From patchwork Sun Feb 25 15:17:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13570859 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A42EA1B7FC; Sun, 25 Feb 2024 15:18:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708874284; cv=none; b=SFVRzyL5FuR/wUXmGmdEkZoTz2AXnKeTS9OXNlJ9QADvEuWz+BMKG2VaYE8ufJlX+vnV/UH0wdLnLV4HbC0goHY7Kw0alp+q9dMGaV04D0ine93hn/b6KLocAoQboGdNeibhyjDnsfg+3w2gfOluB2EHgivxlKiAxmR/hhD6m7A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708874284; c=relaxed/simple; bh=5ZU6O1yZKo2WgktQxSz1C2P+0dzB3kSfvhbv8qkb5cU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=YYsZ2r+dUSwDO8CViKWO+EJW7MHhrPElBflLc7JA8rQK/g+5dGjUcfIC05FQtclgmUDVRdgNVtGrfgEAchgAd2GZTx8TUNKLU0UOyvVRaMzXztbrznTKkZGYEqM2EN/bZXvaC1VWQ0JvVm/Xj4KXmzbuBvzzf6vyJw84G532W68= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P3Smd3zE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P3Smd3zE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E93ADC433F1; Sun, 25 Feb 2024 15:18:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708874284; bh=5ZU6O1yZKo2WgktQxSz1C2P+0dzB3kSfvhbv8qkb5cU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P3Smd3zEvzUnYipzPvMZUKVVbktOK2kiBhXiqldlc2+TNuYRcZgLfv3LtYJ0oLetu /Ehp6CyEzxcj3CYlX/iCzFThmVMyyOU9n2mYnq1cIqTCPUZw08YijD/WP8WPsM5fPj rlXOPL0CY+AP/DbnH7PdotdWwYzUYhP/Rmlx25r+eaBrYLUz+sbFqtwewf8Kiti6J1 x+yN3sDQOfbJH7E8jTuZK7bOQ/jt1FlBaPLJLx6TGC1PsiGeIED9MyxrzmGlUbWT92 ukCwX0tWVYM2Us++bckeON4MM0hEJ9NiwMyPaBF0c8ZZNW3movtQK1C5k/t+ITDK1i 2y/7ugJukzY0Q== From: "Masami Hiramatsu (Google)" To: Alexei Starovoitov , Steven Rostedt , Florent Revest Cc: linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Guo Ren Subject: [PATCH v8 16/35] function_graph: Move graph depth stored data to shadow stack global var Date: Mon, 26 Feb 2024 00:17:58 +0900 Message-Id: <170887427875.564249.12987947642912987283.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <170887410337.564249.6360118840946697039.stgit@devnote2> References: <170887410337.564249.6360118840946697039.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt (VMware) The use of the task->trace_recursion for the logic used for the function graph depth was a bit of an abuse of that variable. Now that there exists global vars that are per stack for registered graph traces, use that instead. Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Masami Hiramatsu (Google) --- include/linux/trace_recursion.h | 29 ----------------------------- kernel/trace/trace.h | 34 ++++++++++++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 31 deletions(-) diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h index 2efd5ec46d7f..00e792bf148d 100644 --- a/include/linux/trace_recursion.h +++ b/include/linux/trace_recursion.h @@ -44,25 +44,6 @@ enum { */ TRACE_IRQ_BIT, - /* - * In the very unlikely case that an interrupt came in - * at a start of graph tracing, and we want to trace - * the function in that interrupt, the depth can be greater - * than zero, because of the preempted start of a previous - * trace. In an even more unlikely case, depth could be 2 - * if a softirq interrupted the start of graph tracing, - * followed by an interrupt preempting a start of graph - * tracing in the softirq, and depth can even be 3 - * if an NMI came in at the start of an interrupt function - * that preempted a softirq start of a function that - * preempted normal context!!!! Luckily, it can't be - * greater than 3, so the next two bits are a mask - * of what the depth is when we set TRACE_GRAPH_FL - */ - - TRACE_GRAPH_DEPTH_START_BIT, - TRACE_GRAPH_DEPTH_END_BIT, - /* * To implement set_graph_notrace, if this bit is set, we ignore * function graph tracing of called functions, until the return @@ -78,16 +59,6 @@ enum { #define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(1<<(bit)); } while (0) #define trace_recursion_test(bit) ((current)->trace_recursion & (1<<(bit))) -#define trace_recursion_depth() \ - (((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3) -#define trace_recursion_set_depth(depth) \ - do { \ - current->trace_recursion &= \ - ~(3 << TRACE_GRAPH_DEPTH_START_BIT); \ - current->trace_recursion |= \ - ((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT; \ - } while (0) - #define TRACE_CONTEXT_BITS 4 #define TRACE_FTRACE_START TRACE_FTRACE_BIT diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index d5501b1a10a6..d8cdcbb4e5a6 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -899,8 +899,38 @@ extern void free_fgraph_ops(struct trace_array *tr); enum { TRACE_GRAPH_FL = 1, + + /* + * In the very unlikely case that an interrupt came in + * at a start of graph tracing, and we want to trace + * the function in that interrupt, the depth can be greater + * than zero, because of the preempted start of a previous + * trace. In an even more unlikely case, depth could be 2 + * if a softirq interrupted the start of graph tracing, + * followed by an interrupt preempting a start of graph + * tracing in the softirq, and depth can even be 3 + * if an NMI came in at the start of an interrupt function + * that preempted a softirq start of a function that + * preempted normal context!!!! Luckily, it can't be + * greater than 3, so the next two bits are a mask + * of what the depth is when we set TRACE_GRAPH_FL + */ + + TRACE_GRAPH_DEPTH_START_BIT, + TRACE_GRAPH_DEPTH_END_BIT, }; +static inline unsigned long ftrace_graph_depth(unsigned long *task_var) +{ + return (*task_var >> TRACE_GRAPH_DEPTH_START_BIT) & 3; +} + +static inline void ftrace_graph_set_depth(unsigned long *task_var, int depth) +{ + *task_var &= ~(3 << TRACE_GRAPH_DEPTH_START_BIT); + *task_var |= (depth & 3) << TRACE_GRAPH_DEPTH_START_BIT; +} + #ifdef CONFIG_DYNAMIC_FTRACE extern struct ftrace_hash __rcu *ftrace_graph_hash; extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash; @@ -933,7 +963,7 @@ ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace) * when the depth is zero. */ *task_var |= TRACE_GRAPH_FL; - trace_recursion_set_depth(trace->depth); + ftrace_graph_set_depth(task_var, trace->depth); /* * If no irqs are to be traced, but a set_graph_function @@ -958,7 +988,7 @@ ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace unsigned long *task_var = fgraph_get_task_var(gops); if ((*task_var & TRACE_GRAPH_FL) && - trace->depth == trace_recursion_depth()) + trace->depth == ftrace_graph_depth(task_var)) *task_var &= ~TRACE_GRAPH_FL; }