include/asm-x86_64/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 with -1 */
  18         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         int nodenumber;             /* number of current node */
  26         unsigned int __softirq_pending;
  27         unsigned int __nmi_count;       /* number of NMI on this CPUs */
  28         short mmu_state;
  29         short isidle;
  30         struct mm_struct *active_mm;
  31         unsigned apic_timer_irqs;
  32 } ____cacheline_aligned_in_smp;
  33
  34 extern struct x8664_pda *_cpu_pda[];
  35 extern struct x8664_pda boot_cpu_pda[];
  36
  37 #define cpu_pda(i) (_cpu_pda[i])
  38
  39 /*
  40  * There is no fast way to get the base address of the PDA, all the accesses
  41  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  42  */
  43 extern void __bad_pda_field(void) __attribute__((noreturn));
  44
  45 /*
  46  * proxy_pda doesn't actually exist, but tell gcc it is accessed for
  47  * all PDA accesses so it gets read/write dependencies right.
  48  */
  49 extern struct x8664_pda _proxy_pda;
  50
  51 #define pda_offset(field) offsetof(struct x8664_pda, field)
  52
  53 #define pda_to_op(op,field,val) do {            \
  54         typedef typeof(_proxy_pda.field) T__;   \
  55         if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */ \
  56         switch (sizeof(_proxy_pda.field)) {     \
  57         case 2:                                 \
  58                 asm(op "w %1,%%gs:%c2" :        \
  59                     "+m" (_proxy_pda.field) :   \
  60                     "ri" ((T__)val),            \
  61                     "i"(pda_offset(field)));    \
  62                 break;                          \
  63         case 4:                                 \
  64                 asm(op "l %1,%%gs:%c2" :        \
  65                     "+m" (_proxy_pda.field) :   \
  66                     "ri" ((T__)val),            \
  67                     "i" (pda_offset(field)));   \
  68                 break;                          \
  69         case 8:                                 \
  70                 asm(op "q %1,%%gs:%c2":         \
  71                     "+m" (_proxy_pda.field) :   \
  72                     "ri" ((T__)val),            \
  73                     "i"(pda_offset(field)));    \
  74                 break;                          \
  75        default:                                 \
  76                 __bad_pda_field();              \
  77        }                                        \
  78        } while (0)
  79
  80 #define pda_from_op(op,field) ({                \
  81         typeof(_proxy_pda.field) ret__;         \
  82         switch (sizeof(_proxy_pda.field)) {     \
  83         case 2:                                 \
  84                 asm(op "w %%gs:%c1,%0" :        \
  85                     "=r" (ret__) :              \
  86                     "i" (pda_offset(field)),    \
  87                     "m" (_proxy_pda.field));    \
  88                  break;                         \
  89         case 4:                                 \
  90                 asm(op "l %%gs:%c1,%0":         \
  91                     "=r" (ret__):               \
  92                     "i" (pda_offset(field)),    \
  93                     "m" (_proxy_pda.field));    \
  94                  break;                         \
  95        case 8:                                  \
  96                 asm(op "q %%gs:%c1,%0":         \
  97                     "=r" (ret__) :              \
  98                     "i" (pda_offset(field)),    \
  99                     "m" (_proxy_pda.field));    \
 100                  break;                         \
 101        default:                                 \
 102                 __bad_pda_field();              \
 103        }                                        \
 104        ret__; })
 105
 106 #define read_pda(field) pda_from_op("mov",field)
 107 #define write_pda(field,val) pda_to_op("mov",field,val)
 108 #define add_pda(field,val) pda_to_op("add",field,val)
 109 #define sub_pda(field,val) pda_to_op("sub",field,val)
 110 #define or_pda(field,val) pda_to_op("or",field,val)
 111
 112 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 113 #define test_and_clear_bit_pda(bit,field) ({            \
 114         int old__;                                              \
 115         asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"            \
 116             : "=r" (old__), "+m" (_proxy_pda.field)             \
 117             : "dIr" (bit), "i" (pda_offset(field)) : "memory"); \
 118         old__;                                                  \
 119 })
 120
 121 #endif
 122
 123 #define PDA_STACKOFFSET (5*8)
 124
 125 #endif