5039e316dd
kexec-tools use boot_params for getting the 1st kernel hardware_subarch, the kexec kernel EFI runtime support also needs to read the old efi_info from boot_params. Currently it exists in debugfs which is not a good place for such infomation. Per HPA, we should avoid "sploit debugfs". In this patch /sys/kernel/boot_params are exported, also the setup_data is exported as a subdirectory. kexec-tools is using debugfs for hardware_subarch for a long time now so we're not removing it yet. Structure is like below: /sys/kernel/boot_params |__ data /* boot_params in binary*/ |__ setup_data | |__ 0 /* the first setup_data node */ | | |__ data /* setup_data node 0 in binary*/ | | |__ type /* setup_data type of setup_data node 0, hex string */ [snip] |__ version /* boot protocal version (in hex, "0x" prefixed)*/ Signed-off-by: Dave Young <dyoung@redhat.com> Acked-by: Borislav Petkov <bp@suse.de> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
38 lines
1.2 KiB
Text
38 lines
1.2 KiB
Text
What: /sys/kernel/boot_params
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Date: December 2013
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Contact: Dave Young <dyoung@redhat.com>
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Description: The /sys/kernel/boot_params directory contains two
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files: "data" and "version" and one subdirectory "setup_data".
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It is used to export the kernel boot parameters of an x86
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platform to userspace for kexec and debugging purpose.
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If there's no setup_data in boot_params the subdirectory will
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not be created.
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"data" file is the binary representation of struct boot_params.
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"version" file is the string representation of boot
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protocol version.
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"setup_data" subdirectory contains the setup_data data
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structure in boot_params. setup_data is maintained in kernel
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as a link list. In "setup_data" subdirectory there's one
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subdirectory for each link list node named with the number
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of the list nodes. The list node subdirectory contains two
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files "type" and "data". "type" file is the string
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representation of setup_data type. "data" file is the binary
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representation of setup_data payload.
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The whole boot_params directory structure is like below:
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/sys/kernel/boot_params
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|__ data
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|__ setup_data
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| |__ 0
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| | |__ data
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| | |__ type
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| |__ 1
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| |__ data
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| |__ type
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|__ version
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Users: Kexec
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