linker: Allow for 999 priority levels in init levels

Some projects may have needs for more than 99 priority levels, so add
a third linker input section for each obj level.

Signed-off-by: Josh DeWitt <josh.dewitt@garmin.com>

cmake/modules/extensions.cmake

@@ -5240,8 +5240,8 @@ endfunction()
 # This is useful content such as struct devices.
 #
 # For example: zephyr_linker_section_obj_level(SECTION init LEVEL PRE_KERNEL_1)
-# will create an input section matching `.z_init_PRE_KERNEL_1_?_` and
-# `.z_init_PRE_KERNEL_1_??_`.
+# will create an input section matching `.z_init_PRE_KERNEL_1_?_`,
+# `.z_init_PRE_KERNEL_1_??_`, and `.z_init_PRE_KERNEL_1_???_`.
 #
 # SECTION <section>: Section in which the objects shall be placed
 # LEVEL <level>    : Priority level, all input sections matching the level
@@ -5274,6 +5274,11 @@ function(zephyr_linker_section_obj_level)
     INPUT ".z_${OBJ_SECTION}_${OBJ_LEVEL}_??_*"
     KEEP SORT NAME
   )
+  zephyr_linker_section_configure(
+    SECTION ${OBJ_SECTION}
+    INPUT ".z_${OBJ_SECTION}_${OBJ_LEVEL}_???_*"
+    KEEP SORT NAME
+  )
 endfunction()
 
 # Usage:

doc/kernel/drivers/index.rst

@@ -366,7 +366,7 @@ initialization levels:
 
 Within each initialization level you may specify a priority level, relative to
 other devices in the same initialization level. The priority level is specified
-as an integer value in the range 0 to 99; lower values indicate earlier
+as an integer value in the range 0 to 999; lower values indicate earlier
 initialization.  The priority level must be a decimal integer literal without
 leading zeroes or sign (e.g. 32), or an equivalent symbolic name (e.g.
 ``\#define MY_INIT_PRIO 32``); symbolic expressions are *not* permitted (e.g.

include/zephyr/init.h

@@ -41,7 +41,7 @@ extern "C" {
  * - `SMP`: Only available if @kconfig{CONFIG_SMP} is enabled, specific for
  *   SMP.
  *
- * Initialization priority can take a value in the range of 0 to 99.
+ * Initialization priority can take a value in the range of 0 to 999.
  *
  * @note The same infrastructure is used by devices.
  * @{

include/zephyr/linker/linker-defs.h

@@ -48,7 +48,8 @@
 #define CREATE_OBJ_LEVEL(object, level)				\
 		__##object##_##level##_start = .;		\
 		KEEP(*(SORT(.z_##object##_##level##_?_*)));	\
-		KEEP(*(SORT(.z_##object##_##level##_??_*)));
+		KEEP(*(SORT(.z_##object##_##level##_??_*)));	\
+		KEEP(*(SORT(.z_##object##_##level##_???_*)));
 /* clang-format on */
 
 /*

tests/kernel/device/src/main.c

@@ -271,10 +271,11 @@ SYS_INIT_NAMED(init1, init_fn, APPLICATION, 1);
 SYS_INIT_NAMED(init2, init_fn, APPLICATION, 2);
 SYS_INIT_NAMED(init3, init_fn, APPLICATION, 2);
 SYS_INIT_NAMED(init4, init_fn, APPLICATION, 99);
+SYS_INIT_NAMED(init5, init_fn, APPLICATION, 999);
 
 ZTEST(device, test_sys_init_multiple)
 {
-	zassert_equal(sys_init_counter, 5, "");
+	zassert_equal(sys_init_counter, 6, "");
 }
 
 /* this is for storing sequence during initialization */