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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D18C5C47DB3 for ; Mon, 29 Jan 2024 17:51:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3E55A6B0071; Mon, 29 Jan 2024 12:51:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 36EA86B0072; Mon, 29 Jan 2024 12:51:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E7BB6B0074; Mon, 29 Jan 2024 12:51:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 0A2726B0071 for ; Mon, 29 Jan 2024 12:51:47 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 9A22B120AD4 for ; Mon, 29 Jan 2024 17:51:43 +0000 (UTC) X-FDA: 81733091286.27.C9DD5BB Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf09.hostedemail.com (Postfix) with ESMTP id C47FF140026 for ; Mon, 29 Jan 2024 17:51:41 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=none; spf=pass (imf09.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706550702; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I0VIBDd6DfErdAISdojY5I2FhLvS5SkKrjLxLsHHdNU=; b=2BxzPon4ohMXoowCnnAk3jBRtNsDXifHegaR/v6oPJsCMQzpGPM1X3ll0bLG3Go1keoJzr j0kp7IpVyh4KrLXZHPwJPdBV1RTugYDDKB6yybNfDWxDyAhfwgBdI0x2bMZL1hVZe1amge MBO13Q9u96fpgAIJZiSOYL4hnwzGcbg= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=none; spf=pass (imf09.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706550702; a=rsa-sha256; cv=none; b=gczKr3D6y/Gc83o7yWyc7o4taxI2EErA2NCUZcvBLLY2SvAJIEf4Wn2kDXhJuZgaMdYYUI sd0RhWy0z1uIxWqDMT+fRnN7eti+oxyK7frAB+ARDzY/ixrXmwNsxgLWOA2TumRmhm4F5k +aytGX6sldkSSVzFaVDFKqCmusr5T1A= 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 58831139F; Mon, 29 Jan 2024 09:52:24 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.48.128]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 529603F738; Mon, 29 Jan 2024 09:51:36 -0800 (PST) Date: Mon, 29 Jan 2024 17:51:33 +0000 From: Mark Rutland To: Tong Tiangen Cc: Catalin Marinas , Will Deacon , James Morse , Robin Murphy , Andrey Ryabinin , Alexander Potapenko , Alexander Viro , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, wangkefeng.wang@huawei.com, Guohanjun Subject: Re: [PATCH v10 2/6] arm64: add support for machine check error safe Message-ID: References: <20240129134652.4004931-1-tongtiangen@huawei.com> <20240129134652.4004931-3-tongtiangen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240129134652.4004931-3-tongtiangen@huawei.com> X-Rspamd-Queue-Id: C47FF140026 X-Rspam-User: X-Stat-Signature: h4qrnkxsy4qnngdm6ico3ywnnwi1c6j5 X-Rspamd-Server: rspam01 X-HE-Tag: 1706550701-47552 X-HE-Meta: U2FsdGVkX19wBx8owEV/iQQY/z9BQLzliLpa7/vO4NUDfW0SqkHE0Ygps2355363ugtDVtmJEGI94qbrJqT/9HA/3KTaz1eHcK4/pbW+QSyi4wrrGsUuwftUAHKEWl5+kxdQJI35LZVPLtKrLg016w7Y2ckwK70mKc9hEhXH/RHE1EpXIdXk48kLdQQ5EPDd+vVkxZKQSAmf4hSQkQBUsYaT8ijUef3fBIktMRWrQGaY4NrgWwuExl/d5b7eStKNbGLJ0eLiu2md8gBtqODIamyUF19wZM37LKNcLGiZ/tiLXKsBuNHIkAIlxNx+sEZn1z6SS8AzCPrDdEcsngtKIpB2lhC7Gk5c9B/thTYVHn/S762Db9UjF9kn5o8KnNkYMXEbXKp3jCisdvicmPKxfTp3BJfP6k6w5jvPIixE7EcDe9XrEWA1j1BnF0kWYp3+QuR1f4z9CZH/ZrsZzn11wYZakFjXdc0NSXL6Ww666pfRbXQfS5o1CR7j1MH0/Hi9PI3pwdB5Mf0liWp00Gd4cbzh229MEQSPcRqEWN7KaolpyCJyXtp8RnSL4LVQkmhJmrIYzAueRwQZe+CwCUgxotVCgxP11D/H2McTWqSPy3pXrikyzHw85FF5mAH2rnePszLBmuodb/dYfzkqIJdXdt5alJ48AmhuVgAM7IsYyoAYcgcxmfabfEfbKaGuFx5Ecu0MgYLOLfT5lMhnGx3C95zymSoibPI70l/4EMJERiH9hXmQxJUWsYOJHqGHALtcch27cp25AVckm6EVeRZ/sZukWiNw4poXnty7AIv8VhZ7xReI2gFWO5/pnWpycWW+rA2ILSh/Ba1kjRjhgd4Ahv6cAUiTD2KNJQZMa82AQPQsP44G0GhGljzvN+vtViWQexzXzqkwmuOxGurJjdKSXkh3+RVSCn52l8XXIwvK3lwsxzVY6bnrfr/84e5J+737t8HtNQ2o3l4hmxIURPZ ErPaS32v 1uMf2OPAV4QYh2LDOnGMgYvo8Britri1cvJ4hfXT5O+qVyJ5HlXTrrzKc9PwAMbRGGPU2U8a+lflZOHPV2Nj5Sfeb/8BHY+/OavxVfvNdbzMyzwIawTxlqNFSNcvCRgNLirdZdYI6DbAAHWVHYgGA8nHhMb4MhQ/vXCpAff+drXw59Q22DSYmu5ACkn2Q5V/IdiNvvP4boXqB2GI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jan 29, 2024 at 09:46:48PM +0800, Tong Tiangen wrote: > For the arm64 kernel, when it processes hardware memory errors for > synchronize notifications(do_sea()), if the errors is consumed within the > kernel, the current processing is panic. However, it is not optimal. > > Take uaccess for example, if the uaccess operation fails due to memory > error, only the user process will be affected. Killing the user process and > isolating the corrupt page is a better choice. > > This patch only enable machine error check framework and adds an exception > fixup before the kernel panic in do_sea(). > > Signed-off-by: Tong Tiangen > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/extable.h | 1 + > arch/arm64/mm/extable.c | 16 ++++++++++++++++ > arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++++++- > 4 files changed, 46 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index aa7c1d435139..2cc34b5e7abb 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -20,6 +20,7 @@ config ARM64 > select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 > select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE > select ARCH_HAS_CACHE_LINE_SIZE > + select ARCH_HAS_COPY_MC if ACPI_APEI_GHES > select ARCH_HAS_CURRENT_STACK_POINTER > select ARCH_HAS_DEBUG_VIRTUAL > select ARCH_HAS_DEBUG_VM_PGTABLE > diff --git a/arch/arm64/include/asm/extable.h b/arch/arm64/include/asm/extable.h > index 72b0e71cc3de..f80ebd0addfd 100644 > --- a/arch/arm64/include/asm/extable.h > +++ b/arch/arm64/include/asm/extable.h > @@ -46,4 +46,5 @@ bool ex_handler_bpf(const struct exception_table_entry *ex, > #endif /* !CONFIG_BPF_JIT */ > > bool fixup_exception(struct pt_regs *regs); > +bool fixup_exception_mc(struct pt_regs *regs); > #endif > diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c > index 228d681a8715..478e639f8680 100644 > --- a/arch/arm64/mm/extable.c > +++ b/arch/arm64/mm/extable.c > @@ -76,3 +76,19 @@ bool fixup_exception(struct pt_regs *regs) > > BUG(); > } > + > +bool fixup_exception_mc(struct pt_regs *regs) Can we please replace 'mc' with something like 'memory_error' ? There's no "machine check" on arm64, and 'mc' is opaque regardless. > +{ > + const struct exception_table_entry *ex; > + > + ex = search_exception_tables(instruction_pointer(regs)); > + if (!ex) > + return false; > + > + /* > + * This is not complete, More Machine check safe extable type can > + * be processed here. > + */ > + > + return false; > +} As with my comment on the subsequenty patch, I'd much prefer that we handle EX_TYPE_UACCESS_ERR_ZERO from the outset. > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 55f6455a8284..312932dc100b 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -730,6 +730,31 @@ static int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs) > return 1; /* "fault" */ > } > > +static bool arm64_do_kernel_sea(unsigned long addr, unsigned int esr, > + struct pt_regs *regs, int sig, int code) > +{ > + if (!IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC)) > + return false; > + > + if (user_mode(regs)) > + return false; This function is called "arm64_do_kernel_sea"; surely the caller should *never* call this for a SEA taken from user mode? > + > + if (apei_claim_sea(regs) < 0) > + return false; > + > + if (!fixup_exception_mc(regs)) > + return false; > + > + if (current->flags & PF_KTHREAD) > + return true; I think this needs a comment; why do we allow kthreads to go on, yet kill user threads? What about helper threads (e.g. for io_uring)? > + > + set_thread_esr(0, esr); Why do we set the ESR to 0? Mark. > + arm64_force_sig_fault(sig, code, addr, > + "Uncorrected memory error on access to user memory\n"); > + > + return true; > +} > + > static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs) > { > const struct fault_info *inf; > @@ -755,7 +780,9 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs) > */ > siaddr = untagged_addr(far); > } > - arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr); > + > + if (!arm64_do_kernel_sea(siaddr, esr, regs, inf->sig, inf->code)) > + arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr); > > return 0; > } > -- > 2.25.1 >