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[2620:137:e000::1:20]) by mx.google.com with ESMTP id i19-20020a17090acf9300b0020d542eb5f0si1372936pju.110.2022.11.16.00.53.00; Wed, 16 Nov 2022 00:53:11 -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; 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237845AbiKPIHp (ORCPT + 90 others); Wed, 16 Nov 2022 03:07:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233122AbiKPIHl (ORCPT ); Wed, 16 Nov 2022 03:07:41 -0500 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 89B2EBC89 for ; Wed, 16 Nov 2022 00:07:32 -0800 (PST) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8DxOdhDmnRjKLIHAA--.20699S3; Wed, 16 Nov 2022 16:07:31 +0800 (CST) Received: from localhost.localdomain (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Dx9VY6mnRjQ54UAA--.36317S6; Wed, 16 Nov 2022 16:07:30 +0800 (CST) From: Qing Zhang To: Huacai Chen , Steven Rostedt , Ingo Molnar Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, Jinyang He Subject: [PATCH v8 4/9] LoongArch/ftrace: Add dynamic function graph tracer support Date: Wed, 16 Nov 2022 16:07:17 +0800 Message-Id: <20221116080722.4745-5-zhangqing@loongson.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20221116080722.4745-1-zhangqing@loongson.cn> References: <20221116080722.4745-1-zhangqing@loongson.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf8Dx9VY6mnRjQ54UAA--.36317S6 X-CM-SenderInfo: x2kd0wptlqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBjvJXoWxGF4DAF1DKw4rGFWUtw4UXFb_yoWrKFyDpr y2y3ZxtrWjkFsakr9Igw4DXrW5J393G342vanrtryrCwsFqF13Aw1xA34qqFyaqw4UCryS vayrAr4jka1UXa7anT9S1TB71UUUUjUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bakYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_JF0_JFyl8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l n4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6x ACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1q6rW5McIj6I8E 87Iv67AKxVW8Jr0_Cr1UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04 k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUXVWUAwC2 0s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI 0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW5JVW7JwCI42IY6xIIjxv2 0xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2js IE14v26F4j6r4UJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIF yTuYvjxU2-eoUUUUU X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_PASS, 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 Once the function_graph tracer is enabled, a filtered function has the following call sequence: 1) ftracer_caller ==> on/off by ftrace_make_call/ftrace_make_nop 2) ftrace_graph_caller 3) ftrace_graph_call ==> on/off by ftrace_en/disable_ftrace_graph_caller 4) prepare_ftrace_return Considering the following DYNAMIC_FTRACE_WITH_REGS feature, it would be more extendable to have a ftrace_graph_caller function, instead of calling prepare_ftrace_return directly in ftrace_caller. Co-developed-by: Jinyang He Signed-off-by: Jinyang He Signed-off-by: Qing Zhang --- arch/loongarch/kernel/ftrace_dyn.c | 45 ++++++++++++++++++++++++++++++ arch/loongarch/kernel/inst.c | 24 ++++++++++++++++ arch/loongarch/kernel/mcount_dyn.S | 33 ++++++++++++++++++++++ 3 files changed, 102 insertions(+) diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c index 1f8955be8b64..3fe791b6783e 100644 --- a/arch/loongarch/kernel/ftrace_dyn.c +++ b/arch/loongarch/kernel/ftrace_dyn.c @@ -109,3 +109,48 @@ int __init ftrace_dyn_arch_init(void) { return 0; } + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +extern void ftrace_graph_call(void); + +void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent) +{ + unsigned long return_hooker = (unsigned long)&return_to_handler; + unsigned long old; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + old = *parent; + + if (!function_graph_enter(old, self_addr, 0, NULL)) + *parent = return_hooker; +} + +static int ftrace_modify_graph_caller(bool enable) +{ + unsigned long pc, func; + u32 branch, nop; + + pc = (unsigned long)&ftrace_graph_call; + func = (unsigned long)&ftrace_graph_caller; + + branch = larch_insn_gen_b(pc, func); + nop = larch_insn_gen_nop(); + + if (enable) + return ftrace_modify_code(pc, nop, branch, true); + else + return ftrace_modify_code(pc, branch, nop, true); +} + +int ftrace_enable_ftrace_graph_caller(void) +{ + return ftrace_modify_graph_caller(true); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_graph_caller(false); +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c index d62cdf4a9ffb..2d2e942eb06a 100644 --- a/arch/loongarch/kernel/inst.c +++ b/arch/loongarch/kernel/inst.c @@ -55,6 +55,30 @@ u32 larch_insn_gen_nop(void) return INSN_NOP; } +u32 larch_insn_gen_b(unsigned long pc, unsigned long dest) +{ + unsigned int immediate_l, immediate_h; + union loongarch_instruction insn; + long offset = dest - pc; + + if ((offset & 3) || offset < -SZ_128M || offset >= SZ_128M) { + pr_warn("The generated b instruction is out of range.\n"); + return INSN_BREAK; + } + + offset >>= 2; + + immediate_l = offset & 0xffff; + offset >>= 16; + immediate_h = offset & 0x3ff; + + insn.reg0i26_format.opcode = b_op; + insn.reg0i26_format.immediate_l = immediate_l; + insn.reg0i26_format.immediate_h = immediate_h; + + return insn.word; +} + u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest) { unsigned int immediate_l, immediate_h; diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S index 205925bc3822..0c12cc108e6f 100644 --- a/arch/loongarch/kernel/mcount_dyn.S +++ b/arch/loongarch/kernel/mcount_dyn.S @@ -62,6 +62,11 @@ SYM_CODE_START(ftrace_common) .globl ftrace_call ftrace_call: bl ftrace_stub +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + .globl ftrace_graph_call +ftrace_graph_call: + nop /* b ftrace_graph_caller */ +#endif /* * As we didn't use S series regs in this assmembly code and all calls * are C function which will save S series regs by themselves, there is @@ -84,6 +89,34 @@ ftrace_common_return: jr t0 SYM_CODE_END(ftrace_common) +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +SYM_CODE_START(ftrace_graph_caller) + PTR_L a0, sp, PT_ERA + PTR_ADDI a0, a0, -8 /* arg0: self_addr */ + PTR_ADDI a1, sp, PT_R1 /* arg1: parent */ + bl prepare_ftrace_return + b ftrace_common_return +SYM_CODE_END(ftrace_graph_caller) + +SYM_CODE_START(return_to_handler) + /* save return value regs */ + PTR_ADDI sp, sp, -2 * SZREG + PTR_S a0, sp, 0 + PTR_S a1, sp, SZREG + + move a0, zero /* Has no check FP now. */ + bl ftrace_return_to_handler + move ra, a0 /* parent ra */ + + /* restore return value regs */ + PTR_L a0, sp, 0 + PTR_L a1, sp, SZREG + PTR_ADDI sp, sp, 2 * SZREG + + jr ra +SYM_CODE_END(return_to_handler) +#endif + SYM_FUNC_START(ftrace_stub) jr ra SYM_FUNC_END(ftrace_stub) -- 2.36.0