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[2620:137:e000::1:20]) by mx.google.com with ESMTP id il7-20020a17090b164700b00213d512f07csi13277327pjb.182.2022.11.15.03.31.11; Tue, 15 Nov 2022 03:31:24 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=CANixlHx; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229937AbiKOK6d (ORCPT + 89 others); Tue, 15 Nov 2022 05:58:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232366AbiKOK5t (ORCPT ); Tue, 15 Nov 2022 05:57:49 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D137D116 for ; Tue, 15 Nov 2022 02:56:01 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D7F45B81886 for ; Tue, 15 Nov 2022 10:55:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F4E6C43470 for ; Tue, 15 Nov 2022 10:55:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668509758; bh=4ROKDeZyaEfqDpOi4UWYR3za1ZxsqLln4FyxV32bExU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=CANixlHxlMpomisFV1+BpeGthH357hDPB7mNmXrV3SDz1Radb8hmy86b+k9955123 bx+SnlGUNICQWZHWtiez6rtE2/OBhpMJM9XE2ijWM4A5gt4QtkVoNh04WME7mI8KBh eKQoIsubDiVjYELoaRe4MxFQxrJ+8+JYenypikOFvcZfJAaJeX63Hcg637GBRYun/M yzrOjduDIvUWc7m2cohxJ5ecoIjzusZL11eOS30pd2VNNhDPli/aPYn27kL2qY6RUC 6cXc8EnkJsLInvtcp7xKaS2oR7/4gUiiC1heffUuYDG2CoRlWVwJG2Ig7VrH3RTfso ZhLxggF9wBZ+Q== Received: by mail-ed1-f53.google.com with SMTP id v17so21298623edc.8 for ; Tue, 15 Nov 2022 02:55:58 -0800 (PST) X-Gm-Message-State: ANoB5pmaoSQ+bULVJ+xug3cUQsgeZc64xVSO3tZzAt0fGPSVAkCowDhw aARPJu8JzKsDPUX/r8An074UVyapW7eAvfsRh+4= X-Received: by 2002:aa7:db85:0:b0:463:f3a:32ce with SMTP id u5-20020aa7db85000000b004630f3a32cemr14659126edt.366.1668509756669; Tue, 15 Nov 2022 02:55:56 -0800 (PST) MIME-Version: 1.0 References: <20221115025527.13382-1-zhangqing@loongson.cn> <20221115025527.13382-6-zhangqing@loongson.cn> <1288f936-7e43-592a-8061-d9df94573c4d@loongson.cn> <10c05114-efa0-fe6d-09cf-46e455c359ff@loongson.cn> In-Reply-To: <10c05114-efa0-fe6d-09cf-46e455c359ff@loongson.cn> From: Huacai Chen Date: Tue, 15 Nov 2022 18:55:44 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v6 5/9] LoongArch/ftrace: Add DYNAMIC_FTRACE_WITH_REGS support To: Qing Zhang Cc: Steven Rostedt , Ingo Molnar , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, Jinyang He Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 15, 2022 at 6:44 PM Qing Zhang wrote: > > > Hi, huacai > On 2022/11/15 =E4=B8=8B=E5=8D=885:24, Huacai Chen wrote: > > On Tue, Nov 15, 2022 at 5:22 PM Qing Zhang wrot= e: > >> > >> Hi, Huacai > >> > >> On 2022/11/15 =E4=B8=8B=E5=8D=884:41, Huacai Chen wrote: > >>> Hi, Qing, > >>> > >>> Patch5 and Patch6 are small and related, maybe they can be combined > >>> with a name "LoongArch/ftrace: Add DYNAMIC_FTRACE_WITH_{ARGS,REGS} > >>> support" > >> I think they should be independent due to different use scenarios. > > From the commit message it seems DYNAMIC_FTRACE_WITH_ARGS depend on > > DYNAMIC_FTRACE_WITH_REGS. > > DYNAMIC_FTRACE_WITH_REGS : which allows trace function saved registers, > It means that these registers can be modified, eg: Kprobe=E3=80=81Livepat= ch. > > DYNAMIC_FTRACE_WITH_ARGS: uses pt_regs as a parameter for get sp, > which means it can be used to access registers on the stack, and > use graph_ops::func to install return_hooker to replace the special > hook, eg: Livepatch. > > From the following Kconfig, they are reasonable as separate patches. > config LIVEPATCH > bool "Kernel Live Patching" > depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS > OK, then keeping them separately is reasonable. Huacai > Thanks > - Qing > > > > Huacai > >> > >> Thanks, > >> -Qing > >>> > >>> Huacai > >>> > >>> On Tue, Nov 15, 2022 at 10:55 AM Qing Zhang w= rote: > >>>> > >>>> This patch implements DYNAMIC_FTRACE_WITH_REGS on LoongArch, which a= llows > >>>> a traced function's arguments (and some other registers) to be captu= red > >>>> into a struct pt_regs, allowing these to be inspected and modified. > >>>> > >>>> Co-developed-by: Jinyang He > >>>> Signed-off-by: Jinyang He > >>>> Signed-off-by: Qing Zhang > >>>> --- > >>>> arch/loongarch/Kconfig | 1 + > >>>> arch/loongarch/include/asm/ftrace.h | 3 +++ > >>>> arch/loongarch/kernel/ftrace_dyn.c | 17 ++++++++++++++ > >>>> arch/loongarch/kernel/mcount-dyn.S | 36 ++++++++++++++++++++++++= +++-- > >>>> 4 files changed, 55 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > >>>> index 615ce62422b8..12e3e91a68ae 100644 > >>>> --- a/arch/loongarch/Kconfig > >>>> +++ b/arch/loongarch/Kconfig > >>>> @@ -90,6 +90,7 @@ config LOONGARCH > >>>> select HAVE_DEBUG_STACKOVERFLOW > >>>> select HAVE_DMA_CONTIGUOUS > >>>> select HAVE_DYNAMIC_FTRACE > >>>> + select HAVE_DYNAMIC_FTRACE_WITH_REGS > >>>> select HAVE_EBPF_JIT > >>>> select HAVE_EXIT_THREAD > >>>> select HAVE_FAST_GUP > >>>> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/in= clude/asm/ftrace.h > >>>> index 76ca58767f4d..a3f974a7a5ce 100644 > >>>> --- a/arch/loongarch/include/asm/ftrace.h > >>>> +++ b/arch/loongarch/include/asm/ftrace.h > >>>> @@ -28,6 +28,9 @@ struct dyn_ftrace; > >>>> int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); > >>>> #define ftrace_init_nop ftrace_init_nop > >>>> > >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > >>>> +#define ARCH_SUPPORTS_FTRACE_OPS 1 > >>>> +#endif > >>>> #endif /* CONFIG_DYNAMIC_FTRACE */ > >>>> #endif /* __ASSEMBLY__ */ > >>>> #endif /* CONFIG_FUNCTION_TRACER */ > >>>> diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/ker= nel/ftrace_dyn.c > >>>> index 3fe791b6783e..ec3d951be50c 100644 > >>>> --- a/arch/loongarch/kernel/ftrace_dyn.c > >>>> +++ b/arch/loongarch/kernel/ftrace_dyn.c > >>>> @@ -99,6 +99,23 @@ int ftrace_make_nop(struct module *mod, struct dy= n_ftrace *rec, > >>>> return ftrace_modify_code(pc, old, new, true); > >>>> } > >>>> > >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > >>>> +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_ad= dr, > >>>> + unsigned long addr) > >>>> +{ > >>>> + unsigned long pc; > >>>> + long offset; > >>>> + u32 old, new; > >>>> + > >>>> + pc =3D rec->ip + LOONGARCH_INSN_SIZE; > >>>> + > >>>> + old =3D larch_insn_gen_bl(pc, old_addr); > >>>> + new =3D larch_insn_gen_bl(pc, addr); > >>>> + > >>>> + return ftrace_modify_code(pc, old, new, true); > >>>> +} > >>>> +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > >>>> + > >>>> void arch_ftrace_update_code(int command) > >>>> { > >>>> command |=3D FTRACE_MAY_SLEEP; > >>>> diff --git a/arch/loongarch/kernel/mcount-dyn.S b/arch/loongarch/ker= nel/mcount-dyn.S > >>>> index 0c12cc108e6f..02835186b463 100644 > >>>> --- a/arch/loongarch/kernel/mcount-dyn.S > >>>> +++ b/arch/loongarch/kernel/mcount-dyn.S > >>>> @@ -27,7 +27,7 @@ > >>>> * follows the LoongArch psABI well. > >>>> */ > >>>> > >>>> - .macro ftrace_regs_entry > >>>> + .macro ftrace_regs_entry allregs=3D0 > >>>> PTR_ADDI sp, sp, -PT_SIZE > >>>> /* Save trace function ra at PT_ERA */ > >>>> PTR_S ra, sp, PT_ERA > >>>> @@ -43,16 +43,48 @@ > >>>> PTR_S a7, sp, PT_R11 > >>>> PTR_S fp, sp, PT_R22 > >>>> > >>>> + .if \allregs > >>>> + PTR_S t0, sp, PT_R12 > >>>> + PTR_S t1, sp, PT_R13 > >>>> + PTR_S t2, sp, PT_R14 > >>>> + PTR_S t3, sp, PT_R15 > >>>> + PTR_S t4, sp, PT_R16 > >>>> + PTR_S t5, sp, PT_R17 > >>>> + PTR_S t6, sp, PT_R18 > >>>> + PTR_S t7, sp, PT_R19 > >>>> + PTR_S t8, sp, PT_R20 > >>>> + PTR_S s0, sp, PT_R23 > >>>> + PTR_S s1, sp, PT_R24 > >>>> + PTR_S s2, sp, PT_R25 > >>>> + PTR_S s3, sp, PT_R26 > >>>> + PTR_S s4, sp, PT_R27 > >>>> + PTR_S s5, sp, PT_R28 > >>>> + PTR_S s6, sp, PT_R29 > >>>> + PTR_S s7, sp, PT_R30 > >>>> + PTR_S s8, sp, PT_R31 > >>>> + PTR_S tp, sp, PT_R2 > >>>> + /* Clear it for later use as a flag sometimes. */ > >>>> + PTR_S zero, sp, PT_R0 > >>>> + PTR_S $r21, sp, PT_R21 > >>>> + .endif > >>>> + > >>>> PTR_ADDI t8, sp, PT_SIZE > >>>> PTR_S t8, sp, PT_R3 > >>>> > >>>> .endm > >>>> > >>>> SYM_CODE_START(ftrace_caller) > >>>> - ftrace_regs_entry > >>>> + ftrace_regs_entry allregs=3D0 > >>>> b ftrace_common > >>>> SYM_CODE_END(ftrace_caller) > >>>> > >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > >>>> +SYM_CODE_START(ftrace_regs_caller) > >>>> + ftrace_regs_entry allregs=3D1 > >>>> + b ftrace_common > >>>> +SYM_CODE_END(ftrace_regs_caller) > >>>> +#endif > >>>> + > >>>> SYM_CODE_START(ftrace_common) > >>>> PTR_ADDI a0, ra, -8 /* arg0: ip */ > >>>> move a1, t0 /* arg1: parent_ip */ > >>>> -- > >>>> 2.36.0 > >>>> > >>>> > >> > >> > >