arch/x86/include/asm/special_insns.h

   1 #ifndef _ASM_X86_SPECIAL_INSNS_H
   2 #define _ASM_X86_SPECIAL_INSNS_H
   3
   4
   5 #ifdef __KERNEL__
   6
   7 static inline void native_clts(void)
   8 {
   9         asm volatile("clts");
  10 }
  11
  12 /*
  13  * Volatile isn't enough to prevent the compiler from reordering the
  14  * read/write functions for the control registers and messing everything up.
  15  * A memory clobber would solve the problem, but would prevent reordering of
  16  * all loads stores around it, which can hurt performance. Solution is to
  17  * use a variable and mimic reads and writes to it to enforce serialization
  18  */
  19 static unsigned long __force_order;
  20
  21 static inline unsigned long native_read_cr0(void)
  22 {
  23         unsigned long val;
  24         asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order));
  25         return val;
  26 }
  27
  28 static inline void native_write_cr0(unsigned long val)
  29 {
  30         asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order));
  31 }
  32
  33 static inline unsigned long native_read_cr2(void)
  34 {
  35         unsigned long val;
  36         asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order));
  37         return val;
  38 }
  39
  40 static inline void native_write_cr2(unsigned long val)
  41 {
  42         asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order));
  43 }
  44
  45 static inline unsigned long native_read_cr3(void)
  46 {
  47         unsigned long val;
  48         asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order));
  49         return val;
  50 }
  51
  52 static inline void native_write_cr3(unsigned long val)
  53 {
  54         asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order));
  55 }
  56
  57 static inline unsigned long native_read_cr4(void)
  58 {
  59         unsigned long val;
  60         asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order));
  61         return val;
  62 }
  63
  64 static inline unsigned long native_read_cr4_safe(void)
  65 {
  66         unsigned long val;
  67         /* This could fault if %cr4 does not exist. In x86_64, a cr4 always
  68          * exists, so it will never fail. */
  69 #ifdef CONFIG_X86_32
  70         asm volatile("1: mov %%cr4, %0\n"
  71                      "2:\n"
  72                      _ASM_EXTABLE(1b, 2b)
  73                      : "=r" (val), "=m" (__force_order) : "0" (0));
  74 #else
  75         val = native_read_cr4();
  76 #endif
  77         return val;
  78 }
  79
  80 static inline void native_write_cr4(unsigned long val)
  81 {
  82         asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order));
  83 }
  84
  85 #ifdef CONFIG_X86_64
  86 static inline unsigned long native_read_cr8(void)
  87 {
  88         unsigned long cr8;
  89         asm volatile("movq %%cr8,%0" : "=r" (cr8));
  90         return cr8;
  91 }
  92
  93 static inline void native_write_cr8(unsigned long val)
  94 {
  95         asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
  96 }
  97 #endif
  98
  99 static inline void native_wbinvd(void)
 100 {
 101         asm volatile("wbinvd": : :"memory");
 102 }
 103
 104 extern void native_load_gs_index(unsigned);
 105
 106 #ifdef CONFIG_PARAVIRT
 107 #include <asm/paravirt.h>
 108 #else
 109
 110 static inline unsigned long read_cr0(void)
 111 {
 112         return native_read_cr0();
 113 }
 114
 115 static inline void write_cr0(unsigned long x)
 116 {
 117         native_write_cr0(x);
 118 }
 119
 120 static inline unsigned long read_cr2(void)
 121 {
 122         return native_read_cr2();
 123 }
 124
 125 static inline void write_cr2(unsigned long x)
 126 {
 127         native_write_cr2(x);
 128 }
 129
 130 static inline unsigned long read_cr3(void)
 131 {
 132         return native_read_cr3();
 133 }
 134
 135 static inline void write_cr3(unsigned long x)
 136 {
 137         native_write_cr3(x);
 138 }
 139
 140 static inline unsigned long read_cr4(void)
 141 {
 142         return native_read_cr4();
 143 }
 144
 145 static inline unsigned long read_cr4_safe(void)
 146 {
 147         return native_read_cr4_safe();
 148 }
 149
 150 static inline void write_cr4(unsigned long x)
 151 {
 152         native_write_cr4(x);
 153 }
 154
 155 static inline void wbinvd(void)
 156 {
 157         native_wbinvd();
 158 }
 159
 160 #ifdef CONFIG_X86_64
 161
 162 static inline unsigned long read_cr8(void)
 163 {
 164         return native_read_cr8();
 165 }
 166
 167 static inline void write_cr8(unsigned long x)
 168 {
 169         native_write_cr8(x);
 170 }
 171
 172 static inline void load_gs_index(unsigned selector)
 173 {
 174         native_load_gs_index(selector);
 175 }
 176
 177 #endif
 178
 179 /* Clear the 'TS' bit */
 180 static inline void clts(void)
 181 {
 182         native_clts();
 183 }
 184
 185 #endif/* CONFIG_PARAVIRT */
 186
 187 #define stts() write_cr0(read_cr0() | X86_CR0_TS)
 188
 189 static inline void clflush(volatile void *__p)
 190 {
 191         asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p));
 192 }
 193
 194 #define nop() asm volatile ("nop")
 195
 196
 197 #endif /* __KERNEL__ */
 198
 199 #endif /* _ASM_X86_SPECIAL_INSNS_H */