include/asm-x86/pda.h

   1 #ifndef X86_64_PDA_H
   2 #define X86_64_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         unsigned long stack_canary;     /* 40 stack canary value */
  20                                         /* gcc-ABI: this canary MUST be at
  21                                            offset 40!!! */
  22         char *irqstackptr;
  23         unsigned int __softirq_pending;
  24         unsigned int __nmi_count;       /* number of NMI on this CPUs */
  25         short mmu_state;
  26         short isidle;
  27         struct mm_struct *active_mm;
  28         unsigned apic_timer_irqs;
  29         unsigned irq0_irqs;
  30         unsigned irq_resched_count;
  31         unsigned irq_call_count;
  32         unsigned irq_tlb_count;
  33         unsigned irq_thermal_count;
  34         unsigned irq_threshold_count;
  35         unsigned irq_spurious_count;
  36 } ____cacheline_aligned_in_smp;
  37
  38 extern struct x8664_pda *_cpu_pda[];
  39 extern struct x8664_pda boot_cpu_pda[];
  40 extern void pda_init(int);
  41
  42 #define cpu_pda(i) (_cpu_pda[i])
  43
  44 /*
  45  * There is no fast way to get the base address of the PDA, all the accesses
  46  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  47  */
  48 extern void __bad_pda_field(void) __attribute__((noreturn));
  49
  50 /*
  51  * proxy_pda doesn't actually exist, but tell gcc it is accessed for
  52  * all PDA accesses so it gets read/write dependencies right.
  53  */
  54 extern struct x8664_pda _proxy_pda;
  55
  56 #define pda_offset(field) offsetof(struct x8664_pda, field)
  57
  58 #define pda_to_op(op, field, val)                                       \
  59 do {                                                                    \
  60         typedef typeof(_proxy_pda.field) T__;                           \
  61         if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */     \
  62         switch (sizeof(_proxy_pda.field)) {                             \
  63         case 2:                                                         \
  64                 asm(op "w %1,%%gs:%c2" :                                \
  65                     "+m" (_proxy_pda.field) :                           \
  66                     "ri" ((T__)val),                                    \
  67                     "i"(pda_offset(field)));                            \
  68                 break;                                                  \
  69         case 4:                                                         \
  70                 asm(op "l %1,%%gs:%c2" :                                \
  71                     "+m" (_proxy_pda.field) :                           \
  72                     "ri" ((T__)val),                                    \
  73                     "i" (pda_offset(field)));                           \
  74                 break;                                                  \
  75         case 8:                                                         \
  76                 asm(op "q %1,%%gs:%c2":                                 \
  77                     "+m" (_proxy_pda.field) :                           \
  78                     "ri" ((T__)val),                                    \
  79                     "i"(pda_offset(field)));                            \
  80                 break;                                                  \
  81         default:                                                        \
  82                 __bad_pda_field();                                      \
  83         }                                                               \
  84 } while (0)
  85
  86 #define pda_from_op(op, field)                  \
  87 ({                                              \
  88         typeof(_proxy_pda.field) ret__;         \
  89         switch (sizeof(_proxy_pda.field)) {     \
  90         case 2:                                 \
  91                 asm(op "w %%gs:%c1,%0" :        \
  92                     "=r" (ret__) :              \
  93                     "i" (pda_offset(field)),    \
  94                     "m" (_proxy_pda.field));    \
  95                 break;                          \
  96         case 4:                                 \
  97                 asm(op "l %%gs:%c1,%0":         \
  98                     "=r" (ret__):               \
  99                     "i" (pda_offset(field)),    \
 100                     "m" (_proxy_pda.field));    \
 101                 break;                          \
 102         case 8:                                 \
 103                 asm(op "q %%gs:%c1,%0":         \
 104                     "=r" (ret__) :              \
 105                     "i" (pda_offset(field)),    \
 106                     "m" (_proxy_pda.field));    \
 107                 break;                          \
 108         default:                                \
 109                 __bad_pda_field();              \
 110         }                                       \
 111         ret__;                                  \
 112 })
 113
 114 #define read_pda(field)         pda_from_op("mov", field)
 115 #define write_pda(field, val)   pda_to_op("mov", field, val)
 116 #define add_pda(field, val)     pda_to_op("add", field, val)
 117 #define sub_pda(field, val)     pda_to_op("sub", field, val)
 118 #define or_pda(field, val)      pda_to_op("or", field, val)
 119
 120 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 121 #define test_and_clear_bit_pda(bit, field)                              \
 122 ({                                                                      \
 123         int old__;                                                      \
 124         asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"                    \
 125                      : "=r" (old__), "+m" (_proxy_pda.field)            \
 126                      : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
 127         old__;                                                          \
 128 })
 129
 130 #endif
 131
 132 #define PDA_STACKOFFSET (5*8)
 133
 134 #define refresh_stack_canary() write_pda(stack_canary, current->stack_canary)
 135 #endif