/*
 * Copyright (c) 2021 Maxime Villard, m00nbsd.net
 * Copyright (c) 2021 The DragonFly Project.
 * All rights reserved.
 *
 * This code is part of the NVMM hypervisor.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Aaron LI <aly@aaronly.me>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _NVMM_OS_H_
#define _NVMM_OS_H_

#ifndef _KERNEL
#error "This file should not be included by userland programs."
#endif

#if defined(__NetBSD__)
#include <sys/cpu.h>
#include <uvm/uvm_object.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm_page.h>
#elif defined(__DragonFly__)
#include <sys/lock.h>
#include <sys/malloc.h> /* contigmalloc, contigfree */
#include <sys/proc.h> /* LWP_MP_URETMASK */
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_param.h> /* KERN_SUCCESS, etc. */
#include <vm/pmap.h> /* pmap_ept_transform, pmap_npt_transform */
#include <machine/cpu.h> /* hvm_break_wanted */
#include <machine/cpufunc.h> /* ffsl, ffs, etc. */
#endif

/* Types. */
#if defined(__NetBSD__)
typedef struct vmspace          os_vmspace_t;
typedef struct uvm_object       os_vmobj_t;
typedef krwlock_t               os_rwl_t;
typedef kmutex_t                os_mtx_t;
#elif defined(__DragonFly__)
typedef struct vmspace          os_vmspace_t;
typedef struct vm_object        os_vmobj_t;
typedef struct lock             os_rwl_t;
typedef struct lock             os_mtx_t;
/* A few standard types. */
typedef vm_offset_t             vaddr_t;
typedef vm_offset_t             voff_t;
typedef vm_size_t               vsize_t;
typedef vm_paddr_t              paddr_t;
#endif

/* Attributes. */
#if defined(__DragonFly__)
#define __cacheline_aligned     __cachealign
#define __diagused              __debugvar
#endif

/* Macros. */
#if defined(__DragonFly__)
#define __arraycount(__x)       (sizeof(__x) / sizeof(__x[0]))
#define __insn_barrier()        __asm __volatile("":::"memory")
#endif

/* Bitops. */
#if defined(__NetBSD__)
#include <sys/bitops.h>
#elif defined(__DragonFly__)
#include <sys/bitops.h>
#ifdef __x86_64__
#undef  __BIT
#define __BIT(__n)              __BIT64(__n)
#undef  __BITS
#define __BITS(__m, __n)        __BITS64(__m, __n)
#endif /* __x86_64__ */
#endif

/* Maps. */
#if defined(__NetBSD__) || defined(__DragonFly__)
#define os_kernel_map           kernel_map
#define os_curproc_map          &curproc->p_vmspace->vm_map
#endif

/* R/W locks. */
#if defined(__NetBSD__)
#define os_rwl_init(lock)       rw_init(lock)
#define os_rwl_destroy(lock)    rw_destroy(lock)
#define os_rwl_rlock(lock)      rw_enter(lock, RW_READER);
#define os_rwl_wlock(lock)      rw_enter(lock, RW_WRITER);
#define os_rwl_unlock(lock)     rw_exit(lock)
#define os_rwl_wheld(lock)      rw_write_held(lock)
#elif defined(__DragonFly__)
#define os_rwl_init(lock)       lockinit(lock, "nvmmrw", 0, 0)
#define os_rwl_destroy(lock)    lockuninit(lock)
#define os_rwl_rlock(lock)      lockmgr(lock, LK_SHARED);
#define os_rwl_wlock(lock)      lockmgr(lock, LK_EXCLUSIVE);
#define os_rwl_unlock(lock)     lockmgr(lock, LK_RELEASE)
#define os_rwl_wheld(lock)      (lockstatus(lock, curthread) == LK_EXCLUSIVE)
#endif

/* Mutexes. */
#if defined(__NetBSD__)
#define os_mtx_init(lock)       mutex_init(lock, MUTEX_DEFAULT, IPL_NONE)
#define os_mtx_destroy(lock)    mutex_destroy(lock)
#define os_mtx_lock(lock)       mutex_enter(lock)
#define os_mtx_unlock(lock)     mutex_exit(lock)
#define os_mtx_owned(lock)      mutex_owned(lock)
#elif defined(__DragonFly__)
#define os_mtx_init(lock)       lockinit(lock, "nvmmmtx", 0, 0)
#define os_mtx_destroy(lock)    lockuninit(lock)
#define os_mtx_lock(lock)       lockmgr(lock, LK_EXCLUSIVE)
#define os_mtx_unlock(lock)     lockmgr(lock, LK_RELEASE)
#define os_mtx_owned(lock)      (lockstatus(lock, curthread) == LK_EXCLUSIVE)
#endif

/* Malloc. */
#if defined(__NetBSD__)
#include <sys/kmem.h>
#define os_mem_alloc(size)      kmem_alloc(size, KM_SLEEP)
#define os_mem_zalloc(size)     kmem_zalloc(size, KM_SLEEP)
#define os_mem_free(ptr, size)  kmem_free(ptr, size)
#elif defined(__DragonFly__)
#include <sys/malloc.h>
MALLOC_DECLARE(M_NVMM);
#define os_mem_alloc(size)      kmalloc(size, M_NVMM, M_WAITOK)
#define os_mem_zalloc(size)     kmalloc(size, M_NVMM, M_WAITOK | M_ZERO)
#define os_mem_free(ptr, size)  kfree(ptr, M_NVMM)
#endif

/* Printf. */
#if defined(__NetBSD__)
#define os_printf               printf
#elif defined(__DragonFly__)
#define os_printf               kprintf
#endif

/* Atomics. */
#if defined(__NetBSD__)
#include <sys/atomic.h>
#define os_atomic_inc_uint(x)   atomic_inc_uint(x)
#define os_atomic_dec_uint(x)   atomic_dec_uint(x)
#define os_atomic_load_uint(x)  atomic_load_relaxed(x)
#define os_atomic_inc_64(x)     atomic_inc_64(x)
#elif defined(__DragonFly__)
#include <machine/atomic.h>
#define os_atomic_inc_uint(x)   atomic_add_int(x, 1)
#define os_atomic_dec_uint(x)   atomic_subtract_int(x, 1)
#define os_atomic_load_uint(x)  atomic_load_int(x)
#define os_atomic_inc_64(x)     atomic_add_64(x, 1)
#endif

/* Pmap. */
#if defined(__NetBSD__)
extern bool pmap_ept_has_ad;
#define os_vmspace_pmap(vm)     ((vm)->vm_map.pmap)
#define os_vmspace_pdirpa(vm)   ((vm)->vm_map.pmap->pm_pdirpa[0])
#define os_pmap_mach(pm)        ((pm)->pm_data)
#elif defined(__DragonFly__)
#define os_vmspace_pmap(vm)     vmspace_pmap(vm)
#define os_vmspace_pdirpa(vm)   (vtophys(vmspace_pmap(vm)->pm_pml4))
#endif

/* CPU. */
#if defined(__NetBSD__)
#include <sys/cpu.h>
typedef struct cpu_info         os_cpu_t;
#define OS_MAXCPUS              MAXCPUS
#define OS_CPU_FOREACH(cpu)     for (CPU_INFO_FOREACH(, cpu))
#define os_cpu_number(cpu)      cpu_index(cpu)
#define os_curcpu()             curcpu()
#define os_curcpu_number()      cpu_number()
#define os_curcpu_tss_sel()     curcpu()->ci_tss_sel
#define os_curcpu_tss()         curcpu()->ci_tss
#define os_curcpu_gdt()         curcpu()->ci_gdt
#define os_curcpu_idt()         curcpu()->ci_idtvec.iv_idt
#elif defined(__DragonFly__)
#include <sys/globaldata.h>
#include <machine/segments.h>
typedef struct globaldata       os_cpu_t;
#define OS_MAXCPUS              SMP_MAXCPU
#define OS_CPU_FOREACH(cpu)     \
        for (int idx = 0; idx < ncpus && (cpu = globaldata_find(idx)); idx++)
#define os_cpu_number(cpu)      (cpu)->gd_cpuid
#define os_curcpu()             mycpu
#define os_curcpu_number()      mycpuid
#define os_curcpu_tss_sel()     GSEL(GPROC0_SEL, SEL_KPL)
#define os_curcpu_tss()         &mycpu->gd_prvspace->common_tss
#define os_curcpu_gdt()         mdcpu->gd_gdt
#define os_curcpu_idt()         r_idt_arr[mycpuid].rd_base
#endif

/* Cpusets. */
#if defined(__NetBSD__)
#include <sys/kcpuset.h>
typedef kcpuset_t               os_cpuset_t;
#define os_cpuset_init(s)       kcpuset_create(s, true)
#define os_cpuset_destroy(s)    kcpuset_destroy(s)
#define os_cpuset_isset(s, c)   kcpuset_isset(s, c)
#define os_cpuset_clear(s, c)   kcpuset_clear(s, c)
#define os_cpuset_setrunning(s) kcpuset_copy(s, kcpuset_running)
#elif defined(__DragonFly__)
#include <sys/cpumask.h>
#include <machine/smp.h> /* smp_active_mask */
typedef cpumask_t               os_cpuset_t;
#define os_cpuset_init(s)       \
        ({ *(s) = kmalloc(sizeof(cpumask_t), M_NVMM, M_WAITOK | M_ZERO); })
#define os_cpuset_destroy(s)    kfree((s), M_NVMM)
#define os_cpuset_isset(s, c)   CPUMASK_TESTBIT(*(s), c)
#define os_cpuset_clear(s, c)   ATOMIC_CPUMASK_NANDBIT(*(s), c)
#define os_cpuset_setrunning(s) ATOMIC_CPUMASK_ORMASK(*(s), smp_active_mask)
#endif

/* Preemption. */
#if defined(__NetBSD__)
#define os_preempt_disable()    kpreempt_disable()
#define os_preempt_enable()     kpreempt_enable()
#define os_preempt_disabled()   kpreempt_disabled()
#elif defined(__DragonFly__)
/*
 * In DragonFly, a thread in kernel mode will not be preemptively migrated
 * to another CPU or preemptively switched to another normal kernel thread,
 * but can be preemptively switched to an interrupt thread (which switches
 * back to the kernel thread it preempted the instant it is done or blocks).
 *
 * However, we still need to use a critical section to prevent this nominal
 * interrupt thread preemption to avoid exposing interrupt threads to
 * guest DB and FP register state.  We operate under the assumption that
 * the hard interrupt code won't mess with this state.
 */
#define os_preempt_disable()    crit_enter()
#define os_preempt_enable()     crit_exit()
#define os_preempt_disabled()   (curthread->td_critcount != 0)
#endif

/* Asserts. */
#if defined(__NetBSD__)
#define OS_ASSERT               KASSERT
#elif defined(__DragonFly__)
#define OS_ASSERT               KKASSERT
#endif

/* Misc. */
#if defined(__DragonFly__)
#define uimin(a, b)             ((u_int)a < (u_int)b ? (u_int)a : (u_int)b)
#endif

/* -------------------------------------------------------------------------- */

os_vmspace_t *  os_vmspace_create(vaddr_t, vaddr_t);
void            os_vmspace_destroy(os_vmspace_t *);
int             os_vmspace_fault(os_vmspace_t *, vaddr_t, vm_prot_t);

os_vmobj_t *    os_vmobj_create(voff_t);
void            os_vmobj_ref(os_vmobj_t *);
void            os_vmobj_rel(os_vmobj_t *);

int             os_vmobj_map(struct vm_map *, vaddr_t *, vsize_t, os_vmobj_t *,
                    voff_t, bool, bool, bool, int, int);
void            os_vmobj_unmap(struct vm_map *map, vaddr_t, vaddr_t, bool);

void *          os_pagemem_zalloc(size_t);
void            os_pagemem_free(void *, size_t);

paddr_t         os_pa_zalloc(void);
void            os_pa_free(paddr_t);

int             os_contigpa_zalloc(paddr_t *, vaddr_t *, size_t);
void            os_contigpa_free(paddr_t, vaddr_t, size_t);

static inline bool
os_return_needed(void)
{
#if defined(__NetBSD__)
        if (preempt_needed()) {
                return true;
        }
        if (curlwp->l_flag & LW_USERRET) {
                return true;
        }
        return false;
#elif defined(__DragonFly__)
        if (__predict_false(hvm_break_wanted())) {
                return true;
        }
        if (__predict_false(curthread->td_lwp->lwp_mpflags & LWP_MP_URETMASK)) {
                return true;
        }
        return false;
#endif
}

/* -------------------------------------------------------------------------- */

/* IPIs. */

#if defined(__NetBSD__)

#include <sys/xcall.h>
#define OS_IPI_FUNC(func)       void func(void *arg, void *unused)

static inline void
os_ipi_unicast(os_cpu_t *cpu, void (*func)(void *, void *), void *arg)
{
        xc_wait(xc_unicast(XC_HIGHPRI, func, arg, NULL, cpu));
}

static inline void
os_ipi_broadcast(void (*func)(void *, void *), void *arg)
{
        xc_wait(xc_broadcast(0, func, arg, NULL));
}

static inline void
os_ipi_kickall(void)
{
        /*
         * XXX: this is probably too expensive. NetBSD should have a dummy
         * interrupt handler that just IRETs without doing anything.
         */
        pmap_tlb_shootdown(pmap_kernel(), -1, PTE_G, TLBSHOOT_NVMM);
}

#elif defined(__DragonFly__)

#include <sys/thread2.h>
#define OS_IPI_FUNC(func)       void func(void *arg)

static inline void
os_ipi_unicast(os_cpu_t *cpu, void (*func)(void *), void *arg)
{
        int seq;

        seq = lwkt_send_ipiq(cpu, func, arg);
        lwkt_wait_ipiq(cpu, seq);
}

static inline void
os_ipi_broadcast(void (*func)(void *), void *arg)
{
        cpumask_t mask;
        int i;

        for (i = 0; i < ncpus; i++) {
                CPUMASK_ASSBIT(mask, i);
                lwkt_cpusync_simple(mask, func, arg);
        }
}

/*
 * On DragonFly, no need to bind the thread, because any normal kernel
 * thread will not migrate to another CPU or be preempted (except by an
 * interrupt thread).
 */
#define curlwp_bind()           ((int)0)
#define curlwp_bindx(bound)     /* nothing */

#endif /* __NetBSD__ */

#endif /* _NVMM_OS_H_ */