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root/include/asm-x86/pda.h

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INCLUDED FROM


#ifndef ASM_X86__PDA_H
#define ASM_X86__PDA_H

#ifndef __ASSEMBLY__
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/cache.h>
#include <asm/page.h>

/* Per processor datastructure. %gs points to it while the kernel runs */
struct x8664_pda {
        struct task_struct *pcurrent;   /* 0  Current process */
        unsigned long data_offset;      /* 8 Per cpu data offset from linker
                                           address */
        unsigned long kernelstack;      /* 16 top of kernel stack for current */
        unsigned long oldrsp;           /* 24 user rsp for system call */
        int irqcount;                   /* 32 Irq nesting counter. Starts -1 */
        unsigned int cpunumber;         /* 36 Logical CPU number */
#ifdef CONFIG_CC_STACKPROTECTOR
        unsigned long stack_canary;     /* 40 stack canary value */
                                        /* gcc-ABI: this canary MUST be at
                                           offset 40!!! */
#endif
        char *irqstackptr;
        short nodenumber;               /* number of current node (32k max) */
        short in_bootmem;               /* pda lives in bootmem */
        unsigned int __softirq_pending;
        unsigned int __nmi_count;       /* number of NMI on this CPUs */
        short mmu_state;
        short isidle;
        struct mm_struct *active_mm;
        unsigned apic_timer_irqs;
        unsigned irq0_irqs;
        unsigned irq_resched_count;
        unsigned irq_call_count;
        unsigned irq_tlb_count;
        unsigned irq_thermal_count;
        unsigned irq_threshold_count;
        unsigned irq_spurious_count;
} ____cacheline_aligned_in_smp;

extern struct x8664_pda **_cpu_pda;
extern void pda_init(int);

#define cpu_pda(i) (_cpu_pda[i])

/*
 * 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.
 */
extern void __bad_pda_field(void) __attribute__((noreturn));

/*
 * proxy_pda doesn't actually exist, but tell gcc it is accessed for
 * all PDA accesses so it gets read/write dependencies right.
 */
extern struct x8664_pda _proxy_pda;

#define pda_offset(field) offsetof(struct x8664_pda, field)

#define pda_to_op(op, field, val)                                       \
do {                                                                    \
        typedef typeof(_proxy_pda.field) T__;                           \
        if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */     \
        switch (sizeof(_proxy_pda.field)) {                             \
        case 2:                                                         \
                asm(op "w %1,%%gs:%c2" :                                \
                    "+m" (_proxy_pda.field) :                           \
                    "ri" ((T__)val),                                    \
                    "i"(pda_offset(field)));                            \
                break;                                                  \
        case 4:                                                         \
                asm(op "l %1,%%gs:%c2" :                                \
                    "+m" (_proxy_pda.field) :                           \
                    "ri" ((T__)val),                                    \
                    "i" (pda_offset(field)));                           \
                break;                                                  \
        case 8:                                                         \
                asm(op "q %1,%%gs:%c2":                                 \
                    "+m" (_proxy_pda.field) :                           \
                    "ri" ((T__)val),                                    \
                    "i"(pda_offset(field)));                            \
                break;                                                  \
        default:                                                        \
                __bad_pda_field();                                      \
        }                                                               \
} while (0)

#define pda_from_op(op, field)                  \
({                                              \
        typeof(_proxy_pda.field) ret__;         \
        switch (sizeof(_proxy_pda.field)) {     \
        case 2:                                 \
                asm(op "w %%gs:%c1,%0" :        \
                    "=r" (ret__) :              \
                    "i" (pda_offset(field)),    \
                    "m" (_proxy_pda.field));    \
                break;                          \
        case 4:                                 \
                asm(op "l %%gs:%c1,%0":         \
                    "=r" (ret__):               \
                    "i" (pda_offset(field)),    \
                    "m" (_proxy_pda.field));    \
                break;                          \
        case 8:                                 \
                asm(op "q %%gs:%c1,%0":         \
                    "=r" (ret__) :              \
                    "i" (pda_offset(field)),    \
                    "m" (_proxy_pda.field));    \
                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)
#define or_pda(field, val)      pda_to_op("or", field, val)

/* This is not atomic against other CPUs -- CPU preemption needs to be off */
#define test_and_clear_bit_pda(bit, field)                              \
({                                                                      \
        int old__;                                                      \
        asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"                    \
                     : "=r" (old__), "+m" (_proxy_pda.field)            \
                     : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
        old__;                                                          \
})

#endif

#define PDA_STACKOFFSET (5*8)

#endif /* ASM_X86__PDA_H */

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