From patchwork Wed Oct 11 07:26:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13416763 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A51B0CD98F7 for ; Wed, 11 Oct 2023 07:28:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1L8ygi61qv2icCtvGbL/1No8sVbu/MozUzLp7b/zGTM=; b=dHvqGcq/GfWGEt jx8rXnKhp2YN89tKDJohPDKnezpw1t1UXCNOvHQpZ4PucLSWykS9FtM2pMnmsqJzAGS6Y538rZltw Hf/Up1l500YeyVvlMNAkiT1jNRFHeseXu0sECNmF2sNkSpdIat9TDBnBgiw7A98LUiaZ+7oxQK8rS MWcbsSoGEZq29nkJZmMy2lHFXWwn/m9hhDdUtGMRiPR6hDsxz793hFs9DH22AKRJwlOWbbvdONQ/u Q8V3yXd0f0+DSznNGFjK8u+4imBBmAvRlBjav/SuVnggArMRxsMxyCYH4LmmGgIIH912drgnxyiB8 0gYK4/9je+o4573Llmjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qqTdi-00F5M8-1u; Wed, 11 Oct 2023 07:28:18 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qqTdX-00F5Cc-1A for linux-arm-kernel@lists.infradead.org; Wed, 11 Oct 2023 07:28:10 +0000 Received: from kwepemi500008.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4S546r0RmzzrTVw; Wed, 11 Oct 2023 15:25:24 +0800 (CST) Received: from huawei.com (10.67.174.55) by kwepemi500008.china.huawei.com (7.221.188.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 11 Oct 2023 15:27:57 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v5.10 05/15] arm64: rework BTI exception handling Date: Wed, 11 Oct 2023 07:26:51 +0000 Message-ID: <20231011072701.876772-6-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231011072701.876772-1-ruanjinjie@huawei.com> References: <20231011072701.876772-1-ruanjinjie@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.55] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi500008.china.huawei.com (7.221.188.139) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231011_002807_744176_FC1E1A56 X-CRM114-Status: GOOD ( 15.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Mark Rutland If a BTI exception is taken from EL1, the entry code will treat this as an unhandled exception and will panic() the kernel. This is inconsistent with the way we handle FPAC exceptions, which have a dedicated handler and only necessarily kill the thread from which the exception was taken from, and we don't log all the information that could be relevant to debug the issue. The code in do_bti() has: BUG_ON(!user_mode(regs)); ... and it seems like the intent was to call this for EL1 BTI exceptions, as with FPAC, but this was omitted due to an oversight. This patch adds separate EL0 and EL1 BTI exception handlers, with the latter calling die() directly to report the original context the BTI exception was taken from. This matches our handling of FPAC exceptions. Prior to this patch, a BTI failure is reported as: | Unhandled 64-bit el1h sync exception on CPU0, ESR 0x0000000034000002 -- BTI | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00131-g7d937ff0221d-dirty #9 | Hardware name: linux,dummy-virt (DT) | pstate: 20400809 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c) | pc : test_bti_callee+0x4/0x10 | lr : test_bti_caller+0x1c/0x28 | sp : ffff80000800bdf0 | x29: ffff80000800bdf0 x28: 0000000000000000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80000a2b8000 x22: 0000000000000000 x21: 0000000000000000 | x20: ffff8000099fa5b0 x19: ffff800009ff7000 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000041a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000040000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000f83 | x5 : ffff80000a2b6000 x4 : ffff0000028d0000 x3 : ffff800009f78378 | x2 : 0000000000000000 x1 : 0000000040210000 x0 : ffff8000080257e4 | Kernel panic - not syncing: Unhandled exception | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00131-g7d937ff0221d-dirty #9 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace.part.0+0xcc/0xe0 | show_stack+0x18/0x5c | dump_stack_lvl+0x64/0x80 | dump_stack+0x18/0x34 | panic+0x170/0x360 | arm64_exit_nmi.isra.0+0x0/0x80 | el1h_64_sync_handler+0x64/0xd0 | el1h_64_sync+0x64/0x68 | test_bti_callee+0x4/0x10 | smp_cpus_done+0xb0/0xbc | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 With this patch applied, a BTI failure is reported as: | Internal error: Oops - BTI: 0000000034000002 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00132-g0ad98265d582-dirty #8 | Hardware name: linux,dummy-virt (DT) | pstate: 20400809 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c) | pc : test_bti_callee+0x4/0x10 | lr : test_bti_caller+0x1c/0x28 | sp : ffff80000800bdf0 | x29: ffff80000800bdf0 x28: 0000000000000000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80000a2b8000 x22: 0000000000000000 x21: 0000000000000000 | x20: ffff8000099fa5b0 x19: ffff800009ff7000 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000041a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000040000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000f83 | x5 : ffff80000a2b6000 x4 : ffff0000028d0000 x3 : ffff800009f78378 | x2 : 0000000000000000 x1 : 0000000040210000 x0 : ffff800008025804 | Call trace: | test_bti_callee+0x4/0x10 | smp_cpus_done+0xb0/0xbc | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 | Code: d50323bf d53cd040 d65f03c0 d503233f (d50323bf) Signed-off-by: Mark Rutland Reviewed-by: Mark Brown Reviewed-by: Anshuman Khandual Cc: Alexandru Elisei Cc: Amit Daniel Kachhap Cc: James Morse Cc: Will Deacon Link: https://lore.kernel.org/r/20220913101732.3925290-6-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/exception.h | 3 ++- arch/arm64/kernel/entry-common.c | 14 +++++++++++++- arch/arm64/kernel/traps.c | 10 +++++++--- 3 files changed, 22 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 6c869d1f51cc..3ed01b913f81 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -34,7 +34,8 @@ void arm64_enter_nmi(struct pt_regs *regs); void arm64_exit_nmi(struct pt_regs *regs); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); void do_undefinstr(struct pt_regs *regs, unsigned long esr); -void do_bti(struct pt_regs *regs); +void do_el0_bti(struct pt_regs *regs); +void do_el1_bti(struct pt_regs *regs, unsigned long esr); asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr); void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, struct pt_regs *regs); diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index b17f848a09c5..53e596aae4e8 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -141,6 +141,15 @@ static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr) exit_to_kernel_mode(regs); } +static void noinstr el1_bti(struct pt_regs *regs, unsigned long esr) +{ + enter_from_kernel_mode(regs); + local_daif_inherit(regs); + do_el1_bti(regs, esr); + local_daif_mask(); + exit_to_kernel_mode(regs); +} + static void noinstr el1_inv(struct pt_regs *regs, unsigned long esr) { enter_from_kernel_mode(regs); @@ -212,6 +221,9 @@ asmlinkage void noinstr el1_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_UNKNOWN: el1_undef(regs, esr); break; + case ESR_ELx_EC_BTI: + el1_bti(regs, esr); + break; case ESR_ELx_EC_BREAKPT_CUR: case ESR_ELx_EC_SOFTSTP_CUR: case ESR_ELx_EC_WATCHPT_CUR: @@ -327,7 +339,7 @@ static void noinstr el0_bti(struct pt_regs *regs) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_bti(regs); + do_el0_bti(regs); } static void noinstr el0_inv(struct pt_regs *regs, unsigned long esr) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5d29ba0d85c1..da13cfeee706 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -411,12 +411,16 @@ void do_undefinstr(struct pt_regs *regs, unsigned long esr) } NOKPROBE_SYMBOL(do_undefinstr); -void do_bti(struct pt_regs *regs) +void do_el0_bti(struct pt_regs *regs) { - BUG_ON(!user_mode(regs)); force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } -NOKPROBE_SYMBOL(do_bti); + +void do_el1_bti(struct pt_regs *regs, unsigned long esr) +{ + die("Oops - BTI", regs, esr); +} +NOKPROBE_SYMBOL(do_el1_bti); void do_el0_fpac(struct pt_regs *regs, unsigned long esr) {