FreeBSD/Linux Kernel Cross Reference
sys/i386/include/xen/xen-os.h

     /*****************************************************************************
      * i386/xen/xen-os.h
      * 
      * Random collection of macros and definition
      *
      * Copyright (c) 2003, 2004 Keir Fraser (on behalf of the Xen team)
      * All rights reserved.
      *
      * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to
     * deal in the Software without restriction, including without limitation the
     * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     * 
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     * 
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
     * DEALINGS IN THE SOFTWARE.
     *
     * $FreeBSD$
     */
    
    #ifndef _MACHINE_XEN_XEN_OS_H_
    #define _MACHINE_XEN_XEN_OS_H_
    
    #ifdef PAE
    #define CONFIG_X86_PAE
    #endif
    
    /* Everything below this point is not included by assembler (.S) files. */
    #ifndef __ASSEMBLY__
    
    /* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
    static inline void rep_nop(void)
    {
        __asm__ __volatile__ ( "rep;nop" : : : "memory" );
    }
    #define cpu_relax() rep_nop()
    
    #ifndef XENHVM
    void xc_printf(const char *fmt, ...);
    
    #ifdef SMP
    extern int gdtset;
    
    #include <sys/time.h> /* XXX for pcpu.h */
    #include <sys/pcpu.h> /* XXX for PCPU_GET */
    static inline int 
    smp_processor_id(void)  
    {
        if (__predict_true(gdtset))
            return PCPU_GET(cpuid);
        return 0;
    }
    
    #else
    #define smp_processor_id() 0
    #endif
    
    #ifndef PANIC_IF
    #define PANIC_IF(exp) if (__predict_false(exp)) {printf("panic - %s: %s:%d\n",#exp, __FILE__, __LINE__); panic("%s: %s:%d", #exp, __FILE__, __LINE__);} 
    #endif
    
    /*
     * Crude memory allocator for memory allocation early in boot.
     */
    void *bootmem_alloc(unsigned int size);
    void bootmem_free(void *ptr, unsigned int size);
    
    /*
     * STI/CLI equivalents. These basically set and clear the virtual
     * event_enable flag in the shared_info structure. Note that when
     * the enable bit is set, there may be pending events to be handled.
     * We may therefore call into do_hypervisor_callback() directly.
     */
    
    #define __cli()                                                         \
    do {                                                                    \
            vcpu_info_t *_vcpu;                                             \
            _vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()]; \
            _vcpu->evtchn_upcall_mask = 1;                                  \
            barrier();                                                      \
    } while (0)
    
    #define __sti()                                                         \
    do {                                                                    \
            vcpu_info_t *_vcpu;                                             \
            barrier();                                                      \
            _vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()]; \
            _vcpu->evtchn_upcall_mask = 0;                                  \
            barrier(); /* unmask then check (avoid races) */                \
            if (__predict_false(_vcpu->evtchn_upcall_pending))              \
                   force_evtchn_callback();                                \
   } while (0)
   
   #define __restore_flags(x)                                              \
   do {                                                                    \
           vcpu_info_t *_vcpu;                                             \
           barrier();                                                      \
           _vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()]; \
           if ((_vcpu->evtchn_upcall_mask = (x)) == 0) {                   \
                   barrier(); /* unmask then check (avoid races) */        \
                   if (__predict_false(_vcpu->evtchn_upcall_pending))      \
                           force_evtchn_callback();                        \
           }                                                               \
   } while (0)
   
   /*
    * Add critical_{enter, exit}?
    *
    */
   #define __save_and_cli(x)                                               \
   do {                                                                    \
           vcpu_info_t *_vcpu;                                             \
           _vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()]; \
           (x) = _vcpu->evtchn_upcall_mask;                                \
           _vcpu->evtchn_upcall_mask = 1;                                  \
           barrier();                                                      \
   } while (0)
   
   
   #define cli() __cli()
   #define sti() __sti()
   #define save_flags(x) __save_flags(x)
   #define restore_flags(x) __restore_flags(x)
   #define save_and_cli(x) __save_and_cli(x)
   
   #define local_irq_save(x)       __save_and_cli(x)
   #define local_irq_restore(x)    __restore_flags(x)
   #define local_irq_disable()     __cli()
   #define local_irq_enable()      __sti()
   
   #define mtx_lock_irqsave(lock, x) {local_irq_save((x)); mtx_lock_spin((lock));}
   #define mtx_unlock_irqrestore(lock, x) {mtx_unlock_spin((lock)); local_irq_restore((x)); }
   #define spin_lock_irqsave mtx_lock_irqsave
   #define spin_unlock_irqrestore mtx_unlock_irqrestore
   
   #endif /* !XENHVM */
   
   /* This is a barrier for the compiler only, NOT the processor! */
   #define barrier() __asm__ __volatile__("": : :"memory")
   
   #define LOCK_PREFIX ""
   #define LOCK ""
   #define ADDR (*(volatile long *) addr)
   /*
    * Make sure gcc doesn't try to be clever and move things around
    * on us. We need to use _exactly_ the address the user gave us,
    * not some alias that contains the same information.
    */
   typedef struct { volatile int counter; } atomic_t;
   
   #define xen_xchg(ptr,v) \
           ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr))))
   struct __xchg_dummy { unsigned long a[100]; };
   #define __xg(x) ((volatile struct __xchg_dummy *)(x))
   static __inline unsigned long __xchg(unsigned long x, volatile void * ptr,
                                      int size)
   {
       switch (size) {
       case 1:
           __asm__ __volatile__("xchgb %b0,%1"
                                :"=q" (x)
                                :"m" (*__xg(ptr)), "" (x)
                                :"memory");
           break;
       case 2:
           __asm__ __volatile__("xchgw %w0,%1"
                                :"=r" (x)
                                :"m" (*__xg(ptr)), "" (x)
                                :"memory");
           break;
       case 4:
           __asm__ __volatile__("xchgl %0,%1"
                                :"=r" (x)
                                :"m" (*__xg(ptr)), "" (x)
                                :"memory");
           break;
       }
       return x;
   }
   
   /**
    * test_and_clear_bit - Clear a bit and return its old value
    * @nr: Bit to set
    * @addr: Address to count from
    *
    * This operation is atomic and cannot be reordered.  
    * It also implies a memory barrier.
    */
   static __inline int test_and_clear_bit(int nr, volatile void * addr)
   {
           int oldbit;
   
           __asm__ __volatile__( LOCK_PREFIX
                   "btrl %2,%1\n\tsbbl %0,%0"
                   :"=r" (oldbit),"=m" (ADDR)
                   :"Ir" (nr) : "memory");
           return oldbit;
   }
   
   static __inline int constant_test_bit(int nr, const volatile void * addr)
   {
       return ((1UL << (nr & 31)) & (((const volatile unsigned int *) addr)[nr >> 5])) != 0;
   }
   
   static __inline int variable_test_bit(int nr, volatile void * addr)
   {
       int oldbit;
       
       __asm__ __volatile__(
           "btl %2,%1\n\tsbbl %0,%0"
           :"=r" (oldbit)
           :"m" (ADDR),"Ir" (nr));
       return oldbit;
   }
   
   #define test_bit(nr,addr) \
   (__builtin_constant_p(nr) ? \
    constant_test_bit((nr),(addr)) : \
    variable_test_bit((nr),(addr)))
   
   
   /**
    * set_bit - Atomically set a bit in memory
    * @nr: the bit to set
    * @addr: the address to start counting from
    *
    * This function is atomic and may not be reordered.  See __set_bit()
    * if you do not require the atomic guarantees.
    * Note that @nr may be almost arbitrarily large; this function is not
    * restricted to acting on a single-word quantity.
    */
   static __inline__ void set_bit(int nr, volatile void * addr)
   {
           __asm__ __volatile__( LOCK_PREFIX
                   "btsl %1,%0"
                   :"=m" (ADDR)
                   :"Ir" (nr));
   }
   
   /**
    * clear_bit - Clears a bit in memory
    * @nr: Bit to clear
    * @addr: Address to start counting from
    *
    * clear_bit() is atomic and may not be reordered.  However, it does
    * not contain a memory barrier, so if it is used for locking purposes,
    * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
    * in order to ensure changes are visible on other processors.
    */
   static __inline__ void clear_bit(int nr, volatile void * addr)
   {
           __asm__ __volatile__( LOCK_PREFIX
                   "btrl %1,%0"
                   :"=m" (ADDR)
                   :"Ir" (nr));
   }
   
   /**
    * atomic_inc - increment atomic variable
    * @v: pointer of type atomic_t
    * 
    * Atomically increments @v by 1.  Note that the guaranteed
    * useful range of an atomic_t is only 24 bits.
    */ 
   static __inline__ void atomic_inc(atomic_t *v)
   {
           __asm__ __volatile__(
                   LOCK "incl %0"
                   :"=m" (v->counter)
                   :"m" (v->counter));
   }
   
   
   #define rdtscll(val) \
        __asm__ __volatile__("rdtsc" : "=A" (val))
   
   #endif /* !__ASSEMBLY__ */
   
   #endif /* _MACHINE_XEN_XEN_OS_H_ */

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