From patchwork Thu Feb 18 23:48:19 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Long X-Patchwork-Id: 8355131 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CF0D7C0553 for ; Thu, 18 Feb 2016 23:53:16 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B30E9203E6 for ; Thu, 18 Feb 2016 23:53:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9F2DD203B6 for ; Thu, 18 Feb 2016 23:53:14 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aWYM1-0007Yx-AA; Thu, 18 Feb 2016 23:51:25 +0000 Received: from mail-qg0-x22a.google.com ([2607:f8b0:400d:c04::22a]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aWYJd-0004Ga-T3 for linux-arm-kernel@lists.infradead.org; Thu, 18 Feb 2016 23:49:04 +0000 Received: by mail-qg0-x22a.google.com with SMTP id b67so50020793qgb.1 for ; Thu, 18 Feb 2016 15:48:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=EF/wyy3lod7SIsQToUrQyVWBtx7rJDo6M8ICUiYtbeA=; b=Xmd9/RoQ6A1pPDtgGwPfwASZRp9z3o+weh2avshLEm5PDfUL2D1eL6N0p7FXjDrSwx ekxcpb7f2YispF6TA5o58DSWADY2Xbs2b3JYSIzony8Qc2cmTCABiF5/wkEdrpLkV1vL fbLx2ftjYbKPjUJZVxghSwdhMoeMETn1Vtuu4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=EF/wyy3lod7SIsQToUrQyVWBtx7rJDo6M8ICUiYtbeA=; b=j+hMK1UCQrAIeiQWO53RHqqwehiPv5seb72oJDay/qcPzJ78J40KFz0MPleLX8V/eL 1u3DnVnqjWVWA/ckfb7KBuN5/IZGGpGwtUM1pehJXCHp1gqS7EzSVkepQgoK86lyz7sW GytsJ/UGnY7fGgL1w/GMx20QGx7rOTGSdNXXVtXHxedTYUbuVLyqveGf3UlpCpgztSmK RwuK4DefnXinoxub3ryCnYhNquWdzL/rq3vaQgMFCXJBIRyLm8+54YdoiN6cddJg8HWU 7NxNc0/uEOpEhoDwNYcOlS+WFIi6/8YkKn6sczbXcfF3ap4RQZPHMewrVkp0fM3Xuqr6 yxbg== X-Gm-Message-State: AG10YOS8yWbtijH7YX0dy+IUhNAkTqUeqUzDLj9ieB3i9jYKI2N304RcoxOQCE+d11qPM3H6 X-Received: by 10.140.104.242 with SMTP id a105mr12408987qgf.1.1455839316890; Thu, 18 Feb 2016 15:48:36 -0800 (PST) Received: from localhost.localdomain (pool-72-71-243-249.cncdnh.fast00.myfairpoint.net. [72.71.243.249]) by smtp.googlemail.com with ESMTPSA id w70sm3711845qge.13.2016.02.18.15.48.35 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 18 Feb 2016 15:48:36 -0800 (PST) From: David Long To: Catalin Marinas , Will Deacon , Sandeepa Prabhu , William Cohen , Pratyush Anand , Steve Capper , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/8] arm64: Add trampoline code for kretprobes Date: Thu, 18 Feb 2016 18:48:19 -0500 Message-Id: <1455839301-26464-7-git-send-email-dave.long@linaro.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1455839301-26464-1-git-send-email-dave.long@linaro.org> References: <1455839301-26464-1-git-send-email-dave.long@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160218_154858_360957_968FD9E0 X-CRM114-Status: GOOD ( 18.26 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Petr Mladek , Viresh Kumar , John Blackwood , Feng Kan , Zi Shen Lim , Dave P Martin , Yang Shi , Vladimir Murzin , Kees Cook , "Suzuki K. Poulose" , Marc Zyngier , Mark Brown , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Ard Biesheuvel , Greg Kroah-Hartman , Mark Salyzyn , James Morse , Christoffer Dall , Andrew Morton , Robin Murphy , Jens Wiklander , Balamurugan Shanmugam MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: William Cohen The trampoline code is used by kretprobes to capture a return from a probed function. This is done by saving the registers, calling the handler, and restoring the registers. The code then returns to the original saved caller return address. It is necessary to do this directly instead of using a software breakpoint because the code used in processing that breakpoint could itself be kprobe'd and cause a problematic reentry into the debug exception handler. Signed-off-by: William Cohen Signed-off-by: David A. Long --- arch/arm64/include/asm/kprobes.h | 2 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/asm-offsets.c | 22 +++++++++++ arch/arm64/kernel/kprobes.c | 5 +++ arch/arm64/kernel/kprobes_trampoline.S | 67 ++++++++++++++++++++++++++++++++++ 5 files changed, 97 insertions(+) create mode 100644 arch/arm64/kernel/kprobes_trampoline.S diff --git a/arch/arm64/include/asm/kprobes.h b/arch/arm64/include/asm/kprobes.h index 79c9511..61b4915 100644 --- a/arch/arm64/include/asm/kprobes.h +++ b/arch/arm64/include/asm/kprobes.h @@ -56,5 +56,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); int kprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr); int kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr); +void kretprobe_trampoline(void); +void __kprobes *trampoline_probe_handler(struct pt_regs *regs); #endif /* _ARM_KPROBES_H */ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 08325e5..f192b7d 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -37,6 +37,7 @@ arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o arm64-obj-$(CONFIG_KGDB) += kgdb.o arm64-obj-$(CONFIG_KPROBES) += kprobes.o kprobes-arm64.o \ + kprobes_trampoline.o \ probes-simulate-insn.o arm64-obj-$(CONFIG_EFI) += efi.o efi-entry.stub.o arm64-obj-$(CONFIG_PCI) += pci.o diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index fffa4ac6..460b54c 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -50,6 +50,28 @@ int main(void) DEFINE(S_X5, offsetof(struct pt_regs, regs[5])); DEFINE(S_X6, offsetof(struct pt_regs, regs[6])); DEFINE(S_X7, offsetof(struct pt_regs, regs[7])); + DEFINE(S_X8, offsetof(struct pt_regs, regs[8])); + DEFINE(S_X9, offsetof(struct pt_regs, regs[9])); + DEFINE(S_X10, offsetof(struct pt_regs, regs[10])); + DEFINE(S_X11, offsetof(struct pt_regs, regs[11])); + DEFINE(S_X12, offsetof(struct pt_regs, regs[12])); + DEFINE(S_X13, offsetof(struct pt_regs, regs[13])); + DEFINE(S_X14, offsetof(struct pt_regs, regs[14])); + DEFINE(S_X15, offsetof(struct pt_regs, regs[15])); + DEFINE(S_X16, offsetof(struct pt_regs, regs[16])); + DEFINE(S_X17, offsetof(struct pt_regs, regs[17])); + DEFINE(S_X18, offsetof(struct pt_regs, regs[18])); + DEFINE(S_X19, offsetof(struct pt_regs, regs[19])); + DEFINE(S_X20, offsetof(struct pt_regs, regs[20])); + DEFINE(S_X21, offsetof(struct pt_regs, regs[21])); + DEFINE(S_X22, offsetof(struct pt_regs, regs[22])); + DEFINE(S_X23, offsetof(struct pt_regs, regs[23])); + DEFINE(S_X24, offsetof(struct pt_regs, regs[24])); + DEFINE(S_X25, offsetof(struct pt_regs, regs[25])); + DEFINE(S_X26, offsetof(struct pt_regs, regs[26])); + DEFINE(S_X27, offsetof(struct pt_regs, regs[27])); + DEFINE(S_X28, offsetof(struct pt_regs, regs[28])); + DEFINE(S_X29, offsetof(struct pt_regs, regs[29])); DEFINE(S_LR, offsetof(struct pt_regs, regs[30])); DEFINE(S_SP, offsetof(struct pt_regs, sp)); #ifdef CONFIG_COMPAT diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c index 52f6c3d..0ce4637 100644 --- a/arch/arm64/kernel/kprobes.c +++ b/arch/arm64/kernel/kprobes.c @@ -531,6 +531,11 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) return 1; } +void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) +{ + return (void *) 0; +} + int __init arch_init_kprobes(void) { return 0; diff --git a/arch/arm64/kernel/kprobes_trampoline.S b/arch/arm64/kernel/kprobes_trampoline.S new file mode 100644 index 0000000..5a336cf --- /dev/null +++ b/arch/arm64/kernel/kprobes_trampoline.S @@ -0,0 +1,67 @@ +/* + * trampoline entry and return code for kretprobes. + */ + +#include +#include + + .text + +ENTRY(kretprobe_trampoline) + + sub sp, sp, #S_FRAME_SIZE + + stp x0, x1, [sp, #S_X0] + stp x2, x3, [sp, #S_X2] + stp x4, x5, [sp, #S_X4] + stp x6, x7, [sp, #S_X6] + stp x8, x9, [sp, #S_X8] + stp x10, x11, [sp, #S_X10] + stp x12, x13, [sp, #S_X12] + stp x14, x15, [sp, #S_X14] + stp x16, x17, [sp, #S_X16] + stp x18, x19, [sp, #S_X18] + stp x20, x21, [sp, #S_X20] + stp x22, x23, [sp, #S_X22] + stp x24, x25, [sp, #S_X24] + stp x26, x27, [sp, #S_X26] + stp x28, x29, [sp, #S_X28] + str x30, [sp, #S_LR] + add x0, sp, #S_FRAME_SIZE + str x0, [sp, #S_SP] + mrs x0, nzcv + mrs x1, daif + orr x0, x0, x1 + /* There seems no easy way to get the mode field so make one up */ + add x0, x0, #5 + str x0, [sp, #S_PSTATE] + + mov x0, sp + bl trampoline_probe_handler + /* Replace trampoline address in lr with actual + orig_ret_addr return address. */ + str x0, [sp, #S_LR] + + ldr x0, [sp, #S_PSTATE] + msr nzcv, x0 + ldp x0, x1, [sp, #S_X0] + ldp x2, x3, [sp, #S_X2] + ldp x4, x5, [sp, #S_X4] + ldp x6, x7, [sp, #S_X6] + ldp x8, x9, [sp, #S_X8] + ldp x10, x11, [sp, #S_X10] + ldp x12, x13, [sp, #S_X12] + ldp x14, x15, [sp, #S_X14] + ldp x16, x17, [sp, #S_X16] + ldp x18, x19, [sp, #S_X18] + ldp x20, x21, [sp, #S_X20] + ldp x22, x23, [sp, #S_X22] + ldp x24, x25, [sp, #S_X24] + ldp x26, x27, [sp, #S_X26] + ldp x28, x29, [sp, #S_X28] + ldr x30, [sp, #S_LR] + + add sp, sp, #S_FRAME_SIZE + ret + +ENDPROC(kretprobe_trampoline)