| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|
| 2 | /* |
|---|
| 3 | * PowerPC ELF notes. |
|---|
| 4 | * |
|---|
| 5 | * Copyright 2019, IBM Corporation |
|---|
| 6 | */ |
|---|
| 7 | |
|---|
| 8 | #include <linux/elfnote.h> |
|---|
| 9 | #include <asm/elfnote.h> |
|---|
| 10 | |
|---|
| 11 | /* |
|---|
| 12 | * Ultravisor-capable bit (PowerNV only). |
|---|
| 13 | * |
|---|
| 14 | * Bit 0 indicates that the powerpc kernel binary knows how to run in an |
|---|
| 15 | * ultravisor-enabled system. |
|---|
| 16 | * |
|---|
| 17 | * In an ultravisor-enabled system, some machine resources are now controlled |
|---|
| 18 | * by the ultravisor. If the kernel is not ultravisor-capable, but it ends up |
|---|
| 19 | * being run on a machine with ultravisor, the kernel will probably crash |
|---|
| 20 | * trying to access ultravisor resources. For instance, it may crash in early |
|---|
| 21 | * boot trying to set the partition table entry 0. |
|---|
| 22 | * |
|---|
| 23 | * In an ultravisor-enabled system, a bootloader could warn the user or prevent |
|---|
| 24 | * the kernel from being run if the PowerPC ultravisor capability doesn't exist |
|---|
| 25 | * or the Ultravisor-capable bit is not set. |
|---|
| 26 | */ |
|---|
| 27 | #ifdef CONFIG_PPC_POWERNV |
|---|
| 28 | #define PPCCAP_ULTRAVISOR_BIT (1 << 0) |
|---|
| 29 | #else |
|---|
| 30 | #define PPCCAP_ULTRAVISOR_BIT 0 |
|---|
| 31 | #endif |
|---|
| 32 | |
|---|
| 33 | /* |
|---|
| 34 | * Add the PowerPC Capabilities in the binary ELF note. It is a bitmap that |
|---|
| 35 | * can be used to advertise kernel capabilities to userland. |
|---|
| 36 | */ |
|---|
| 37 | #define PPC_CAPABILITIES_BITMAP (PPCCAP_ULTRAVISOR_BIT) |
|---|
| 38 | |
|---|
| 39 | ELFNOTE(PowerPC, PPC_ELFNOTE_CAPABILITIES, |
|---|
| 40 | .long PPC_CAPABILITIES_BITMAP) |
|---|
| 41 | |
|---|
