_cmd);
	258	*/
	259	#define ll_start(_type) \
	260	({ \
	261	static char start[0] __aligned(4) __attribute__((unused, \
	262	section(".u_boot_list_1"))); \
	263	(_type *)&start; \
	264	})
	265
	266	/**
	267	* ll_entry_end() - Point after last entry of last linker-generated array
	268	* @_type: Data type of the entry
	269	*
	270	* This function returns (_type *) pointer after the very last entry of
	271	* the very last linker-generated array.
	272	*
	273	* Since this macro defines the end of the linker-generated arrays,
	274	* its leftmost index must be 3.
	275	*
	276	* Example:
	277	* struct my_sub_cmd *msc = ll_end(struct my_sub_cmd);
	278	*/
	279	#define ll_end(_type) \
	280	({ \
	281	static char end[0] __aligned(4) __attribute__((unused, \
	282	section(".u_boot_list_3"))); \
	283	(_type *)&end; \
	284	})
	285
	286	#endif /* __ASSEMBLY__ */
	287
42ebaae3	288	#endif /* __LINKER_LISTS_H__ */