1 | /* |
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2 | * fixmap.h: compile-time virtual memory allocation |
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3 | * |
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4 | * This file is subject to the terms and conditions of the GNU General Public |
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5 | * License. See the file "COPYING" in the main directory of this archive |
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6 | * for more details. |
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7 | * |
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8 | * Copyright (C) 1998 Ingo Molnar |
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9 | */ |
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10 | |
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11 | #ifndef _ASM_FIXMAP_H |
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12 | #define _ASM_FIXMAP_H |
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13 | |
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14 | #include <linux/kernel.h> |
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15 | #include <asm/apicdef.h> |
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16 | #include <asm/page.h> |
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17 | #include <asm/vsyscall.h> |
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18 | #include <asm/vsyscall32.h> |
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19 | #include <asm/acpi.h> |
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20 | |
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21 | /* |
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22 | * Here we define all the compile-time 'special' virtual |
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23 | * addresses. The point is to have a constant address at |
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24 | * compile time, but to set the physical address only |
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25 | * in the boot process. |
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26 | * |
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27 | * these 'compile-time allocated' memory buffers are |
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28 | * fixed-size 4k pages. (or larger if used with an increment |
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29 | * highger than 1) use fixmap_set(idx,phys) to associate |
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30 | * physical memory with fixmap indices. |
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31 | * |
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32 | * TLB entries of such buffers will not be flushed across |
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33 | * task switches. |
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34 | */ |
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35 | |
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36 | enum fixed_addresses { |
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37 | VSYSCALL_LAST_PAGE, |
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38 | VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1, |
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39 | VSYSCALL_HPET, |
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40 | FIX_HPET_BASE, |
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41 | #ifdef CONFIG_X86_LOCAL_APIC |
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42 | FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */ |
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43 | #endif |
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44 | #ifdef CONFIG_X86_IO_APIC |
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45 | FIX_IO_APIC_BASE_0, |
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46 | FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1, |
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47 | #endif |
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48 | #ifdef CONFIG_ACPI |
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49 | FIX_ACPI_BEGIN, |
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50 | FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1, |
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51 | #endif |
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52 | FIX_SHARED_INFO, |
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53 | #define NR_FIX_ISAMAPS 256 |
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54 | FIX_ISAMAP_END, |
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55 | FIX_ISAMAP_BEGIN = FIX_ISAMAP_END + NR_FIX_ISAMAPS - 1, |
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56 | __end_of_permanent_fixed_addresses, |
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57 | /* temporary boot-time mappings, used before ioremap() is functional */ |
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58 | #define NR_FIX_BTMAPS 16 |
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59 | FIX_BTMAP_END = __end_of_permanent_fixed_addresses, |
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60 | FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1, |
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61 | __end_of_fixed_addresses |
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62 | }; |
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63 | |
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64 | extern void __set_fixmap (enum fixed_addresses idx, |
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65 | unsigned long phys, pgprot_t flags); |
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66 | |
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67 | #define set_fixmap(idx, phys) \ |
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68 | __set_fixmap(idx, phys, PAGE_KERNEL) |
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69 | /* |
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70 | * Some hardware wants to get fixmapped without caching. |
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71 | */ |
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72 | #define set_fixmap_nocache(idx, phys) \ |
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73 | __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) |
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74 | |
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75 | #define clear_fixmap(idx) \ |
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76 | __set_fixmap(idx, 0, __pgprot(0)) |
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77 | |
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78 | #define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE) |
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79 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
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80 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) |
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81 | |
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82 | /* Only covers 32bit vsyscalls currently. Need another set for 64bit. */ |
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83 | #define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL) |
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84 | #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE) |
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85 | |
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86 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) |
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87 | |
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88 | extern void __this_fixmap_does_not_exist(void); |
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89 | |
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90 | /* |
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91 | * 'index to address' translation. If anyone tries to use the idx |
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92 | * directly without translation, we catch the bug with a NULL-deference |
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93 | * kernel oops. Illegal ranges of incoming indices are caught too. |
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94 | */ |
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95 | static __always_inline unsigned long fix_to_virt(const unsigned int idx) |
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96 | { |
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97 | /* |
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98 | * this branch gets completely eliminated after inlining, |
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99 | * except when someone tries to use fixaddr indices in an |
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100 | * illegal way. (such as mixing up address types or using |
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101 | * out-of-range indices). |
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102 | * |
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103 | * If it doesn't get removed, the linker will complain |
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104 | * loudly with a reasonably clear error message.. |
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105 | */ |
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106 | if (idx >= __end_of_fixed_addresses) |
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107 | __this_fixmap_does_not_exist(); |
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108 | |
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109 | return __fix_to_virt(idx); |
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110 | } |
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111 | |
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112 | #endif |
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