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#ifndef X86_64_PDA_H

#define X86_64_PDA_H

#include <linux/cache.h>

/* Per processor datastructure. %gs points to it while the kernel runs */

/* To use a new field with the *_pda macros it needs to be added to tools/offset.c */

struct x8664_pda {

        unsigned long kernelstack;  /* TOS for current process */

        unsigned long oldrsp;       /* user rsp for system call */

        unsigned long irqrsp;       /* Old rsp for interrupts. */

        struct task_struct *pcurrent;   /* Current process */

        int irqcount;               /* Irq nesting counter. Starts with -1 */

        int cpunumber;              /* Logical CPU number */

        /* XXX: could be a single list */

        unsigned long *pgd_quick;

        unsigned long *pmd_quick;

        unsigned long *pte_quick;

        unsigned long pgtable_cache_sz;

        char *irqstackptr;      /* top of irqstack */

        unsigned long volatile *level4_pgt;

} ____cacheline_aligned;

#define PDA_STACKOFFSET (5*8)

#define IRQSTACK_ORDER 2

#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER) 

extern struct x8664_pda cpu_pda[];

/*

 * There is no fast way to get the base address of the PDA, all the accesses

 * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.

 */

#define sizeof_field(type,field)  (sizeof(((type *)0)->field))

#define typeof_field(type,field)  typeof(((type *)0)->field)

extern void __bad_pda_field(void);

/* Don't use offsetof because it requires too much infrastructure */

#define pda_offset(field) ((unsigned long)&((struct x8664_pda *)0)->field)

#define pda_to_op(op,field,val) do { \

       switch (sizeof_field(struct x8664_pda, field)) {                 \

       case 2: asm volatile(op "w %0,%%gs:%P1" :: "r" (val), "i"(pda_offset(field)):"memory"); break;   \

       case 4: asm volatile(op "l %0,%%gs:%P1" :: "r" (val), "i"(pda_offset(field)):"memory"); break;   \

       case 8: asm volatile(op "q %0,%%gs:%P1" :: "r" (val), "i"(pda_offset(field)):"memory"); break;   \

       default: __bad_pda_field();                                      \

       } \

       } while (0)

#define pda_from_op(op,field) ({ \

       typedef typeof_field(struct x8664_pda, field) T__; T__ ret__; \

       switch (sizeof_field(struct x8664_pda, field)) {                 \

       case 2: asm volatile(op "w %%gs:%P1,%0":"=r" (ret__): "i" (pda_offset(field)):"memory"); break;  \

       case 4: asm volatile(op "l %%gs:%P1,%0":"=r" (ret__): "i" (pda_offset(field)):"memory"); break;  \

       case 8: asm volatile(op "q %%gs:%P1,%0":"=r" (ret__): "i" (pda_offset(field)):"memory"); break;  \

       default: __bad_pda_field();                                      \

       } \

       ret__; })

#define read_pda(field) pda_from_op("mov",field)

#define write_pda(field,val) pda_to_op("mov",field,val)

#define add_pda(field,val) pda_to_op("add",field,val)

#define sub_pda(field,val) pda_to_op("sub",field,val)

#endif