From patchwork Wed Sep 9 14:07:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765493 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5CFE7746 for ; Wed, 9 Sep 2020 14:10:05 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 124F221D7D for ; Wed, 9 Sep 2020 14:10:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YQ4vAuGH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 124F221D7D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=yjoF/RQi0qYu8xFrHsbauYD4x9c9valQFiDIpXKgToQ=; b=YQ4vAuGH9HJSdKt/+RTuXZIZrw j73W8kh5l9+gbMmLK6jkqBNjKsFs7NEZMvYzvsmEaVKiEwbiNmptDqfm5neXFG7H+4WE77Dy3ua6R wE13H5ORAehi3UrCjopbMVoZ3sBf0wcN6u09YHdqxxE6S4xUEadLqMIhBnV56fRVOgRJRwdy1Nfzf SAncf9Z8c4ejydSIjSlFFjDS5GDwPizIlxyy050YhOF94iWFKRMNYqwOw9am5EzDgAzFXc7I8F6be eRldtZDXr0MdDC6ajPVAOX7VcnFsioCABD4pF3/o4gRqIa8hZbxcweObix+4GN4fL0iHefFqivdWr hsHMltzQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0lx-0008WB-1J; Wed, 09 Sep 2020 14:08:29 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0lu-0008Vl-HU for linux-arm-kernel@lists.infradead.org; Wed, 09 Sep 2020 14:08:27 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F1A6E31B; Wed, 9 Sep 2020 07:08:24 -0700 (PDT) Received: from a077416.arm.com (unknown [10.57.14.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6F2063F66E; Wed, 9 Sep 2020 07:08:17 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 1/6] arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions Date: Wed, 9 Sep 2020 19:37:54 +0530 Message-Id: <20200909140759.4170-2-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100826_698826_125757C2 X-CRM114-Status: GOOD ( 13.26 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Currently the ARMv8.3-PAuth combined branch instructions (braa, retaa etc.) are not simulated for out-of-line execution with a handler. Hence the uprobe of such instructions leads to kernel warnings in a loop as they are not explicitly checked and fall into INSN_GOOD categories. Other combined instructions like LDRAA and LDRBB can be probed. The issue of the combined branch instructions is fixed by adding group definitions of all such instructions and rejecting their probes. The instruction groups added are br_auth(braa, brab, braaz and brabz), blr_auth(blraa, blrab, blraaz and blrabz), ret_auth(retaa and retab) and eret_auth(eretaa and eretab). Warning log: WARNING: CPU: 0 PID: 156 at arch/arm64/kernel/probes/uprobes.c:182 uprobe_single_step_handler+0x34/0x50 Modules linked in: CPU: 0 PID: 156 Comm: func Not tainted 5.9.0-rc3 #188 Hardware name: Foundation-v8A (DT) pstate: 804003c9 (Nzcv DAIF +PAN -UAO BTYPE=--) pc : uprobe_single_step_handler+0x34/0x50 lr : single_step_handler+0x70/0xf8 sp : ffff800012af3e30 x29: ffff800012af3e30 x28: ffff000878723b00 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 x23: 0000000060001000 x22: 00000000cb000022 x21: ffff800012065ce8 x20: ffff800012af3ec0 x19: ffff800012068d50 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffff800010085c90 x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffff80001205a9c8 x5 : ffff80001205a000 x4 : ffff80001233db80 x3 : ffff8000100a7a60 x2 : 0020000000000003 x1 : 0000fffffffff008 x0 : ffff800012af3ec0 Call trace: uprobe_single_step_handler+0x34/0x50 single_step_handler+0x70/0xf8 do_debug_exception+0xb8/0x130 el0_sync_handler+0x138/0x1b8 el0_sync+0x158/0x180 Fixes: 74afda4016a7 ("arm64: compile the kernel with ptrauth return address signing") Fixes: 04ca3204fa09 ("arm64: enable pointer authentication") Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- Changes since v6: * Clubbed Ptrauth combined branch instructions as suggested by Will. arch/arm64/include/asm/insn.h | 4 ++++ arch/arm64/kernel/insn.c | 5 ++++- arch/arm64/kernel/probes/decode-insn.c | 3 ++- 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 0bc46149e491..4b39293d0f72 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -359,9 +359,13 @@ __AARCH64_INSN_FUNCS(brk, 0xFFE0001F, 0xD4200000) __AARCH64_INSN_FUNCS(exception, 0xFF000000, 0xD4000000) __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) +__AARCH64_INSN_FUNCS(br_auth, 0xFEFFF800, 0xD61F0800) __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) +__AARCH64_INSN_FUNCS(blr_auth, 0xFEFFF800, 0xD63F0800) __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) +__AARCH64_INSN_FUNCS(ret_auth, 0xFFFFFBFF, 0xD65F0BFF) __AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F03E0) +__AARCH64_INSN_FUNCS(eret_auth, 0xFFFFFBFF, 0xD69F0BFF) __AARCH64_INSN_FUNCS(mrs, 0xFFF00000, 0xD5300000) __AARCH64_INSN_FUNCS(msr_imm, 0xFFF8F01F, 0xD500401F) __AARCH64_INSN_FUNCS(msr_reg, 0xFFF00000, 0xD5100000) diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index a107375005bc..ccc8c9e22b25 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -176,7 +176,7 @@ bool __kprobes aarch64_insn_uses_literal(u32 insn) bool __kprobes aarch64_insn_is_branch(u32 insn) { - /* b, bl, cb*, tb*, b.cond, br, blr */ + /* b, bl, cb*, tb*, ret*, b.cond, br*, blr* */ return aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) || @@ -185,8 +185,11 @@ bool __kprobes aarch64_insn_is_branch(u32 insn) aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) || aarch64_insn_is_ret(insn) || + aarch64_insn_is_ret_auth(insn) || aarch64_insn_is_br(insn) || + aarch64_insn_is_br_auth(insn) || aarch64_insn_is_blr(insn) || + aarch64_insn_is_blr_auth(insn) || aarch64_insn_is_bcond(insn); } diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index 263d5fba4c8a..c541fb48886e 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -29,7 +29,8 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) aarch64_insn_is_msr_imm(insn) || aarch64_insn_is_msr_reg(insn) || aarch64_insn_is_exception(insn) || - aarch64_insn_is_eret(insn)) + aarch64_insn_is_eret(insn) || + aarch64_insn_is_eret_auth(insn)) return false; /* From patchwork Wed Sep 9 14:07:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765499 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 94B8E15AB for ; Wed, 9 Sep 2020 14:10:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 509AB21D90 for ; 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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0m6-00007O-7F; Wed, 09 Sep 2020 14:08:38 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0m3-00006s-B7 for linux-arm-kernel@lists.infradead.org; Wed, 09 Sep 2020 14:08:36 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D6BB931B; Wed, 9 Sep 2020 07:08:32 -0700 (PDT) Received: from a077416.arm.com (unknown [10.57.14.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 644A23F66E; Wed, 9 Sep 2020 07:08:25 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 2/6] arm64: traps: Allow force_signal_inject to pass esr error code Date: Wed, 9 Sep 2020 19:37:55 +0530 Message-Id: <20200909140759.4170-3-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100835_483274_ED3C0C68 X-CRM114-Status: GOOD ( 16.02 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Some error signal need to pass proper ARM esr error code to userspace to better identify the cause of the signal. So the function force_signal_inject is extended to pass this as a parameter. The existing code is not affected by this change. Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- arch/arm64/include/asm/traps.h | 2 +- arch/arm64/kernel/fpsimd.c | 4 ++-- arch/arm64/kernel/traps.c | 14 +++++++------- 3 files changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index cee5928e1b7d..d96dc2c7c09d 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -24,7 +24,7 @@ struct undef_hook { void register_undef_hook(struct undef_hook *hook); void unregister_undef_hook(struct undef_hook *hook); -void force_signal_inject(int signal, int code, unsigned long address); +void force_signal_inject(int signal, int code, unsigned long address, unsigned int err); void arm64_notify_segfault(unsigned long addr); void arm64_force_sig_fault(int signo, int code, void __user *addr, const char *str); void arm64_force_sig_mceerr(int code, void __user *addr, short lsb, const char *str); diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 55c8f3ec6705..77484359d44a 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -312,7 +312,7 @@ static void fpsimd_save(void) * re-enter user with corrupt state. * There's no way to recover, so kill it: */ - force_signal_inject(SIGKILL, SI_KERNEL, 0); + force_signal_inject(SIGKILL, SI_KERNEL, 0, 0); return; } @@ -936,7 +936,7 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) { /* Even if we chose not to use SVE, the hardware could still trap: */ if (unlikely(!system_supports_sve()) || WARN_ON(is_compat_task())) { - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); return; } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 13ebd5ca2070..29fd00fe94f2 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -412,7 +412,7 @@ static int call_undef_hook(struct pt_regs *regs) return fn ? fn(regs, instr) : 1; } -void force_signal_inject(int signal, int code, unsigned long address) +void force_signal_inject(int signal, int code, unsigned long address, unsigned int err) { const char *desc; struct pt_regs *regs = current_pt_regs(); @@ -438,7 +438,7 @@ void force_signal_inject(int signal, int code, unsigned long address) signal = SIGKILL; } - arm64_notify_die(desc, regs, signal, code, (void __user *)address, 0); + arm64_notify_die(desc, regs, signal, code, (void __user *)address, err); } /* @@ -455,7 +455,7 @@ void arm64_notify_segfault(unsigned long addr) code = SEGV_ACCERR; mmap_read_unlock(current->mm); - force_signal_inject(SIGSEGV, code, addr); + force_signal_inject(SIGSEGV, code, addr, 0); } void do_undefinstr(struct pt_regs *regs) @@ -468,14 +468,14 @@ void do_undefinstr(struct pt_regs *regs) return; BUG_ON(!user_mode(regs)); - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } NOKPROBE_SYMBOL(do_undefinstr); void do_bti(struct pt_regs *regs) { BUG_ON(!user_mode(regs)); - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } NOKPROBE_SYMBOL(do_bti); @@ -528,7 +528,7 @@ static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs) __user_cache_maint("ic ivau", address, ret); break; default: - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); return; } @@ -581,7 +581,7 @@ static void mrs_handler(unsigned int esr, struct pt_regs *regs) sysreg = esr_sys64_to_sysreg(esr); if (do_emulate_mrs(regs, sysreg, rt) != 0) - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } static void wfi_handler(unsigned int esr, struct pt_regs *regs) From patchwork Wed Sep 9 14:07:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765497 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7DAE51599 for ; Wed, 9 Sep 2020 14:10:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B5D721D7D for ; 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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0mA-00009N-QN; Wed, 09 Sep 2020 14:08:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0m6-00007Z-P0 for linux-arm-kernel@lists.infradead.org; Wed, 09 Sep 2020 14:08:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4841131B; Wed, 9 Sep 2020 07:08:38 -0700 (PDT) Received: from a077416.arm.com (unknown [10.57.14.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A74333F66E; Wed, 9 Sep 2020 07:08:33 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 3/6] arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements Date: Wed, 9 Sep 2020 19:37:56 +0530 Message-Id: <20200909140759.4170-4-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100838_950394_AE8F2F10 X-CRM114-Status: GOOD ( 20.09 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Some Armv8.3 Pointer Authentication enhancements have been introduced which are mandatory for Armv8.6 and optional for Armv8.3. These features are, * ARMv8.3-PAuth2 - An enhanced PAC generation logic is added which hardens finding the correct PAC value of the authenticated pointer. * ARMv8.3-FPAC - Fault is generated now when the ptrauth authentication instruction fails in authenticating the PAC present in the address. This is different from earlier case when such failures just adds an error code in the top byte and waits for subsequent load/store to abort. The ptrauth instructions which may cause this fault are autiasp, retaa etc. The above features are now represented by additional configurations for the Address Authentication cpufeature and a new ESR exception class. The userspace fault received in the kernel due to ARMv8.3-FPAC is treated as Illegal instruction and hence signal SIGILL is injected with ILL_ILLOPN as the signal code. Note that this is different from earlier ARMv8.3 ptrauth where signal SIGSEGV is issued due to Pointer authentication failures. The in-kernel PAC fault causes kernel to crash. Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- arch/arm64/include/asm/esr.h | 4 +++- arch/arm64/include/asm/exception.h | 1 + arch/arm64/include/asm/sysreg.h | 24 ++++++++++++++++-------- arch/arm64/kernel/entry-common.c | 21 +++++++++++++++++++++ arch/arm64/kernel/traps.c | 12 ++++++++++++ 5 files changed, 53 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index 035003acfa87..22c81f1edda2 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -35,7 +35,9 @@ #define ESR_ELx_EC_SYS64 (0x18) #define ESR_ELx_EC_SVE (0x19) #define ESR_ELx_EC_ERET (0x1a) /* EL2 only */ -/* Unallocated EC: 0x1b - 0x1E */ +/* Unallocated EC: 0x1B */ +#define ESR_ELx_EC_FPAC (0x1C) /* EL1 and above */ +/* Unallocated EC: 0x1D - 0x1E */ #define ESR_ELx_EC_IMP_DEF (0x1f) /* EL3 only */ #define ESR_ELx_EC_IABT_LOW (0x20) #define ESR_ELx_EC_IABT_CUR (0x21) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 7577a754d443..99b9383cd036 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -47,4 +47,5 @@ void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr); void do_cp15instr(unsigned int esr, struct pt_regs *regs); void do_el0_svc(struct pt_regs *regs); void do_el0_svc_compat(struct pt_regs *regs); +void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr); #endif /* __ASM_EXCEPTION_H */ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 554a7e8ecb07..b738bc793369 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -636,14 +636,22 @@ #define ID_AA64ISAR1_APA_SHIFT 4 #define ID_AA64ISAR1_DPB_SHIFT 0 -#define ID_AA64ISAR1_APA_NI 0x0 -#define ID_AA64ISAR1_APA_ARCHITECTED 0x1 -#define ID_AA64ISAR1_API_NI 0x0 -#define ID_AA64ISAR1_API_IMP_DEF 0x1 -#define ID_AA64ISAR1_GPA_NI 0x0 -#define ID_AA64ISAR1_GPA_ARCHITECTED 0x1 -#define ID_AA64ISAR1_GPI_NI 0x0 -#define ID_AA64ISAR1_GPI_IMP_DEF 0x1 +#define ID_AA64ISAR1_APA_NI 0x0 +#define ID_AA64ISAR1_APA_ARCHITECTED 0x1 +#define ID_AA64ISAR1_APA_ARCH_EPAC 0x2 +#define ID_AA64ISAR1_APA_ARCH_EPAC2 0x3 +#define ID_AA64ISAR1_APA_ARCH_EPAC2_FPAC 0x4 +#define ID_AA64ISAR1_APA_ARCH_EPAC2_FPAC_CMB 0x5 +#define ID_AA64ISAR1_API_NI 0x0 +#define ID_AA64ISAR1_API_IMP_DEF 0x1 +#define ID_AA64ISAR1_API_IMP_DEF_EPAC 0x2 +#define ID_AA64ISAR1_API_IMP_DEF_EPAC2 0x3 +#define ID_AA64ISAR1_API_IMP_DEF_EPAC2_FPAC 0x4 +#define ID_AA64ISAR1_API_IMP_DEF_EPAC2_FPAC_CMB 0x5 +#define ID_AA64ISAR1_GPA_NI 0x0 +#define ID_AA64ISAR1_GPA_ARCHITECTED 0x1 +#define ID_AA64ISAR1_GPI_NI 0x0 +#define ID_AA64ISAR1_GPI_IMP_DEF 0x1 /* id_aa64pfr0 */ #define ID_AA64PFR0_CSV3_SHIFT 60 diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index d3be9dbf5490..43d4c329775f 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -66,6 +66,13 @@ static void notrace el1_dbg(struct pt_regs *regs, unsigned long esr) } NOKPROBE_SYMBOL(el1_dbg); +static void notrace el1_fpac(struct pt_regs *regs, unsigned long esr) +{ + local_daif_inherit(regs); + do_ptrauth_fault(regs, esr); +} +NOKPROBE_SYMBOL(el1_fpac); + asmlinkage void notrace el1_sync_handler(struct pt_regs *regs) { unsigned long esr = read_sysreg(esr_el1); @@ -92,6 +99,9 @@ asmlinkage void notrace el1_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_BRK64: el1_dbg(regs, esr); break; + case ESR_ELx_EC_FPAC: + el1_fpac(regs, esr); + break; default: el1_inv(regs, esr); } @@ -227,6 +237,14 @@ static void notrace el0_svc(struct pt_regs *regs) } NOKPROBE_SYMBOL(el0_svc); +static void notrace el0_fpac(struct pt_regs *regs, unsigned long esr) +{ + user_exit_irqoff(); + local_daif_restore(DAIF_PROCCTX); + do_ptrauth_fault(regs, esr); +} +NOKPROBE_SYMBOL(el0_fpac); + asmlinkage void notrace el0_sync_handler(struct pt_regs *regs) { unsigned long esr = read_sysreg(esr_el1); @@ -272,6 +290,9 @@ asmlinkage void notrace el0_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_BRK64: el0_dbg(regs, esr); break; + case ESR_ELx_EC_FPAC: + el0_fpac(regs, esr); + break; default: el0_inv(regs, esr); } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 29fd00fe94f2..b24f81197a68 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -479,6 +479,17 @@ void do_bti(struct pt_regs *regs) } NOKPROBE_SYMBOL(do_bti); +void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr) +{ + /* + * Unexpected FPAC exception or pointer authentication failure in + * the kernel: kill the task before it does any more harm. + */ + BUG_ON(!user_mode(regs)); + force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr); +} +NOKPROBE_SYMBOL(do_ptrauth_fault); + #define __user_cache_maint(insn, address, res) \ if (address >= user_addr_max()) { \ res = -EFAULT; \ @@ -775,6 +786,7 @@ static const char *esr_class_str[] = { [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)", [ESR_ELx_EC_SVE] = "SVE", [ESR_ELx_EC_ERET] = "ERET/ERETAA/ERETAB", + [ESR_ELx_EC_FPAC] = "FPAC", [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF", [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)", [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)", From patchwork Wed Sep 9 14:07:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765505 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9BACB746 for ; Wed, 9 Sep 2020 14:10:28 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6BB8221D81 for ; Wed, 9 Sep 2020 14:10:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nuDslpFV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6BB8221D81 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sdTn03qObWH4dBT7cQryo39RLS8B139K39ACpoPqUPM=; b=nuDslpFVFons8Oc23wrLj2Cbdc wl3cjIAP+ad7XIUhDKPMcnQktR3WgrY42K8kiWx330ZmbTHQ199CjxeOTZXi+++NKpXgbEtNAPIZk FLmzE0na4MevVxsL4XRnVUyk3Z23Tzsc9nwYfONS+X6cYO6fWkkf78gHeABwlX5kMeszj29q41cg+ qrn043Tx7w2FHhgFiresLzcUayFYD4t/C9vITXemkdCBHuayrLruo5LnLMHPxO+3rHNY3p88/YY65 OQR1TT3jf1HtDdkHb5qPUrAr6MsPh+k+9gm1b9B9NA3KrVt0M/VCxCI05RI9GURhdyxHVjFR7johb WHlI12Dw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0mJ-0000CA-7v; Wed, 09 Sep 2020 14:08:51 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kG0mE-0000Ah-G4 for linux-arm-kernel@lists.infradead.org; Wed, 09 Sep 2020 14:08:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 72CD631B; Wed, 9 Sep 2020 07:08:45 -0700 (PDT) Received: from a077416.arm.com (unknown [10.57.14.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E1DEB3F66E; Wed, 9 Sep 2020 07:08:38 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 4/6] arm64: cpufeature: Modify address authentication cpufeature to exact Date: Wed, 9 Sep 2020 19:37:57 +0530 Message-Id: <20200909140759.4170-5-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100846_876432_AE5AE5A8 X-CRM114-Status: GOOD ( 21.42 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The current address authentication cpufeature levels are set as LOWER_SAFE which is not compatible with the different configurations added for Armv8.3 ptrauth enhancements as the different levels have different behaviour and there is no tunable to enable the lower safe versions. This is rectified by setting those cpufeature type as EXACT. The current cpufeature framework also does not interfere in the booting of non-exact secondary cpus but rather marks them as tainted. As a workaround this is fixed by replacing the generic match handler with a new handler specific to ptrauth. After this change, if there is any variation in ptrauth configurations in secondary cpus from boot cpu then those mismatched cpus are parked in an infinite loop. Following ptrauth crash log is oberserved in Arm fastmodel with mismatched cpus without this fix, CPU features: SANITY CHECK: Unexpected variation in SYS_ID_AA64ISAR1_EL1. Boot CPU: 0x11111110211402, CPU4: 0x11111110211102 CPU features: Unsupported CPU feature variation detected. GICv3: CPU4: found redistributor 100 region 0:0x000000002f180000 CPU4: Booted secondary processor 0x0000000100 [0x410fd0f0] Unable to handle kernel paging request at virtual address bfff800010dadf3c Mem abort info: ESR = 0x86000004 EC = 0x21: IABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 [bfff800010dadf3c] address between user and kernel address ranges Internal error: Oops: 86000004 [#1] PREEMPT SMP Modules linked in: CPU: 4 PID: 29 Comm: migration/4 Tainted: G S 5.8.0-rc4-00005-ge658591d66d1-dirty #158 Hardware name: Foundation-v8A (DT) pstate: 60000089 (nZCv daIf -PAN -UAO BTYPE=--) pc : 0xbfff800010dadf3c lr : __schedule+0x2b4/0x5a8 sp : ffff800012043d70 x29: ffff800012043d70 x28: 0080000000000000 x27: ffff800011cbe000 x26: ffff00087ad37580 x25: ffff00087ad37000 x24: ffff800010de7d50 x23: ffff800011674018 x22: 0784800010dae2a8 x21: ffff00087ad37000 x20: ffff00087acb8000 x19: ffff00087f742100 x18: 0000000000000030 x17: 0000000000000000 x16: 0000000000000000 x15: ffff800011ac1000 x14: 00000000000001bd x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 71519a147ddfeb82 x9 : 825d5ec0fb246314 x8 : ffff00087ad37dd8 x7 : 0000000000000000 x6 : 00000000fffedb0e x5 : 00000000ffffffff x4 : 0000000000000000 x3 : 0000000000000028 x2 : ffff80086e11e000 x1 : ffff00087ad37000 x0 : ffff00087acdc600 Call trace: 0xbfff800010dadf3c schedule+0x78/0x110 schedule_preempt_disabled+0x24/0x40 __kthread_parkme+0x68/0xd0 kthread+0x138/0x160 ret_from_fork+0x10/0x34 Code: bad PC value Signed-off-by: Amit Daniel Kachhap [Suzuki: Introduce new matching function for address authentication] Suggested-by: Suzuki K Poulose Reviewed-by: Suzuki K Poulose --- arch/arm64/kernel/cpufeature.c | 46 +++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6424584be01e..4bb3f2b2ffed 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -197,9 +197,9 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = { ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), - FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_API_SHIFT, 4, 0), + FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_API_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), - FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_APA_SHIFT, 4, 0), + FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_APA_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0), ARM64_FTR_END, }; @@ -1648,11 +1648,39 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused) #endif /* CONFIG_ARM64_RAS_EXTN */ #ifdef CONFIG_ARM64_PTR_AUTH -static bool has_address_auth(const struct arm64_cpu_capabilities *entry, - int __unused) +static bool has_address_auth_cpucap(const struct arm64_cpu_capabilities *entry, int scope) { - return __system_matches_cap(ARM64_HAS_ADDRESS_AUTH_ARCH) || - __system_matches_cap(ARM64_HAS_ADDRESS_AUTH_IMP_DEF); + int boot_val, sec_val; + + /* We don't expect to be called with SCOPE_SYSTEM */ + WARN_ON(scope == SCOPE_SYSTEM); + /* + * The ptr-auth feature levels are not intercompatible with lower + * levels. Hence we must match ptr-auth feature level of the secondary + * CPUs with that of the boot CPU. The level of boot cpu is fetched + * from the sanitised register whereas direct register read is done for + * the secondary CPUs. + * The sanitised feature state is guaranteed to match that of the + * boot CPU as a mismatched secondary CPU is parked before it gets + * a chance to update the state, with the capability. + */ + boot_val = cpuid_feature_extract_field(read_sanitised_ftr_reg(entry->sys_reg), + entry->field_pos, entry->sign); + if (scope & SCOPE_BOOT_CPU) { + return boot_val >= entry->min_field_value; + } else if (scope & SCOPE_LOCAL_CPU) { + sec_val = cpuid_feature_extract_field(__read_sysreg_by_encoding(entry->sys_reg), + entry->field_pos, entry->sign); + return (sec_val >= entry->min_field_value) && (sec_val == boot_val); + } + return false; +} + +static bool has_address_auth_metacap(const struct arm64_cpu_capabilities *entry, + int scope) +{ + return has_address_auth_cpucap(cpu_hwcaps_ptrs[ARM64_HAS_ADDRESS_AUTH_ARCH], scope) || + has_address_auth_cpucap(cpu_hwcaps_ptrs[ARM64_HAS_ADDRESS_AUTH_IMP_DEF], scope); } static bool has_generic_auth(const struct arm64_cpu_capabilities *entry, @@ -2021,7 +2049,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .sign = FTR_UNSIGNED, .field_pos = ID_AA64ISAR1_APA_SHIFT, .min_field_value = ID_AA64ISAR1_APA_ARCHITECTED, - .matches = has_cpuid_feature, + .matches = has_address_auth_cpucap, }, { .desc = "Address authentication (IMP DEF algorithm)", @@ -2031,12 +2059,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .sign = FTR_UNSIGNED, .field_pos = ID_AA64ISAR1_API_SHIFT, .min_field_value = ID_AA64ISAR1_API_IMP_DEF, - .matches = has_cpuid_feature, + .matches = has_address_auth_cpucap, }, { .capability = ARM64_HAS_ADDRESS_AUTH, .type = ARM64_CPUCAP_BOOT_CPU_FEATURE, - .matches = has_address_auth, + .matches = has_address_auth_metacap, }, { .desc = "Generic authentication (architected algorithm)", From patchwork Wed Sep 9 14:07:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765501 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E4B0C746 for ; 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Wed, 9 Sep 2020 07:08:45 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 5/6] arm64: kprobe: disable probe of fault prone ptrauth instruction Date: Wed, 9 Sep 2020 19:37:58 +0530 Message-Id: <20200909140759.4170-6-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100852_141890_76F9E959 X-CRM114-Status: GOOD ( 10.20 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org With the addition of ARMv8.3-FPAC feature, the probe of authenticate ptrauth instructions (AUT*) may cause ptrauth fault exception in case of authenticate failure so they cannot be safely single stepped. Hence the probe of authenticate instructions is disallowed but the corresponding pac ptrauth instruction (PAC*) is not affected and they can still be probed. Also AUTH* instructions do not make sense at function entry points so most realistic probes would be unaffected by this change. Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- arch/arm64/kernel/insn.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index ccc8c9e22b25..6c0de2f60ea9 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -60,16 +60,10 @@ bool __kprobes aarch64_insn_is_steppable_hint(u32 insn) case AARCH64_INSN_HINT_XPACLRI: case AARCH64_INSN_HINT_PACIA_1716: case AARCH64_INSN_HINT_PACIB_1716: - case AARCH64_INSN_HINT_AUTIA_1716: - case AARCH64_INSN_HINT_AUTIB_1716: case AARCH64_INSN_HINT_PACIAZ: case AARCH64_INSN_HINT_PACIASP: case AARCH64_INSN_HINT_PACIBZ: case AARCH64_INSN_HINT_PACIBSP: - case AARCH64_INSN_HINT_AUTIAZ: - case AARCH64_INSN_HINT_AUTIASP: - case AARCH64_INSN_HINT_AUTIBZ: - case AARCH64_INSN_HINT_AUTIBSP: case AARCH64_INSN_HINT_BTI: case AARCH64_INSN_HINT_BTIC: case AARCH64_INSN_HINT_BTIJ: From patchwork Wed Sep 9 14:07:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11765509 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F115B1599 for ; 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Wed, 9 Sep 2020 07:08:51 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 6/6] arm64: kprobe: clarify the comment of steppable hint instructions Date: Wed, 9 Sep 2020 19:37:59 +0530 Message-Id: <20200909140759.4170-7-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200909140759.4170-1-amit.kachhap@arm.com> References: <20200909140759.4170-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200909_100859_195186_16222404 X-CRM114-Status: GOOD ( 12.46 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The existing comment about steppable hint instruction is not complete and only describes NOP instructions as steppable. As the function aarch64_insn_is_steppable_hint allows all white-listed instruction to be probed so the comment is updated to reflect this. Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- arch/arm64/kernel/probes/decode-insn.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index c541fb48886e..104101f633b1 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -43,8 +43,10 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) != AARCH64_INSN_SPCLREG_DAIF; /* - * The HINT instruction is is problematic when single-stepping, - * except for the NOP case. + * The HINT instruction is steppable only if it is in whitelist + * and the rest of other such instructions are blocked for + * single stepping as they may cause exception or other + * unintended behaviour. */ if (aarch64_insn_is_hint(insn)) return aarch64_insn_is_steppable_hint(insn);