/* * 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 */ #ifndef _ASM_FIXMAP_H #define _ASM_FIXMAP_H #include <linux/kernel.h> #include <asm/apicdef.h> #include <asm/page.h> #include <asm/vsyscall.h> #include <asm/vsyscall32.h> /* * Here we define all the compile-time 'special' virtual * addresses. The point is to have a constant address at * compile time, but to set the physical address only * in the boot process. * * these 'compile-time allocated' memory buffers are * fixed-size 4k pages. (or larger if used with an increment * highger than 1) use fixmap_set(idx,phys) to associate * physical memory with fixmap indices. * * TLB entries of such buffers will not be flushed across * task switches. */ enum fixed_addresses { VSYSCALL_LAST_PAGE, VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1, VSYSCALL_HPET, FIX_HPET_BASE, FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */ FIX_IO_APIC_BASE_0, FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1, __end_of_fixed_addresses }; extern void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags); #define set_fixmap(idx, phys) \ __set_fixmap(idx, phys, PAGE_KERNEL) /* * Some hardware wants to get fixmapped without caching. */ #define set_fixmap_nocache(idx, phys) \ __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) #define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE) #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) /* Only covers 32bit vsyscalls currently. Need another set for 64bit. */ #define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL) #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE) #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) extern void __this_fixmap_does_not_exist(void); /* * '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) { /* * this branch gets completely eliminated after inlining, * except when someone tries to use fixaddr indices in an * illegal way. (such as mixing up address types or using * out-of-range indices). * * If it doesn't get removed, the linker will complain * loudly with a reasonably clear error message.. */ if (idx >= __end_of_fixed_addresses) __this_fixmap_does_not_exist(); return __fix_to_virt(idx); } #endif