From patchwork Mon Apr 15 12:50:32 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: 13629921 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 D200912E1D9; Mon, 15 Apr 2024 12:50:38 +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=1713185438; cv=none; b=orJDddiEJHA9zQ07UJ6p6w1/vOk0XhSfjDdn5MHx1ih2/NS8oGDXs214Q91T1jEjZVfEhY+Sn+CgzcNV7UJYJ27ExUgSEQrE3Q85jcPS/jhzd2731htqMdHO6QALmc/aMM8bR3j33qS+sqNOHczpFDBd6u7qUBE5RC7dCCfYA4Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713185438; c=relaxed/simple; bh=OxU5Qdy/S03nyrb3IpkyfdM0xFyVAyEfc31WiC4iEWM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=XRPt4or0um+hcxXhts5Kc6q1WW/fk4uya0CGRmFAm3OKS6wZgxMTEwaBHL5H+SMAKS2sDrBhdAyLR+4f55EpShIzLrT+2Y+2ByDZrnh795OJhkNySR/PI10MRiHin3FL97/HRhQrXEOletgfjv9GsKxk9su3Yk9jYz3dAE87xiU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hQqenmxx; 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="hQqenmxx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 779B2C32783; Mon, 15 Apr 2024 12:50:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713185438; bh=OxU5Qdy/S03nyrb3IpkyfdM0xFyVAyEfc31WiC4iEWM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hQqenmxxG9cLKAMPWbG2hcvJ9hjThCprSmDU0Avm9cbqwR7clBKyFS744+hlVYyNY WLUGiMVk46URjDsrBJ0WEOFkkHIV8uup43yuBYt5i7VaHEb0KRW4URMGoz4kTT0T7C o4iYgHGJ4mYZ4tWop6ZJVh5+0+bYqtk4ImSHrAg/XETFV5uT8MZ3Cd8zcL/0MF6zWt KVkNaMeq98DZPwJ3YoCYz4yD8X8hoOkgqdqO0qLD1GA51PupfkTgWK6K4QQPPiKO6m kiBdR6SCFHSkhEuqhQQIxUsjeFtGc+dkSfEvNxpHa9EuH1tt/80elQYCIaDqSwj3ki 4FF55HS80nMAg== 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 v9 08/36] function_graph: Remove logic around ftrace_graph_entry and return Date: Mon, 15 Apr 2024 21:50:32 +0900 Message-Id: <171318543205.254850.1420437462860854437.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <171318533841.254850.15841395205784342850.stgit@devnote2> References: <171318533841.254850.15841395205784342850.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 function pointers ftrace_graph_entry and ftrace_graph_return are no longer called via the function_graph tracer. Instead, an array structure is now used that will allow for multiple users of the function_graph infrastructure. The variables are still used by the architecture code for non dynamic ftrace configs, where a test is made against them to see if they point to the default stub function or not. This is how the static function tracing knows to call into the function graph tracer infrastructure or not. Two new stub functions are made. entry_run() and return_run(). The ftrace_graph_entry and ftrace_graph_return are set to them respectively when the function graph tracer is enabled, and this will trigger the architecture specific function graph code to be executed. This also requires checking the global_ops hash for all calls into the function_graph tracer. Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Masami Hiramatsu (Google) --- Changes in v2: - Fix typo and make lines shorter than 76 chars in the description. - Remove unneeded return from return_run() function. --- kernel/trace/fgraph.c | 67 +++++++++------------------------------- kernel/trace/ftrace.c | 2 - kernel/trace/ftrace_internal.h | 2 - 3 files changed, 15 insertions(+), 56 deletions(-) diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index b9a2399b75ee..6f3ba8e113c1 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -145,6 +145,17 @@ add_fgraph_index_bitmap(struct task_struct *t, int offset, unsigned long bitmap) t->ret_stack[offset] |= (bitmap << FGRAPH_INDEX_SHIFT); } +/* ftrace_graph_entry set to this to tell some archs to run function graph */ +static int entry_run(struct ftrace_graph_ent *trace) +{ + return 0; +} + +/* ftrace_graph_return set to this to tell some archs to run function graph */ +static void return_run(struct ftrace_graph_ret *trace) +{ +} + /* * @offset: The index into @t->ret_stack to find the ret_stack entry * @index: Where to place the index into @t->ret_stack of that entry @@ -675,7 +686,6 @@ extern void ftrace_stub_graph(struct ftrace_graph_ret *); /* The callbacks that hook a function */ trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph; trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; -static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub; /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ static int alloc_retstack_tasklist(unsigned long **ret_stack_list) @@ -758,46 +768,6 @@ ftrace_graph_probe_sched_switch(void *ignore, bool preempt, } } -static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) -{ - if (!ftrace_ops_test(&global_ops, trace->func, NULL)) - return 0; - return __ftrace_graph_entry(trace); -} - -/* - * The function graph tracer should only trace the functions defined - * by set_ftrace_filter and set_ftrace_notrace. If another function - * tracer ops is registered, the graph tracer requires testing the - * function against the global ops, and not just trace any function - * that any ftrace_ops registered. - */ -void update_function_graph_func(void) -{ - struct ftrace_ops *op; - bool do_test = false; - - /* - * The graph and global ops share the same set of functions - * to test. If any other ops is on the list, then - * the graph tracing needs to test if its the function - * it should call. - */ - do_for_each_ftrace_op(op, ftrace_ops_list) { - if (op != &global_ops && op != &graph_ops && - op != &ftrace_list_end) { - do_test = true; - /* in double loop, break out with goto */ - goto out; - } - } while_for_each_ftrace_op(op); - out: - if (do_test) - ftrace_graph_entry = ftrace_graph_entry_test; - else - ftrace_graph_entry = __ftrace_graph_entry; -} - static DEFINE_PER_CPU(unsigned long *, idle_ret_stack); static void @@ -939,18 +909,12 @@ int register_ftrace_graph(struct fgraph_ops *gops) ftrace_graph_active--; goto out; } - - ftrace_graph_return = gops->retfunc; - /* - * Update the indirect function to the entryfunc, and the - * function that gets called to the entry_test first. Then - * call the update fgraph entry function to determine if - * the entryfunc should be called directly or not. + * Some archs just test to see if these are not + * the default function */ - __ftrace_graph_entry = gops->entryfunc; - ftrace_graph_entry = ftrace_graph_entry_test; - update_function_graph_func(); + ftrace_graph_return = return_run; + ftrace_graph_entry = entry_run; ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); } @@ -986,7 +950,6 @@ void unregister_ftrace_graph(struct fgraph_ops *gops) if (!ftrace_graph_active) { ftrace_graph_return = ftrace_stub_graph; ftrace_graph_entry = ftrace_graph_entry_stub; - __ftrace_graph_entry = ftrace_graph_entry_stub; ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index da1710499698..fef833f63647 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -235,8 +235,6 @@ static void update_ftrace_function(void) func = ftrace_ops_list_func; } - update_function_graph_func(); - /* If there's no change, then do nothing more here */ if (ftrace_trace_function == func) return; diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h index 5012c04f92c0..19eddcb91584 100644 --- a/kernel/trace/ftrace_internal.h +++ b/kernel/trace/ftrace_internal.h @@ -42,10 +42,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) #ifdef CONFIG_FUNCTION_GRAPH_TRACER extern int ftrace_graph_active; -void update_function_graph_func(void); #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ # define ftrace_graph_active 0 -static inline void update_function_graph_func(void) { } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ #else /* !CONFIG_FUNCTION_TRACER */