arch/x86/include/asm/pda.h

   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 */