cregit-Linux how code gets into the kernel

Release 4.12 include/asm-generic/fixmap.h

 * fixmap.h: compile-time virtual memory allocation
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 * Copyright (C) 1998 Ingo Molnar
 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
 * Break out common bits to asm-generic by Mark Salter, November 2013



#include <linux/bug.h>

#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))

#define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)

#ifndef __ASSEMBLY__
 * 'index to address' translation. If anyone tries to use the idx
 * directly without translation, we catch the bug with a NULL-deference
 * kernel oops. Illegal ranges of incoming indices are caught too.

static __always_inline unsigned long fix_to_virt(const unsigned int idx) { BUILD_BUG_ON(idx >= __end_of_fixed_addresses); return __fix_to_virt(idx); }


Mark Salter26100.00%1100.00%

static inline unsigned long virt_to_fix(const unsigned long vaddr) { BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); return __virt_to_fix(vaddr); }


Mark Salter30100.00%1100.00%

/* * Provide some reasonable defaults for page flags. * Not all architectures use all of these different types and some * architectures use different names. */ #ifndef FIXMAP_PAGE_NORMAL #define FIXMAP_PAGE_NORMAL PAGE_KERNEL #endif #if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO) #define FIXMAP_PAGE_RO PAGE_KERNEL_RO #endif #ifndef FIXMAP_PAGE_NOCACHE #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE #endif #ifndef FIXMAP_PAGE_IO #define FIXMAP_PAGE_IO PAGE_KERNEL_IO #endif #ifndef FIXMAP_PAGE_CLEAR #define FIXMAP_PAGE_CLEAR __pgprot(0) #endif #ifndef set_fixmap #define set_fixmap(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL) #endif #ifndef clear_fixmap #define clear_fixmap(idx) \ __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR) #endif /* Return a pointer with offset calculated */ #define __set_fixmap_offset(idx, phys, flags) \ ({ \ unsigned long ________addr; \ __set_fixmap(idx, phys, flags); \ ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \ ________addr; \ }) #define set_fixmap_offset(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL) /* * Some hardware wants to get fixmapped without caching. */ #define set_fixmap_nocache(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE) #define set_fixmap_offset_nocache(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE) /* * Some fixmaps are for IO */ #define set_fixmap_io(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_IO) #define set_fixmap_offset_io(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO) #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_FIXMAP_H */

Overall Contributors

Mark Salter20987.82%125.00%
Juergen Gross187.56%125.00%
Marc Zyngier104.20%125.00%
Mark Rutland10.42%125.00%
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