From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 07EDF130499; Tue, 23 Jul 2024 01:40:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721698828; cv=none; b=ltNGnAa/3dOSqps7pwl50g4wiz3hNnVz1lOwcnaeyg8vLN2GKXduCUZV5JnwU2hSOuZkZ5F+7gNy0AaDCbaeydp63J5qX8Q6WPEcKPsmPC60SqpLqYLz7l6tye6ukqbcQR4ra0QnEBW5KNFQGqQcseTJc5gm/cSqDu/3/fmm8O0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721698828; c=relaxed/simple; bh=sVjvHNuUXm641spj6PIypEZZtH0+lkWxhOlwvo3ea5o=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=dHlGaQ9Cui0a7EpawvUTOki9AdF5Uq9tNNl7KoLPWiTu63On7IWufa+MyZ9XX9qrFTPUE0I6lH/XlJEf6BFFHF3qnO9PDw3j20dJH5UueGtWBTk6gKnCJUYn/3AGyRr64ajrDchw6GOF0zIK3j3nB8M4jvUcRWriXqxG6Ong1i8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4WSfth5z5rzdjqy; Tue, 23 Jul 2024 09:38:36 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 46DA818005F; Tue, 23 Jul 2024 09:40:23 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 23 Jul 2024 09:40:22 +0800 Message-ID: Date: Tue, 23 Jul 2024 09:40:21 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH v3 2/2] riscv: stacktrace: Add USER_STACKTRACE support Content-Language: en-US To: , , , , , , , , , , , , , , , , , , References: <20240708032847.2998158-1-ruanjinjie@huawei.com> <20240708032847.2998158-3-ruanjinjie@huawei.com> From: Jinjie Ruan In-Reply-To: <20240708032847.2998158-3-ruanjinjie@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemi100008.china.huawei.com (7.221.188.57) On 2024/7/8 11:28, Jinjie Ruan wrote: > Currently, userstacktrace is unsupported for riscv. So use the > perf_callchain_user() code as blueprint to implement the > arch_stack_walk_user() which add userstacktrace support on riscv. > Meanwhile, we can use arch_stack_walk_user() to simplify the implementation > of perf_callchain_user(). > > A ftrace test case is shown as below: > > # cd /sys/kernel/debug/tracing > # echo 1 > options/userstacktrace > # echo 1 > options/sym-userobj > # echo 1 > events/sched/sched_process_fork/enable > # cat trace > ...... > bash-178 [000] ...1. 97.968395: sched_process_fork: comm=bash pid=178 child_comm=bash child_pid=231 > bash-178 [000] ...1. 97.970075: > => /lib/libc.so.6[+0xb5090] > > Also a simple perf test is ok as below: > > # perf record -e cpu-clock --call-graph fp top > # perf report --call-graph > > ..... > [[31m 66.54%[[m 0.00% top [kernel.kallsyms] [k] ret_from_exception > | > ---ret_from_exception > | > |--[[31m58.97%[[m--do_trap_ecall_u > | | > | |--[[31m17.34%[[m--__riscv_sys_read > | | ksys_read > | | | > | | --[[31m16.88%[[m--vfs_read > | | | > | | |--[[31m10.90%[[m--seq_read Gentle ping. > > Signed-off-by: Jinjie Ruan > Tested-by: Jinjie Ruan > Cc: Björn Töpel > --- > v3: > - Remove the LTP message as Björn suggested. > - Keep fp 16-bytes aligned in arch_stack_walk_user(). > - Add the test info. > v2: > - Fix the cocci warning, !A || A && B is equivalent to !A || B. > --- > --- > arch/riscv/Kconfig | 1 + > arch/riscv/kernel/perf_callchain.c | 46 ++---------------------------- > arch/riscv/kernel/stacktrace.c | 43 ++++++++++++++++++++++++++++ > 3 files changed, 47 insertions(+), 43 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 3b44e7b51436..46121dbcf750 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -194,6 +194,7 @@ config RISCV > select THREAD_INFO_IN_TASK > select TRACE_IRQFLAGS_SUPPORT > select UACCESS_MEMCPY if !MMU > + select USER_STACKTRACE_SUPPORT > select ZONE_DMA32 if 64BIT > > config CLANG_SUPPORTS_DYNAMIC_FTRACE > diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c > index 2932791e9388..c7468af77c66 100644 > --- a/arch/riscv/kernel/perf_callchain.c > +++ b/arch/riscv/kernel/perf_callchain.c > @@ -6,37 +6,9 @@ > > #include > > -/* > - * Get the return address for a single stackframe and return a pointer to the > - * next frame tail. > - */ > -static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, > - unsigned long fp, unsigned long reg_ra) > +static bool fill_callchain(void *entry, unsigned long pc) > { > - struct stackframe buftail; > - unsigned long ra = 0; > - unsigned long __user *user_frame_tail = > - (unsigned long __user *)(fp - sizeof(struct stackframe)); > - > - /* Check accessibility of one struct frame_tail beyond */ > - if (!access_ok(user_frame_tail, sizeof(buftail))) > - return 0; > - if (__copy_from_user_inatomic(&buftail, user_frame_tail, > - sizeof(buftail))) > - return 0; > - > - if (reg_ra != 0) > - ra = reg_ra; > - else > - ra = buftail.ra; > - > - fp = buftail.fp; > - if (ra != 0) > - perf_callchain_store(entry, ra); > - else > - return 0; > - > - return fp; > + return perf_callchain_store(entry, pc) == 0; > } > > /* > @@ -56,19 +28,7 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, > void perf_callchain_user(struct perf_callchain_entry_ctx *entry, > struct pt_regs *regs) > { > - unsigned long fp = 0; > - > - fp = regs->s0; > - perf_callchain_store(entry, regs->epc); > - > - fp = user_backtrace(entry, fp, regs->ra); > - while (fp && !(fp & 0x7) && entry->nr < entry->max_stack) > - fp = user_backtrace(entry, fp, 0); > -} > - > -static bool fill_callchain(void *entry, unsigned long pc) > -{ > - return perf_callchain_store(entry, pc) == 0; > + arch_stack_walk_user(fill_callchain, entry, regs); > } > > void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c > index 0d3f00eb0bae..5480cc11b523 100644 > --- a/arch/riscv/kernel/stacktrace.c > +++ b/arch/riscv/kernel/stacktrace.c > @@ -161,3 +161,46 @@ noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry, void > { > walk_stackframe(task, regs, consume_entry, cookie); > } > + > +/* > + * Get the return address for a single stackframe and return a pointer to the > + * next frame tail. > + */ > +static unsigned long unwind_user_frame(stack_trace_consume_fn consume_entry, > + void *cookie, unsigned long fp, > + unsigned long reg_ra) > +{ > + struct stackframe buftail; > + unsigned long ra = 0; > + unsigned long __user *user_frame_tail = > + (unsigned long __user *)(fp - sizeof(struct stackframe)); > + > + /* Check accessibility of one struct frame_tail beyond */ > + if (!access_ok(user_frame_tail, sizeof(buftail))) > + return 0; > + if (__copy_from_user_inatomic(&buftail, user_frame_tail, > + sizeof(buftail))) > + return 0; > + > + ra = reg_ra ? : buftail.ra; > + > + fp = buftail.fp; > + if (!ra || !consume_entry(cookie, ra)) > + return 0; > + > + return fp; > +} > + > +void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, > + const struct pt_regs *regs) > +{ > + unsigned long fp = 0; > + > + fp = regs->s0; > + if (!consume_entry(cookie, regs->epc)) > + return; > + > + fp = unwind_user_frame(consume_entry, cookie, fp, regs->ra); > + while (fp && !(fp & 0x7)) > + fp = unwind_user_frame(consume_entry, cookie, fp, 0); > +}