[PATCH V11 5/5] acpi, apei: use appropriate pgprot_t to map GHES memory

From: Jonathan (Zhixiong) Zhang
Date: Sat Aug 08 2015 - 13:19:44 EST

From: "Jonathan (Zhixiong) Zhang" <zjzhang@xxxxxxxxxxxxxx>

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.

GHES memory region should be mapped with page protection type
according to what is returned from arch_apei_get_mem_attribute(),
instead of always with PAGE_KERNEL (eg. cached attribute).

Acked-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx>
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 cf198ef5c381..c9caa92f2d13 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -172,8 +172,10 @@ 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,
+ ioremap_page_range(vaddr,
+ vaddr + PAGE_SIZE,
+ pfn << PAGE_SHIFT,
+ arch_apei_get_mem_attribute(pfn << PAGE_SHIFT));

return (void __iomem *)vaddr;
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