From patchwork Fri Mar 24 03:33:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Shuai X-Patchwork-Id: 13186384 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 5CDDCC6FD1C for ; Fri, 24 Mar 2023 03:33:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230382AbjCXDdz (ORCPT ); Thu, 23 Mar 2023 23:33:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230329AbjCXDdy (ORCPT ); Thu, 23 Mar 2023 23:33:54 -0400 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52D7612D; Thu, 23 Mar 2023 20:33:53 -0700 (PDT) Received: by mail-pj1-x102c.google.com with SMTP id f6-20020a17090ac28600b0023b9bf9eb63so374425pjt.5; Thu, 23 Mar 2023 20:33:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679628833; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=BAx0j+E95ZpO1Fw67Pe/A4U5yDelnoFnmIVPjliTduc=; b=qPaMBc8Mvcz+5zEsAMKeR8YVsdfNzbbDNXa+iyjhO7nVhTNEx5k1KIjX0wi2dOIeET jbgCdDjsM2qQvBINQZYHKNBniSgWdn7W7KIgFXDrajOO8d9UlY0oiBE7fsC+WOEg3vlH wP2kewLwVAUJ1uLWoUrnVwpu24AD46ZH5NdCsXIJEBz1NDyD0bHJX33UtZkOZ8zsh0qW 3T4N6aPpcbzdzj+fUezLcXk738pNlsBwRgbwjo6hJknTsaEReCZiEO7WDxwBTjyR/wai k83EykGQQRPLDgKfhMSjTYRCEp9gbhU4iJVZVuY4hWmwQ4gQ1ZFeujqzfeViZsqLAa3x s3nA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679628833; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=BAx0j+E95ZpO1Fw67Pe/A4U5yDelnoFnmIVPjliTduc=; b=y4w2cFvghxKpyRW6j3hT7GGb5QmPrCvrX/bekb7ZhIxPaunqvrFM2b8PUC0pTD4yYU Bm4qjwKXGTQFuhoysIh+wVrdbw/V2o4V9im+WzZEnqIfiqvPYPT/vMeqSPHL4JIkJ6F0 puVIVYbD0AyboKiS4eF/+j/B6Npj0tRFNQe60qMZ4N+l+amuraEgW+7/aidA20kyZOuQ kSrGmoA79WFP7na1ysqEZWWfNX8gLTsPA5v77APy1DpujfXBas7rQexkPyx0fTYse9V6 d54zAEI3bra73PmGep9600ak8sp5hxc7b2Jvac0xBSINdlFsRIXeg6VFFnNIWdCa0bdG GQLg== X-Gm-Message-State: AAQBX9dd4/a1syBySFH8VoGGYmEtPOS/GBJkxrh7hzeuaQWURTYbZD4o oWqX385G71tH6hzJYl6XwUo= X-Google-Smtp-Source: AKy350b7p3w/RuZt0YQ+5kuDidz4v/0Z0IY7BeObcaQ4RaJGUuMXzoTQcP/BnvJ+LxHeIw6fOH+pHQ== X-Received: by 2002:a17:90a:1953:b0:23f:7196:2faf with SMTP id 19-20020a17090a195300b0023f71962fafmr1399783pjh.19.1679628832561; Thu, 23 Mar 2023 20:33:52 -0700 (PDT) Received: from localhost.localdomain ([221.226.144.218]) by smtp.gmail.com with ESMTPSA id h13-20020a170902f7cd00b0019d1f42b00csm13014101plw.17.2023.03.23.20.33.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Mar 2023 20:33:51 -0700 (PDT) From: Song Shuai To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, guoren@kernel.org, e.shatokhin@yadro.com Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Song Shuai Subject: [PATCH V8 0/4] riscv: Optimize function trace Date: Fri, 24 Mar 2023 11:33:38 +0800 Message-Id: <20230324033342.3177979-1-suagrfillet@gmail.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org The first 3 independent patches has been picked in the V7 version of this series, this version continues the following 4 patches. select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1] (patch 1) ========================================================== In RISC-V, -fpatchable-function-entry option is used to support dynamic ftrace in this commit afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount don't have to be called to create the __mcount_loc section before the vmlinux linking. Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell Makefile not to run recordmcount. Make function graph use ftrace directly [2] (patch 2) ======================================================== In RISC-V architecture, when we enable the ftrace_graph tracer on some functions, the function tracings on other functions will suffer extra graph tracing work. In essence, graph_ops isn't limited by its func_hash due to the global ftrace_graph_[regs]_call label. That should be corrected. What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function graph use ftrace directly") that uses graph_ops::func function to install return_hooker and makes the function called against its func_hash. This series of patches makes function graph use ftrace directly for riscv. If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call so that it can be replaced with the calling of prepare_ftrace_return by the enable/disable helper. As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the necessary regs against the pt_regs layout, so it can reasonably call the graph_ops::func function - ftrace_graph_func. And ftrace_graph_[regs]_call and its enable/disable helper aren't needed. Test log: The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the local qemu-system-riscv64 virt machine. The following is the log during startup. ``` Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1: Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0) Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0) Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365) Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399) Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071) Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2: Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0) Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0) Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2) Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126) Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078) Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup: Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much Nov 15 03:07:13 stage4 kernel: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED ``` Add WITH_DIRECT_CALLS support [3] (patch 3, 4) ============================================== This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V. SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI are also included here as the samples for testing DIRECT_CALLS related interface. First, select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide register_ftrace_direct[_multi] interfaces allowing user to register the customed trampoline (direct_caller) as the mcount for one or more target functions. And modify_ftrace_direct[_multi] are also provided for modify direct_caller. At the same time, the samples in ./samples/ftrace/ can be built as kerenl module for testing these interfaces with SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI selected. Second, to make the direct_caller and the other ftrace hooks (eg. function/fgraph tracer, k[ret]probes) co-exist, a temporary register are nominated to store the address of direct_caller in ftrace_regs_caller. After the setting of the address direct_caller by direct_ops->func and the RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to by the `jr` inst. The following tests have been passed in my local qemu-riscv64 virt machine. 1. tests with CONFIG_FTRACE_STARTUP_TEST 2. tests of samples/ftrace/ftrace*.ko 3. manual tests with any combination of the following hooks - function/function_graph tracer - ftrace*.ko - kprobe/kretprobe For your reference, here is the log when function tracer, kretprobe and ftrace-direct-too.ko co-hooks the handle_mm_fault function. ``` [root@stage4 tracing]# echo handle_mm_fault > set_ftrace_filter [root@stage4 tracing]# echo 'r:myr handle_mm_fault' > kprobe_events [root@stage4 tracing]# echo function > current_tracer [root@stage4 tracing]# echo 1 > events/kprobes/myr/enable [root@stage4 tracing]# insmod /root/ftrace-direct-too.ko [root@stage4 tracing]# [root@stage4 tracing]# cat trace | tail cat-388 [000] ...1. 583.051438: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) cat-388 [000] ...2. 583.057930: handle_mm_fault <-do_page_fault cat-388 [000] ..... 583.057990: my_direct_func: handle mm fault vma=000000002d9fe19c address=ffffffae9b7000 flags=215 cat-388 [000] ...1. 583.058284: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) tail-389 [001] ...2. 583.059062: handle_mm_fault <-do_page_fault tail-389 [001] ..... 583.059104: my_direct_func: handle mm fault vma=0000000017f3c48e address=aaaaaabebf3000 flags=215 tail-389 [001] ...1. 583.059325: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) tail-389 [001] ...2. 583.060371: handle_mm_fault <-do_page_fault tail-389 [001] ..... 583.060410: my_direct_func: handle mm fault vma=0000000017f3c48e address=aaaaaabebf1000 flags=255 tail-389 [001] ...1. 583.060996: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) ``` Note1: The checkpatch.pl will output some warnings on this series, like this ``` WARNING: Prefer using '"%s...", __func__' to using 'my_direct_func2', this function's name, in a string 111: FILE: samples/ftrace/ftrace-direct-multi-modify.c:48: +" call my_direct_func2\n" ``` The reason is that checkpatch depends on patch context providing the function name. In the above warning, my_direct_func2 has some codeline distance with the changed trunk, so its declaration doesn't come into the patch, and then the warning jumps out. You may notice the location of `my_ip` variable changes in the 2nd patch. I did that for reducing the warnings to some extent. But killing all the warnings will makes the patch less readable, so I stopped here. [1] https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t [2] https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/ [3] https://lore.kernel.org/linux-riscv/20221123142025.1504030-1-suagrfillet@gmail.com/ The series's changes related these patches ========================================== Changes in v8: - Fix incorrect address values in the 4nd patch - Rebased on v6.3-rc2 Changes in v7: https://lore.kernel.org/linux-riscv/20230112090603.1295340-1-guoren@kernel.org/ - Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite. - Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY - Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT & HAVE_SAMPLE_FTRACE_DIRECT_MULTI Changes in v6: https://lore.kernel.org/linux-riscv/20230107133549.4192639-1-guoren@kernel.org/ - Replace 8 with MCOUNT_INSN_SIZE - Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra" - Add Evgenii Shatokhin comment Changes in v5: https://lore.kernel.org/linux-riscv/20221208091244.203407-1-guoren@kernel.org/ - Sort Kconfig entries in alphabetical order. Changes in v4: https://lore.kernel.org/linux-riscv/20221129033230.255947-1-guoren@kernel.org/ - Include [3] for maintenance. [Song Shuai] Changes in V3: https://lore.kernel.org/linux-riscv/20221123153950.2911981-1-guoren@kernel.org/ - Include [2] for maintenance. [Song Shuai] Song Shuai (4): riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY riscv: ftrace: Add ftrace_graph_func riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI] arch/riscv/Kconfig | 4 + arch/riscv/include/asm/ftrace.h | 19 ++- arch/riscv/kernel/ftrace.c | 30 ++-- arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++----- samples/ftrace/ftrace-direct-modify.c | 33 +++++ samples/ftrace/ftrace-direct-multi-modify.c | 39 ++++++ samples/ftrace/ftrace-direct-multi.c | 23 ++++ samples/ftrace/ftrace-direct-too.c | 26 ++++ samples/ftrace/ftrace-direct.c | 22 +++ 9 files changed, 284 insertions(+), 55 deletions(-)