From patchwork Wed Nov 27 17:29:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andy Chiu X-Patchwork-Id: 13887247 Received: from mail-pf1-f171.google.com (mail-pf1-f171.google.com [209.85.210.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB1C020103A; Wed, 27 Nov 2024 17:29:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728596; cv=none; b=iKmP2FoX2avIqOWUE2+OXdUyUq0JXh/bAozFbN69rAWkzVM79hIgj5uF7uqqyjILWfib7ggNJtXyLKCiAcQww5d+5O6mbaVR2+JLfc6FfC0oobgzH0kYpQaIEqGgcMY3P7yGiNLiUWDOdLjB+gzb04QVjCNQuAE3ywPXYIl4YgI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728596; c=relaxed/simple; bh=bpMqPVQ3HsfWe+bk5gds1iHBJEE9VMgZp3CPDFR8+go=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=KjlYuXVtdnzT8neAczl5XtWXXemLXrtgbXmvDmuE+bqVLdm7WW9sBMaUrXNQt30Zr/Xu9oPy5tsvMeGjr0zh0L6aqp8hvs7bK/G7ahcF+4o7L9nrL3p0lO5XGiMTI7dIjn9Xz9DhK3JqEQhNiHiuXxZGOYtJyKBj8SmHaPP2AB4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=dnHNZHz2; arc=none smtp.client-ip=209.85.210.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dnHNZHz2" Received: by mail-pf1-f171.google.com with SMTP id d2e1a72fcca58-7251331e756so16749b3a.3; Wed, 27 Nov 2024 09:29:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732728594; x=1733333394; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=VhqF3E4/w+YtOL58NNfG2rcUNmjyen3grJ9NA1x6juQ=; b=dnHNZHz2Ak6h4F+UgCuK1b26TtEdgxyo92ke2v/2SFjvcdhkW1Lu3GXJxygApSMVKW OQnrF1nn/CFe+zLrDy8vsqA0RIgHxvCEosAsG+B8UUVP3KxFnze37KBlCP1vhqaHjB/B prSjGdp3ghZ9nj9VUzoYckFoua0HKInV849NCxh22ntFUSRiauAiva+arAuRJMfMgrme /sKZD2CsX+EPDSI+setBN8wTR6t+nrXaHSJRFtZbqypJaMgq8IFeOtXJWtXgb8SkfVu/ i8m1rwnuUy8hk04DdgkUW88BwaIejhA1XrLCxUuSlsJh8syyorltRf3MuZEN0TA5OabW C83A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732728594; x=1733333394; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VhqF3E4/w+YtOL58NNfG2rcUNmjyen3grJ9NA1x6juQ=; b=n8hMrqCrLoRW9L/kC90J2uowKA3T22hMN4cZrQuWuTh85yRczZWlOfJAFMsfmsW8O0 1eusmFTMuBlQ77icCbjJAzEoPjVHDnDtshXN/+dN9Pa4AOXlAiXr6ywrXPzffGt2qmLr w3EMhMNVmUDi6F6qpM6H/0WURafnu5StzF5avqPSpKl4APqMBwRplzfNTnis31eXhiXb 9eB8iZ37sCK4qoP4dhh5Rk1jdS1HFLA0zEV4p9/ZXMTkMoTJrZPnoz7+Z947NGyKFBdR nkWg+D+Uhu2U8EjPRVqtAnfSqUX7A7YauGQFrBel9rLmEZrtaUsDDicy30QoXedH6rC0 ad+g== X-Forwarded-Encrypted: i=1; AJvYcCUsR40oLdfCmqRuMVpwe7fPWJn/pmuTdxAzC48cqvh4nsrneejKct72MZFNEDfLhmuKAaBhIf+8OOqxNZkWaVl7ntc=@vger.kernel.org X-Gm-Message-State: AOJu0YzeTJduwr3HWQdel1BolJrVG1cE3W+G91Vpf3y3GMfMa7njyb5Z fvfJp5JWjw7t27BwWZWA57rV4NIJU3rANWPAvBhlYU7KrZLbK0UC X-Gm-Gg: ASbGncuWasBTcoi3lWu/yX0+2oEVNCmI5A52rwjEBVn9nuZ3ZeMYnCZn7mz/uwA0yuJ eDE3XRBVt3La/je2m80f6J8B9xBWJS1wYCluzvIVj6Jm2/hxP42KSHvE3xqPu/Lfv7MXk84d+7p QUT4ymbgj11p3Ru0dh1nkOFZlqjHFoWsEkK3Ob+58z9uhNgaAEB9oaural3jPpM8eMTB7mETzJF 8CZakyKEfNQDXCzrxhZIwAG2aYt7nL7Zm6Lfch5e3Y+UiTYf5LwDzjxHYCpbqymnlhBNccVKioT spEHgs1GWBJYPkpjcb51DZDNu7WY X-Google-Smtp-Source: AGHT+IHe4vfUFn689BzH733Y3azaB4OQQfGNQ2U5d2DUk6y3aLJvqA63KG7l5W6jxcEPLUbmlo8oFg== X-Received: by 2002:a05:6a00:3c89:b0:724:eac3:576a with SMTP id d2e1a72fcca58-725301a5b92mr5270747b3a.25.1732728594123; Wed, 27 Nov 2024 09:29:54 -0800 (PST) Received: from localhost.localdomain (1-171-29-17.dynamic-ip.hinet.net. [1.171.29.17]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7fbcc1e3fdbsm9359582a12.30.2024.11.27.09.29.50 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 27 Nov 2024 09:29:53 -0800 (PST) From: Andy Chiu To: Steven Rostedt , Masami Hiramatsu , Mark Rutland , Paul Walmsley , Palmer Dabbelt , Albert Ou , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, llvm@lists.linux.dev, bjorn@rivosinc.com, puranjay12@gmail.com, alexghiti@rivosinc.com, yongxuan.wang@sifive.com, greentime.hu@sifive.com, nick.hu@sifive.com, nylon.chen@sifive.com, tommy.wu@sifive.com, eric.lin@sifive.com, viccent.chen@sifive.com, zong.li@sifive.com, samuel.holland@sifive.com Subject: [PATCH v3 1/7] riscv: ftrace: support fastcc in Clang for WITH_ARGS Date: Thu, 28 Nov 2024 01:29:02 +0800 Message-Id: <20241127172908.17149-2-andybnac@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-145) In-Reply-To: <20241127172908.17149-1-andybnac@gmail.com> References: <20241127172908.17149-1-andybnac@gmail.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Andy Chiu Some caller-saved registers which are not defined as function arguments in the ABI can still be passed as arguments when the kernel is compiled with Clang. As a result, we must save and restore those registers to prevent ftrace from clobbering them. - [1]: https://reviews.llvm.org/D68559 Reported-by: Evgenii Shatokhin Closes: https://lore.kernel.org/linux-riscv/7e7c7914-445d-426d-89a0-59a9199c45b1@yadro.com/ Acked-by: Nathan Chancellor Signed-off-by: Andy Chiu Reviewed-by: Björn Töpel --- arch/riscv/include/asm/ftrace.h | 7 +++++++ arch/riscv/kernel/asm-offsets.c | 7 +++++++ arch/riscv/kernel/mcount-dyn.S | 16 ++++++++++++++-- 3 files changed, 28 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 2cddd79ff21b..4ca7ce7f34d7 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -143,6 +143,13 @@ struct ftrace_regs { unsigned long a5; unsigned long a6; unsigned long a7; +#ifdef CONFIG_CC_IS_CLANG + unsigned long t2; + unsigned long t3; + unsigned long t4; + unsigned long t5; + unsigned long t6; +#endif }; }; }; diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c index e94180ba432f..59789dfb2d5d 100644 --- a/arch/riscv/kernel/asm-offsets.c +++ b/arch/riscv/kernel/asm-offsets.c @@ -504,6 +504,13 @@ void asm_offsets(void) DEFINE(FREGS_SP, offsetof(struct ftrace_regs, sp)); DEFINE(FREGS_S0, offsetof(struct ftrace_regs, s0)); DEFINE(FREGS_T1, offsetof(struct ftrace_regs, t1)); +#ifdef CONFIG_CC_IS_CLANG + DEFINE(FREGS_T2, offsetof(struct ftrace_regs, t2)); + DEFINE(FREGS_T3, offsetof(struct ftrace_regs, t3)); + DEFINE(FREGS_T4, offsetof(struct ftrace_regs, t4)); + DEFINE(FREGS_T5, offsetof(struct ftrace_regs, t5)); + DEFINE(FREGS_T6, offsetof(struct ftrace_regs, t6)); +#endif DEFINE(FREGS_A0, offsetof(struct ftrace_regs, a0)); DEFINE(FREGS_A1, offsetof(struct ftrace_regs, a1)); DEFINE(FREGS_A2, offsetof(struct ftrace_regs, a2)); diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S index 745dd4c4a69c..e988bd26b28b 100644 --- a/arch/riscv/kernel/mcount-dyn.S +++ b/arch/riscv/kernel/mcount-dyn.S @@ -96,7 +96,13 @@ REG_S x8, FREGS_S0(sp) #endif REG_S x6, FREGS_T1(sp) - +#ifdef CONFIG_CC_IS_CLANG + REG_S x7, FREGS_T2(sp) + REG_S x28, FREGS_T3(sp) + REG_S x29, FREGS_T4(sp) + REG_S x30, FREGS_T5(sp) + REG_S x31, FREGS_T6(sp) +#endif // save the arguments REG_S x10, FREGS_A0(sp) REG_S x11, FREGS_A1(sp) @@ -115,7 +121,13 @@ REG_L x8, FREGS_S0(sp) #endif REG_L x6, FREGS_T1(sp) - +#ifdef CONFIG_CC_IS_CLANG + REG_L x7, FREGS_T2(sp) + REG_L x28, FREGS_T3(sp) + REG_L x29, FREGS_T4(sp) + REG_L x30, FREGS_T5(sp) + REG_L x31, FREGS_T6(sp) +#endif // restore the arguments REG_L x10, FREGS_A0(sp) REG_L x11, FREGS_A1(sp) From patchwork Wed Nov 27 17:29:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Chiu X-Patchwork-Id: 13887248 Received: from mail-ot1-f45.google.com (mail-ot1-f45.google.com [209.85.210.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8360113D899; Wed, 27 Nov 2024 17:30:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728606; cv=none; b=K0MzDOLrdNw1Yn8Sj9/8x82YuVN1/e0BGFa7Qz+gKzfkzqmD2LpqWv5kgoxXMWXkxbEOBPmDFJ7yiLO42E+54NvKegSNd4Wfvi/W+hErHb9FyIQo5kI3yeZbY5wZloSBf+soTbqVFBtyXy15ZW7+9qkeOStHjILR/qdaGYxCvV0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728606; c=relaxed/simple; bh=ycDrQrX8gZHEUT0jV8doyx6zCNX6hRoiZ/fYCbDs2vo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=TOEuEw7Cs7VqH5rFBQN70kZSEgE50kYiyXVyZq7PZ9XOV9luUAI1esVn6+bwUoU0I/Z0p7WBlAkZExFdym6vB0D9eAu0LorkBUqE/JUBDRiYO6QZHUimSOpay/vSIHkrIpuEYkuQS0MdDpwgDjo6n0VpHxNSN9+kYIkcCERnMAI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=CkCamA2m; arc=none smtp.client-ip=209.85.210.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CkCamA2m" Received: by mail-ot1-f45.google.com with SMTP id 46e09a7af769-71d4fceec9aso1651668a34.3; Wed, 27 Nov 2024 09:30:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732728603; x=1733333403; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=1IR7fJnOIGqt6b1nWAQZJYrqcHCadpu+itzDI+rPODg=; b=CkCamA2mA7cVEDeWY7M7kty9ev1sHPUGKUqEOBSLPPaiAEFnM3FGHtT5sWvi6+weMv y9IdfvqmRISNq71d6ObmZb4UTke0pIMHuCAIzxHCsTIcJ4aKu4auViFhEUPOCWkf0bVv WyNrbNBqsIbW4WIdii6KbkFAZc2lTpiPASEPKXr6QaLjH97yX1AG099f45PzTRFVtBDw 3SgAcRxBA/au+eU/Pnvt89S5/A8SQSpnreRHqwZVsJrrFb3MHIVwmyPsmeIj079FhfeY W3mSknNYWA56JY8wdqlJx0WQZE/+S1OmyiQU0qh4xzyfzgKJ8XVYBmr4e0ybm8Rna9NI ueLg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732728603; x=1733333403; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=1IR7fJnOIGqt6b1nWAQZJYrqcHCadpu+itzDI+rPODg=; b=XCQYuYPDv6cXt+Cuj1Us9A9y0yPgLzKHNZwR0fLL7B4fueS+xbCwiYE5sCraoDPNjd 2wWVNnp7ZNDkHhR3JegvaXRXOFPoelmk8DGiUWx/GA82qQupsbZK6qx1YhcvLrbe08IQ JYTS8z2UCfcmPx2MnC50JXXcKxnED6/YpNd11kitVQYvZL60osxmPTuUzpMl4MRekfDo 0tNc0SF7i5GkmWh0WE0cOJYedeo27qnVXba9p/Jd+dhKshQ9gwOeAM+RIu6bfxdhuUuR uBCSmvpyG8bJrydbiQXlvsJKZIHp3aNnzpb9jLYSjoyt3SiYLGgimasTCoWZVfT0Qngb YpKA== X-Forwarded-Encrypted: i=1; AJvYcCWzFaAhokSWAtILxyt9Meh5mVLYhy9kLHpWj2IyS7kvZixNjN4g+hmtKzguxbIz78NxBM0tJUfPg72GT3yUABZdjug=@vger.kernel.org X-Gm-Message-State: AOJu0Yx+yLH3BQhOlMFEHUmpRv1bGYzGOkEtbgEeqwiSKfTyx6CSL5Uu bCbdAP67eMWVbWnDYFJ1R7Cb3CILLOEmlCexfPdBC62FGuLefmNCTVgChbyD X-Gm-Gg: ASbGncsQhCU7wSPpASqX7g+QbJYw3ozUr7c4QCaj8oF4kNETAH/Jt4AL81UdQnNggEq kz8yo7afHBKnrHG2u65uHmguk+4eBczfr0HNtOpZcOrnnK0dJO2FweA2yAwbaHdFbl6UU2F3DVP hR7bzLmYyO0MA2dwFsrg6OturtmE7zZ5a8y3SWSOXeoAfFeQX853bc8uRGepiQzIjKwk5tEFWxX X1hoJGs9TZXtCvmmU7MFN3jvyaO0TGXul9y9Kx1wdONhaMBrRo1gPqxlIUpDHInOmFOEd7sXegY XuUDzjvyhsaqlHQ+ImaGS2k+PlnE X-Google-Smtp-Source: AGHT+IHruXTFUTfiaojyTMlhAizY2Drw8OyNcxeu1vFbTUarM1m1Pec3RyTRvOVVRoAzScO0flWjxQ== X-Received: by 2002:a05:6830:6e90:b0:71d:4bd9:8b98 with SMTP id 46e09a7af769-71d65d07e94mr4292715a34.25.1732728603299; Wed, 27 Nov 2024 09:30:03 -0800 (PST) Received: from localhost.localdomain (1-171-29-17.dynamic-ip.hinet.net. [1.171.29.17]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7fbcc1e3fdbsm9359582a12.30.2024.11.27.09.29.59 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 27 Nov 2024 09:30:02 -0800 (PST) From: Andy Chiu To: Steven Rostedt , Masami Hiramatsu , Mark Rutland , Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, bjorn@rivosinc.com, puranjay12@gmail.com, alexghiti@rivosinc.com, yongxuan.wang@sifive.com, greentime.hu@sifive.com, nick.hu@sifive.com, nylon.chen@sifive.com, tommy.wu@sifive.com, eric.lin@sifive.com, viccent.chen@sifive.com, zong.li@sifive.com, samuel.holland@sifive.com Subject: [PATCH v3 3/7] riscv: ftrace: prepare ftrace for atomic code patching Date: Thu, 28 Nov 2024 01:29:04 +0800 Message-Id: <20241127172908.17149-4-andybnac@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-145) In-Reply-To: <20241127172908.17149-1-andybnac@gmail.com> References: <20241127172908.17149-1-andybnac@gmail.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Andy Chiu We use an AUIPC+JALR pair to jump into a ftrace trampoline. Since instruction fetch can break down to 4 byte at a time, it is impossible to update two instructions without a race. In order to mitigate it, we initialize the patchable entry to AUIPC + NOP4. Then, the run-time code patching can change NOP4 to JALR to eable/disable ftrcae from a function. This limits the reach of each ftrace entry to +-2KB displacing from ftrace_caller. Starting from the trampoline, we add a level of indirection for it to reach ftrace caller target. Now, it loads the target address from a memory location, then perform the jump. This enable the kernel to update the target atomically. The ordering of reading/updating the targert address should be guarded by generic ftrace code, where it sends smp_rmb ipi. Signed-off-by: Andy Chiu --- arch/riscv/include/asm/ftrace.h | 4 ++ arch/riscv/kernel/ftrace.c | 80 +++++++++++++++++++++------------ arch/riscv/kernel/mcount-dyn.S | 9 ++-- 3 files changed, 62 insertions(+), 31 deletions(-) diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 4ca7ce7f34d7..36734d285aad 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -80,6 +80,7 @@ struct dyn_arch_ftrace { #define JALR_T0 (0x000282e7) #define AUIPC_T0 (0x00000297) #define NOP4 (0x00000013) +#define JALR_RANGE (JALR_SIGN_MASK - 1) #define to_jalr_t0(offset) \ (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0) @@ -117,6 +118,9 @@ do { \ * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here. */ #define MCOUNT_INSN_SIZE 8 +#define MCOUNT_AUIPC_SIZE 4 +#define MCOUNT_JALR_SIZE 4 +#define MCOUNT_NOP4_SIZE 4 #ifndef __ASSEMBLY__ struct dyn_ftrace; diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 4b95c574fd04..5ebe412280ef 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -64,42 +64,64 @@ static int ftrace_check_current_call(unsigned long hook_pos, return 0; } -static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target, - bool enable, bool ra) +static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target, bool validate) { unsigned int call[2]; - unsigned int nops[2] = {NOP4, NOP4}; + unsigned int replaced[2]; + + make_call_t0(hook_pos, target, call); - if (ra) - make_call_ra(hook_pos, target, call); - else - make_call_t0(hook_pos, target, call); + if (validate) { + /* + * Read the text we want to modify; + * return must be -EFAULT on read error + */ + if (copy_from_kernel_nofault(replaced, (void *)hook_pos, + MCOUNT_INSN_SIZE)) + return -EFAULT; + + if (replaced[0] != call[0]) { + pr_err("%p: expected (%08x) but got (%08x)\n", + (void *)hook_pos, call[0], replaced[0]); + return -EINVAL; + } + } - /* Replace the auipc-jalr pair at once. Return -EPERM on write error. */ - if (patch_insn_write((void *)hook_pos, enable ? call : nops, MCOUNT_INSN_SIZE)) + /* Replace the jalr at once. Return -EPERM on write error. */ + if (patch_insn_write((void *)(hook_pos + MCOUNT_AUIPC_SIZE), call + 1, MCOUNT_JALR_SIZE)) return -EPERM; return 0; } -int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +static int __ftrace_modify_call_site(ftrace_func_t *hook_pos, ftrace_func_t target, bool enable) { - unsigned int call[2]; + ftrace_func_t call = target; + ftrace_func_t nops = &ftrace_stub; - make_call_t0(rec->ip, addr, call); - - if (patch_insn_write((void *)rec->ip, call, MCOUNT_INSN_SIZE)) - return -EPERM; + WRITE_ONCE(*hook_pos, enable ? call : nops); return 0; } +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long distance, orig_addr; + + orig_addr = (unsigned long)&ftrace_caller; + distance = addr > orig_addr ? addr - orig_addr : orig_addr - addr; + if (distance > JALR_RANGE) + return -EINVAL; + + return __ftrace_modify_call(rec->ip, addr, false); +} + int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - unsigned int nops[2] = {NOP4, NOP4}; + unsigned int nops[1] = {NOP4}; - if (patch_insn_write((void *)rec->ip, nops, MCOUNT_INSN_SIZE)) + if (patch_insn_write((void *)(rec->ip + MCOUNT_AUIPC_SIZE), nops, MCOUNT_NOP4_SIZE)) return -EPERM; return 0; @@ -114,21 +136,23 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, */ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { + unsigned int nops[2]; int out; + make_call_t0(rec->ip, &ftrace_caller, nops); + nops[1] = NOP4; + mutex_lock(&text_mutex); - out = ftrace_make_nop(mod, rec, MCOUNT_ADDR); + out = patch_insn_write((void *)rec->ip, nops, MCOUNT_INSN_SIZE); mutex_unlock(&text_mutex); return out; } +ftrace_func_t ftrace_call_dest = ftrace_stub; int ftrace_update_ftrace_func(ftrace_func_t func) { - int ret = __ftrace_modify_call((unsigned long)&ftrace_call, - (unsigned long)func, true, true); - - return ret; + return __ftrace_modify_call_site(&ftrace_call_dest, func, true); } struct ftrace_modify_param { @@ -182,7 +206,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, if (ret) return ret; - return __ftrace_modify_call(caller, addr, true, false); + return __ftrace_modify_call(caller, addr, true); } #endif @@ -217,17 +241,17 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, prepare_ftrace_return(&fregs->ra, ip, fregs->s0); } #else /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */ -extern void ftrace_graph_call(void); +ftrace_func_t ftrace_graph_call_dest = ftrace_stub; int ftrace_enable_ftrace_graph_caller(void) { - return __ftrace_modify_call((unsigned long)&ftrace_graph_call, - (unsigned long)&prepare_ftrace_return, true, true); + return __ftrace_modify_call_site(&ftrace_graph_call_dest, + &prepare_ftrace_return, true); } int ftrace_disable_ftrace_graph_caller(void) { - return __ftrace_modify_call((unsigned long)&ftrace_graph_call, - (unsigned long)&prepare_ftrace_return, false, true); + return __ftrace_modify_call_site(&ftrace_graph_call_dest, + &prepare_ftrace_return, false); } #endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */ #endif /* CONFIG_DYNAMIC_FTRACE */ diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S index e988bd26b28b..bc06e8ab81cf 100644 --- a/arch/riscv/kernel/mcount-dyn.S +++ b/arch/riscv/kernel/mcount-dyn.S @@ -162,7 +162,8 @@ SYM_FUNC_START(ftrace_caller) mv a3, sp SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) - call ftrace_stub + REG_L ra, ftrace_call_dest + jalr 0(ra) #ifdef CONFIG_FUNCTION_GRAPH_TRACER addi a0, sp, ABI_RA @@ -172,7 +173,8 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) mv a2, s0 #endif SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) - call ftrace_stub + REG_L ra, ftrace_graph_call_dest + jalr 0(ra) #endif RESTORE_ABI jr t0 @@ -185,7 +187,8 @@ SYM_FUNC_START(ftrace_caller) PREPARE_ARGS SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) - call ftrace_stub + REG_L ra, ftrace_call_dest + jalr 0(ra) RESTORE_ABI_REGS bnez t1, .Ldirect From patchwork Wed Nov 27 17:29:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Chiu X-Patchwork-Id: 13887249 Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A542B2010FB; Wed, 27 Nov 2024 17:30:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728610; cv=none; b=sBcRxJmpL7xRzPJcxcDw9Kz1Wl5tD9s8UK5hWQm9d2uPhwqsjWpZnAu/5jvtMj4FsGhDXFg5b4ft8EokU/0RgHclzczSGZHrFPa/fxq80M7zpfUPIteWcCUhqMXDQaUqrQ0JZ3dpRmpGLhPE4uaIKCdd23/ScaglA3nhsLx4F4Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732728610; c=relaxed/simple; bh=jB6V5LnOG2FU2rWhkR2mAKb1UPOirED+m9TxmqTlLDg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Hxs0/b20ZbG9tkKntSFf4cT4oUh8RctWy2UO2RMj00iNesvd4eSBvSdBP+yXP9ds66QSIaqqHBdbUdVJmVv7AZo+WBXmOOhrDcTA+dW3ZhtBdeIDlZB5aQF/LTQiz2rHi3MRilQUp5ZPhUjTKPMufE+qSso6xob/j3oNlEKuiAU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=i5D9kcQj; arc=none smtp.client-ip=209.85.215.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="i5D9kcQj" Received: by mail-pg1-f176.google.com with SMTP id 41be03b00d2f7-7e9e38dd5f1so5960400a12.0; Wed, 27 Nov 2024 09:30:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732728608; x=1733333408; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=IJ4wyksNmGKwRpxqsruWC4A8GzGFI32FmHe+iaxPpao=; b=i5D9kcQjX0UQJpfGstl06rvbkIxxCU7ZLV22+4ZeO33ePlezqTYF3DCUFYwl/p4O1Z uJTBxgwc9XoOeWU1L9StQGV09hhpAJfOQH70u7QJfpb5Qg4j521VWESqk/KHni4IKmLb 2S6Mp2VQJyKi/TtMav8hsR6IBKbpkPw0qy2Rncmeg5p1skfQNjMBFO3ivhORiAncYYob qil9T3DxqCDDBdPx32JEzG7+9EpJNhcDxB6BeiGYjNowhClNVm5lCIWVqp5zRpMk80m7 +iB5vfktkgXTn2NQbehin0zT6MpoZtICmAYS2aGrPL2ALLcgNXMx8BQck9EcffdQIYW1 vCgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732728608; x=1733333408; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=IJ4wyksNmGKwRpxqsruWC4A8GzGFI32FmHe+iaxPpao=; b=k/25DkIa5QSIfjPF/6azPzOTH7nvi51EW6jMs7CAI0A77mYjZGqKJUqEIh8D48gOfM LbfYRBHt/waWtX5P1pbn/9P/+XyueEOXWa3HPUR+Yx0JzGtkdRM4mG4fD1f0I3uk7Pgv NjjmKbdDQ8j/q3eDt/iyLCFx0Et1isoJqrCdj9beAKfUcsjaEEHCphJzQm3/X8tCrEOm WJQX3f5y9vd4fKTJ4hQcemrvAs34pg/cuOObINAMrotmfUj67BONqnLl58wza/kGpykP kBxsJs1Y9v6K47F7anYJIeTyajsRTjIiTaWhQEuW+3hrrSCIvftlousNCDbyZJI/jnos jcsA== X-Forwarded-Encrypted: i=1; AJvYcCUCG1NI/m4Ro25sn1Aab1NHIpq8Z+97wklnwYw7WMk6QteBmElJ0N8Zl5sNoqWesQyElhTqEd92+/gNOkpKvMqMes0=@vger.kernel.org X-Gm-Message-State: AOJu0YwbSahKbXNm+e+2DIl5Lb4vwVAOmW6ZJj821oM0k3v0C4T8q/kZ BCjY51ZEd/RncWyOBmBW12eFo4kIvqjaAXVV4P53ne9rIzoq1wHS X-Gm-Gg: ASbGncsiMs31gGz+rBwjEJ/3Z5LMFXVOCLtIqnLgO1pY9U2QQeBVeZyHwVtBlAls/B8 hEgqyiaO9AgmJvtuLrROiw9dzh0xI31z/PujSZtWcnlsAXqx8i6O0mMWwCcnUghHi2kx94cpBJ4 dtc+2PrsMvik4WSKUY4eWwDB5ksNxy/2WGWb4MAb4cfV58QlWoL1v9fHZk9h3uz/uPHfIjSq0lX OKN0s+jRinwVLeox1u5QNi5O2ir0S/tG+kmasq7uZtTWA0j+68oVL3fYr5IuBxu1fWwcKugJQ9K 6UC+1Ac1pZ87C7B8KTjJaEAQDyny X-Google-Smtp-Source: AGHT+IF4fq/f76pFPUxSVNMwuLs8cfvtvFw2AwTwF+Xja2556ySDeUDGNdUbpJFYW6y4k7ZnLfhsXg== X-Received: by 2002:a05:6a20:914b:b0:1e0:d123:7154 with SMTP id adf61e73a8af0-1e0e0ade54cmr5763536637.17.1732728607749; Wed, 27 Nov 2024 09:30:07 -0800 (PST) Received: from localhost.localdomain (1-171-29-17.dynamic-ip.hinet.net. [1.171.29.17]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7fbcc1e3fdbsm9359582a12.30.2024.11.27.09.30.04 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 27 Nov 2024 09:30:07 -0800 (PST) From: Andy Chiu To: Steven Rostedt , Masami Hiramatsu , Mark Rutland , Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, bjorn@rivosinc.com, puranjay12@gmail.com, alexghiti@rivosinc.com, yongxuan.wang@sifive.com, greentime.hu@sifive.com, nick.hu@sifive.com, nylon.chen@sifive.com, tommy.wu@sifive.com, eric.lin@sifive.com, viccent.chen@sifive.com, zong.li@sifive.com, samuel.holland@sifive.com Subject: [PATCH v3 4/7] riscv: ftrace: do not use stop_machine to update code Date: Thu, 28 Nov 2024 01:29:05 +0800 Message-Id: <20241127172908.17149-5-andybnac@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-145) In-Reply-To: <20241127172908.17149-1-andybnac@gmail.com> References: <20241127172908.17149-1-andybnac@gmail.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Andy Chiu Now it is safe to remove dependency from stop_machine() for us to patch code in ftrace. Signed-off-by: Andy Chiu --- arch/riscv/kernel/ftrace.c | 53 +++----------------------------------- 1 file changed, 4 insertions(+), 49 deletions(-) diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 5ebe412280ef..57a6558e212e 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -13,23 +13,13 @@ #include #ifdef CONFIG_DYNAMIC_FTRACE -void ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex) +void arch_ftrace_update_code(int command) { mutex_lock(&text_mutex); - - /* - * The code sequences we use for ftrace can't be patched while the - * kernel is running, so we need to use stop_machine() to modify them - * for now. This doesn't play nice with text_mutex, we use this flag - * to elide the check. - */ - riscv_patch_in_stop_machine = true; -} - -void ftrace_arch_code_modify_post_process(void) __releases(&text_mutex) -{ - riscv_patch_in_stop_machine = false; + command |= FTRACE_MAY_SLEEP; + ftrace_modify_all_code(command); mutex_unlock(&text_mutex); + flush_icache_all(); } static int ftrace_check_current_call(unsigned long hook_pos, @@ -155,41 +145,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return __ftrace_modify_call_site(&ftrace_call_dest, func, true); } -struct ftrace_modify_param { - int command; - atomic_t cpu_count; -}; - -static int __ftrace_modify_code(void *data) -{ - struct ftrace_modify_param *param = data; - - if (atomic_inc_return(¶m->cpu_count) == num_online_cpus()) { - ftrace_modify_all_code(param->command); - /* - * Make sure the patching store is effective *before* we - * increment the counter which releases all waiting CPUs - * by using the release variant of atomic increment. The - * release pairs with the call to local_flush_icache_all() - * on the waiting CPU. - */ - atomic_inc_return_release(¶m->cpu_count); - } else { - while (atomic_read(¶m->cpu_count) <= num_online_cpus()) - cpu_relax(); - - local_flush_icache_all(); - } - - return 0; -} - -void arch_ftrace_update_code(int command) -{ - struct ftrace_modify_param param = { command, ATOMIC_INIT(0) }; - - stop_machine(__ftrace_modify_code, ¶m, cpu_online_mask); -} #endif #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS