kernel/module: add __dyndbg_classes section

Add __dyndbg_classes section, using __dyndbg as a model. Use it:

vmlinux.lds.h:

KEEP the new section, which also silences orphan section warning on
loadable modules.  Add (__start_/__stop_)__dyndbg_classes linker
symbols for the c externs (below).

kernel/module/main.c:
- fill new fields in find_module_sections(), using section_objs()
- extend callchain prototypes
  to pass classes, length
  load_module(): pass new info to dynamic_debug_setup()
  dynamic_debug_setup(): new params, pass through to ddebug_add_module()

dynamic_debug.c:
- add externs to the linker symbols.

ddebug_add_module():
- It currently builds a debug_table, and *will* find and attach classes.

dynamic_debug_init():
- add class fields to the _ddebug_info cursor var: di.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220904214134.408619-16-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jim Cromie 2022-09-04 15:40:52 -06:00 committed by Greg Kroah-Hartman
parent aad0214f30
commit 66f4006b6a
4 changed files with 14 additions and 0 deletions

View File

@ -345,6 +345,9 @@
*(__tracepoints) \
/* implement dynamic printk debug */ \
. = ALIGN(8); \
__start___dyndbg_classes = .; \
KEEP(*(__dyndbg_classes)) \
__stop___dyndbg_classes = .; \
__start___dyndbg = .; \
KEEP(*(__dyndbg)) \
__stop___dyndbg = .; \

View File

@ -114,7 +114,9 @@ struct ddebug_class_map {
/* encapsulate linker provided built-in (or module) dyndbg data */
struct _ddebug_info {
struct _ddebug *descs;
struct ddebug_class_map *classes;
unsigned int num_descs;
unsigned int num_classes;
};
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)

View File

@ -2113,6 +2113,8 @@ static int find_module_sections(struct module *mod, struct load_info *info)
info->dyndbg.descs = section_objs(info, "__dyndbg",
sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs);
info->dyndbg.classes = section_objs(info, "__dyndbg_classes",
sizeof(*info->dyndbg.classes), &info->dyndbg.num_classes);
return 0;
}

View File

@ -41,6 +41,8 @@
extern struct _ddebug __start___dyndbg[];
extern struct _ddebug __stop___dyndbg[];
extern struct ddebug_class_map __start___dyndbg_classes[];
extern struct ddebug_class_map __stop___dyndbg_classes[];
struct ddebug_table {
struct list_head link;
@ -1079,7 +1081,9 @@ static int __init dynamic_debug_init(void)
struct _ddebug_info di = {
.descs = __start___dyndbg,
.classes = __start___dyndbg_classes,
.num_descs = __stop___dyndbg - __start___dyndbg,
.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
};
if (&__start___dyndbg == &__stop___dyndbg) {
@ -1122,6 +1126,9 @@ static int __init dynamic_debug_init(void)
i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
(int)((i * sizeof(struct _ddebug)) >> 10));
if (di.num_classes)
v2pr_info(" %d builtin ddebug class-maps\n", di.num_classes);
/* now that ddebug tables are loaded, process all boot args
* again to find and activate queries given in dyndbg params.
* While this has already been done for known boot params, it