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C/C++ Source or Header  |  2008-12-24  |  3.9 KB  |  138 lines
  1. #ifndef _ASM_X86_PDA_H
  2. #define _ASM_X86_PDA_H
  3.  
  4. #ifndef __ASSEMBLY__
  5. #include <linux/stddef.h>
  6. #include <linux/types.h>
  7. #include <linux/cache.h>
  8. #include <asm/page.h>
  9.  
  10. /* Per processor datastructure. %gs points to it while the kernel runs */
  11. struct x8664_pda {
  12.     struct task_struct *pcurrent;    /* 0  Current process */
  13.     unsigned long data_offset;    /* 8 Per cpu data offset from linker
  14.                        address */
  15.     unsigned long kernelstack;    /* 16 top of kernel stack for current */
  16.     unsigned long oldrsp;        /* 24 user rsp for system call */
  17.     int irqcount;            /* 32 Irq nesting counter. Starts -1 */
  18.     unsigned int cpunumber;        /* 36 Logical CPU number */
  19. #ifdef CONFIG_CC_STACKPROTECTOR
  20.     unsigned long stack_canary;    /* 40 stack canary value */
  21.                     /* gcc-ABI: this canary MUST be at
  22.                        offset 40!!! */
  23. #endif
  24.     char *irqstackptr;
  25.     short nodenumber;        /* number of current node (32k max) */
  26.     short in_bootmem;        /* pda lives in bootmem */
  27.     unsigned int __softirq_pending;
  28.     unsigned int __nmi_count;    /* number of NMI on this CPUs */
  29.     short mmu_state;
  30.     short isidle;
  31.     struct mm_struct *active_mm;
  32.     unsigned apic_timer_irqs;
  33.     unsigned irq0_irqs;
  34.     unsigned irq_resched_count;
  35.     unsigned irq_call_count;
  36.     unsigned irq_tlb_count;
  37.     unsigned irq_thermal_count;
  38.     unsigned irq_threshold_count;
  39.     unsigned irq_spurious_count;
  40. } ____cacheline_aligned_in_smp;
  41.  
  42. extern struct x8664_pda **_cpu_pda;
  43. extern void pda_init(int);
  44.  
  45. #define cpu_pda(i) (_cpu_pda[i])
  46.  
  47. /*
  48.  * There is no fast way to get the base address of the PDA, all the accesses
  49.  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  50.  */
  51. extern void __bad_pda_field(void) __attribute__((noreturn));
  52.  
  53. /*
  54.  * proxy_pda doesn't actually exist, but tell gcc it is accessed for
  55.  * all PDA accesses so it gets read/write dependencies right.
  56.  */
  57. extern struct x8664_pda _proxy_pda;
  58.  
  59. #define pda_offset(field) offsetof(struct x8664_pda, field)
  60.  
  61. #define pda_to_op(op, field, val)                    \
  62. do {                                    \
  63.     typedef typeof(_proxy_pda.field) T__;                \
  64.     if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */    \
  65.     switch (sizeof(_proxy_pda.field)) {                \
  66.     case 2:                                \
  67.         asm(op "w %1,%%gs:%c2" :                \
  68.             "+m" (_proxy_pda.field) :                \
  69.             "ri" ((T__)val),                    \
  70.             "i"(pda_offset(field)));                \
  71.         break;                            \
  72.     case 4:                                \
  73.         asm(op "l %1,%%gs:%c2" :                \
  74.             "+m" (_proxy_pda.field) :                \
  75.             "ri" ((T__)val),                    \
  76.             "i" (pda_offset(field)));                \
  77.         break;                            \
  78.     case 8:                                \
  79.         asm(op "q %1,%%gs:%c2":                    \
  80.             "+m" (_proxy_pda.field) :                \
  81.             "ri" ((T__)val),                    \
  82.             "i"(pda_offset(field)));                \
  83.         break;                            \
  84.     default:                            \
  85.         __bad_pda_field();                    \
  86.     }                                \
  87. } while (0)
  88.  
  89. #define pda_from_op(op, field)            \
  90. ({                        \
  91.     typeof(_proxy_pda.field) ret__;        \
  92.     switch (sizeof(_proxy_pda.field)) {    \
  93.     case 2:                    \
  94.         asm(op "w %%gs:%c1,%0" :    \
  95.             "=r" (ret__) :        \
  96.             "i" (pda_offset(field)),    \
  97.             "m" (_proxy_pda.field));    \
  98.         break;                \
  99.     case 4:                    \
  100.         asm(op "l %%gs:%c1,%0":        \
  101.             "=r" (ret__):        \
  102.             "i" (pda_offset(field)),    \
  103.             "m" (_proxy_pda.field));    \
  104.         break;                \
  105.     case 8:                    \
  106.         asm(op "q %%gs:%c1,%0":        \
  107.             "=r" (ret__) :        \
  108.             "i" (pda_offset(field)),    \
  109.             "m" (_proxy_pda.field));    \
  110.         break;                \
  111.     default:                \
  112.         __bad_pda_field();        \
  113.     }                    \
  114.     ret__;                    \
  115. })
  116.  
  117. #define read_pda(field)        pda_from_op("mov", field)
  118. #define write_pda(field, val)    pda_to_op("mov", field, val)
  119. #define add_pda(field, val)    pda_to_op("add", field, val)
  120. #define sub_pda(field, val)    pda_to_op("sub", field, val)
  121. #define or_pda(field, val)    pda_to_op("or", field, val)
  122.  
  123. /* This is not atomic against other CPUs -- CPU preemption needs to be off */
  124. #define test_and_clear_bit_pda(bit, field)                \
  125. ({                                    \
  126.     int old__;                            \
  127.     asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"            \
  128.              : "=r" (old__), "+m" (_proxy_pda.field)        \
  129.              : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
  130.     old__;                                \
  131. })
  132.  
  133. #endif
  134.  
  135. #define PDA_STACKOFFSET (5*8)
  136.  
  137. #endif /* _ASM_X86_PDA_H */
  138.