On 6/12/2015 9:29 AM, Borislav Petkov wrote:
On Thu, Jun 11, 2015 at 11:26:00AM -0700, Jonathan (Zhixiong) Zhang wrote:From: "Jonathan (Zhixiong) Zhang" <zjzhang@xxxxxxxxxxxxxx> With ACPI APEI firmware first handling, generic hardware error record is updated by firmware in GHES memory region. When firmware updated GHES memory region with uncached access attribute, Linux reads stale data from cache. GHES memory region should be mapped with cache attributes according to EFI memory map when applicable. On such system, if firmware updates RAM directly without going through cache, EFI memory map has GHES memory region defined as uncached; If firmware updates cache, EFI memory map has GHES memory region defined as cached. On EFI system, if GHES memory region has EFI_MEMORY_UC attribute defined, map the page with arch defined UC page protection type. Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx> --- drivers/acpi/apei/ghes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index e82d0976a5d0..5cfd951ebf67 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -48,6 +48,7 @@ #include <linux/pci.h> #include <linux/aer.h> #include <linux/nmi.h> +#include <linux/efi.h> #include <acpi/ghes.h> #include <acpi/apei.h> @@ -164,8 +165,14 @@ static void __iomem *ghes_ioremap_pfn_irq(u64 pfn) unsigned long vaddr; vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr); - ioremap_page_range(vaddr, vaddr + PAGE_SIZE, + + if (efi_mem_attributes(pfn << PAGE_SHIFT) & EFI_MEMORY_UC) { + ioremap_page_range(vaddr, vaddr + PAGE_SIZE, + pfn << PAGE_SHIFT, ARCH_APEI_PAGE_KERNEL_UC); + } else { + ioremap_page_range(vaddr, vaddr + PAGE_SIZE, pfn << PAGE_SHIFT, PAGE_KERNEL); + } return (void __iomem *)vaddr;This is still hacky. All of a sudden, ghes code gets to know about EFI which looks like a mishmash to me. Maybe it would be cleaner if you added an arch-specific arch_get_mem_attribute(phys_addr); which returns a pgprot_t thing which you can use directly above, like so: ioremap_page_range(vaddr, vaddr + PAGE_SIZE, pfn << PAGE_SHIFT, arch_get_mem_attribute(pfn << PAGE_SHIFT)); Each arch can then return what it likes with arch_get_mem_attribute().
> Thanks for the review, Borislav. I will do that. Since such function is only needed for APEI functionality, at least as of today, I will name it arch_apei_get_mem_attribute(). I will add implementations for arm64 and x86 since those are the only archs having HAVE_ACPI_APEI defined in Kconfig. The upstream kernel today does not have HAVE_ACPI_APEI defined for arm64, but it needs to be and will be. -- Jonathan (Zhixiong) Zhang The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
