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[24.9.77.57]) by smtp.googlemail.com with ESMTPSA id t10sm405096ils.36.2021.05.11.11.51.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 May 2021 11:51:52 -0700 (PDT) From: Jim Cromie To: Jason Baron , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Jim Cromie Subject: [RFC PATCH v5 24/28] dyndbg: make site pointer and checks on it optional (not quite) Date: Tue, 11 May 2021 12:50:53 -0600 Message-Id: <20210511185057.3815777-25-jim.cromie@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210511185057.3815777-1-jim.cromie@gmail.com> References: <20210511185057.3815777-1-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Wrap declaration and uses of _ddebug.site pointer in ifdefs. Mostly, this eliminates all the WARN_ONs in ddebug_site_get(), which seem to be mostly proven (they were BUG_ONs). This adds macro indirection around ifdef SITE_CHK; adding SITE_INIT_ to adjust the .site initializations, and SITE_COND, which abstracts a logic test used by is_dyndbg_header_pair(i,s). TODO: breaks when !defined SITE_CHK - the header, being just a struct _ddebug, also lost the .site member. Need to specialize the header struct, then unionize it back in. Signed-off-by: Jim Cromie --- include/linux/dynamic_debug.h | 20 ++++++++++++++++---- lib/dynamic_debug.c | 13 ++++++++++--- 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 06ae1d8d8c10..46901b5348ee 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -6,6 +6,18 @@ #include #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("__dyndbg") name = { \ - .site = &name##_site, \ + SITE_INIT_(name##_site) \ .format = (fmt), \ .lineno = __LINE__, \ .flags = _DPRINTK_FLAGS_DEFAULT, \ @@ -138,13 +150,13 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, __weak struct _ddebug __used __aligned(8) \ __section(".gnu.linkonce.dyndbg") \ _LINKONCE_dyndbg_header = { \ - .site = &_LINKONCE_dyndbg_site_header, \ + SITE_INIT_(_LINKONCE_dyndbg_site_header) \ .format = KBUILD_MODNAME \ } /* 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 b83187e72ee0..9551c0d406b6 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