From mboxrd@z Thu Jan 1 00:00:00 1970 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 88A46C54EBC for ; Tue, 10 Jan 2023 17:16:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234385AbjAJRQr (ORCPT ); Tue, 10 Jan 2023 12:16:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232141AbjAJRQj (ORCPT ); Tue, 10 Jan 2023 12:16:39 -0500 Received: from mta-01.yadro.com (mta-02.yadro.com [89.207.88.252]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7E2A30540 for ; Tue, 10 Jan 2023 09:16:37 -0800 (PST) Received: from mta-01.yadro.com (localhost.localdomain [127.0.0.1]) by mta-01.yadro.com (Proxmox) with ESMTP id 514D734192D; Tue, 10 Jan 2023 20:16:36 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yadro.com; h=cc :cc:content-transfer-encoding:content-type:content-type:date :from:from:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=mta-01; bh=u38bkopYCABOQQMld0 fsTvGWfjgN43w21eXoZMwdjkM=; b=hT1vkwCujVp3CQXHZa7YMwJsdWcqk4Ej5Z UXT+cGHfYCJSE1XU4gE34iWh+eSgKewhfVqziDmPE7aHuhYrvQXlK0rBY4WLX0Ch dcrd+Ura7j2U0r3X8DKRQoW6TCNUxi8JRRbQxOW/kg198aM+dI8xAxiLlNXJsV+4 8Pn9mjhtA= Received: from T-EXCH-08.corp.yadro.com (unknown [172.17.10.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Proxmox) with ESMTPS id 4427F34191B; Tue, 10 Jan 2023 20:16:36 +0300 (MSK) Received: from [10.199.21.212] (10.199.21.212) by T-EXCH-08.corp.yadro.com (172.17.11.58) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1118.9; Tue, 10 Jan 2023 20:16:35 +0300 Message-ID: Date: Tue, 10 Jan 2023 20:16:35 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH -next V6 5/7] riscv: ftrace: Make ftrace_caller call ftrace_graph_func Content-Language: en-US To: CC: , , , , , , , , , , , , , , References: <20230107133549.4192639-1-guoren@kernel.org> <20230107133549.4192639-6-guoren@kernel.org> From: Evgenii Shatokhin In-Reply-To: <20230107133549.4192639-6-guoren@kernel.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.199.21.212] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-08.corp.yadro.com (172.17.11.58) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07.01.2023 16:35, guoren@kernel.org wrote: > From: Song Shuai > > In order to make the function graph use ftrace directly, ftrace_caller > should be adjusted to save the necessary regs against the pt_regs layout > so it can call ftrace_graph_func reasonably. > > SAVE_ALL now saves all the regs according to the pt_regs struct. Here > supersedes SAVE_ALL by SAVE_ABI_REGS which has an extra option to allow > saving only the necessary ABI-related regs for ftrace_caller. > > ftrace_caller and ftrace_regs_caller save their regs with the respective > option of SAVE_ABI_REGS, then call the tracing function, especially > graph_ops's ftrace_graph_func. So the ftrace_graph_[regs]_call labels > aren't needed anymore if FTRACE_WITH_REGS is defined. > > As the previous patch described, the ftrace_caller remains with its > ftrace_graph_call if FTRACE_WITH_REGS isn't defined, > > For convenience, the original argument setup for the tracing function in > ftrace_[regs]_caller is separated as PREPARE_ARGS. > > Signed-off-by: Song Shuai > Tested-by: Guo Ren > Signed-off-by: Guo Ren > --- > arch/riscv/kernel/mcount-dyn.S | 142 ++++++++++++++++++++++++--------- > 1 file changed, 104 insertions(+), 38 deletions(-) > > diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S > index b75332ced757..d7d4d51b4bd7 100644 > --- a/arch/riscv/kernel/mcount-dyn.S > +++ b/arch/riscv/kernel/mcount-dyn.S > @@ -57,19 +57,52 @@ > .endm > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > - .macro SAVE_ALL > + > +/** > +* SAVE_ABI_REGS - save regs against the pt_regs struct > +* > +* @all: tell if saving all the regs > +* > +* If all is set, all the regs will be saved, otherwise only ABI > +* related regs (a0-a7,epc,ra and optional s0) will be saved. > +* > +* After the stack is established, > +* > +* 0(sp) stores the PC of the traced function which can be accessed > +* by &(fregs)->regs->epc in tracing function. Note that the real > +* function entry address should be computed with -FENTRY_RA_OFFSET. > +* > +* 8(sp) stores the function return address (i.e. parent IP) that > +* can be accessed by &(fregs)->regs->ra in tracing function. > +* > +* The other regs are saved at the respective localtion and accessed > +* by the respective pt_regs member. > +* > +* Here is the layout of stack for your reference. > +* > +* PT_SIZE_ON_STACK -> +++++++++ > +* + ..... + > +* + t3-t6 + > +* + s2-s11+ > +* + a0-a7 + --++++-> ftrace_caller saved > +* + s1 + + > +* + s0 + --+ > +* + t0-t2 + + > +* + tp + + > +* + gp + + > +* + sp + + > +* + ra + --+ // parent IP > +* sp -> + epc + --+ // PC > +* +++++++++ > +**/ > + .macro SAVE_ABI_REGS, all=0 > addi sp, sp, -PT_SIZE_ON_STACK > > REG_S t0, PT_EPC(sp) > REG_S x1, PT_RA(sp) > - REG_S x2, PT_SP(sp) > - REG_S x3, PT_GP(sp) > - REG_S x4, PT_TP(sp) > - REG_S x5, PT_T0(sp) > - REG_S x6, PT_T1(sp) > - REG_S x7, PT_T2(sp) > - REG_S x8, PT_S0(sp) > - REG_S x9, PT_S1(sp) > + > + // always save the ABI regs > + > REG_S x10, PT_A0(sp) > REG_S x11, PT_A1(sp) > REG_S x12, PT_A2(sp) > @@ -78,6 +111,18 @@ > REG_S x15, PT_A5(sp) > REG_S x16, PT_A6(sp) > REG_S x17, PT_A7(sp) > + > + // save the leftover regs > + > + .if \all == 1 > + REG_S x2, PT_SP(sp) > + REG_S x3, PT_GP(sp) > + REG_S x4, PT_TP(sp) > + REG_S x5, PT_T0(sp) > + REG_S x6, PT_T1(sp) > + REG_S x7, PT_T2(sp) > + REG_S x8, PT_S0(sp) > + REG_S x9, PT_S1(sp) > REG_S x18, PT_S2(sp) > REG_S x19, PT_S3(sp) > REG_S x20, PT_S4(sp) > @@ -92,19 +137,19 @@ > REG_S x29, PT_T4(sp) > REG_S x30, PT_T5(sp) > REG_S x31, PT_T6(sp) > + > + // save s0 if FP_TEST defined > + > + .else > +#ifdef HAVE_FUNCTION_GRAPH_FP_TEST > + REG_S x8, PT_S0(sp) > +#endif > + .endif > .endm > > - .macro RESTORE_ALL > + .macro RESTORE_ABI_REGS, all=0 > REG_L t0, PT_EPC(sp) > REG_L x1, PT_RA(sp) > - REG_L x2, PT_SP(sp) > - REG_L x3, PT_GP(sp) > - REG_L x4, PT_TP(sp) > - REG_L x5, PT_T0(sp) > - REG_L x6, PT_T1(sp) > - REG_L x7, PT_T2(sp) > - REG_L x8, PT_S0(sp) > - REG_L x9, PT_S1(sp) > REG_L x10, PT_A0(sp) > REG_L x11, PT_A1(sp) > REG_L x12, PT_A2(sp) > @@ -113,6 +158,16 @@ > REG_L x15, PT_A5(sp) > REG_L x16, PT_A6(sp) > REG_L x17, PT_A7(sp) > + > + .if \all == 1 > + REG_L x2, PT_SP(sp) > + REG_L x3, PT_GP(sp) > + REG_L x4, PT_TP(sp) > + REG_L x5, PT_T0(sp) Same as for the patch #3, please skip "REG_L x5, PT_T0(sp)" here. The correct value of t0/x5 has already been read from PT_EPC(sp) at this point. > + REG_L x6, PT_T1(sp) > + REG_L x7, PT_T2(sp) > + REG_L x8, PT_S0(sp) > + REG_L x9, PT_S1(sp) > REG_L x18, PT_S2(sp) > REG_L x19, PT_S3(sp) > REG_L x20, PT_S4(sp) > @@ -128,10 +183,25 @@ > REG_L x30, PT_T5(sp) > REG_L x31, PT_T6(sp) > > + .else > +#ifdef HAVE_FUNCTION_GRAPH_FP_TEST > + REG_L x8, PT_S0(sp) > +#endif > + .endif > addi sp, sp, PT_SIZE_ON_STACK > .endm > + > + .macro PREPARE_ARGS > + addi a0, t0, -FENTRY_RA_OFFSET // ip > + la a1, function_trace_op > + REG_L a2, 0(a1) // op > + mv a1, ra // parent_ip > + mv a3, sp // fregs > + .endm > + > #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > +#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS > ENTRY(ftrace_caller) > SAVE_ABI > > @@ -160,33 +230,29 @@ ftrace_graph_call: > jr t0 > ENDPROC(ftrace_caller) > > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > ENTRY(ftrace_regs_caller) > - SAVE_ALL > - > - addi a0, t0, -FENTRY_RA_OFFSET > - la a1, function_trace_op > - REG_L a2, 0(a1) > - mv a1, ra > - mv a3, sp > + SAVE_ABI_REGS 1 > + PREPARE_ARGS > > ftrace_regs_call: > .global ftrace_regs_call > call ftrace_stub > > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER > - addi a0, sp, PT_RA > - REG_L a1, PT_T0(sp) > - addi a1, a1, -FENTRY_RA_OFFSET > -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST > - mv a2, s0 > -#endif > -ftrace_graph_regs_call: > - .global ftrace_graph_regs_call > - call ftrace_stub > -#endif > > - RESTORE_ALL > + RESTORE_ABI_REGS 1 > jr t0 > ENDPROC(ftrace_regs_caller) > + > +ENTRY(ftrace_caller) > + SAVE_ABI_REGS 0 > + PREPARE_ARGS > + > +ftrace_call: > + .global ftrace_call > + call ftrace_stub > + > + RESTORE_ABI_REGS 0 > + jr t0 > +ENDPROC(ftrace_caller) > #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > -- > 2.36.1 > > Regards, Evgenii