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;   /* Current process */
  13         unsigned long data_offset;      /* Per cpu data offset from linker address */
  14         unsigned long kernelstack;  /* top of kernel stack for current */
  15         unsigned long oldrsp;       /* user rsp for system call */
  16 #if DEBUG_STKSZ > EXCEPTION_STKSZ
  17         unsigned long debugstack;   /* #DB/#BP stack. */
  18 #endif
  19         int irqcount;               /* Irq nesting counter. Starts with -1 */
  20         int cpunumber;              /* Logical CPU number */
  21         char *irqstackptr;      /* top of irqstack */
  22         int nodenumber;             /* number of current node */
  23         unsigned int __softirq_pending;
  24         unsigned int __nmi_count;       /* number of NMI on this CPUs */
  25         struct mm_struct *active_mm;
  26         int mmu_state;
  27         unsigned apic_timer_irqs;
  28 } ____cacheline_aligned_in_smp;
  29
  30 extern struct x8664_pda _cpu_pda[];
  31
  32 #define cpu_pda(i) (&_cpu_pda[i])
  33
  34 /*
  35  * There is no fast way to get the base address of the PDA, all the accesses
  36  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  37  */
  38 #define sizeof_field(type,field)  (sizeof(((type *)0)->field))
  39 #define typeof_field(type,field)  typeof(((type *)0)->field)
  40
  41 extern void __bad_pda_field(void);
  42
  43 #define pda_offset(field) offsetof(struct x8664_pda, field)
  44
  45 #define pda_to_op(op,field,val) do { \
  46         typedef typeof_field(struct x8664_pda, field) T__; \
  47        switch (sizeof_field(struct x8664_pda, field)) {                 \
  48 case 2: \
  49 asm volatile(op "w %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  50 case 4: \
  51 asm volatile(op "l %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  52 case 8: \
  53 asm volatile(op "q %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  54        default: __bad_pda_field();                                      \
  55        } \
  56        } while (0)
  57
  58 /*
  59  * AK: PDA read accesses should be neither volatile nor have an memory clobber.
  60  * Unfortunately removing them causes all hell to break lose currently.
  61  */
  62 #define pda_from_op(op,field) ({ \
  63        typeof_field(struct x8664_pda, field) ret__; \
  64        switch (sizeof_field(struct x8664_pda, field)) {                 \
  65 case 2: \
  66 asm volatile(op "w %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  67 case 4: \
  68 asm volatile(op "l %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  69 case 8: \
  70 asm volatile(op "q %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  71        default: __bad_pda_field();                                      \
  72        } \
  73        ret__; })
  74
  75
  76 #define read_pda(field) pda_from_op("mov",field)
  77 #define write_pda(field,val) pda_to_op("mov",field,val)
  78 #define add_pda(field,val) pda_to_op("add",field,val)
  79 #define sub_pda(field,val) pda_to_op("sub",field,val)
  80 #define or_pda(field,val) pda_to_op("or",field,val)
  81
  82 #endif
  83
  84 #define PDA_STACKOFFSET (5*8)
  85
  86 #endif