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 #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         unsigned 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         unsigned irq0_irqs;
  33         unsigned irq_resched_count;
  34         unsigned irq_call_count;
  35         unsigned irq_tlb_count;
  36         unsigned irq_thermal_count;
  37         unsigned irq_threshold_count;
  38         unsigned irq_spurious_count;
  39 } ____cacheline_aligned_in_smp;
  40
  41 extern struct x8664_pda *_cpu_pda[];
  42 extern struct x8664_pda boot_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) do {          \
  62         typedef typeof(_proxy_pda.field) T__;   \
  63         if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */ \
  64         switch (sizeof(_proxy_pda.field)) {     \
  65         case 2:                                 \
  66                 asm(op "w %1,%%gs:%c2" :        \
  67                     "+m" (_proxy_pda.field) :   \
  68                     "ri" ((T__)val),            \
  69                     "i"(pda_offset(field)));    \
  70                 break;                          \
  71         case 4:                                 \
  72                 asm(op "l %1,%%gs:%c2" :        \
  73                     "+m" (_proxy_pda.field) :   \
  74                     "ri" ((T__)val),            \
  75                     "i" (pda_offset(field)));   \
  76                 break;                          \
  77         case 8:                                 \
  78                 asm(op "q %1,%%gs:%c2":         \
  79                     "+m" (_proxy_pda.field) :   \
  80                     "ri" ((T__)val),            \
  81                     "i"(pda_offset(field)));    \
  82                 break;                          \
  83         default:                                \
  84                 __bad_pda_field();              \
  85         }                                       \
  86         } while (0)
  87
  88 #define pda_from_op(op,field) ({                \
  89         typeof(_proxy_pda.field) ret__;         \
  90         switch (sizeof(_proxy_pda.field)) {     \
  91         case 2:                                 \
  92                 asm(op "w %%gs:%c1,%0" :        \
  93                     "=r" (ret__) :              \
  94                     "i" (pda_offset(field)),    \
  95                     "m" (_proxy_pda.field));    \
  96                  break;                         \
  97         case 4:                                 \
  98                 asm(op "l %%gs:%c1,%0":         \
  99                     "=r" (ret__):               \
 100                     "i" (pda_offset(field)),    \
 101                     "m" (_proxy_pda.field));    \
 102                  break;                         \
 103         case 8:                                 \
 104                 asm(op "q %%gs:%c1,%0":         \
 105                     "=r" (ret__) :              \
 106                     "i" (pda_offset(field)),    \
 107                     "m" (_proxy_pda.field));    \
 108                  break;                         \
 109         default:                                \
 110                 __bad_pda_field();              \
 111        }                                        \
 112        ret__; })
 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         int old__;                                              \
 123         asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"            \
 124             : "=r" (old__), "+m" (_proxy_pda.field)             \
 125             : "dIr" (bit), "i" (pda_offset(field)) : "memory"); \
 126         old__;                                                  \
 127 })
 128
 129 #endif
 130
 131 #define PDA_STACKOFFSET (5*8)
 132
 133 #endif