LXR linux/include/asm-x86/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 */ 
  11struct x8664_pda {
  12        struct task_struct *pcurrent;   /* 0  Current process */
  13        unsigned long data_offset;      /* 8 Per cpu data offset from linker
  14                                           address */
  15        unsigned long kernelstack;  /* 16 top of kernel stack for current */
  16        unsigned long oldrsp;       /* 24 user rsp for system call */
  17        int irqcount;               /* 32 Irq nesting counter. Starts with -1 */
  18        int cpunumber;              /* 36 Logical CPU number */
  19#ifdef CONFIG_CC_STACKPROTECTOR
  20        unsigned long stack_canary;     /* 40 stack canary value */
  21                                        /* gcc-ABI: this canary MUST be at
  22                                           offset 40!!! */
  23#endif
  24        char *irqstackptr;
  25        int nodenumber;             /* number of current node */
  26        unsigned int __softirq_pending;
  27        unsigned int __nmi_count;       /* number of NMI on this CPUs */
  28        short mmu_state;
  29        short isidle;
  30        struct mm_struct *active_mm;
  31        unsigned apic_timer_irqs;
  32        unsigned irq0_irqs;
  33        unsigned irq_resched_count;
  34        unsigned irq_call_count;
  35        unsigned irq_tlb_count;
  36        unsigned irq_thermal_count;
  37        unsigned irq_threshold_count;
  38        unsigned irq_spurious_count;
  39} ____cacheline_aligned_in_smp;
  40
  41extern struct x8664_pda *_cpu_pda[];
  42extern struct x8664_pda boot_cpu_pda[];
  43
  44#define cpu_pda(i) (_cpu_pda[i])
  45
  46/* 
  47 * There is no fast way to get the base address of the PDA, all the accesses
  48 * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
  49 */ 
  50extern void __bad_pda_field(void) __attribute__((noreturn));
  51
  52/*
  53 * proxy_pda doesn't actually exist, but tell gcc it is accessed for
  54 * all PDA accesses so it gets read/write dependencies right.
  55 */
  56extern struct x8664_pda _proxy_pda;
  57
  58#define pda_offset(field) offsetof(struct x8664_pda, field)
  59
  60#define pda_to_op(op,field,val) do {            \
  61        typedef typeof(_proxy_pda.field) T__;   \
  62        if (0) { T__ tmp__; tmp__ = (val); }    /* type checking */ \
  63        switch (sizeof(_proxy_pda.field)) {     \
  64        case 2:                                 \
  65                asm(op "w %1,%%gs:%c2" :        \
  66                    "+m" (_proxy_pda.field) :   \
  67                    "ri" ((T__)val),            \
  68                    "i"(pda_offset(field)));    \
  69                break;                          \
  70        case 4:                                 \
  71                asm(op "l %1,%%gs:%c2" :        \
  72                    "+m" (_proxy_pda.field) :   \
  73                    "ri" ((T__)val),            \
  74                    "i" (pda_offset(field)));   \
  75                break;                          \
  76        case 8:                                 \
  77                asm(op "q %1,%%gs:%c2":         \
  78                    "+m" (_proxy_pda.field) :   \
  79                    "ri" ((T__)val),            \
  80                    "i"(pda_offset(field)));    \
  81                break;                          \
  82       default:                                 \
  83                __bad_pda_field();              \
  84       }                                        \
  85       } while (0)
  86
  87#define pda_from_op(op,field) ({                \
  88        typeof(_proxy_pda.field) ret__;         \
  89        switch (sizeof(_proxy_pda.field)) {     \
  90        case 2:                                 \
  91                asm(op "w %%gs:%c1,%0" :        \
  92                    "=r" (ret__) :              \
  93                    "i" (pda_offset(field)),    \
  94                    "m" (_proxy_pda.field));    \
  95                 break;                         \
  96        case 4:                                 \
  97                asm(op "l %%gs:%c1,%0":         \
  98                    "=r" (ret__):               \
  99                    "i" (pda_offset(field)),    \
 100                    "m" (_proxy_pda.field));    \
 101                 break;                         \
 102       case 8:                                  \
 103                asm(op "q %%gs:%c1,%0":         \
 104                    "=r" (ret__) :              \
 105                    "i" (pda_offset(field)),    \
 106                    "m" (_proxy_pda.field));    \
 107                 break;                         \
 108       default:                                 \
 109                __bad_pda_field();              \
 110       }                                        \
 111       ret__; })
 112
 113#define read_pda(field) pda_from_op("mov",field)
 114#define write_pda(field,val) pda_to_op("mov",field,val)
 115#define add_pda(field,val) pda_to_op("add",field,val)
 116#define sub_pda(field,val) pda_to_op("sub",field,val)
 117#define or_pda(field,val) pda_to_op("or",field,val)
 118
 119/* This is not atomic against other CPUs -- CPU preemption needs to be off */
 120#define test_and_clear_bit_pda(bit,field) ({            \
 121        int old__;                                              \
 122        asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"            \
 123            : "=r" (old__), "+m" (_proxy_pda.field)             \
 124            : "dIr" (bit), "i" (pda_offset(field)) : "memory"); \
 125        old__;                                                  \
 126})
 127
 128#endif
 129
 130#define PDA_STACKOFFSET (5*8)
 131
 132#endif
 133