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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AB0FC433EF for ; Fri, 1 Jul 2022 14:17:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231349AbiGAOQ7 (ORCPT ); Fri, 1 Jul 2022 10:16:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229562AbiGAOQ5 (ORCPT ); Fri, 1 Jul 2022 10:16:57 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC7C839165; Fri, 1 Jul 2022 07:16:55 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 886F71FFCE; Fri, 1 Jul 2022 14:16:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1656685014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=t0biNoxFr1aDMPWz/5vBUkSHpR2jUX5N7DeLsTbNOZc=; b=XysSLuJySInIdkK0lVZMUQF69iVx3McotBxqnEsRsWv+Nnr/qj/smghZpjL6MSpZq2Tds1 XB6Eux5k7QS4pQRo6NcrKGWSKk9x/IZ0yHQ7/kCZhQEU1rgvqfE8KCxStOkoKdb3tTHE01 J5GikShi2gBEJKbQcCFq7OJccBZzU7E= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1656685014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=t0biNoxFr1aDMPWz/5vBUkSHpR2jUX5N7DeLsTbNOZc=; b=tlTvbUzN4iqa0S0pMKOZWl68JFjFRiB1eilXyFsp6/U12zlkxte3RYeiEIdHSvzDPOTCgN 4yKtXZ4BB0vvbgDA== Received: from pobox.suse.cz (pobox.suse.cz [10.100.2.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 95AE92C141; Fri, 1 Jul 2022 14:16:53 +0000 (UTC) Date: Fri, 1 Jul 2022 16:16:53 +0200 (CEST) From: Miroslav Benes To: madvenka@linux.microsoft.com cc: 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 Subject: Re: [RFC PATCH v2 19/20] arm64: Miscellaneous changes required for enabling livepatch In-Reply-To: <20220524001637.1707472-20-madvenka@linux.microsoft.com> Message-ID: References: <20220524001637.1707472-1-madvenka@linux.microsoft.com> <20220524001637.1707472-20-madvenka@linux.microsoft.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, sorry for the late reply... On Mon, 23 May 2022, madvenka@linux.microsoft.com wrote: > 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/livepatch.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 long ip) > +{ > + struct pt_regs *regs = ftrace_get_regs(fregs); > + > + regs->pc = ip; > +} kernel/livepatch/ does not use klp_arch_set_pc() anymore. It was replaced by ftrace_instruction_pointer_set() and CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS. > +/* > + * 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 = faddr + AARCH64_INSN_SIZE; > + > +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) > + addr = ftrace_location_range(addr, addr + AARCH64_INSN_SIZE); > +#endif > + > + return addr; > +} This is not needed either. peterz improved the ftrace code and livepatch now uses ftrace_location() which gives the proper location directly. > 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) > > #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) > > #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 > > @@ -938,6 +939,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) > (void __user *)NULL, current); > } > > + if (thread_flags & _TIF_PATCH_PENDING) > + klp_update_patch_state(current); > + > if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) > do_signal(regs); The rest should be fine. Regards Miroslav