xref: /freebsd-10-stable/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)), "0" (x)
                             :"memory");
        break;
    case 2:
        __asm__ __volatile__("xchgw %w0,%1"
                             :"=r" (x)
                             :"m" (*__xg(ptr)), "0" (x)
                             :"memory");
        break;
    case 4:
        __asm__ __volatile__("xchgl %0,%1"
                             :"=r" (x)
                             :"m" (*__xg(ptr)), "0" (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_ */