On Fri, 14 Aug, at 03:37:30PM, Jonathan (Zhixiong) Zhang wrote:
> From: "Jonathan (Zhixiong) Zhang" <zjzh...@codeaurora.org>
>
> With ACPI APEI firmware first handling, generic hardware error
> record is updated by firmware in GHES memory region. On an arm64
> platform, firmware updates GHES memory region with uncached
> access attribute, and then Linux reads stale data from cache.
>
> With current code, GHES memory region is mapped with PAGE_KERNEL
> based on the assumption that cache coherency of GHES memory region
> is maintained by firmware on all platforms. This assumption is
> not true for above mentioned arm64 platform.
>
> Instead GHES memory region should be mapped with page protection type
> according to what is returned from arch_apei_get_mem_attribute().
>
> Acked-by: Borislav Petkov <b...@suse.de>
> Signed-off-by: Jonathan (Zhixiong) Zhang <zjzh...@codeaurora.org>
> ---
> drivers/acpi/apei/ghes.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 23981ac1c6c2..f742335bd8bb 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -160,8 +160,10 @@ 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,
> - pfn << PAGE_SHIFT, PAGE_KERNEL);
> + ioremap_page_range(vaddr,
> + vaddr + PAGE_SIZE,
> + pfn << PAGE_SHIFT,
> + arch_apei_get_mem_attribute(pfn << PAGE_SHIFT));
>
> return (void __iomem *)vaddr;
> }
Y'know, this would be more readable if written as,
unsigned long vaddr, paddr;
pgprot_t prot;
vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr);
paddr = pfn << PAGE_SHIFT;
prot = arch_apei_get_mem_attribute(paddr);
ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot);
But either way,
Reviewed-by: Matt Fleming <matt.flem...@intel.com>
--
Matt Fleming, Intel Open Source Technology Center
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