From patchwork Fri May 17 08:43:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mao Han X-Patchwork-Id: 10947493 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 953181515 for ; Fri, 17 May 2019 08:44:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 826FC212BE for ; Fri, 17 May 2019 08:44:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7681F228C8; Fri, 17 May 2019 08:44:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4332D212BE for ; Fri, 17 May 2019 08:44:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=WtITFHlIWgL3vnrNeTK5KgGrYbFBenHisprNGx3ti+U=; b=cxyVfYdBmYzrZ6DRitQ7x6tyN8 lusAnSt6hkL/2hbp0bAS3prwNU5RnwZLVTfUw1TDX1j3yuu9AucCg6dThGyU+lmwchi9iumqK0hTg tI1R2GW7347YeB+IGOAeCf06CX3B9thhyJ03272kxep/BXF9x598JWJOSHglrQGZMr1kOgDuPMcxf BfKZ7dgpVZFwk4eq+NzZIdGZ2a2JpTXhrid48cDL137b30PHHtnBbbEIWVNbkdNU8LwrFlvTOKUJZ UWxD4NzGpdZkE8OOsLRfwT1MISpquP/OSTP+uffsajR3fJT5p2VOztmNmytWGvF7v6AT8bw2DEUdv YUUWNvDA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hRYTw-0008PM-9f; Fri, 17 May 2019 08:44:48 +0000 Received: from smtp2200-217.mail.aliyun.com ([121.197.200.217]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hRYTs-0008NM-A9 for linux-riscv@lists.infradead.org; Fri, 17 May 2019 08:44:46 +0000 X-Alimail-AntiSpam: AC=CONTINUE; BC=0.07436283|-1; CH=green; DM=CONTINUE|CONTINUE|true|0.692448-0.0313479-0.276204; FP=0|0|0|0|0|-1|-1|-1; HT=e01l01425; MF=han_mao@c-sky.com; NM=1; PH=DS; RN=6; RT=6; SR=0; TI=SMTPD_---.EZL5.tj_1558082676; Received: from localhost(mailfrom:han_mao@c-sky.com fp:SMTPD_---.EZL5.tj_1558082676) by smtp.aliyun-inc.com(10.147.41.137); Fri, 17 May 2019 16:44:36 +0800 From: Mao Han To: linux-kernel@vger.kernel.org Subject: [PATCH V3 1/3] riscv: Add perf callchain support Date: Fri, 17 May 2019 16:43:02 +0800 Message-Id: <58bdfc163926422b6abe7f18a5a995dbc39aaaab.1558081981.git.han_mao@c-sky.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190517_014444_604441_A1E90C53 X-CRM114-Status: GOOD ( 17.88 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-riscv , Palmer Dabbelt , Guo Ren , Christoph Hellwig , Mao Han MIME-Version: 1.0 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+patchwork-linux-riscv=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This patch add support for perf callchain sampling on riscv platform. The return address of leaf function is retrieved from pt_regs as it is not saved in the outmost frame. Signed-off-by: Mao Han CC: Palmer Dabbelt CC: linux-riscv CC: Christoph Hellwig CC: Guo Ren --- arch/riscv/Makefile | 3 + arch/riscv/kernel/Makefile | 3 +- arch/riscv/kernel/perf_callchain.c | 113 +++++++++++++++++++++++++++++++++++++ 3 files changed, 118 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/kernel/perf_callchain.c diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index c6342e6..4396abc 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -59,6 +59,9 @@ endif ifeq ($(CONFIG_MODULE_SECTIONS),y) KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/riscv/kernel/module.lds endif +ifeq ($(CONFIG_PERF_EVENTS),y) + KBUILD_CFLAGS += -fno-omit-frame-pointer +endif KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax) diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 5985681..dd2ba44 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o obj-$(CONFIG_DYNAMIC_FTRACE) += mcount-dyn.o -obj-$(CONFIG_PERF_EVENTS) += perf_event.o +obj-$(CONFIG_PERF_EVENTS) += perf_event.o +obj-$(CONFIG_PERF_EVENTS) += perf_callchain.o clean: diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c new file mode 100644 index 0000000..8b57903 --- /dev/null +++ b/arch/riscv/kernel/perf_callchain.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd. */ + +#include +#include + +/* Kernel callchain */ +struct stackframe { + unsigned long fp; + unsigned long ra; +}; + +static int unwind_frame_kernel(struct stackframe *frame) +{ + if (kstack_end((void *)frame->fp)) + return -EPERM; + if (frame->fp & 0x3 || frame->fp < TASK_SIZE) + return -EPERM; + + *frame = *((struct stackframe *)frame->fp - 1); + if (__kernel_text_address(frame->ra)) { + int graph = 0; + + frame->ra = ftrace_graph_ret_addr(NULL, &graph, frame->ra, + NULL); + } + return 0; +} + +static void notrace walk_stackframe(struct stackframe *fr, + struct perf_callchain_entry_ctx *entry) +{ + do { + perf_callchain_store(entry, fr->ra); + } while (unwind_frame_kernel(fr) >= 0); +} + +/* + * 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) +{ + struct stackframe buftail; + unsigned long ra = 0; + unsigned long *user_frame_tail = + (unsigned long *)(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; + perf_callchain_store(entry, ra); + + return fp; +} + +/* + * This will be called when the target is in user mode + * This function will only be called when we use + * "PERF_SAMPLE_CALLCHAIN" in + * kernel/events/core.c:perf_prepare_sample() + * + * How to trigger perf_callchain_[user/kernel] : + * $ perf record -e cpu-clock --call-graph fp ./program + * $ perf report --call-graph + * + * On RISC-V platform, the program being sampled and the C library + * need to be compiled with -fno-omit-frame-pointer, otherwise + * the user stack will not contain function frame. + */ +void perf_callchain_user(struct perf_callchain_entry_ctx *entry, + struct pt_regs *regs) +{ + unsigned long fp = 0; + + /* RISC-V does not support virtualization. */ + if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) + return; + + fp = regs->s0; + perf_callchain_store(entry, regs->sepc); + + fp = user_backtrace(entry, fp, regs->ra); + while (fp && !(fp & 0x3) && entry->nr < entry->max_stack) + fp = user_backtrace(entry, fp, 0); +} + +void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, + struct pt_regs *regs) +{ + struct stackframe fr; + + /* RISC-V does not support virtualization. */ + if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { + pr_warn("RISC-V does not support perf in guest mode!"); + return; + } + + fr.fp = regs->s0; + fr.ra = regs->ra; + walk_stackframe(&fr, entry); +}