[Intel-gfx] [PATCH v6 15/57] kernel/module: add __dyndbg_classes section

Jim Cromie
2022-09-04T21:46:25Z

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>
---
include/asm-generic/vmlinux.lds.h | 3 +++
include/linux/dynamic_debug.h | 2 ++
kernel/module/main.c | 2 ++
lib/dynamic_debug.c | 7 +++++++
4 files changed, 14 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 7515a465ec03..9b8bd5504ad9 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -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 = .; \
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 98dbf1d49984..9073a43a2039 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -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)
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 4c20bc3ff203..6aa6153aa6e0 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -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;
}
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c358ccdf4a39..fb31a1a2fc3f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -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
--
2.37.2