Messages in this thread Patch in this message |  | | From | Jim Cromie <> | Subject | [RFC PATCH v6 25/34] dyndbg: make site pointer and checks on it optional (almost) | Date | Sat, 29 May 2021 14:00:20 -0600 |
| |
Hide declaration and uses of _ddebug.site pointer in SITE_* macros, defined alternately for SITE_CHK true/undefined.
Mostly, this eliminates all the WARN_ONs in ddebug_site_get(), which seem to be mostly proven (they were BUG_ONs).
NOTE:
This breaks when !defined SITE_CHK - the header, being just a struct _ddebug, also loses the .site member. Need to specialize the header struct to keep it, then unionize it back into the sites vector.
In DEFINE_DYNAMIC_DEBUG_TABLE, we keep the raw initialization; we want this init when specialization & unionization is finished.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- include/linux/dynamic_debug.h | 18 +++++++++++++++--- lib/dynamic_debug.c | 13 ++++++++++--- 2 files changed, 25 insertions(+), 6 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index a99973221f94..7acd4c88411d 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -6,6 +6,18 @@ #include <linux/jump_label.h> #endif +#define SITE_CHK /* include .site pointer and checks on it */ + +#ifdef SITE_CHK +#define SITE_CHK_(...) __VA_ARGS__ +#define SITE_COND(_i, _s) (_s == _i->site) +#define SITE_INIT_(_name) .site = &_name, +#else +#define SITE_CHK_(...) +#define SITE_COND(_i, _s) (true) +#define SITE_INIT_(name) +#endif + /* * A pair of these structs are created in 2 special ELF sections * (__dyndbg, __dyndbg_sites) for every dynamic debug callsite. @@ -25,7 +37,7 @@ struct _ddebug_site { } __aligned(8); struct _ddebug { - struct _ddebug_site *site; + SITE_CHK_(struct _ddebug_site *site;) /* format is always needed, lineno shares word with flags */ const char *format; const unsigned lineno:18; @@ -106,7 +118,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, }; \ static struct _ddebug __aligned(8) \ __section("__dyndbgs") name = { \ - .site = &name##_site, \ + SITE_INIT_(name##_site) \ .format = (fmt), \ .lineno = __LINE__, \ .flags = _DPRINTK_FLAGS_DEFAULT, \ @@ -144,7 +156,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, /* The header initializations as a distinguishing predicate */ #define is_dyndbg_header_pair(iter, sitep) \ - (sitep == iter->site \ + (SITE_COND(iter, sitep) \ && (!iter->lineno) \ && (iter->format == sitep->modname) \ && (sitep->modname == sitep->function) \ diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 9a089b8d2ccd..f333fcb6cf1f 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -151,7 +151,7 @@ static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp) struct _ddebug *dh = dp - (dp->_index); WARN_ON(!is_dyndbg_header_pair(dh, dh->site)); - +#ifdef SITE_CHK if (dp >= __start___dyndbg && dp < __stop___dyndbg) { v5pr_info("get: %s is builtin: %d %s:%s:%d\n", @@ -177,6 +177,9 @@ static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp) WARN_ON(&dh->site[dp->_index] != dp->site); return dp->site; +#else + return &dh->site[dp->_index]; +#endif } static inline void ddebug_site_put(struct _ddebug *dp) { @@ -241,6 +244,7 @@ static void ddebug_alter_site(struct _ddebug *dp, } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT) static_branch_enable(&dp->key.dd_key_true); #endif +#ifdef SITE_CHK /* delete site info for this callsite */ if (modifiers->flags & _DPRINTK_FLAGS_DELETE_SITE) { if (dp->site) { @@ -249,6 +253,7 @@ static void ddebug_alter_site(struct _ddebug *dp, dp->site = NULL; } } +#endif } /* @@ -1073,7 +1078,9 @@ static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites, v3pr_info(" header: %d %s.%s.%d\n", tab[0]._index, modname, tab[0].site->function, tab[0].lineno); - WARN_ON(tab[0].site != &sites[0]); + + SITE_CHK_(BUG_ON(tab[0].site != &sites[0])); + if (numdbgs <= 1) { v3pr_info(" skip header %s\n", modname); return 0; @@ -1251,7 +1258,7 @@ static int __init dynamic_debug_init(void) for (i = 0; iter < __stop___dyndbg; iter++, site++, i++) { - WARN_ON(site != iter->site); + SITE_CHK_(WARN_ON(site != iter->site)); if (strcmp(modname, site->modname)) { modct++; -- 2.31.1
|  |