| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fixmap.h: compile-time virtual memory allocation |
| 3 | * |
| 4 | * This file is subject to the terms and conditions of the GNU General Public |
| 5 | * License. See the file "COPYING" in the main directory of this archive |
| 6 | * for more details. |
| 7 | * |
| 8 | * Copyright (C) 1998 Ingo Molnar |
| 9 | */ |
| 10 | |
| 11 | #ifndef _ASM_FIXMAP_H |
| 12 | #define _ASM_FIXMAP_H |
| 13 | |
| 14 | #include <linux/config.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <asm/apicdef.h> |
| 17 | #include <asm/page.h> |
| 18 | #include <asm/vsyscall.h> |
| 19 | #include <asm/vsyscall32.h> |
| 20 | |
| 21 | /* |
| 22 | * Here we define all the compile-time 'special' virtual |
| 23 | * addresses. The point is to have a constant address at |
| 24 | * compile time, but to set the physical address only |
| 25 | * in the boot process. |
| 26 | * |
| 27 | * these 'compile-time allocated' memory buffers are |
| 28 | * fixed-size 4k pages. (or larger if used with an increment |
| 29 | * highger than 1) use fixmap_set(idx,phys) to associate |
| 30 | * physical memory with fixmap indices. |
| 31 | * |
| 32 | * TLB entries of such buffers will not be flushed across |
| 33 | * task switches. |
| 34 | */ |
| 35 | |
| 36 | enum fixed_addresses { |
| 37 | VSYSCALL_LAST_PAGE, |
| 38 | VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1, |
| 39 | VSYSCALL_HPET, |
| 40 | FIX_HPET_BASE, |
| 41 | #ifdef CONFIG_X86_LOCAL_APIC |
| 42 | FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */ |
| 43 | #endif |
| 44 | #ifdef CONFIG_X86_IO_APIC |
| 45 | FIX_IO_APIC_BASE_0, |
| 46 | FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1, |
| 47 | #endif |
| 48 | __end_of_fixed_addresses |
| 49 | }; |
| 50 | |
| 51 | extern void __set_fixmap (enum fixed_addresses idx, |
| 52 | unsigned long phys, pgprot_t flags); |
| 53 | |
| 54 | #define set_fixmap(idx, phys) \ |
| 55 | __set_fixmap(idx, phys, PAGE_KERNEL) |
| 56 | /* |
| 57 | * Some hardware wants to get fixmapped without caching. |
| 58 | */ |
| 59 | #define set_fixmap_nocache(idx, phys) \ |
| 60 | __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) |
| 61 | |
| 62 | #define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE) |
| 63 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
| 64 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) |
| 65 | |
| 66 | /* Only covers 32bit vsyscalls currently. Need another set for 64bit. */ |
| 67 | #define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL) |
| 68 | #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE) |
| 69 | |
| 70 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) |
| 71 | |
| 72 | extern void __this_fixmap_does_not_exist(void); |
| 73 | |
| 74 | /* |
| 75 | * 'index to address' translation. If anyone tries to use the idx |
| 76 | * directly without translation, we catch the bug with a NULL-deference |
| 77 | * kernel oops. Illegal ranges of incoming indices are caught too. |
| 78 | */ |
| 79 | extern inline unsigned long fix_to_virt(const unsigned int idx) |
| 80 | { |
| 81 | /* |
| 82 | * this branch gets completely eliminated after inlining, |
| 83 | * except when someone tries to use fixaddr indices in an |
| 84 | * illegal way. (such as mixing up address types or using |
| 85 | * out-of-range indices). |
| 86 | * |
| 87 | * If it doesn't get removed, the linker will complain |
| 88 | * loudly with a reasonably clear error message.. |
| 89 | */ |
| 90 | if (idx >= __end_of_fixed_addresses) |
| 91 | __this_fixmap_does_not_exist(); |
| 92 | |
| 93 | return __fix_to_virt(idx); |
| 94 | } |
| 95 | |
| 96 | #endif |