From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755237AbbHXS0G (ORCPT ); Mon, 24 Aug 2015 14:26:06 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:42054 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754987AbbHXS0D (ORCPT ); Mon, 24 Aug 2015 14:26:03 -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: Mon, 24 Aug 2015 11:25:57 -0700 Message-Id: <1440440757-4526-1-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" GHES memory region is used as a communication buffer for reporting hardware errors from the firmware to kernel. Essentially the firmware writes hardware error records there, 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, kernel reports there is no new hardware error when there actually is; this may lead to further damage in various scenarios, such as error propagation caused data corruption. 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