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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /Documentation/powerpc/elfnote.rst | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/powerpc/elfnote.rst')
-rw-r--r-- | Documentation/powerpc/elfnote.rst | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/powerpc/elfnote.rst b/Documentation/powerpc/elfnote.rst new file mode 100644 index 0000000000..3ec8d61e9a --- /dev/null +++ b/Documentation/powerpc/elfnote.rst @@ -0,0 +1,41 @@ +========================== +ELF Note PowerPC Namespace +========================== + +The PowerPC namespace in an ELF Note of the kernel binary is used to store +capabilities and information which can be used by a bootloader or userland. + +Types and Descriptors +--------------------- + +The types to be used with the "PowerPC" namespace are defined in [#f1]_. + + 1) PPC_ELFNOTE_CAPABILITIES + +Define the capabilities supported/required by the kernel. This type uses a +bitmap as "descriptor" field. Each bit is described below: + +- Ultravisor-capable bit (PowerNV only). + +.. code-block:: c + + #define PPCCAP_ULTRAVISOR_BIT (1 << 0) + +Indicate that the powerpc kernel binary knows how to run in an +ultravisor-enabled system. + +In an ultravisor-enabled system, some machine resources are now controlled +by the ultravisor. If the kernel is not ultravisor-capable, but it ends up +being run on a machine with ultravisor, the kernel will probably crash +trying to access ultravisor resources. For instance, it may crash in early +boot trying to set the partition table entry 0. + +In an ultravisor-enabled system, a bootloader could warn the user or prevent +the kernel from being run if the PowerPC ultravisor capability doesn't exist +or the Ultravisor-capable bit is not set. + +References +---------- + +.. [#f1] arch/powerpc/include/asm/elfnote.h + |