diff options
| author | Dave Young <dyoung@redhat.com> | 2013-12-20 18:02:21 +0800 |
|---|---|---|
| committer | Matt Fleming <matt.fleming@intel.com> | 2013-12-29 13:09:07 +0000 |
| commit | 5039e316dde3fb71c79e95e97c5bca8e4724d8f2 (patch) | |
| tree | 9446e8ce0df0d9849bfec4fab93bd30f59d7c919 /Documentation | |
| parent | 456a29ddada79198c5965300e04103c40c481f62 (diff) | |
x86: Export x86 boot_params to sysfs
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>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-boot_params | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-boot_params b/Documentation/ABI/testing/sysfs-kernel-boot_params new file mode 100644 index 000000000000..eca38ce2852d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-boot_params @@ -0,0 +1,38 @@ +What: /sys/kernel/boot_params +Date: December 2013 +Contact: Dave Young <dyoung@redhat.com> +Description: The /sys/kernel/boot_params directory contains two + files: "data" and "version" and one subdirectory "setup_data". + It is used to export the kernel boot parameters of an x86 + platform to userspace for kexec and debugging purpose. + + If there's no setup_data in boot_params the subdirectory will + not be created. + + "data" file is the binary representation of struct boot_params. + + "version" file is the string representation of boot + protocol version. + + "setup_data" subdirectory contains the setup_data data + structure in boot_params. setup_data is maintained in kernel + as a link list. In "setup_data" subdirectory there's one + subdirectory for each link list node named with the number + of the list nodes. The list node subdirectory contains two + files "type" and "data". "type" file is the string + representation of setup_data type. "data" file is the binary + representation of setup_data payload. + + The whole boot_params directory structure is like below: + /sys/kernel/boot_params + |__ data + |__ setup_data + | |__ 0 + | | |__ data + | | |__ type + | |__ 1 + | |__ data + | |__ type + |__ version + +Users: Kexec |