From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 772A9ECDE44 for ; Fri, 26 Oct 2018 14:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3838A20665 for ; Fri, 26 Oct 2018 14:21:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3838A20665 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727524AbeJZW7J (ORCPT ); Fri, 26 Oct 2018 18:59:09 -0400 Received: from verein.lst.de ([213.95.11.211]:37757 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726296AbeJZW7I (ORCPT ); Fri, 26 Oct 2018 18:59:08 -0400 Received: by newverein.lst.de (Postfix, from userid 2005) id 5F0D868C95; Fri, 26 Oct 2018 16:21:52 +0200 (CEST) To: Will Deacon , Catalin Marinas , Julien Thierry , Steven Rostedt , Josh Poimboeuf , Ingo Molnar , Ard Biesheuvel , Arnd Bergmann , AKASHI Takahiro Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Subject: [PATCH v4 2/3] arm64: implement live patching In-Reply-To: <20181026142008.D922868C94@newverein.lst.de> References: <20181026142008.D922868C94@newverein.lst.de> Message-Id: <20181026142152.5F0D868C95@newverein.lst.de> Date: Fri, 26 Oct 2018 16:21:52 +0200 (CEST) From: duwe@lst.de (Torsten Duwe) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Based on ftrace with regs, do the usual thing. (see Documentation/livepatch/livepatch.txt) Use task flag bit 6 to track patch transisiton state for the consistency model. Add it to the work mask so it gets cleared on all kernel exits to userland. Tell livepatch regs->pc is the place to change the return address. Make sure the graph tracer call hook is only called on the final function entry in case regs->pc gets modified after an interception. Signed-off-by: Torsten Duwe --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -120,6 +120,7 @@ config ARM64 select HAVE_GENERIC_DMA_COHERENT select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING + select HAVE_LIVEPATCH select HAVE_MEMBLOCK select HAVE_MEMBLOCK_NODE_MAP if NUMA select HAVE_NMI @@ -1350,4 +1351,6 @@ if CRYPTO source "arch/arm64/crypto/Kconfig" endif +source "kernel/livepatch/Kconfig" + source "lib/Kconfig" --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -76,6 +76,7 @@ void arch_release_task_struct(struct tas #define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */ #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */ #define TIF_FSCHECK 5 /* Check FS is USER_DS on return */ +#define TIF_PATCH_PENDING 6 #define TIF_NOHZ 7 #define TIF_SYSCALL_TRACE 8 #define TIF_SYSCALL_AUDIT 9 @@ -94,6 +95,7 @@ void arch_release_task_struct(struct tas #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE) +#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) #define _TIF_NOHZ (1 << TIF_NOHZ) #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) @@ -106,7 +108,8 @@ void arch_release_task_struct(struct tas #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ - _TIF_UPROBE | _TIF_FSCHECK) + _TIF_UPROBE | _TIF_FSCHECK | \ + _TIF_PATCH_PENDING) #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \ --- /dev/null +++ b/arch/arm64/include/asm/livepatch.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * livepatch.h - arm64-specific Kernel Live Patching Core + * + * Copyright (C) 2016,2018 SUSE + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ +#ifndef _ASM_ARM64_LIVEPATCH_H +#define _ASM_ARM64_LIVEPATCH_H + +#include + +static inline int klp_check_compiler_support(void) +{ + return 0; +} + +static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) +{ + regs->pc = ip; +} + +#endif /* _ASM_ARM64_LIVEPATCH_H */ --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -226,6 +226,7 @@ ftrace_common: /* The program counter just after the ftrace call site */ str lr, [x9, #S_PC] + /* The stack pointer as it was on ftrace_caller entry... */ add x28, fp, #16 str x28, [x9, #S_SP] @@ -233,6 +234,10 @@ ftrace_common: ldr x28, [fp, 8] str x28, [x9, #S_LR] /* to pt_regs.r[30] */ +#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_FUNCTION_GRAPH_TRACER) + mov x28, lr /* remember old return address */ +#endif + ldr_l x2, function_trace_op, x0 ldr x1, [fp, #8] sub x0, lr, #8 /* function entry == IP */ @@ -245,6 +250,17 @@ ftrace_call: bl ftrace_stub +#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_FUNCTION_GRAPH_TRACER) + /* Is the trace function a live patcher an has messed with + * the return address? + */ + add x9, sp, #16 /* advance to pt_regs for restore */ + ldr x0, [x9, #S_PC] + cmp x0, x28 /* compare with the value we remembered */ + /* to not call graph tracer's "call" mechanism twice! */ + b.ne ftrace_common_return +#endif + #ifdef CONFIG_FUNCTION_GRAPH_TRACER .global ftrace_graph_call ftrace_graph_call: // ftrace_graph_caller(); --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -934,6 +935,9 @@ asmlinkage void do_notify_resume(struct if (thread_flags & _TIF_UPROBE) uprobe_notify_resume(regs); + if (thread_flags & _TIF_PATCH_PENDING) + klp_update_patch_state(current); + if (thread_flags & _TIF_SIGPENDING) do_signal(regs);