From patchwork Tue Sep 27 22:28:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 12991435 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 529C6C54EE9 for ; Tue, 27 Sep 2022 22:30:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ceSqM51ANZZKea7nhxQd8nvotCS09HXu/J29LVTwk3k=; b=QB1j1hpaAZ5ZNdcHucSlbG7M0m 5Z1OtysczD5MYifqsA8DuPQqPYEU1xcuIYxy52BAzbwOYAHm0JyzH0ea9uchIyLBEaYcAAjHb12h2 /c4SgbzSN1TAAd7vAZQMiWwTG/9tu4DbYZLVRGMcnEFE7+8bSL34chFU6DIYZ+KQU3tH2YEyso3DB iEZssc+2XFrf88fAmPKSZD1J5QrCat4K9wyznmvA494zmiKhAgQM8oudy9p8OTJoM/yUxtt+COlSF rXmAcIljKUtnUFjTkwDo0q+jcatlPBWicbkNIVJClMbBNdW0qgp9nkWn93NrqUKJcAPKQ9AwfZQ1y 1ddBnn7Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1odJ4b-00CvDB-KC; Tue, 27 Sep 2022 22:29:05 +0000 Received: from mail-yw1-x114a.google.com ([2607:f8b0:4864:20::114a]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1odJ4W-00CvC1-5n for linux-arm-kernel@lists.infradead.org; Tue, 27 Sep 2022 22:29:02 +0000 Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-34d3fbc7cfcso103803337b3.7 for ; Tue, 27 Sep 2022 15:28:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date; bh=5j26k1RGiLW8Uo7IC6/3OcmNOF3gkmfBt6Q6TAoi2Kg=; b=eTS62RFlLiYCwo0bfgrnrZ1Bv/rYVcKToDsEPknTdQ4tOdafMyvJsFt+BqAgtPYc9b kBHlAlp0QrtVRA0pCmC/mNrX/hEUBzzA6u/8UlMROXlHhvO3ublVSioFzQRaj2vmU/wy wyUG79hGZGNs+hB5WjPZAzwy71tX3kYxXoTPzX3iPOGhvxBYcKejY43tJX/I0aurw6+v Cnt2sLOSRE183PzmrLIaksWD9L9zzuUABYwnFMSJRgobaBMNVaLZtm0s/54JcoAo3+c3 5+F7HfdbtzNe6japhDwRg0GJ3kiL4bE5Xw5C943QmPJa/QGUboc/z9QiezVOpRzo4d0s H0Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date; bh=5j26k1RGiLW8Uo7IC6/3OcmNOF3gkmfBt6Q6TAoi2Kg=; b=7udkAsxLpBfT7mBE7Ihcyrgr6WZQcXYoDo0rShehrQKUrZJlZBBvmG269FLqILli+M bKBkUhhM3GHI5632ey5wXvgnMhaMrBGZaDGd88PxTSljLyORpjEGsP0cWXCOjq7bL1VW gE15KouW7O/1pSIWIyglH/Xhcv38bAr3Zwqr21F3UyyEbYACdgYYa8BpmTtwwWlEb/IB 9PNQ89fM+QyZIin7gt82AdEPB975ON4t6TunkGFdB1z6SWg9qE8rw6m4nxm/FEdJkwA4 +5JDDTQSOeCO7K6b+NWWmzEEx1kFDD+Ub3TImuM5lmPKva8g/+MJ2psxKmPOynyaI/F3 w3Ow== X-Gm-Message-State: ACrzQf1vMRNz1cpXr1LQZeVJQWrMLCRtblD8b5QKijYNT+gEs1OcTGEG QoUaBqvsb2QgLh1kZvvn1SYhCN2V+s/PBakPigc= X-Google-Smtp-Source: AMsMyM60ZIOlgv0PrY0oMbc25dEzaRc1LSNuTavk8kcVFGWzbMliM8AFc3YFMNfUSy2bGF5YOCX7T8pSWU+AXFy0IXg= X-Received: from ndesaulniers-desktop.svl.corp.google.com ([2620:0:100e:712:5d88:f716:dcf7:513]) (user=ndesaulniers job=sendgmr) by 2002:a25:20d5:0:b0:6bb:7593:21a2 with SMTP id g204-20020a2520d5000000b006bb759321a2mr12398904ybg.634.1664317735924; Tue, 27 Sep 2022 15:28:55 -0700 (PDT) Date: Tue, 27 Sep 2022 15:28:51 -0700 In-Reply-To: Mime-Version: 1.0 References: X-Developer-Key: i=ndesaulniers@google.com; a=ed25519; pk=UIrHvErwpgNbhCkRZAYSX0CFd/XFEwqX3D0xqtqjNug= X-Developer-Signature: v=1; a=ed25519-sha256; t=1664317731; l=7639; i=ndesaulniers@google.com; s=20220923; h=from:subject; bh=7ljV5O3Ap6RBvMjpLNXnocrDpcDmzzVqDCFOYQu6Rmw=; b=cJ85ndrhcQE+tZSRc1g7hiFqbLYIxBNn/D0xJqazvVvr89fgsZkALE+RRpVvt2Z+nxXYKgrZrMTR xd+S0D/KC7yGuCnyFNDn9/vMijdu98epuO4xeizXMm+LaLb/PllX X-Mailer: git-send-email 2.37.3.998.g577e59143f-goog Message-ID: <20220927222851.37550-1-ndesaulniers@google.com> Subject: [PATCH v2] ARM: kprobes: move __kretprobe_trampoline to out of line assembler From: Nick Desaulniers To: Russell King , Masami Hiramatsu Cc: "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" , Arnd Bergmann , Nathan Chancellor , Tom Rix , sparkhuang , Ard Biesheuvel , Steven Rostedt , Linus Walleij , Chen Zhongjin , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, Naresh Kamboju , regressions@lists.linux.dev, lkft-triage@lists.linaro.org, Nick Desaulniers , Linux Kernel Functional Testing , Logan Chien X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220927_152900_910117_A9354D82 X-CRM114-Status: GOOD ( 22.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org commit 1069c1dd20a3 ("ARM: 9231/1: Recover kretprobes return address for EABI stack unwinder") tickled a bug in clang's integrated assembler where the .save and .pad directives must have corresponding .fnstart directives. The integrated assembler is unaware that the compiler will be generating the .fnstart directive. arch/arm/probes/kprobes/core.c:409:30: error: .fnstart must precede .save or .vsave directives :3:2: note: instantiated into assembly here .save {sp, lr, pc} ^ arch/arm/probes/kprobes/core.c:412:29: error: .fnstart must precede .pad directive :6:2: note: instantiated into assembly here .pad #52 ^ __kretprobe_trampoline's definition is already entirely inline asm. Move it to out-of-line asm to avoid breaking the build. Link: https://github.com/llvm/llvm-project/issues/57993 Link: https://github.com/ClangBuiltLinux/linux/issues/1718 Reported-by: Nathan Chancellor Reported-by: Linux Kernel Functional Testing Suggested-by: Logan Chien Signed-off-by: Nick Desaulniers --- Changes v1 -> v2: * rebase on linux-next again. * drop commented out declaration of __kretprobe_trampoline from v1. arch/arm/probes/kprobes/Makefile | 1 + arch/arm/probes/kprobes/core.c | 50 +---------------- .../arm/probes/kprobes/kretprobe-trampoline.S | 55 +++++++++++++++++++ include/asm-generic/kprobes.h | 13 +++-- 4 files changed, 68 insertions(+), 51 deletions(-) create mode 100644 arch/arm/probes/kprobes/kretprobe-trampoline.S diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile index 6159010dac4a..cdbe9dd99e28 100644 --- a/arch/arm/probes/kprobes/Makefile +++ b/arch/arm/probes/kprobes/Makefile @@ -3,6 +3,7 @@ KASAN_SANITIZE_actions-common.o := n KASAN_SANITIZE_actions-arm.o := n KASAN_SANITIZE_actions-thumb.o := n obj-$(CONFIG_KPROBES) += core.o actions-common.o checkers-common.o +obj-$(CONFIG_KPROBES) += kretprobe-trampoline.o obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o test-kprobes-objs := test-core.o diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 9090c3a74dcc..53f17529d2cb 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -365,54 +365,8 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, return NOTIFY_DONE; } -/* - * When a retprobed function returns, trampoline_handler() is called, - * calling the kretprobe's handler. We construct a struct pt_regs to - * give a view of registers r0-r11, sp, lr, and pc to the user - * return-handler. This is not a complete pt_regs structure, but that - * should be enough for stacktrace from the return handler with or - * without pt_regs. - */ -void __naked __kprobes __kretprobe_trampoline(void) -{ - __asm__ __volatile__ ( -#ifdef CONFIG_FRAME_POINTER - "ldr lr, =__kretprobe_trampoline \n\t" - /* __kretprobe_trampoline makes a framepointer on pt_regs. */ -#ifdef CONFIG_CC_IS_CLANG - "stmdb sp, {sp, lr, pc} \n\t" - "sub sp, sp, #12 \n\t" - /* In clang case, pt_regs->ip = lr. */ - "stmdb sp!, {r0 - r11, lr} \n\t" - /* fp points regs->r11 (fp) */ - "add fp, sp, #44 \n\t" -#else /* !CONFIG_CC_IS_CLANG */ - /* In gcc case, pt_regs->ip = fp. */ - "stmdb sp, {fp, sp, lr, pc} \n\t" - "sub sp, sp, #16 \n\t" - "stmdb sp!, {r0 - r11} \n\t" - /* fp points regs->r15 (pc) */ - "add fp, sp, #60 \n\t" -#endif /* CONFIG_CC_IS_CLANG */ -#else /* !CONFIG_FRAME_POINTER */ - "sub sp, sp, #16 \n\t" - "stmdb sp!, {r0 - r11} \n\t" -#endif /* CONFIG_FRAME_POINTER */ - "mov r0, sp \n\t" - "bl trampoline_handler \n\t" - "mov lr, r0 \n\t" - "ldmia sp!, {r0 - r11} \n\t" - "add sp, sp, #16 \n\t" -#ifdef CONFIG_THUMB2_KERNEL - "bx lr \n\t" -#else - "mov pc, lr \n\t" -#endif - : : : "memory"); -} - /* Called from __kretprobe_trampoline */ -static __used __kprobes void *trampoline_handler(struct pt_regs *regs) +__kprobes void *trampoline_handler(struct pt_regs *regs) { return (void *)kretprobe_trampoline_handler(regs, (void *)regs->ARM_fp); } @@ -420,6 +374,8 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { + extern void __kretprobe_trampoline(void); + ri->ret_addr = (kprobe_opcode_t *)regs->ARM_lr; ri->fp = (void *)regs->ARM_fp; diff --git a/arch/arm/probes/kprobes/kretprobe-trampoline.S b/arch/arm/probes/kprobes/kretprobe-trampoline.S new file mode 100644 index 000000000000..261c99b8c17f --- /dev/null +++ b/arch/arm/probes/kprobes/kretprobe-trampoline.S @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include +#include + +/* + * When a retprobed function returns, trampoline_handler() is called, + * calling the kretprobe's handler. We construct a struct pt_regs to + * give a view of registers r0-r11, sp, lr, and pc to the user + * return-handler. This is not a complete pt_regs structure, but that + * should be enough for stacktrace from the return handler with or + * without pt_regs. + */ +__KPROBE +SYM_FUNC_START(__kretprobe_trampoline) +UNWIND(.fnstart) + ldr lr, =__kretprobe_trampoline +#ifdef CONFIG_FRAME_POINTER + /* __kretprobe_trampoline makes a framepointer on pt_regs. */ +#ifdef CONFIG_CC_IS_CLANG + stmdb sp, {sp, lr, pc} + sub sp, sp, #12 + /* In clang case, pt_regs->ip = lr. */ + stmdb sp!, {r0 - r11, lr} + /* fp points regs->r11 (fp) */ + add fp, sp, #44 +#else /* !CONFIG_CC_IS_CLANG */ + /* In gcc case, pt_regs->ip = fp. */ + stmdb sp, {fp, sp, lr, pc} + sub sp, sp, #16 + stmdb sp!, {r0 - r11} + /* fp points regs->r15 (pc) */ + add fp, sp, #60 +#endif /* CONFIG_CC_IS_CLANG */ +#else /* !CONFIG_FRAME_POINTER */ + /* store SP, LR on stack and add EABI unwind hint */ + stmdb sp, {sp, lr, pc} +UNWIND(.save {sp, lr, pc}) + sub sp, sp, #16 + stmdb sp!, {r0 - r11} +UNWIND(.pad #52) +#endif /* CONFIG_FRAME_POINTER */ + mov r0, sp + bl trampoline_handler + mov lr, r0 + ldmia sp!, {r0 - r11} + add sp, sp, #16 +#ifdef CONFIG_THUMB2_KERNEL + bx lr +#else + mov pc, lr +#endif +UNWIND(.fnend) +SYM_FUNC_END(__kretprobe_trampoline) diff --git a/include/asm-generic/kprobes.h b/include/asm-generic/kprobes.h index 060eab094e5a..1509daa281b8 100644 --- a/include/asm-generic/kprobes.h +++ b/include/asm-generic/kprobes.h @@ -2,7 +2,11 @@ #ifndef _ASM_GENERIC_KPROBES_H #define _ASM_GENERIC_KPROBES_H -#if defined(__KERNEL__) && !defined(__ASSEMBLY__) +#ifdef __KERNEL__ + +#ifdef __ASSEMBLY__ +# define __KPROBE .section ".kprobes.text", "ax" +#else #ifdef CONFIG_KPROBES /* * Blacklist ganerating macro. Specify functions which is not probed @@ -16,11 +20,12 @@ static unsigned long __used \ /* Use this to forbid a kprobes attach on very low level functions */ # define __kprobes __section(".kprobes.text") # define nokprobe_inline __always_inline -#else +#else /* !defined(CONFIG_KPROBES) */ # define NOKPROBE_SYMBOL(fname) # define __kprobes # define nokprobe_inline inline -#endif -#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */ +#endif /* defined(CONFIG_KPROBES) */ +#endif /* defined(__ASSEMBLY__) */ +#endif /* defined(__KERNEL__) */ #endif /* _ASM_GENERIC_KPROBES_H */