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