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| Started by | "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org> |
|---|---|
| First post | 2015-08-08 19:20 +0200 |
| Last post | 2015-08-12 07:40 +0200 |
| Articles | 3 — 3 participants |
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[PATCH V11 4/5] arm64: apei: implement arch_apei_get_mem_attributes() "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org> - 2015-08-08 19:20 +0200
Re: [PATCH V11 4/5] arm64: apei: implement arch_apei_get_mem_attributes() Matt Fleming <matt@codeblueprint.co.uk> - 2015-08-12 00:00 +0200
Re: [PATCH V11 4/5] arm64: apei: implement arch_apei_get_mem_attributes() Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-08-12 07:40 +0200
| From | "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org> |
|---|---|
| Date | 2015-08-08 19:20 +0200 |
| Subject | [PATCH V11 4/5] arm64: apei: implement arch_apei_get_mem_attributes() |
| Message-ID | <pVfWN-5cg-9@gated-at.bofh.it> |
From: "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org>
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 <catalin.marinas@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
---
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
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| From | Matt Fleming <matt@codeblueprint.co.uk> |
|---|---|
| Date | 2015-08-12 00:00 +0200 |
| Subject | Re: [PATCH V11 4/5] arm64: apei: implement arch_apei_get_mem_attributes() |
| Message-ID | <pWpKs-YT-65@gated-at.bofh.it> |
| In reply to | #1203329 |
On Sat, 08 Aug, at 10:18:52AM, Jonathan (Zhixiong) Zhang wrote:
> From: "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org>
>
> 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 <catalin.marinas@arm.com>
> Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
> Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
> ---
> 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
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| From | Ard Biesheuvel <ard.biesheuvel@linaro.org> |
|---|---|
| Date | 2015-08-12 07:40 +0200 |
| Message-ID | <pWwVA-3pD-7@gated-at.bofh.it> |
| In reply to | #1205452 |
On 11 August 2015 at 23:57, Matt Fleming <matt@codeblueprint.co.uk> wrote:
> On Sat, 08 Aug, at 10:18:52AM, Jonathan (Zhixiong) Zhang wrote:
>> From: "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org>
>>
>> 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 <catalin.marinas@arm.com>
>> Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
>> Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
>> ---
>> 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 <ard.biesheuvel@linaro.org>
Thanks,
Ard.
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