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 apic_perf_irqs;
  34         unsigned irq0_irqs;
  35         unsigned irq_resched_count;
  36         unsigned irq_call_count;
  37         unsigned irq_tlb_count;
  38         unsigned irq_thermal_count;
  39         unsigned irq_threshold_count;
  40         unsigned irq_spurious_count;
  41 } ____cacheline_aligned_in_smp;
  42
  43 extern struct x8664_pda **_cpu_pda;
  44 extern void pda_init(int);
  45
  46 #define cpu_pda(i) (_cpu_pda[i])
  47
  48 /*
  49  * There is no fast way to get the base address of the PDA, all the accesses
  50  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  51  */
  52 extern void __bad_pda_field(void) __attribute__((noreturn));
  53
  54 /*
  55  * proxy_pda doesn't actually exist, but tell gcc it is accessed for
  56  * all PDA accesses so it gets read/write dependencies right.
  57  */
  58 extern struct x8664_pda _proxy_pda;
  59
  60 #define pda_offset(field) offsetof(struct x8664_pda, field)
  61
  62 #define pda_to_op(op, field, val)                                       \
  63 do {                                                                    \
  64         typedef typeof(_proxy_pda.field) T__;                           \
  65         if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */     \
  66         switch (sizeof(_proxy_pda.field)) {                             \
  67         case 2:                                                         \
  68                 asm(op "w %1,%%gs:%c2" :                                \
  69                     "+m" (_proxy_pda.field) :                           \
  70                     "ri" ((T__)val),                                    \
  71                     "i"(pda_offset(field)));                            \
  72                 break;                                                  \
  73         case 4:                                                         \
  74                 asm(op "l %1,%%gs:%c2" :                                \
  75                     "+m" (_proxy_pda.field) :                           \
  76                     "ri" ((T__)val),                                    \
  77                     "i" (pda_offset(field)));                           \
  78                 break;                                                  \
  79         case 8:                                                         \
  80                 asm(op "q %1,%%gs:%c2":                                 \
  81                     "+m" (_proxy_pda.field) :                           \
  82                     "ri" ((T__)val),                                    \
  83                     "i"(pda_offset(field)));                            \
  84                 break;                                                  \
  85         default:                                                        \
  86                 __bad_pda_field();                                      \
  87         }                                                               \
  88 } while (0)
  89
  90 #define pda_from_op(op, field)                  \
  91 ({                                              \
  92         typeof(_proxy_pda.field) ret__;         \
  93         switch (sizeof(_proxy_pda.field)) {     \
  94         case 2:                                 \
  95                 asm(op "w %%gs:%c1,%0" :        \
  96                     "=r" (ret__) :              \
  97                     "i" (pda_offset(field)),    \
  98                     "m" (_proxy_pda.field));    \
  99                 break;                          \
 100         case 4:                                 \
 101                 asm(op "l %%gs:%c1,%0":         \
 102                     "=r" (ret__):               \
 103                     "i" (pda_offset(field)),    \
 104                     "m" (_proxy_pda.field));    \
 105                 break;                          \
 106         case 8:                                 \
 107                 asm(op "q %%gs:%c1,%0":         \
 108                     "=r" (ret__) :              \
 109                     "i" (pda_offset(field)),    \
 110                     "m" (_proxy_pda.field));    \
 111                 break;                          \
 112         default:                                \
 113                 __bad_pda_field();              \
 114         }                                       \
 115         ret__;                                  \
 116 })
 117
 118 #define read_pda(field)         pda_from_op("mov", field)
 119 #define write_pda(field, val)   pda_to_op("mov", field, val)
 120 #define add_pda(field, val)     pda_to_op("add", field, val)
 121 #define sub_pda(field, val)     pda_to_op("sub", field, val)
 122 #define or_pda(field, val)      pda_to_op("or", field, val)
 123
 124 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 125 #define test_and_clear_bit_pda(bit, field)                              \
 126 ({                                                                      \
 127         int old__;                                                      \
 128         asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"                    \
 129                      : "=r" (old__), "+m" (_proxy_pda.field)            \
 130                      : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
 131         old__;                                                          \
 132 })
 133
 134 #endif
 135
 136 #define PDA_STACKOFFSET (5*8)
 137
 138 #endif /* _ASM_X86_PDA_H */