From: "Jonathan (Zhixiong) Zhang" <[email protected]>
On a platform with APEI (ACPI Platform Error Interface) enabled, firmware
updates a memory region with hardware error record using nocache
attribute. When OS reads the region, since it maps the region with
cacahed attribute even though EFI memory map defines this region as
uncached, OS gets stale data and errorneously reports there is no new
HW error.
When ghes driver maps the memory region, it uses the cache attribute
according to EFI memory map, if EFI memory map feature is enabled
at runtime.
Since both arch/x86 and arch/ia64 implemented architecture agnostic EFI
memory map attribue lookup function efi_memattributes(), the code is
moved from arch/x86 into EFI subsystem and is declared as __weak; archs
other than ia64 should not override the default implementation.
V11:
1. Changed how we deal with superimposed memory region attributes as
provided in UEFI memory map, on arm64.
V10:
1. Fixed compilation issue on x86.
V9:
1. Rebased to arm64-upstream-14543 of arm64/master.
2. Match strict MM type in arch_apei_get_mem_attribute().
V8:
1. For x86, always return PAGE_KERNEL for arch_apei_get_mem_attribute().
The rational is explained in comment.
2. Rebased to arm64-upstream-14201 of arm64/master,
next-20150724 of linux-next/master.
V7:
1. Added PROT_DEVICE_nGnRnE and PROT_NORMAL_WT to support all
possible UEFI memory types for arm64.
V6:
1. Implemented arch_apei_get_mem_attributes() for arm64 as inline
function.
2. Rebased to efi-next-14364 of efi/next, pm+acpi-4.2-rc3 of
linux-pm/master, arm64-upstream-13521 of arm64/master,
next-20150720 of linux-next/master.
V5:
1. Rebased to next-20150713 of linux-next/master, efi-next-14359 of
efi/next, pm+acpi-4.2-rc2 of linux-pm/master,
arm64-fixes-1215 of arm64/master.
2. Added comment for efi_mem_attributes(), explained why it is marked
as __weak at the function definition site.
V4:
1. Introduced arch_apei_get_mem_attributes() to allow arch specific
implementation of getting pgprot_t appropriate for a physical
address.
2. Implemented arch_apei_get_mem_attributes() for x86 and for arm64.
V3:
1. Rebased to v4.1-rc7.
2. Moved efi_mem_attributes() from arch/x86 to drivers/firmware/efi
and declared it as __weak.
3. Introduced ARCH_APEI_PAGE_KERNEL_UC to allow arch specific page
protection type for UC.
4. Removed efi_ioremap(). It can not be used for GHES memory region
mapping purpose since ioremap can not be used in atomic context.
V2:
1. Rebased to v4.1-rc5.
2. Split removal of efi_mem_attributes() and creation of efi_ioremap()
into two patches.
Jonathan (Zhixiong) Zhang (5):
efi: x86: rearrange efi_mem_attributes()
x86: acpi: implement arch_apei_get_mem_attributes()
arm64: mm: add PROT_DEVICE_nGnRnE and PROT_NORMAL_WT
arm64: apei: implement arch_apei_get_mem_attributes()
acpi, apei: use appropriate pgprot_t to map GHES memory
arch/arm64/include/asm/acpi.h | 30 ++++++++++++++++++++++++++++++
arch/arm64/include/asm/memory.h | 1 +
arch/arm64/include/asm/pgtable.h | 2 ++
arch/arm64/mm/proc.S | 4 +++-
arch/x86/include/asm/acpi.h | 24 ++++++++++++++++++++++++
arch/x86/platform/efi/efi.c | 18 ------------------
drivers/acpi/apei/ghes.c | 6 ++++--
drivers/firmware/efi/efi.c | 31 +++++++++++++++++++++++++++++++
8 files changed, 95 insertions(+), 21 deletions(-)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
From: "Jonathan (Zhixiong) Zhang" <[email protected]>
x86 and ia64 implement efi_mem_attributes() differently. This
function needs to be available for other arch (such as arm64)
as well, such as for the purpose of ACPI/APEI.
ia64 efi does not setup memmap variable and does not set
EFI_MEMMAP flag, so it needs to have its unique implementation
of efi_mem_attributes().
Move efi_mem_attributes() implementation from x86 to efi, and
declare it with __weak. It is recommended that other archs
should not override the default implementation.
Reviewed-by: Matt Fleming <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
arch/x86/platform/efi/efi.c | 18 ------------------
drivers/firmware/efi/efi.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index dbc8627a5cdf..88b3ebaeb72f 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -917,24 +917,6 @@ u32 efi_mem_type(unsigned long phys_addr)
return 0;
}
-u64 efi_mem_attributes(unsigned long phys_addr)
-{
- efi_memory_desc_t *md;
- void *p;
-
- if (!efi_enabled(EFI_MEMMAP))
- return 0;
-
- for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
- md = p;
- if ((md->phys_addr <= phys_addr) &&
- (phys_addr < (md->phys_addr +
- (md->num_pages << EFI_PAGE_SHIFT))))
- return md->attribute;
- }
- return 0;
-}
-
static int __init arch_parse_efi_cmdline(char *str)
{
if (parse_option_str(str, "old_map"))
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3061bb8629dc..bf4190a4f3f5 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -517,3 +517,34 @@ char * __init efi_md_typeattr_format(char *buf, size_t size,
attr & EFI_MEMORY_UC ? "UC" : "");
return buf;
}
+
+/*
+ * efi_mem_attributes - lookup memmap attributes for physical address
+ * @phys_addr: the physical address to lookup
+ *
+ * Search in the EFI memory map for the region covering
+ * @phys_addr. Returns the EFI memory attributes if the region
+ * was found in the memory map, 0 otherwise.
+ *
+ * Despite being marked __weak, most architectures should *not*
+ * override this function. It is __weak solely for the benefit
+ * of ia64 which has a funky EFI memory map that doesn't work
+ * the same way as other architectures.
+ */
+u64 __weak efi_mem_attributes(unsigned long phys_addr)
+{
+ efi_memory_desc_t *md;
+ void *p;
+
+ if (!efi_enabled(EFI_MEMMAP))
+ return 0;
+
+ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+ md = p;
+ if ((md->phys_addr <= phys_addr) &&
+ (phys_addr < (md->phys_addr +
+ (md->num_pages << EFI_PAGE_SHIFT))))
+ return md->attribute;
+ }
+ return 0;
+}
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
From: "Jonathan (Zhixiong) Zhang" <[email protected]>
... to allow arch specific implementation of getting page
protection type associated with a physical address.
On x86, we currently have no way to lookup the EFI memory map
attributes for a region in a consistent way because the
memmap is discarded after efi_free_boot_services(). So if
you call efi_mem_attributes() during boot and at runtime,
you could theoretically see different attributes.
Since we are yet to see any x86 platforms that require
anything other than PAGE_KERNEL (some arm64 platforms
require the equivalent of PAGE_KERNEL_NOCACHE), return that
until we know differently.
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
arch/x86/include/asm/acpi.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 3a45668f6dc3..ffe22c6b17bd 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -32,6 +32,10 @@
#include <asm/mpspec.h>
#include <asm/realmode.h>
+#ifdef CONFIG_ACPI_APEI
+#include <asm/pgtable_types.h>
+#endif
+
#ifdef CONFIG_ACPI
extern int acpi_lapic;
extern int acpi_ioapic;
@@ -147,4 +151,24 @@ extern int x86_acpi_numa_init(void);
#define acpi_unlazy_tlb(x) leave_mm(x)
+#ifdef CONFIG_ACPI_APEI
+static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
+{
+ /*
+ * We currently have no way to lookup the EFI memory map
+ * attributes for a region in a consistent way because the
+ * memmap is discarded after efi_free_boot_services(). So if
+ * you call efi_mem_attributes() during boot and at runtime,
+ * you could theoretically see different attributes.
+ *
+ * Since we are yet to see any x86 platforms that require
+ * anything other than PAGE_KERNEL (some arm64 platforms
+ * require the equivalent of PAGE_KERNEL_NOCACHE), return that
+ * until we know differently.
+ */
+
+ return PAGE_KERNEL;
+}
+#endif
+
#endif /* _ASM_X86_ACPI_H */
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
From: "Jonathan (Zhixiong) Zhang" <[email protected]>
UEFI spec 2.5 section 2.3.6.1 defines that EFI_MEMORY_[UC|WC|WT|WB] are
possible EFI memory types for AArch64. Each of those EFI memory types
is mapped to a corresponding AArch64 memory type. So we need to define
PROT_DEVICE_nGnRnE and PROT_NORMWL_WT additionaly.
MT_NORMAL_WT is defined, and its encoding is added to MAIR_EL1 when
initializing cpu.
Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
arch/arm64/include/asm/memory.h | 1 +
arch/arm64/include/asm/pgtable.h | 2 ++
arch/arm64/mm/proc.S | 4 +++-
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index f800d45ea226..4112b3d7468e 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -100,6 +100,7 @@
#define MT_DEVICE_GRE 2
#define MT_NORMAL_NC 3
#define MT_NORMAL 4
+#define MT_NORMAL_WT 5
/*
* Memory types for Stage-2 translation
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 800ec0e87ed9..5c108ad13558 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -61,8 +61,10 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
#define PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF)
#endif
+#define PROT_DEVICE_nGnRnE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRnE))
#define PROT_DEVICE_nGnRE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
#define PROT_NORMAL_NC (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_NC))
+#define PROT_NORMAL_WT (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_WT))
#define PROT_NORMAL (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL))
#define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 4fe4b7d1d65f..2ddb82ff38c2 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -233,12 +233,14 @@ ENTRY(__cpu_setup)
* DEVICE_GRE 010 00001100
* NORMAL_NC 011 01000100
* NORMAL 100 11111111
+ * NORMAL_WT 101 10111011
*/
ldr x5, =MAIR(0x00, MT_DEVICE_nGnRnE) | \
MAIR(0x04, MT_DEVICE_nGnRE) | \
MAIR(0x0c, MT_DEVICE_GRE) | \
MAIR(0x44, MT_NORMAL_NC) | \
- MAIR(0xff, MT_NORMAL)
+ MAIR(0xff, MT_NORMAL) | \
+ MAIR(0xbb, MT_NORMAL_WT)
msr mair_el1, x5
/*
* Prepare SCTLR
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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: Catalin Marinas <[email protected]>
Acked-by: Hanjun Guo <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
arch/arm64/include/asm/acpi.h | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 614096732839..b77a2d133da9 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -19,6 +19,11 @@
#include <asm/psci.h>
#include <asm/smp_plat.h>
+#ifdef CONFIG_ACPI_APEI
+#include <linux/efi.h>
+#include <asm/pgtable.h>
+#endif
+
/* Macros for consistency checks of the GICC subtable of MADT */
#define ACPI_MADT_GICC_LENGTH \
(acpi_gbl_FADT.header.revision < 6 ? 76 : 80)
@@ -91,4 +95,29 @@ static inline const char *acpi_get_enable_method(int cpu)
{
return acpi_psci_present() ? "psci" : NULL;
}
+
+#ifdef CONFIG_ACPI_APEI
+static inline 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
+ * 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
+
#endif /*_ASM_ACPI_H*/
--
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.
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 <[email protected]>
Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
---
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,
- 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;
}
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On Sat, 08 Aug, at 10:18:52AM, Jonathan (Zhixiong) Zhang wrote:
> 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: Catalin Marinas <[email protected]>
> Acked-by: Hanjun Guo <[email protected]>
> Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
> ---
> arch/arm64/include/asm/acpi.h | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 614096732839..b77a2d133da9 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -19,6 +19,11 @@
> #include <asm/psci.h>
> #include <asm/smp_plat.h>
>
> +#ifdef CONFIG_ACPI_APEI
> +#include <linux/efi.h>
> +#include <asm/pgtable.h>
> +#endif
> +
> /* Macros for consistency checks of the GICC subtable of MADT */
> #define ACPI_MADT_GICC_LENGTH \
> (acpi_gbl_FADT.header.revision < 6 ? 76 : 80)
> @@ -91,4 +95,29 @@ static inline const char *acpi_get_enable_method(int cpu)
> {
> return acpi_psci_present() ? "psci" : NULL;
> }
> +
> +#ifdef CONFIG_ACPI_APEI
> +static inline 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
> + * 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
> +
> #endif /*_ASM_ACPI_H*/
Everyone happy with this change? Ard?
--
Matt Fleming, Intel Open Source Technology Center
On 11 August 2015 at 23:57, Matt Fleming <[email protected]> wrote:
> On Sat, 08 Aug, at 10:18:52AM, Jonathan (Zhixiong) Zhang wrote:
>> 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: Catalin Marinas <[email protected]>
>> Acked-by: Hanjun Guo <[email protected]>
>> Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]>
>> ---
>> arch/arm64/include/asm/acpi.h | 30 ++++++++++++++++++++++++++++++
>> 1 file changed, 30 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
>> index 614096732839..b77a2d133da9 100644
>> --- a/arch/arm64/include/asm/acpi.h
>> +++ b/arch/arm64/include/asm/acpi.h
>> @@ -19,6 +19,11 @@
>> #include <asm/psci.h>
>> #include <asm/smp_plat.h>
>>
>> +#ifdef CONFIG_ACPI_APEI
>> +#include <linux/efi.h>
>> +#include <asm/pgtable.h>
>> +#endif
>> +
>> /* Macros for consistency checks of the GICC subtable of MADT */
>> #define ACPI_MADT_GICC_LENGTH \
>> (acpi_gbl_FADT.header.revision < 6 ? 76 : 80)
>> @@ -91,4 +95,29 @@ static inline const char *acpi_get_enable_method(int cpu)
>> {
>> return acpi_psci_present() ? "psci" : NULL;
>> }
>> +
>> +#ifdef CONFIG_ACPI_APEI
>> +static inline 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
>> + * 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
>> +
>> #endif /*_ASM_ACPI_H*/
>
> Everyone happy with this change? Ard?
>
Yes, this looks fine. As long as any region that has the EFI_MEMORY_WB
attribute gets mapped as PAGE_KERNEL, we know we won't be violating
any architectural mismatched attributes constraints (since all
EFI_MEMORY_WB regions, even the occupied ones, are covered by the
kernel direct mapping as well)
For the other ones, it is merely an optimization, but arguably still
an improvement.
Reviewed-by: Ard Biesheuvel <[email protected]>
Thanks,
Ard.