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4735037b5d
Add text patching api's to use in subsequent jump_label implementation. We use a new fixmap FIX_TEXT_POKE0 entry to temporarily override MMU mappings to allow read only text pages to be written to. Previously, __set_fix was marked with __init as it was only used during the EARLYCON stage. Now that TEXT_POKE mappings require post-init usage (e.g., FIX_TEXT_POKE0), keeping __init would cause runtime bugs whenset_fixmap accesses invalid memory. Thus, we remove the __init flag to ensure __set_fix remains valid beyond initialization. A new function patch_insn_write is exposed to allow single instruction patching. Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t Signed-off-by: chenmiao <chenmiao.ku@gmail.com> Signed-off-by: Stafford Horne <shorne@gmail.com>
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* OpenRISC Linux
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* OpenRISC implementation:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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* et al.
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*/
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#ifndef __ASM_OPENRISC_FIXMAP_H
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#define __ASM_OPENRISC_FIXMAP_H
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/* Why exactly do we need 2 empty pages between the top of the fixed
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* addresses and the top of virtual memory? Something is using that
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* memory space but not sure what right now... If you find it, leave
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* a comment here.
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*/
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#define FIXADDR_TOP ((unsigned long) (-2*PAGE_SIZE))
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#include <linux/kernel.h>
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#include <linux/bug.h>
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#include <asm/page.h>
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enum fixed_addresses {
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FIX_EARLYCON_MEM_BASE,
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FIX_TEXT_POKE0,
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__end_of_fixed_addresses
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};
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#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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/* FIXADDR_BOTTOM might be a better name here... */
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#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
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#define FIXMAP_PAGE_IO PAGE_KERNEL_NOCACHE
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extern void __set_fixmap(enum fixed_addresses idx,
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phys_addr_t phys, pgprot_t flags);
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#include <asm-generic/fixmap.h>
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#endif
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