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[24.9.77.57]) by smtp.googlemail.com with ESMTPSA id c18sm1843446iod.18.2022.01.06.21.30.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jan 2022 21:30:11 -0800 (PST) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, linux@rasmusvillemoes.dk, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: quic_saipraka@quicinc.com, will@kernel.org, catalin.marinas@arm.com, quic_psodagud@quicinc.com, maz@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, mingo@redhat.com, jim.cromie@gmail.com Subject: [PATCH v11 18/19] dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks Date: Thu, 6 Jan 2022 22:29:41 -0700 Message-Id: <20220107052942.1349447-19-jim.cromie@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220107052942.1349447-1-jim.cromie@gmail.com> References: <20220107052942.1349447-1-jim.cromie@gmail.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220106_213012_997763_7076BD7B X-CRM114-Status: GOOD ( 23.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, classes..) allows users to create a drm.debug style (bitmap) sysfs interface, to control sets of pr_debug's according to their .class_id's 1st, due to a recent commit, this already works: echo "module drm class 1 +p ; module drm class 3 +p" >control With the macro, this is basically equivalent: # this also turns off all other classes. echo 0x05 > /sys/module/drm/parameters/debug To use: DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "drm.debug - bits => categories:", /* vector of uint:4 symbols, ala enum drm_debug_category */ DRM_UT_CORE, DRM_UT_DRIVER, DRM_UT_KMS ... ); To support the macro, the patch includes: - int param_set_dyndbg_classbits() - int param_get_dyndbg_classbits() - struct kernel_param_ops param_ops_dyndbg_classbits Following the model of kernel/params.c STANDARD_PARAM_DEFS, these are non-static and exported. get/set use an augmented kernel_param; the arg refs a new struct dyndbg_bitmap_param containing: A- the vector of classes (drm.debug "categories") being controlled For CONFIG_DRM_USE_DYNDBG=y, enum drm_debug_category is initialized into (struct _ddebug).class_id, so its already available to select on. B- a pointer to the user module's ulong holding the bits/state. By sharing bit-state in __drm_debug, we coordinate with existing code that still uses drm_debug_enabled(), so they work unchanged. NOTES: param_set_dyndbg_classbits() compares new vs old bits, and only updates each class on changes. This maximally preserves the underlying state, which may have been customized via later `echo $cmd >control`. So if a user really wants to know that all prdbgs are set precisely, they must pre-clear then set. Signed-off-by: Jim Cromie --- include/linux/dynamic_debug.h | 45 ++++++++++++++++++++- lib/dynamic_debug.c | 75 +++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+), 1 deletion(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index e9483cd9ac1c..318ac44a0d4a 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -20,7 +20,9 @@ struct _ddebug { const char *function; const char *filename; const char *format; - unsigned int class_id:4; +#define CLS_BITS 4 +#define DD_MAX_CLASSES (1 << CLS_BITS) + unsigned int class_id:CLS_BITS; unsigned int lineno:18; /* * The flags field controls the behaviour at the callsite. @@ -202,6 +204,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, KERN_DEBUG, prefix_str, prefix_type, \ rowsize, groupsize, buf, len, ascii) +struct kernel_param; +int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp); +int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp); + #else /* !CONFIG_DYNAMIC_DEBUG_CORE */ #include @@ -248,6 +254,43 @@ static inline int dynamic_debug_exec_queries(const char *query, const char *modn return 0; } +struct kernel_param; +static inline int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp) +{ return 0; } +static inline int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp) +{ return 0; } + #endif /* !CONFIG_DYNAMIC_DEBUG_CORE */ +struct dyndbg_classbits_param { + unsigned long *bits; /* ref to shared state */ + const int classes[]; /* indexed by bitpos */ +}; + +#if defined(CONFIG_DYNAMIC_DEBUG) || defined(CONFIG_DYNAMIC_DEBUG_CORE) +/** + * DEFINE_DYNAMIC_DEBUG_CLASSBITS() - bitmap control of classed pr_debugs + * @sysname: sysfs-node name + * @_var: C-identifier holding bit-vector (Bits 0-15 are usable) + * @desc: string summarizing the controls provided + * @classes: vector of callsite.class_id's (uint:4, 0 is reserved) + * + * This macro implements a DRM.debug API style bitmap, mapping bits + * 0-15 to classes of prdbg's, as initialized in their .class_id fields. + */ +#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, _var, desc, ...) \ + MODULE_PARM_DESC(fsname, desc); \ + static struct dyndbg_classbits_param ddcats_##_var = { \ + .bits = &(_var), .classes = { __VA_ARGS__, 0 } }; \ + module_param_cb(fsname, ¶m_ops_dyndbg_classbits, &ddcats_##_var, 0644) + +extern const struct kernel_param_ops param_ops_dyndbg_classbits; + +#else /* no dyndbg configured, throw error on macro use */ + +#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, ...) \ + BUILD_BUG_ON_MSG(1, "CONFIG_DYNAMIC_DEBUG|_CORE && -DDYNAMIC_DEBUG_MODULE needed to use this macro: " #fsname #var) + +#endif + #endif diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 419d4664e724..40ca7973a0f8 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -610,6 +610,81 @@ int dynamic_debug_exec_queries(const char *query, const char *modname) } EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries); +#ifdef CONFIG_MODULES +#define KP_MOD_NAME kp->mod->name +#else +#define KP_MOD_NAME NULL /* wildcard */ +#endif +#define FMT_QUERY_SIZE 128 /* typically need <40 */ +/** + * param_set_dyndbg_classbits - bits => categories >control setter + * @instr: string echo>d to sysfs + * @kp: kp->arg has state: bits, map + * + * Enable/disable prdbgs by their "category", as specified in the + * DEFINE_DYNAMIC_DEBUG_BITGRPS.classbits argument. + * + * Returns: 0 or <0 if error. + */ +int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp) +{ + unsigned long inbits; + int rc, i, matches = 0, totct = 0; + char query[FMT_QUERY_SIZE]; + const struct dyndbg_classbits_param *dcp = kp->arg; + + if (dcp) { + pr_err("set_dyndbg_classbits: no bits=>queries map\n"); + return -EINVAL; + } + rc = kstrtoul(instr, 0, &inbits); + if (rc) { + pr_err("set_dyndbg_classbits: expecting unsigned int\n"); + return rc; + } + vpr_info("set_dyndbg_classbits: new 0x%lx old 0x%lx\n", inbits, *dcp->bits); + + for (i = 0; i < DD_MAX_CLASSES && dcp->classes[i]; i++) { + if (test_bit(i, &inbits) == test_bit(i, dcp->bits)) + continue; + snprintf(query, FMT_QUERY_SIZE, "class %d %cT", dcp->classes[i], + test_bit(i, &inbits) ? '+' : '-'); + + matches = ddebug_exec_queries(query, KP_MOD_NAME); + + v2pr_info("bit-%d: %d matches on class:%u\n", i, + matches, dcp->classes[i]); + totct += matches; + } + *dcp->bits = inbits; + vpr_info("total matches: %d\n", totct); + return 0; +} +EXPORT_SYMBOL(param_set_dyndbg_classbits); + +/** + * param_get_dyndbg_classbits - classbits reader + * @buffer: string description of controlled bits -> classes + * @kp: kp->arg has state: bits, map + * + * Reads last written bits, underlying prdbg state may have changed since. + * Returns: #chars written or <0 on error + */ +int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp) +{ + const struct dyndbg_classbits_param *p = kp->arg; + unsigned long val = *p->bits; + + return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", val); +} +EXPORT_SYMBOL(param_get_dyndbg_classbits); + +const struct kernel_param_ops param_ops_dyndbg_classbits = { + .set = param_set_dyndbg_classbits, + .get = param_get_dyndbg_classbits, +}; +EXPORT_SYMBOL(param_ops_dyndbg_classbits); + #define PREFIX_SIZE 64 static int remaining(int wrote)