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