forked from mirrors/linux
2dc10ad81f
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
merged from tip/irq/for-arm to allow the arm64-specific part to be
upstreamed via the arm64 tree
- CPU feature detection reworked to cope with heterogeneous systems
where CPUs may not have exactly the same features. The features
reported by the kernel via internal data structures or ELF_HWCAP are
delayed until all the CPUs are up (and before user space starts)
- Support for 16KB pages, with the additional bonus of a 36-bit VA
space, though the latter only depending on EXPERT
- Implement native {relaxed, acquire, release} atomics for arm64
- New ASID allocation algorithm which avoids IPI on roll-over, together
with TLB invalidation optimisations (using local vs global where
feasible)
- KASan support for arm64
- EFI_STUB clean-up and isolation for the kernel proper (required by
KASan)
- copy_{to,from,in}_user optimisations (sharing the memcpy template)
- perf: moving arm64 to the arm32/64 shared PMU framework
- L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
- Support for the contiguous PTE hint on kernel mapping (16 consecutive
entries may be able to use a single TLB entry)
- Generic CONFIG_HZ now used on arm64
- defconfig updates
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
merged from tip/irq/for-arm to allow the arm64-specific part to be
upstreamed via the arm64 tree
- CPU feature detection reworked to cope with heterogeneous systems
where CPUs may not have exactly the same features. The features
reported by the kernel via internal data structures or ELF_HWCAP are
delayed until all the CPUs are up (and before user space starts)
- Support for 16KB pages, with the additional bonus of a 36-bit VA
space, though the latter only depending on EXPERT
- Implement native {relaxed, acquire, release} atomics for arm64
- New ASID allocation algorithm which avoids IPI on roll-over, together
with TLB invalidation optimisations (using local vs global where
feasible)
- KASan support for arm64
- EFI_STUB clean-up and isolation for the kernel proper (required by
KASan)
- copy_{to,from,in}_user optimisations (sharing the memcpy template)
- perf: moving arm64 to the arm32/64 shared PMU framework
- L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
- Support for the contiguous PTE hint on kernel mapping (16 consecutive
entries may be able to use a single TLB entry)
- Generic CONFIG_HZ now used on arm64
- defconfig updates
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (91 commits)
arm64/efi: fix libstub build under CONFIG_MODVERSIONS
ARM64: Enable multi-core scheduler support by default
arm64/efi: move arm64 specific stub C code to libstub
arm64: page-align sections for DEBUG_RODATA
arm64: Fix build with CONFIG_ZONE_DMA=n
arm64: Fix compat register mappings
arm64: Increase the max granular size
arm64: remove bogus TASK_SIZE_64 check
arm64: make Timer Interrupt Frequency selectable
arm64/mm: use PAGE_ALIGNED instead of IS_ALIGNED
arm64: cachetype: fix definitions of ICACHEF_* flags
arm64: cpufeature: declare enable_cpu_capabilities as static
genirq: Make the cpuhotplug migration code less noisy
arm64: Constify hwcap name string arrays
arm64/kvm: Make use of the system wide safe values
arm64/debug: Make use of the system wide safe value
arm64: Move FP/ASIMD hwcap handling to common code
arm64/HWCAP: Use system wide safe values
arm64/capabilities: Make use of system wide safe value
arm64: Delay cpu feature capability checks
...
60 lines
2.9 KiB
Text
60 lines
2.9 KiB
Text
UEFI, the Unified Extensible Firmware Interface, is a specification
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governing the behaviours of compatible firmware interfaces. It is
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maintained by the UEFI Forum - http://www.uefi.org/.
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UEFI is an evolution of its predecessor 'EFI', so the terms EFI and
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UEFI are used somewhat interchangeably in this document and associated
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source code. As a rule, anything new uses 'UEFI', whereas 'EFI' refers
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to legacy code or specifications.
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UEFI support in Linux
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=====================
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Booting on a platform with firmware compliant with the UEFI specification
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makes it possible for the kernel to support additional features:
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- UEFI Runtime Services
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- Retrieving various configuration information through the standardised
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interface of UEFI configuration tables. (ACPI, SMBIOS, ...)
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For actually enabling [U]EFI support, enable:
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- CONFIG_EFI=y
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- CONFIG_EFI_VARS=y or m
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The implementation depends on receiving information about the UEFI environment
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in a Flattened Device Tree (FDT) - so is only available with CONFIG_OF.
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UEFI stub
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=========
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The "stub" is a feature that extends the Image/zImage into a valid UEFI
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PE/COFF executable, including a loader application that makes it possible to
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load the kernel directly from the UEFI shell, boot menu, or one of the
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lightweight bootloaders like Gummiboot or rEFInd.
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The kernel image built with stub support remains a valid kernel image for
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booting in non-UEFI environments.
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UEFI kernel support on ARM
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==========================
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UEFI kernel support on the ARM architectures (arm and arm64) is only available
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when boot is performed through the stub.
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When booting in UEFI mode, the stub deletes any memory nodes from a provided DT.
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Instead, the kernel reads the UEFI memory map.
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The stub populates the FDT /chosen node with (and the kernel scans for) the
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following parameters:
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________________________________________________________________________________
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Name | Size | Description
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================================================================================
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linux,uefi-system-table | 64-bit | Physical address of the UEFI System Table.
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--------------------------------------------------------------------------------
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linux,uefi-mmap-start | 64-bit | Physical address of the UEFI memory map,
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| | populated by the UEFI GetMemoryMap() call.
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--------------------------------------------------------------------------------
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linux,uefi-mmap-size | 32-bit | Size in bytes of the UEFI memory map
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| | pointed to in previous entry.
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--------------------------------------------------------------------------------
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linux,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI
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| | memory map.
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--------------------------------------------------------------------------------
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linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format.
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--------------------------------------------------------------------------------
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