From patchwork Mon May 16 22:56:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Cromie X-Patchwork-Id: 12851600 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1F50C433F5 for ; Mon, 16 May 2022 22:58:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349987AbiEPW6G (ORCPT ); Mon, 16 May 2022 18:58:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350057AbiEPW5f (ORCPT ); Mon, 16 May 2022 18:57:35 -0400 Received: from mail-io1-xd29.google.com (mail-io1-xd29.google.com [IPv6:2607:f8b0:4864:20::d29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A9A044772; Mon, 16 May 2022 15:57:32 -0700 (PDT) Received: by mail-io1-xd29.google.com with SMTP id m6so17635985iob.4; Mon, 16 May 2022 15:57:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=caFoAHAZrN6Nrr5FNeRmlwujqgilZpBF2BSLNzuccOo=; b=NinNvSUN/V7+ZBcOy7kFMOYb2ewqtyqY6O7HWY3BR6FV7Yhj9jnrpeooDnoAcckWIr ELrZbo+4SuvVcAbWbb+xUAL306VSI3QFk6P2p3HXVez72y347OrXoSSKXNosPuUIP+67 r6swfAiLyWz75WRG32WMwXcJ6C33jUFVgQtXkikEfYfA3YG8jpZxKu4XpBImCxI5UNmO UQVXa/N1t8AxBA65WVkCUgRmxqoq8aWSlc1tiWE3HbLH4t8OVTa1Xk8keeXy0JU23E8P FdF6AAajZkc7+S635APfipItn1/LufrGU4CxiBzyrYWiTCMpNCwVvx7yDdGtGyywjj5l smZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=caFoAHAZrN6Nrr5FNeRmlwujqgilZpBF2BSLNzuccOo=; b=SMgqhwabznJE+TdDpfFLOMxCK/FLXuefewjqtkGUZsKR4E9/zEbZqKqE2e7MoHN7Zl rsTcS/qugcTvYLvF00EYgXMqPJek1+mc5aLo/lL73hanVKMhBPRuGH8WKkzNAc9k86eh S81E/QLWxJZFpZby08jA9Fjmvs1KGTEhI6QdNIpIcfkZ3WlYPxa/ZoB7kF12mJwNGkh+ pR+nzUe37z24uL9NWCRCm7Up2A7WQ18JLeFwXT87dcn+rVEq7+uc0bwPAU7UxzxU/1al s+EjUFkJQtW/Q1gorB6A/HKUVARXP7+HpVf1eowEDQJ83MQ4CUAHce9bGek1boSNagRU VsSg== X-Gm-Message-State: AOAM531wzAFfyR9HFtODQvtqdnoIgW6MVcFzrYmURsrH2aXkkzGzm0DI JDmt98o7ICSqB8skl8FJUfQ= X-Google-Smtp-Source: ABdhPJxexOwsRq4mvWcqWxBeARmtX2+64hrtcuD4DHJKBDexKi2pI1LKCe+a949qXkiCGFOgxAz29Q== X-Received: by 2002:a05:6638:19c:b0:32e:fba:fdfe with SMTP id a28-20020a056638019c00b0032e0fbafdfemr7493119jaq.88.1652741852141; Mon, 16 May 2022 15:57:32 -0700 (PDT) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::dd9f]) by smtp.googlemail.com with ESMTPSA id k26-20020a02661a000000b0032b74686763sm3133949jac.76.2022.05.16.15.57.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 15:57:31 -0700 (PDT) From: Jim Cromie To: jbaron@akamai.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: gregkh@linuxfoundation.org, daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, 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, vincent.whitchurch@axis.com Subject: [PATCH v2 25/27] dyndbg: add write-events-to-tracefs code Date: Mon, 16 May 2022 16:56:38 -0600 Message-Id: <20220516225640.3102269-26-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220516225640.3102269-1-jim.cromie@gmail.com> References: <20220516225640.3102269-1-jim.cromie@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org adds: ddebug_trace() uses trace_console() temporarily to issue printk:console event uses internal-ish __ftrace_trace_stack code: 4-context buffer stack, barriers per Steve Rostedt call it from new funcs: ddebug_printk() - print to both syslog/tracefs ddebug_dev_printk() - dev-print to both syslog/tracefs These handle both _DPRINTK_FLAGS_PRINTK and _DPRINTK_FLAGS_TRACE cases, allowing to vsnprintf the message once and use it for both, skipping past the KERN_DEBUG character for tracing. Finally, adjust the callers: __ddebug_{pr_debug,{,net,ib}dev_dbg}, replacing printk and dev_printk with the new funcs above. The _DPRINTK_FLAGS_TRACE flag character is 'T', so the following finds all callsites enabled for tracing: grep -P =p?T /proc/dynamic_debug/control This patch,~1,~2 are basically copies of: https://lore.kernel.org/lkml/20200825153338.17061-1-vincent.whitchurch@axis.com/ with a few differences: - s/dynamic_/ddebug_/ on Vincent's additions - __printf attrs on the _printk funcs - reuses trace_console() event, not adding a new "printk:dyndbg" event. next patch replaces this with 2 new events CC: vincent.whitchurch@axis.com Signed-off-by: Jim Cromie --- .../admin-guide/dynamic-debug-howto.rst | 1 + drivers/gpu/drm/drm_print.c | 4 +- lib/dynamic_debug.c | 156 +++++++++++++++--- 3 files changed, 133 insertions(+), 28 deletions(-) diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 01ca6f635dcc..b8c6772b88ac 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -239,6 +239,7 @@ of the characters:: The flags are:: p enables the pr_debug() callsite. + T enables callsite to issue a dyndbg:* trace-event f Include the function name in the printed message l Include line number in the printed message m Include module name in the printed message diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 77b56399147a..63125a507577 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -280,11 +280,11 @@ void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev, vaf.va = &args; if (dev) { - if (desc->flags && _DPRINTK_FLAGS_PRINTK) + if (desc->flags & _DPRINTK_FLAGS_PRINTK) dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf); } else { - if (desc->flags && _DPRINTK_FLAGS_PRINTK) + if (desc->flags & _DPRINTK_FLAGS_PRINTK) printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf); } diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 5682ee477677..81cfe6e21d15 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -36,6 +36,7 @@ #include #include #include +#include #include @@ -88,6 +89,7 @@ static inline const char *trim_prefix(const char *path) static struct { unsigned flag:8; char opt_char; } opt_array[] = { { _DPRINTK_FLAGS_PRINTK, 'p' }, + { _DPRINTK_FLAGS_TRACE, 'T' }, { _DPRINTK_FLAGS_INCL_MODNAME, 'm' }, { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' }, { _DPRINTK_FLAGS_INCL_LINENO, 'l' }, @@ -770,6 +772,98 @@ static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf) return buf; } +/* + * This code is heavily based on __ftrace_trace_stack(). + * + * Allow 4 levels of nesting: normal, softirq, irq, NMI. + */ +#define DYNAMIC_TRACE_NESTING 4 + +struct ddebug_trace_buf { + char buf[256]; +}; + +struct ddebug_trace_bufs { + struct ddebug_trace_buf bufs[DYNAMIC_TRACE_NESTING]; +}; + +static DEFINE_PER_CPU(struct ddebug_trace_bufs, ddebug_trace_bufs); +static DEFINE_PER_CPU(int, ddebug_trace_reserve); + +static void ddebug_trace(const char *fmt, va_list args) +{ + struct ddebug_trace_buf *buf; + int bufidx; + int len; + + preempt_disable_notrace(); + + bufidx = __this_cpu_inc_return(ddebug_trace_reserve) - 1; + + if (WARN_ON_ONCE(bufidx > DYNAMIC_TRACE_NESTING)) + goto out; + + /* For the same reasons as in __ftrace_trace_stack(). */ + barrier(); + + buf = this_cpu_ptr(ddebug_trace_bufs.bufs) + bufidx; + + len = vscnprintf(buf->buf, sizeof(buf->buf), fmt, args); + trace_console(buf->buf, len); + +out: + /* As above. */ + barrier(); + __this_cpu_dec(ddebug_trace_reserve); + preempt_enable_notrace(); +} + +__printf(2, 3) +static void ddebug_printk(unsigned int flags, const char *fmt, ...) +{ + if (flags & _DPRINTK_FLAGS_TRACE) { + va_list args; + + va_start(args, fmt); + /* + * All callers include the KERN_DEBUG prefix to keep the + * vprintk case simple; strip it out for tracing. + */ + ddebug_trace(fmt + strlen(KERN_DEBUG), args); + va_end(args); + } + + if (flags & _DPRINTK_FLAGS_PRINTK) { + va_list args; + + va_start(args, fmt); + vprintk(fmt, args); + va_end(args); + } +} + +__printf(3, 4) +static void ddebug_dev_printk(unsigned int flags, const struct device *dev, + const char *fmt, ...) +{ + + if (flags & _DPRINTK_FLAGS_TRACE) { + va_list args; + + va_start(args, fmt); + ddebug_trace(fmt, args); + va_end(args); + } + + if (flags & _DPRINTK_FLAGS_PRINTK) { + va_list args; + + va_start(args, fmt); + dev_vprintk_emit(LOGLEVEL_DEBUG, dev, fmt, args); + va_end(args); + } +} + void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) { va_list args; @@ -784,16 +878,18 @@ void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) vaf.fmt = fmt; vaf.va = &args; - printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf); + ddebug_printk(descriptor->flags, KERN_DEBUG "%s%pV", + dynamic_emit_prefix(descriptor, buf), &vaf); va_end(args); } EXPORT_SYMBOL(__dynamic_pr_debug); void __dynamic_dev_dbg(struct _ddebug *descriptor, - const struct device *dev, const char *fmt, ...) + const struct device *dev, const char *fmt, ...) { struct va_format vaf; + unsigned int flags; va_list args; BUG_ON(!descriptor); @@ -803,16 +899,18 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor, vaf.fmt = fmt; vaf.va = &args; + flags = descriptor->flags; if (!dev) { - printk(KERN_DEBUG "(NULL device *): %pV", &vaf); + ddebug_printk(flags, KERN_DEBUG "(NULL device *): %pV", + &vaf); } else { char buf[PREFIX_SIZE] = ""; - dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV", - dynamic_emit_prefix(descriptor, buf), - dev_driver_string(dev), dev_name(dev), - &vaf); + ddebug_dev_printk(flags, dev, "%s%s %s: %pV", + dynamic_emit_prefix(descriptor, buf), + dev_driver_string(dev), dev_name(dev), + &vaf); } va_end(args); @@ -825,6 +923,7 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor, const struct net_device *dev, const char *fmt, ...) { struct va_format vaf; + unsigned int flags; va_list args; BUG_ON(!descriptor); @@ -834,22 +933,24 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor, vaf.fmt = fmt; vaf.va = &args; + flags = descriptor->flags; if (dev && dev->dev.parent) { char buf[PREFIX_SIZE] = ""; - dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent, - "%s%s %s %s%s: %pV", - dynamic_emit_prefix(descriptor, buf), - dev_driver_string(dev->dev.parent), - dev_name(dev->dev.parent), - netdev_name(dev), netdev_reg_state(dev), - &vaf); + ddebug_dev_printk(flags, dev->dev.parent, + "%s%s %s %s%s: %pV", + dynamic_emit_prefix(descriptor, buf), + dev_driver_string(dev->dev.parent), + dev_name(dev->dev.parent), + netdev_name(dev), netdev_reg_state(dev), + &vaf); } else if (dev) { - printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev), - netdev_reg_state(dev), &vaf); + ddebug_printk(flags, KERN_DEBUG "%s%s: %pV", + netdev_name(dev), netdev_reg_state(dev), &vaf); } else { - printk(KERN_DEBUG "(NULL net_device): %pV", &vaf); + ddebug_printk(flags, KERN_DEBUG "(NULL net_device): %pV", + &vaf); } va_end(args); @@ -865,26 +966,29 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, { struct va_format vaf; va_list args; + unsigned int flags; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; + flags = descriptor->flags; if (ibdev && ibdev->dev.parent) { char buf[PREFIX_SIZE] = ""; - dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent, - "%s%s %s %s: %pV", - dynamic_emit_prefix(descriptor, buf), - dev_driver_string(ibdev->dev.parent), - dev_name(ibdev->dev.parent), - dev_name(&ibdev->dev), - &vaf); + ddebug_dev_printk(flags, ibdev->dev.parent, + "%s%s %s %s: %pV", + dynamic_emit_prefix(descriptor, buf), + dev_driver_string(ibdev->dev.parent), + dev_name(ibdev->dev.parent), + dev_name(&ibdev->dev), + &vaf); } else if (ibdev) { - printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf); + ddebug_printk(flags, KERN_DEBUG "%s: %pV", + dev_name(&ibdev->dev), &vaf); } else { - printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf); + ddebug_printk(flags, KERN_DEBUG "(NULL ip_device): %pV", &vaf); } va_end(args);