From nobody Wed Apr 24 22:24:08 2024 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 39AC7C433EF for ; Tue, 24 May 2022 00:18:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232182AbiEXASl (ORCPT ); Mon, 23 May 2022 20:18:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232084AbiEXAR3 (ORCPT ); Mon, 23 May 2022 20:17:29 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 89A1E95DC0; Mon, 23 May 2022 17:17:06 -0700 (PDT) Received: from x64host.home (unknown [47.189.24.195]) by linux.microsoft.com (Postfix) with ESMTPSA id 861EF20B8952; Mon, 23 May 2022 17:17:05 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 861EF20B8952 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1653351426; bh=W+kmmdWYfiBwaaGDXXPjvGV5/gA5GGveaxkzrHm/ZVs=; h=From:To:Subject:Date:In-Reply-To:References:From; b=jRvS00IvG4gtA8YIpC6RWC8bSYDRRjmfL4vLqLYf2/ydDSDLS0PCBoYu0pfmvGR9L vEW0prNJHP8P2Nns+JNS7mMiuIMB7TUO3JXJvmdUlPdwnnft3eMYz1Pxt7r1h46vXh 7pGFMc1xoaAVrp5whBjOG+WSNAjmkKv6bwpyC0Mo= From: madvenka@linux.microsoft.com To: jpoimboe@redhat.com, peterz@infradead.org, chenzhongjin@huawei.com, mark.rutland@arm.com, broonie@kernel.org, nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com, catalin.marinas@arm.com, will@kernel.org, jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [RFC PATCH v2 19/20] arm64: Miscellaneous changes required for enabling livepatch Date: Mon, 23 May 2022 19:16:36 -0500 Message-Id: <20220524001637.1707472-20-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220524001637.1707472-1-madvenka@linux.microsoft.com> References: <20220524001637.1707472-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Madhavan T. Venkataraman" - Create arch/arm64/include/asm/livepatch.h and define klp_arch_set_pc() and klp_get_ftrace_location() which are required for livepatch. - Define TIF_PATCH_PENDING in arch/arm64/include/asm/thread_info.h for livepatch. - Check TIF_PATCH_PENDING in do_notify_resume() to patch the current task for livepatch. Signed-off-by: Suraj Jitindar Singh Signed-off-by: Madhavan T. Venkataraman --- arch/arm64/include/asm/livepatch.h | 42 ++++++++++++++++++++++++++++ arch/arm64/include/asm/thread_info.h | 4 ++- arch/arm64/kernel/signal.c | 4 +++ 3 files changed, 49 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/livepatch.h diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/li= vepatch.h new file mode 100644 index 000000000000..72d7cd86f158 --- /dev/null +++ b/arch/arm64/include/asm/livepatch.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * livepatch.h - arm64-specific Kernel Live Patching Core + */ +#ifndef _ASM_ARM64_LIVEPATCH_H +#define _ASM_ARM64_LIVEPATCH_H + +#include + +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned lon= g ip) +{ + struct pt_regs *regs =3D ftrace_get_regs(fregs); + + regs->pc =3D ip; +} + +/* + * klp_get_ftrace_location is expected to return the address of the BL to = the + * relevant ftrace handler in the callsite. The location of this can vary = based + * on several compilation options. + * CONFIG_DYNAMIC_FTRACE_WITH_REGS + * - Inserts 2 nops on function entry the second of which is the BL + * referenced above. (See ftrace_init_nop() for the callsite sequence) + * (this is required by livepatch and must be selected) + * CONFIG_ARM64_BTI_KERNEL: + * - Inserts a hint #0x22 on function entry if the function is called + * indirectly (to satisfy BTI requirements), which is inserted before + * the two nops from above. + */ +#define klp_get_ftrace_location klp_get_ftrace_location +static inline unsigned long klp_get_ftrace_location(unsigned long faddr) +{ + unsigned long addr =3D faddr + AARCH64_INSN_SIZE; + +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) + addr =3D ftrace_location_range(addr, addr + AARCH64_INSN_SIZE); +#endif + + return addr; +} + +#endif /* _ASM_ARM64_LIVEPATCH_H */ diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/= thread_info.h index e1317b7c4525..a1d8999dbdcc 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -68,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst, #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */ #define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */ #define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */ +#define TIF_PATCH_PENDING 7 /* pending live patching update */ #define TIF_SYSCALL_TRACE 8 /* syscall trace active */ #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */ #define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */ @@ -98,11 +99,12 @@ int arch_dup_task_struct(struct task_struct *dst, #define _TIF_SVE (1 << TIF_SVE) #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) +#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) =20 #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ _TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \ - _TIF_NOTIFY_SIGNAL) + _TIF_NOTIFY_SIGNAL | _TIF_PATCH_PENDING) =20 #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \ diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 4a4122ef6f39..cbec9597349f 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include =20 @@ -938,6 +939,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned lo= ng thread_flags) (void __user *)NULL, current); } =20 + if (thread_flags & _TIF_PATCH_PENDING) + klp_update_patch_state(current); + if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) do_signal(regs); =20 --=20 2.25.1