include/asm-x86/system.h

   1 #ifndef _ASM_X86_SYSTEM_H_
   2 #define _ASM_X86_SYSTEM_H_
   3
   4 #include <asm/asm.h>
   5 #include <asm/segment.h>
   6 #include <asm/cpufeature.h>
   7 #include <asm/cmpxchg.h>
   8 #include <asm/nops.h>
   9
  10 #include <linux/kernel.h>
  11 #include <linux/irqflags.h>
  12
  13 /* entries in ARCH_DLINFO: */
  14 #ifdef CONFIG_IA32_EMULATION
  15 # define AT_VECTOR_SIZE_ARCH 2
  16 #else
  17 # define AT_VECTOR_SIZE_ARCH 1
  18 #endif
  19
  20 #ifdef CONFIG_X86_32
  21
  22 struct task_struct; /* one of the stranger aspects of C forward declarations */
  23 extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
  24                                                 struct task_struct *next));
  25
  26 /*
  27  * Saving eflags is important. It switches not only IOPL between tasks,
  28  * it also protects other tasks from NT leaking through sysenter etc.
  29  */
  30 #define switch_to(prev, next, last) do {                                \
  31         unsigned long esi, edi;                                         \
  32         asm volatile("pushfl\n\t"               /* Save flags */        \
  33                      "pushl %%ebp\n\t"                                  \
  34                      "movl %%esp,%0\n\t"        /* save ESP */          \
  35                      "movl %5,%%esp\n\t"        /* restore ESP */       \
  36                      "movl $1f,%1\n\t"          /* save EIP */          \
  37                      "pushl %6\n\t"             /* restore EIP */       \
  38                      "jmp __switch_to\n"                                \
  39                      "1:\t"                                             \
  40                      "popl %%ebp\n\t"                                   \
  41                      "popfl"                                            \
  42                      :"=m" (prev->thread.sp), "=m" (prev->thread.ip),   \
  43                       "=a" (last), "=S" (esi), "=D" (edi)               \
  44                      :"m" (next->thread.sp), "m" (next->thread.ip),     \
  45                       "2" (prev), "d" (next));                          \
  46 } while (0)
  47
  48 /*
  49  * disable hlt during certain critical i/o operations
  50  */
  51 #define HAVE_DISABLE_HLT
  52 #else
  53 #define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
  54 #define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"
  55
  56 /* frame pointer must be last for get_wchan */
  57 #define SAVE_CONTEXT    "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
  58 #define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"
  59
  60 #define __EXTRA_CLOBBER  \
  61         , "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
  62           "r12", "r13", "r14", "r15"
  63
  64 /* Save restore flags to clear handle leaking NT */
  65 #define switch_to(prev, next, last) \
  66         asm volatile(SAVE_CONTEXT                                                   \
  67              "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */       \
  68              "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */    \
  69              "call __switch_to\n\t"                                       \
  70              ".globl thread_return\n"                                     \
  71              "thread_return:\n\t"                                         \
  72              "movq %%gs:%P[pda_pcurrent],%%rsi\n\t"                       \
  73              "movq %P[thread_info](%%rsi),%%r8\n\t"                       \
  74              LOCK_PREFIX "btr  %[tif_fork],%P[ti_flags](%%r8)\n\t"        \
  75              "movq %%rax,%%rdi\n\t"                                       \
  76              "jc   ret_from_fork\n\t"                                     \
  77              RESTORE_CONTEXT                                              \
  78              : "=a" (last)                                                \
  79              : [next] "S" (next), [prev] "D" (prev),                      \
  80                [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \
  81                [ti_flags] "i" (offsetof(struct thread_info, flags)),      \
  82                [tif_fork] "i" (TIF_FORK),                                 \
  83                [thread_info] "i" (offsetof(struct task_struct, stack)),   \
  84                [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent))  \
  85              : "memory", "cc" __EXTRA_CLOBBER)
  86 #endif
  87
  88 #ifdef __KERNEL__
  89 #define _set_base(addr, base) do { unsigned long __pr; \
  90 __asm__ __volatile__ ("movw %%dx,%1\n\t" \
  91         "rorl $16,%%edx\n\t" \
  92         "movb %%dl,%2\n\t" \
  93         "movb %%dh,%3" \
  94         :"=&d" (__pr) \
  95         :"m" (*((addr)+2)), \
  96          "m" (*((addr)+4)), \
  97          "m" (*((addr)+7)), \
  98          "0" (base) \
  99         ); } while (0)
 100
 101 #define _set_limit(addr, limit) do { unsigned long __lr; \
 102 __asm__ __volatile__ ("movw %%dx,%1\n\t" \
 103         "rorl $16,%%edx\n\t" \
 104         "movb %2,%%dh\n\t" \
 105         "andb $0xf0,%%dh\n\t" \
 106         "orb %%dh,%%dl\n\t" \
 107         "movb %%dl,%2" \
 108         :"=&d" (__lr) \
 109         :"m" (*(addr)), \
 110          "m" (*((addr)+6)), \
 111          "0" (limit) \
 112         ); } while (0)
 113
 114 #define set_base(ldt, base) _set_base(((char *)&(ldt)) , (base))
 115 #define set_limit(ldt, limit) _set_limit(((char *)&(ldt)) , ((limit)-1))
 116
 117 extern void load_gs_index(unsigned);
 118
 119 /*
 120  * Load a segment. Fall back on loading the zero
 121  * segment if something goes wrong..
 122  */
 123 #define loadsegment(seg, value)                 \
 124         asm volatile("\n"                       \
 125                 "1:\t"                          \
 126                 "movl %k0,%%" #seg "\n"         \
 127                 "2:\n"                          \
 128                 ".section .fixup,\"ax\"\n"      \
 129                 "3:\t"                          \
 130                 "movl %k1, %%" #seg "\n\t"      \
 131                 "jmp 2b\n"                      \
 132                 ".previous\n"                   \
 133                 ".section __ex_table,\"a\"\n\t" \
 134                 _ASM_ALIGN "\n\t"               \
 135                 _ASM_PTR " 1b,3b\n"             \
 136                 ".previous"                     \
 137                 : :"r" (value), "r" (0))
 138
 139
 140 /*
 141  * Save a segment register away
 142  */
 143 #define savesegment(seg, value) \
 144         asm volatile("mov %%" #seg ",%0":"=rm" (value))
 145
 146 static inline unsigned long get_limit(unsigned long segment)
 147 {
 148         unsigned long __limit;
 149         __asm__("lsll %1,%0"
 150                 :"=r" (__limit):"r" (segment));
 151         return __limit+1;
 152 }
 153
 154 static inline void native_clts(void)
 155 {
 156         asm volatile ("clts");
 157 }
 158
 159 /*
 160  * Volatile isn't enough to prevent the compiler from reordering the
 161  * read/write functions for the control registers and messing everything up.
 162  * A memory clobber would solve the problem, but would prevent reordering of
 163  * all loads stores around it, which can hurt performance. Solution is to
 164  * use a variable and mimic reads and writes to it to enforce serialization
 165  */
 166 static unsigned long __force_order;
 167
 168 static inline unsigned long native_read_cr0(void)
 169 {
 170         unsigned long val;
 171         asm volatile("mov %%cr0,%0\n\t" :"=r" (val), "=m" (__force_order));
 172         return val;
 173 }
 174
 175 static inline void native_write_cr0(unsigned long val)
 176 {
 177         asm volatile("mov %0,%%cr0": :"r" (val), "m" (__force_order));
 178 }
 179
 180 static inline unsigned long native_read_cr2(void)
 181 {
 182         unsigned long val;
 183         asm volatile("mov %%cr2,%0\n\t" :"=r" (val), "=m" (__force_order));
 184         return val;
 185 }
 186
 187 static inline void native_write_cr2(unsigned long val)
 188 {
 189         asm volatile("mov %0,%%cr2": :"r" (val), "m" (__force_order));
 190 }
 191
 192 static inline unsigned long native_read_cr3(void)
 193 {
 194         unsigned long val;
 195         asm volatile("mov %%cr3,%0\n\t" :"=r" (val), "=m" (__force_order));
 196         return val;
 197 }
 198
 199 static inline void native_write_cr3(unsigned long val)
 200 {
 201         asm volatile("mov %0,%%cr3": :"r" (val), "m" (__force_order));
 202 }
 203
 204 static inline unsigned long native_read_cr4(void)
 205 {
 206         unsigned long val;
 207         asm volatile("mov %%cr4,%0\n\t" :"=r" (val), "=m" (__force_order));
 208         return val;
 209 }
 210
 211 static inline unsigned long native_read_cr4_safe(void)
 212 {
 213         unsigned long val;
 214         /* This could fault if %cr4 does not exist. In x86_64, a cr4 always
 215          * exists, so it will never fail. */
 216 #ifdef CONFIG_X86_32
 217         asm volatile("1: mov %%cr4, %0          \n"
 218                 "2:                             \n"
 219                 ".section __ex_table,\"a\"      \n"
 220                 ".long 1b,2b                    \n"
 221                 ".previous                      \n"
 222                 : "=r" (val), "=m" (__force_order) : "0" (0));
 223 #else
 224         val = native_read_cr4();
 225 #endif
 226         return val;
 227 }
 228
 229 static inline void native_write_cr4(unsigned long val)
 230 {
 231         asm volatile("mov %0,%%cr4": :"r" (val), "m" (__force_order));
 232 }
 233
 234 #ifdef CONFIG_X86_64
 235 static inline unsigned long native_read_cr8(void)
 236 {
 237         unsigned long cr8;
 238         asm volatile("movq %%cr8,%0" : "=r" (cr8));
 239         return cr8;
 240 }
 241
 242 static inline void native_write_cr8(unsigned long val)
 243 {
 244         asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
 245 }
 246 #endif
 247
 248 static inline void native_wbinvd(void)
 249 {
 250         asm volatile("wbinvd": : :"memory");
 251 }
 252 #ifdef CONFIG_PARAVIRT
 253 #include <asm/paravirt.h>
 254 #else
 255 #define read_cr0()      (native_read_cr0())
 256 #define write_cr0(x)    (native_write_cr0(x))
 257 #define read_cr2()      (native_read_cr2())
 258 #define write_cr2(x)    (native_write_cr2(x))
 259 #define read_cr3()      (native_read_cr3())
 260 #define write_cr3(x)    (native_write_cr3(x))
 261 #define read_cr4()      (native_read_cr4())
 262 #define read_cr4_safe() (native_read_cr4_safe())
 263 #define write_cr4(x)    (native_write_cr4(x))
 264 #define wbinvd()        (native_wbinvd())
 265 #ifdef CONFIG_X86_64
 266 #define read_cr8()      (native_read_cr8())
 267 #define write_cr8(x)    (native_write_cr8(x))
 268 #endif
 269
 270 /* Clear the 'TS' bit */
 271 #define clts()          (native_clts())
 272
 273 #endif/* CONFIG_PARAVIRT */
 274
 275 #define stts() write_cr0(8 | read_cr0())
 276
 277 #endif /* __KERNEL__ */
 278
 279 static inline void clflush(void *__p)
 280 {
 281         asm volatile("clflush %0" : "+m" (*(char __force *)__p));
 282 }
 283
 284 #define nop() __asm__ __volatile__ ("nop")
 285
 286 void disable_hlt(void);
 287 void enable_hlt(void);
 288
 289 extern int es7000_plat;
 290 void cpu_idle_wait(void);
 291
 292 extern unsigned long arch_align_stack(unsigned long sp);
 293 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
 294
 295 void default_idle(void);
 296
 297 /*
 298  * Force strict CPU ordering.
 299  * And yes, this is required on UP too when we're talking
 300  * to devices.
 301  */
 302 #ifdef CONFIG_X86_32
 303 /*
 304  * For now, "wmb()" doesn't actually do anything, as all
 305  * Intel CPU's follow what Intel calls a *Processor Order*,
 306  * in which all writes are seen in the program order even
 307  * outside the CPU.
 308  *
 309  * I expect future Intel CPU's to have a weaker ordering,
 310  * but I'd also expect them to finally get their act together
 311  * and add some real memory barriers if so.
 312  *
 313  * Some non intel clones support out of order store. wmb() ceases to be a
 314  * nop for these.
 315  */
 316 #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
 317 #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
 318 #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
 319 #else
 320 #define mb()    asm volatile("mfence":::"memory")
 321 #define rmb()   asm volatile("lfence":::"memory")
 322 #define wmb()   asm volatile("sfence" ::: "memory")
 323 #endif
 324
 325 /**
 326  * read_barrier_depends - Flush all pending reads that subsequents reads
 327  * depend on.
 328  *
 329  * No data-dependent reads from memory-like regions are ever reordered
 330  * over this barrier.  All reads preceding this primitive are guaranteed
 331  * to access memory (but not necessarily other CPUs' caches) before any
 332  * reads following this primitive that depend on the data return by
 333  * any of the preceding reads.  This primitive is much lighter weight than
 334  * rmb() on most CPUs, and is never heavier weight than is
 335  * rmb().
 336  *
 337  * These ordering constraints are respected by both the local CPU
 338  * and the compiler.
 339  *
 340  * Ordering is not guaranteed by anything other than these primitives,
 341  * not even by data dependencies.  See the documentation for
 342  * memory_barrier() for examples and URLs to more information.
 343  *
 344  * For example, the following code would force ordering (the initial
 345  * value of "a" is zero, "b" is one, and "p" is "&a"):
 346  *
 347  * <programlisting>
 348  *      CPU 0                           CPU 1
 349  *
 350  *      b = 2;
 351  *      memory_barrier();
 352  *      p = &b;                         q = p;
 353  *                                      read_barrier_depends();
 354  *                                      d = *q;
 355  * </programlisting>
 356  *
 357  * because the read of "*q" depends on the read of "p" and these
 358  * two reads are separated by a read_barrier_depends().  However,
 359  * the following code, with the same initial values for "a" and "b":
 360  *
 361  * <programlisting>
 362  *      CPU 0                           CPU 1
 363  *
 364  *      a = 2;
 365  *      memory_barrier();
 366  *      b = 3;                          y = b;
 367  *                                      read_barrier_depends();
 368  *                                      x = a;
 369  * </programlisting>
 370  *
 371  * does not enforce ordering, since there is no data dependency between
 372  * the read of "a" and the read of "b".  Therefore, on some CPUs, such
 373  * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
 374  * in cases like this where there are no data dependencies.
 375  **/
 376
 377 #define read_barrier_depends()  do { } while (0)
 378
 379 #ifdef CONFIG_SMP
 380 #define smp_mb()        mb()
 381 #ifdef CONFIG_X86_PPRO_FENCE
 382 # define smp_rmb()      rmb()
 383 #else
 384 # define smp_rmb()      barrier()
 385 #endif
 386 #ifdef CONFIG_X86_OOSTORE
 387 # define smp_wmb()      wmb()
 388 #else
 389 # define smp_wmb()      barrier()
 390 #endif
 391 #define smp_read_barrier_depends()      read_barrier_depends()
 392 #define set_mb(var, value) do { (void) xchg(&var, value); } while (0)
 393 #else
 394 #define smp_mb()        barrier()
 395 #define smp_rmb()       barrier()
 396 #define smp_wmb()       barrier()
 397 #define smp_read_barrier_depends()      do { } while (0)
 398 #define set_mb(var, value) do { var = value; barrier(); } while (0)
 399 #endif
 400
 401 /*
 402  * Stop RDTSC speculation. This is needed when you need to use RDTSC
 403  * (or get_cycles or vread that possibly accesses the TSC) in a defined
 404  * code region.
 405  *
 406  * (Could use an alternative three way for this if there was one.)
 407  */
 408 static inline void rdtsc_barrier(void)
 409 {
 410         alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
 411         alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
 412 }
 413
 414 #endif