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         int mmu_state;
  26         struct mm_struct *active_mm;
  27         unsigned apic_timer_irqs;
  28 } ____cacheline_aligned_in_smp;
  29
  30 extern struct x8664_pda *_cpu_pda[];
  31 extern struct x8664_pda boot_cpu_pda[];
  32
  33 #define cpu_pda(i) (_cpu_pda[i])
  34
  35 /*
  36  * There is no fast way to get the base address of the PDA, all the accesses
  37  * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  38  */
  39 #define sizeof_field(type,field)  (sizeof(((type *)0)->field))
  40 #define typeof_field(type,field)  typeof(((type *)0)->field)
  41
  42 extern void __bad_pda_field(void);
  43
  44 #define pda_offset(field) offsetof(struct x8664_pda, field)
  45
  46 #define pda_to_op(op,field,val) do { \
  47         typedef typeof_field(struct x8664_pda, field) T__; \
  48        switch (sizeof_field(struct x8664_pda, field)) {                 \
  49 case 2: \
  50 asm volatile(op "w %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  51 case 4: \
  52 asm volatile(op "l %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  53 case 8: \
  54 asm volatile(op "q %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \
  55        default: __bad_pda_field();                                      \
  56        } \
  57        } while (0)
  58
  59 /*
  60  * AK: PDA read accesses should be neither volatile nor have an memory clobber.
  61  * Unfortunately removing them causes all hell to break lose currently.
  62  */
  63 #define pda_from_op(op,field) ({ \
  64        typeof_field(struct x8664_pda, field) ret__; \
  65        switch (sizeof_field(struct x8664_pda, field)) {                 \
  66 case 2: \
  67 asm volatile(op "w %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  68 case 4: \
  69 asm volatile(op "l %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  70 case 8: \
  71 asm volatile(op "q %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
  72        default: __bad_pda_field();                                      \
  73        } \
  74        ret__; })
  75
  76
  77 #define read_pda(field) pda_from_op("mov",field)
  78 #define write_pda(field,val) pda_to_op("mov",field,val)
  79 #define add_pda(field,val) pda_to_op("add",field,val)
  80 #define sub_pda(field,val) pda_to_op("sub",field,val)
  81 #define or_pda(field,val) pda_to_op("or",field,val)
  82
  83 #endif
  84
  85 #define PDA_STACKOFFSET (5*8)
  86
  87 #endif