From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755557AbbHYR1d (ORCPT ); Tue, 25 Aug 2015 13:27:33 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:41038 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751854AbbHYR1c (ORCPT ); Tue, 25 Aug 2015 13:27:32 -0400 From: "Jonathan (Zhixiong) Zhang" To: Will Deacon , Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" , "linux-kernel @ vger . kernel . org" , "linux-efi @ vger . kernel . org" , Matt Fleming , Borislav Petkov , Ard Biesheuvel , Catalin Marinas , Matt Fleming Cc: "Jonathan (Zhixiong) Zhang" Subject: [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory Date: Tue, 25 Aug 2015 10:27:22 -0700 Message-Id: <1440523642-31373-1-git-send-email-zjzhang@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jonathan (Zhixiong) Zhang" If the ACPI APEI firmware handles hardware error first (called "firmware first handling"), the firmware updates the GHES memory region with hardware error record (called "generic hardware error record"). Essentially the firmware writes hardware error records in the GHES memory region, triggers an NMI/interrupt, then the GHES driver goes off and grabs the error record from the GHES region. The kernel currently maps the GHES memory region as cacheable (PAGE_KERNEL) for all architectures. However, on some arm64 platforms, there is a mismatch between how the kernel maps the GHES region (PAGE_KERNEL) and how the firmware maps it (EFI_MEMORY_UC, ie. uncacheable), leading to the possibility of the kernel GHES driver reading stale data from the cache when it receives the interrupt. With stale data being read, the kernel is unaware there is new hardware error to be handled when there actually is; this may lead to further damage in various scenarios, such as error propagation caused data corruption. If uncorrected error (such as double bit ECC error) happened in memory operation and if the kernel is unaware of such event happening, errorneous data may be propagated to the disk. Instead GHES memory region should be mapped with page protection type according to what is returned from arch_apei_get_mem_attribute(). Reviewed-by: Matt Fleming Acked-by: Borislav Petkov Signed-off-by: Jonathan (Zhixiong) Zhang --- drivers/acpi/apei/ghes.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 23981ac1c6c2..3dd9c462d22a 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -157,11 +157,15 @@ static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn) static void __iomem *ghes_ioremap_pfn_irq(u64 pfn) { - unsigned long vaddr; + unsigned long vaddr, paddr; + pgprot_t prot; vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr); - ioremap_page_range(vaddr, vaddr + PAGE_SIZE, - pfn << PAGE_SHIFT, PAGE_KERNEL); + + paddr = pfn << PAGE_SHIFT; + prot = arch_apei_get_mem_attribute(paddr); + + ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot); return (void __iomem *)vaddr; } -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jonathan (Zhixiong) Zhang" Subject: [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory Date: Tue, 25 Aug 2015 10:27:22 -0700 Message-ID: <1440523642-31373-1-git-send-email-zjzhang@codeaurora.org> Return-path: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Will Deacon , Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" , "linux-kernel @ vger . kernel . org" , "linux-efi @ vger . kernel . org" , Matt Fleming , Borislav Petkov , Ard Biesheuvel , Catalin Marinas , Matt Fleming Cc: "Jonathan (Zhixiong) Zhang" List-Id: linux-efi@vger.kernel.org From: "Jonathan (Zhixiong) Zhang" If the ACPI APEI firmware handles hardware error first (called "firmware first handling"), the firmware updates the GHES memory region with hardware error record (called "generic hardware error record"). Essentially the firmware writes hardware error records in the GHES memory region, triggers an NMI/interrupt, then the GHES driver goes off and grabs the error record from the GHES region. The kernel currently maps the GHES memory region as cacheable (PAGE_KERNEL) for all architectures. However, on some arm64 platforms, there is a mismatch between how the kernel maps the GHES region (PAGE_KERNEL) and how the firmware maps it (EFI_MEMORY_UC, ie. uncacheable), leading to the possibility of the kernel GHES driver reading stale data from the cache when it receives the interrupt. With stale data being read, the kernel is unaware there is new hardware error to be handled when there actually is; this may lead to further damage in various scenarios, such as error propagation caused data corruption. If uncorrected error (such as double bit ECC error) happened in memory operation and if the kernel is unaware of such event happening, errorneous data may be propagated to the disk. Instead GHES memory region should be mapped with page protection type according to what is returned from arch_apei_get_mem_attribute(). Reviewed-by: Matt Fleming Acked-by: Borislav Petkov Signed-off-by: Jonathan (Zhixiong) Zhang --- drivers/acpi/apei/ghes.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 23981ac1c6c2..3dd9c462d22a 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -157,11 +157,15 @@ static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn) static void __iomem *ghes_ioremap_pfn_irq(u64 pfn) { - unsigned long vaddr; + unsigned long vaddr, paddr; + pgprot_t prot; vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr); - ioremap_page_range(vaddr, vaddr + PAGE_SIZE, - pfn << PAGE_SHIFT, PAGE_KERNEL); + + paddr = pfn << PAGE_SHIFT; + prot = arch_apei_get_mem_attribute(paddr); + + ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot); return (void __iomem *)vaddr; } -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project