70ed86f4de
Add the PowerPC name and the PPC_ELFNOTE_CAPABILITIES type in the kernel binary ELF note. This type is a bitmap that can be used to advertise kernel capabilities to userland. This patch also defines PPCCAP_ULTRAVISOR_BIT as being the bit zero. Suggested-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com> [ maxiwell: Define the 'PowerPC' type in the elfnote.h ] Signed-off-by: Maxiwell S. Garcia <maxiwell@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190829155021.2915-2-maxiwell@linux.ibm.com
41 lines
1.2 KiB
ArmAsm
41 lines
1.2 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* PowerPC ELF notes.
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*
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* Copyright 2019, IBM Corporation
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*/
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#include <linux/elfnote.h>
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#include <asm/elfnote.h>
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/*
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* Ultravisor-capable bit (PowerNV only).
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*
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* Bit 0 indicates that the powerpc kernel binary knows how to run in an
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* ultravisor-enabled system.
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*
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* In an ultravisor-enabled system, some machine resources are now controlled
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* by the ultravisor. If the kernel is not ultravisor-capable, but it ends up
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* being run on a machine with ultravisor, the kernel will probably crash
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* trying to access ultravisor resources. For instance, it may crash in early
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* boot trying to set the partition table entry 0.
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*
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* In an ultravisor-enabled system, a bootloader could warn the user or prevent
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* the kernel from being run if the PowerPC ultravisor capability doesn't exist
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* or the Ultravisor-capable bit is not set.
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*/
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#ifdef CONFIG_PPC_POWERNV
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#define PPCCAP_ULTRAVISOR_BIT (1 << 0)
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#else
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#define PPCCAP_ULTRAVISOR_BIT 0
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#endif
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/*
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* Add the PowerPC Capabilities in the binary ELF note. It is a bitmap that
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* can be used to advertise kernel capabilities to userland.
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*/
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#define PPC_CAPABILITIES_BITMAP (PPCCAP_ULTRAVISOR_BIT)
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ELFNOTE(PowerPC, PPC_ELFNOTE_CAPABILITIES,
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.long PPC_CAPABILITIES_BITMAP)
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