[PATCH V8 5/5] acpi, apei: use appropriate pgprot_t to map GHES memory

From: Jonathan (Zhixiong) Zhang
Date: Fri Jul 24 2015 - 19:51:54 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).

Change-Id: Ie63440381e0f68100d4387e268058a2e2f9d63c6
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 b979b5dbe5bc..98609b404dae 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -173,8 +173,10 @@ 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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