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Date: Wed, 17 Mar 2021 00:54:08 -0600
From: Jim Cromie <jim.cromie@...il.com>
To: jbaron@...mai.com, gregkh@...uxfoundation.org,
linux-kernel@...r.kernel.org
Cc: Jim Cromie <jim.cromie@...il.com>
Subject: [RFC PATCH v4 15/19] dyndbg: add _index to struct _ddebug
We currently use dp->site to map: &__dyndbg[N] -> &__dyndbg_sites[N].
We want to drop site, new _ddebug._index provides the N.
The mapping is done in ddebug_site_get():
For builtin modules, a _ddebug *ptr is between __start___dyndbg and
__stop___dyndbg, and we can use &__start___dyndbg_sites[N] directly.
For loadable modules, we still need work, so we print rubbish, and
just return site pointer (which is correct).
ddebug_add_module() handles _index initialization:
Its new task is to number each module consecutively, so it gets new
base arg to pass the next starting index.
To actually drop site, We need both the module's __dyndbg* section
addys, and we need their relative placement to have a base-to-base
offset.
PLAN - a table header connecting 2 tables.
- ddebug_table points to both __dyndbgs & __dyndbg_sites.
but *ddebugs & *sites are independent.
no path from ddebugs[n] -> ddebug_sites[n]
If we have a header record in-situ, which keeps the site pointer we
seek to eliminate from _ddebug, and its in element[0] of both vectors,
we can go:
ddebugs[n] -> ddebugs[0] -> containerof -> site[n]
union ddebug_table_header {
struct ddebug_table *owner;
struct _ddebug item;
}
and
struct ddebug_table_vector {
struct ddebug_table *owner;
struct _ddebug vector[];
}
Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
include/linux/dynamic_debug.h | 2 ++
lib/dynamic_debug.c | 40 +++++++++++++++++++++++++++++------
2 files changed, 36 insertions(+), 6 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 7d33475d226a..18689db0e2c0 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -29,6 +29,7 @@ struct _ddebug {
/* format is always needed, lineno shares word with flags */
const char *format;
const unsigned lineno:18;
+ unsigned _index:14;
/*
* The flags field controls the behaviour at the callsite.
* The bits here are changed dynamically when the user
@@ -56,6 +57,7 @@ struct _ddebug {
#define _DPRINTK_FLAGS_DEFAULT 0
#endif
unsigned int flags:8;
+
#ifdef CONFIG_JUMP_LABEL
union {
struct static_key_true dd_key_true;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1f59407b6a83..54737647556c 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -123,6 +123,8 @@ do { \
#define vpr_info(fmt, ...) vnpr_info(1, fmt, ##__VA_ARGS__)
#define v2pr_info(fmt, ...) vnpr_info(2, fmt, ##__VA_ARGS__)
#define v3pr_info(fmt, ...) vnpr_info(3, fmt, ##__VA_ARGS__)
+#define v4pr_info(fmt, ...) vnpr_info(4, fmt, ##__VA_ARGS__)
+#define v5pr_info(fmt, ...) vnpr_info(5, fmt, ##__VA_ARGS__)
static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
{
@@ -146,7 +148,17 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
{
- return dp->site; /* passthru abstraction */
+ v4pr_info("get %d: %s.%s.%d\n", dp->_index, dp->site->modname,
+ dp->site->function, dp->lineno);
+
+ if (dp >= __start___dyndbg && dp < __stop___dyndbg) {
+ v4pr_info(" is builtin: %d %ld\n", dp->_index, dp - __start___dyndbg);
+ return &__start___dyndbg_sites[ dp - __start___dyndbg ];
+ } else {
+ v3pr_info(" is loaded: %d %ld\n", dp->_index, dp - __start___dyndbg);
+ return dp->site;
+ }
+ return dp->site;
}
static inline void ddebug_site_put(struct _ddebug *dp)
{
@@ -1034,10 +1046,12 @@ 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, struct _ddebug_site *sites,
- unsigned int numdbgs, const char *modname)
+static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
+ unsigned numdbgs, unsigned base,
+ const char *modname)
{
struct ddebug_table *dt;
+ int i;
dt = kzalloc(sizeof(*dt), GFP_KERNEL);
if (dt == NULL) {
@@ -1055,6 +1069,13 @@ int ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
dt->ddebugs = tab;
dt->sites = sites;
+ v3pr_info("add-module: %s\n", modname);
+ for (i = 0; i < numdbgs; i++) {
+ tab[i]._index = base++;
+ v3pr_info(" %d %d %s.%s.%d\n", i, tab[i]._index, modname,
+ tab[i].site->function, tab[i].lineno);
+ }
+
mutex_lock(&ddebug_lock);
list_add(&dt->link, &ddebug_tables);
mutex_unlock(&ddebug_lock);
@@ -1063,6 +1084,12 @@ int ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
return 0;
}
+int ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
+ unsigned int numdbgs, const char *modname)
+{
+ return __ddebug_add_module(tab, sites, numdbgs, 0, modname);
+}
+
/* helper for ddebug_dyndbg_(boot|module)_param_cb */
static int ddebug_dyndbg_param_cb(char *param, char *val,
const char *modname, int on_err)
@@ -1177,6 +1204,7 @@ static int __init dynamic_debug_init(void)
char *cmdline;
int ret = 0;
int site_ct = 0, entries = 0, modct = 0;
+ int mod_index = 0;
if (&__start___dyndbg == &__stop___dyndbg) {
if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
@@ -1200,8 +1228,8 @@ static int __init dynamic_debug_init(void)
if (strcmp(modname, site->modname)) {
modct++;
- ret = ddebug_add_module(iter_mod_start, site_mod_start,
- site_ct, modname);
+ ret = __ddebug_add_module(iter_mod_start, site_mod_start,
+ site_ct, mod_index, modname);
if (ret)
goto out_err;
site_ct = 0;
@@ -1211,7 +1239,7 @@ static int __init dynamic_debug_init(void)
}
site_ct++;
}
- ret = ddebug_add_module(iter_mod_start, site_mod_start, site_ct, modname);
+ ret = __ddebug_add_module(iter_mod_start, site_mod_start, site_ct, mod_index, modname);
if (ret)
goto out_err;
--
2.29.2
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