926172d460
kexec kernel will need exactly same mapping for EFI runtime memory ranges. Thus here export the runtime ranges mapping to sysfs, kexec-tools will assemble them and pass to 2nd kernel via setup_data. Introducing a new directory /sys/firmware/efi/runtime-map just like /sys/firmware/memmap. Containing below attribute in each file of that directory: attribute num_pages phys_addr type virt_addr Signed-off-by: Dave Young <dyoung@redhat.com> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
35 lines
1.2 KiB
Plaintext
35 lines
1.2 KiB
Plaintext
What: /sys/firmware/efi/runtime-map/
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Date: December 2013
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Contact: Dave Young <dyoung@redhat.com>
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Description: Switching efi runtime services to virtual mode requires
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that all efi memory ranges which have the runtime attribute
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bit set to be mapped to virtual addresses.
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The efi runtime services can only be switched to virtual
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mode once without rebooting. The kexec kernel must maintain
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the same physical to virtual address mappings as the first
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kernel. The mappings are exported to sysfs so userspace tools
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can reassemble them and pass them into the kexec kernel.
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/sys/firmware/efi/runtime-map/ is the directory the kernel
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exports that information in.
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subdirectories are named with the number of the memory range:
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/sys/firmware/efi/runtime-map/0
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/sys/firmware/efi/runtime-map/1
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/sys/firmware/efi/runtime-map/2
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/sys/firmware/efi/runtime-map/3
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...
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Each subdirectory contains five files:
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attribute : The attributes of the memory range.
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num_pages : The size of the memory range in pages.
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phys_addr : The physical address of the memory range.
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type : The type of the memory range.
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virt_addr : The virtual address of the memory range.
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Above values are all hexadecimal numbers with the '0x' prefix.
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Users: Kexec
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