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