From: "Jonathan (Zhixiong) Zhang" <[email protected]>
Table 8 of UEFI 2.5 section 2.3.6.1 defines mappings from EFI
memory types to MAIR attribute encodings for arm64.
If the physical address has memory attributes defined by EFI
memmap as EFI_MEMORY_[UC|WC|WT], return approprate page protection
type according to the UEFI spec. Otherwise, return PAGE_KERNEL.
Reviewed-by: Matt Fleming <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Acked-by: Hanjun Guo <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
---
V3: Updated Reviewed-by.
V2: Changed arm64's implementation of arch_apei_get_mem_attributes()
from inline function to out of line function, based on Ingo's
feedback.
arch/arm64/include/asm/acpi.h | 5 +++++
arch/arm64/kernel/acpi.c | 29 +++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 406485ed110a..8084f3640006 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -92,4 +92,9 @@ static inline const char *acpi_get_enable_method(int cpu)
{
return acpi_psci_present() ? "psci" : NULL;
}
+
+#ifdef CONFIG_ACPI_APEI
+pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr);
+#endif
+
#endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 19de7537e7d3..9f083606e5bf 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -29,6 +29,11 @@
#include <asm/cpu_ops.h>
#include <asm/smp_plat.h>
+#ifdef CONFIG_ACPI_APEI
+#include <linux/efi.h>
+#include <asm/pgtable.h>
+#endif
+
int acpi_noirq = 1; /* skip ACPI IRQ initialization */
int acpi_disabled = 1;
EXPORT_SYMBOL(acpi_disabled);
@@ -230,3 +235,27 @@ void __init acpi_gic_init(void)
early_acpi_os_unmap_memory((char *)table, tbl_size);
}
+
+#ifdef CONFIG_ACPI_APEI
+pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
+{
+ /*
+ * According to "Table 8 Map: EFI memory types to AArch64 memory
+ * types" of UEFI 2.5 section 2.3.6.1, each EFI memory type is
+ * mapped to a corresponding MAIR attribute encoding.
+ * The EFI memory attribute advises all possible capabilities
+ * of a memory region. We use the most efficient capability.
+ */
+
+ u64 attr;
+
+ attr = efi_mem_attributes(addr);
+ if (attr & EFI_MEMORY_WB)
+ return PAGE_KERNEL;
+ if (attr & EFI_MEMORY_WT)
+ return __pgprot(PROT_NORMAL_WT);
+ if (attr & EFI_MEMORY_WC)
+ return __pgprot(PROT_NORMAL_NC);
+ return __pgprot(PROT_DEVICE_nGnRnE);
+}
+#endif
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
From: "Jonathan (Zhixiong) Zhang" <[email protected]>
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().
Reviewed-by: Matt Fleming <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
drivers/acpi/apei/ghes.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 23981ac1c6c2..3dd9c462d22a 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -157,11 +157,15 @@ static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
static void __iomem *ghes_ioremap_pfn_irq(u64 pfn)
{
- unsigned long vaddr;
+ unsigned long vaddr, paddr;
+ pgprot_t prot;
vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr);
- ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
- pfn << PAGE_SHIFT, PAGE_KERNEL);
+
+ paddr = pfn << PAGE_SHIFT;
+ prot = arch_apei_get_mem_attribute(paddr);
+
+ ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot);
return (void __iomem *)vaddr;
}
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project