[PATCH V4 4/4] acpi, apei: use appropriate pgprot_t to map GHES memory

From: Jonathan (Zhixiong) Zhang
Date: Fri Jun 12 2015 - 21:02:40 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. When firmware
updated GHES memory region with uncached access attribute, 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).

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 e82d0976a5d0..91b1f6d93079 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -164,8 +164,10 @@ 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;
}
--
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a Linux Foundation Collaborative Project

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