[PATCH v4 13/41] kernel/module: add __dyndbg_classes section
Jim Cromie
jim.cromie at gmail.com
Wed Jul 20 15:32:05 UTC 2022
Like existing sections, particularly __dyndbg, this new one is an
array/address and its length. In a close imitation of __dyndbg
handling, these are defined, then passed around, as follows:
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/internal.h:
- add new fields for classes,length to struct load_info,
kernel/module.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(): add params for classes, length.
- It currently builds a debug_table, and *will* find and attach classes.
dynamic_debug_init(): compute num_classes from linker symbols, and add
new _start, num_classes params to ddebug_add_module() calls.
Signed-off-by: Jim Cromie <jim.cromie at gmail.com>
---
include/asm-generic/vmlinux.lds.h | 3 +++
include/linux/dynamic_debug.h | 9 ++++++---
kernel/module/internal.h | 2 ++
kernel/module/main.c | 10 +++++++---
lib/dynamic_debug.c | 22 ++++++++++++++++------
5 files changed, 34 insertions(+), 12 deletions(-)
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 84e97cd0e8c4..f57076e02767 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -115,8 +115,10 @@ struct ddebug_class_map {
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
-int ddebug_add_module(struct _ddebug *tab, unsigned int n,
- const char *modname);
+int ddebug_add_module(struct _ddebug *tab, unsigned int num_debugs,
+ struct ddebug_class_map *classes, unsigned int num_classes,
+ const char *modname);
+
extern int ddebug_remove_module(const char *mod_name);
extern __printf(2, 3)
void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
@@ -285,7 +287,8 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
#include <linux/errno.h>
#include <linux/printk.h>
-static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n,
+static inline int ddebug_add_module(struct _ddebug *tab, unsigned int num_debugs,
+ struct ddebug_class_map *classes, unsigned int num_classes,
const char *modname)
{
return 0;
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index bc5507ab8450..02601dfe452b 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -60,7 +60,9 @@ struct load_info {
char *secstrings, *strtab;
unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
struct _ddebug *debug;
+ struct ddebug_class_map *debug_classes;
unsigned int num_debug;
+ unsigned int num_debug_classes;
bool sig_ok;
#ifdef CONFIG_KALLSYMS
unsigned long mod_kallsyms_init_off;
diff --git a/kernel/module/main.c b/kernel/module/main.c
index fed58d30725d..0f8e888908df 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1593,11 +1593,12 @@ static void free_modinfo(struct module *mod)
}
}
-static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
+static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num,
+ struct ddebug_class_map *classes, unsigned int num_classes)
{
if (!debug)
return;
- ddebug_add_module(debug, num, mod->name);
+ ddebug_add_module(debug, num, classes, num_classes, mod->name);
}
static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
@@ -2093,6 +2094,8 @@ static int find_module_sections(struct module *mod, struct load_info *info)
if (section_addr(info, "__obsparm"))
pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
+ info->debug_classes = section_objs(info, "__dyndbg_classes",
+ sizeof(*info->debug_classes), &info->num_debug_classes);
info->debug = section_objs(info, "__dyndbg",
sizeof(*info->debug), &info->num_debug);
@@ -2783,7 +2786,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
}
init_build_id(mod, info);
- dynamic_debug_setup(mod, info->debug, info->num_debug);
+ dynamic_debug_setup(mod, info->debug, info->num_debug,
+ info->debug_classes, info->num_debug_classes);
/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
ftrace_module_init(mod);
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e96dc216463b..b6d80ba25bf5 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;
@@ -923,8 +925,9 @@ static const struct proc_ops proc_fops = {
* Allocate a new ddebug_table for the given module
* and add it to the global list.
*/
-int ddebug_add_module(struct _ddebug *tab, unsigned int n,
- const char *name)
+int ddebug_add_module(struct _ddebug *tab, unsigned int num_debugs,
+ struct ddebug_class_map *classes, unsigned int num_classes,
+ const char *name)
{
struct ddebug_table *dt;
@@ -940,14 +943,14 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
* this struct ddebug_table.
*/
dt->mod_name = name;
- dt->num_ddebugs = n;
+ dt->num_ddebugs = num_debugs;
dt->ddebugs = tab;
mutex_lock(&ddebug_lock);
list_add_tail(&dt->link, &ddebug_tables);
mutex_unlock(&ddebug_lock);
- vpr_info("%3u debug prints in module %s\n", n, dt->mod_name);
+ vpr_info("%3u debug prints in module %s\n", num_debugs, dt->mod_name);
return 0;
}
@@ -1064,6 +1067,7 @@ static int __init dynamic_debug_init(void)
char *cmdline;
int ret = 0;
int n = 0, entries = 0, modct = 0;
+ int num_classes = __stop___dyndbg_classes - __start___dyndbg_classes;
if (&__start___dyndbg == &__stop___dyndbg) {
if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
@@ -1081,7 +1085,9 @@ static int __init dynamic_debug_init(void)
entries++;
if (strcmp(modname, iter->modname)) {
modct++;
- ret = ddebug_add_module(iter_start, n, modname);
+ ret = ddebug_add_module(iter_start, n,
+ __start___dyndbg_classes, num_classes,
+ modname);
if (ret)
goto out_err;
n = 0;
@@ -1090,7 +1096,8 @@ static int __init dynamic_debug_init(void)
}
n++;
}
- ret = ddebug_add_module(iter_start, n, modname);
+ ret = ddebug_add_module(iter_start, n,
+ __start___dyndbg_classes, num_classes, modname);
if (ret)
goto out_err;
@@ -1099,6 +1106,9 @@ static int __init dynamic_debug_init(void)
entries, modct, (int)((modct * sizeof(struct ddebug_table)) >> 10),
(int)((entries * sizeof(struct _ddebug)) >> 10));
+ if (num_classes)
+ v2pr_info(" %d builtin ddebug class-maps\n", 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
--
2.36.1
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