/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/vmmeter.h>
#include <sys/eventhandler.h>

#include <machine/bus.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_phys.h>

#include <cheriintrin.h>
#include <cheri/cheric.h>

#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <assert.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/errno.h>
#include <stdint.h>
#include <stdio.h>
#include 	<unistd.h>


#include <stddef.h>
#include <stdlib.h>
#include <string.h>

// added to print uint 
// 64
// #include <inttypes.h>

struct contigmem_buffer {
	void           *addr;
	int             refcnt;
	struct mtx      mtx;
};

struct contigmem_vm_handle {
	int             buffer_index;
};

static int              contigmem_load(void);
static int              contigmem_unload(void);
static int              contigmem_physaddr(SYSCTL_HANDLER_ARGS);

static d_mmap_single_t  contigmem_mmap_single;
static d_open_t         contigmem_open;
static d_close_t        contigmem_close;

static int              contigmem_num_buffers = RTE_CONTIGMEM_DEFAULT_NUM_BUFS;
static int64_t          contigmem_buffer_size = RTE_CONTIGMEM_DEFAULT_BUF_SIZE;

static eventhandler_tag contigmem_eh_tag;
static struct contigmem_buffer contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
static struct cdev     *contigmem_cdev = NULL;
static int              contigmem_refcnt;

TUNABLE_INT("hw.contigmem.num_buffers", &contigmem_num_buffers);
TUNABLE_QUAD("hw.contigmem.buffer_size", &contigmem_buffer_size);

static SYSCTL_NODE(_hw, OID_AUTO, contigmem, CTLFLAG_RD, 0, "contigmem");

SYSCTL_INT(_hw_contigmem, OID_AUTO, num_buffers, CTLFLAG_RD,
	&contigmem_num_buffers, 0, "Number of contigmem buffers allocated");
SYSCTL_QUAD(_hw_contigmem, OID_AUTO, buffer_size, CTLFLAG_RD,
	&contigmem_buffer_size, 0, "Size of each contiguous buffer");
SYSCTL_INT(_hw_contigmem, OID_AUTO, num_references, CTLFLAG_RD,
	&contigmem_refcnt, 0, "Number of references to contigmem");

static SYSCTL_NODE(_hw_contigmem, OID_AUTO, physaddr, CTLFLAG_RD, 0,
	"physaddr");

MALLOC_DEFINE(M_CONTIGMEM, "customcontigmem", "customcontigmem(4) allocations");

void *ptr;
int MallocCounter;

#define	MAXPAGESIZES	2


/*
 * The offset in sysent where the syscall is allocated.
 */
static int offset = NO_SYSCALL;

static int contigmem_modevent(module_t mod, int type, void *arg)
{
	int error = 0;

	switch (type) {
	case MOD_LOAD:
		error = contigmem_load();
		break;
	case MOD_UNLOAD:
		error = contigmem_unload();
		break;
	default:
		break;
	}

	return error;
}

moduledata_t contigmem_mod = {
	"contigmem",
	(modeventhand_t)contigmem_modevent,
	0
};

DECLARE_MODULE(contigmem, contigmem_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(contigmem, 1);

static struct cdevsw contigmem_ops = {
	.d_name         = "contigmem",
	.d_version      = D_VERSION,
	.d_flags        = D_TRACKCLOSE,
	.d_mmap_single  = contigmem_mmap_single,
	.d_open         = contigmem_open,
	.d_close        = contigmem_close,
};

static int
pagesizes(size_t ps[MAXPAGESIZES])
{
	int pscnt;

	pscnt = getpagesizes(ps, MAXPAGESIZES);
	// ATF_REQUIRE_MSG(pscnt != -1, "getpagesizes failed; errno=%d", errno);
	// ATF_REQUIRE_MSG(ps[0] != 0, "psind 0 is %zu", ps[0]);
	// ATF_REQUIRE_MSG(pscnt <= MAXPAGESIZES, "invalid pscnt %d", pscnt);
	// if (pscnt == 1){
   //    printf("pscnt is 1");
   // }
     
	// 	atf_tc_skip("no large page support");
	return (pscnt);
}

static int
contigmem_load()
{

   size_t sz;
   // Pre Allocate 1GB huge page
   sz = 1073741824;

   int error, fd, pscnt, pn;

   size_t ps[MAXPAGESIZES];

   size_t size[3];

   pn = getpagesizes(size, 3);
   printf("page size is [%d]", size[2]);

   pscnt = pagesizes(ps);

	fd = shm_create_largepage(SHM_ANON, O_CREAT | O_RDWR, 1, SHM_LARGEPAGE_ALLOC_DEFAULT, 0);

   if (fd < 0 && errno == ENOTTY) {
      perror("sh_create_largepages");
      close(fd);
   }
   // if (fd < 0)
   //     perror("no large page supported");
   //     exit(EXIT_FAILURE);
	// if (fd < 0 && errno == ENOTTY)
	// 	atf_tc_skip("no large page support");
	// ATF_REQUIRE_MSG(fd >= 0, "shm_create_largepage failed; errno=%d", errno);

	if (ftruncate(fd, sz) < 0) {
        perror("ftruncate");
        close(fd);
    }
	// if (error != 0 && errno == ENOMEM)
	// 	/*
	// 	 * The test system might not have enough memory to accommodate
	// 	 * the request.
	// 	 */
	// 	atf_tc_skip("failed to allocate %zu-byte superpage", sz);
	// ATF_REQUIRE_MSG(error == 0, "ftruncate failed; errno=%d", errno);

   	ptr = mmap(NULL, sz,
    PROT_READ|PROT_WRITE, MAP_SHARED,fd,0);

   // Added error handling
    if(ptr == MAP_FAILED)
    {
        perror("mmap");
        exit(EXIT_FAILURE);
    }

    MallocCounter = (int)sz;

	return 0;
}

static int
contigmem_unload()
{
	int i;

	if (contigmem_refcnt > 0)
		return EBUSY;

	if (contigmem_cdev != NULL)
		destroy_dev(contigmem_cdev);

	if (contigmem_eh_tag != NULL)
		EVENTHANDLER_DEREGISTER(process_exit, contigmem_eh_tag);

	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++) {
		if (contigmem_buffers[i].addr != NULL)
			contigfree(contigmem_buffers[i].addr,
				contigmem_buffer_size, M_CONTIGMEM);
		if (mtx_initialized(&contigmem_buffers[i].mtx))
			mtx_destroy(&contigmem_buffers[i].mtx);
	}

	return 0;
}

static int
contigmem_physaddr(SYSCTL_HANDLER_ARGS)
{
	uint64_t	physaddr;
	int		index = (int)(uintptr_t)arg1;

	physaddr = (uint64_t)vtophys(contigmem_buffers[index].addr);
	return sysctl_handle_64(oidp, &physaddr, 0, req);
}

static int
contigmem_open(struct cdev *cdev, int fflags, int devtype,
		struct thread *td)
{

	printf("Contigmem opened \n");

	atomic_add_int(&contigmem_refcnt, 1);

	return 0;
}

static int
contigmem_close(struct cdev *cdev, int fflags, int devtype,
		struct thread *td)
{

	atomic_subtract_int(&contigmem_refcnt, 1);

	return 0;
}

static int
contigmem_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
		vm_ooffset_t foff, struct ucred *cred, u_short *color)
{
	struct contigmem_vm_handle *vmh = handle;
	struct contigmem_buffer *buf;

	buf = &contigmem_buffers[vmh->buffer_index];

	atomic_add_int(&contigmem_refcnt, 1);

	mtx_lock(&buf->mtx);
	if (buf->refcnt == 0)
		memset(buf->addr, 0, contigmem_buffer_size);
	buf->refcnt++;
	mtx_unlock(&buf->mtx);

	return 0;
}

static void
contigmem_cdev_pager_dtor(void *handle)
{
	struct contigmem_vm_handle *vmh = handle;
	struct contigmem_buffer *buf;

	buf = &contigmem_buffers[vmh->buffer_index];

	mtx_lock(&buf->mtx);
	buf->refcnt--;
	mtx_unlock(&buf->mtx);

	free(vmh, M_CONTIGMEM);

	atomic_subtract_int(&contigmem_refcnt, 1);
}

static int
contigmem_cdev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
		vm_page_t *mres)
{
	vm_paddr_t paddr;
	vm_page_t m_paddr, page;
	vm_memattr_t memattr, memattr1;

	memattr = object->memattr;

	VM_OBJECT_WUNLOCK(object);

	paddr = offset;

	m_paddr = vm_phys_paddr_to_vm_page(paddr);
	if (m_paddr != NULL) {
		memattr1 = pmap_page_get_memattr(m_paddr);
		if (memattr1 != memattr)
			memattr = memattr1;
	}

	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
		/*
		 * If the passed in result page is a fake page, update it with
		 * the new physical address.
		 */
		page = *mres;
		VM_OBJECT_WLOCK(object);
		vm_page_updatefake(page, paddr, memattr);
	} else {
		/*
		 * Replace the passed in reqpage page with our own fake page and
		 * free up the original page.
		 */
		page = vm_page_getfake(paddr, memattr);
		VM_OBJECT_WLOCK(object);
#if __FreeBSD__ >= 13
		vm_page_replace(page, object, (*mres)->pindex, *mres);
#else
		vm_page_t mret = vm_page_replace(page, object, (*mres)->pindex);
		KASSERT(mret == *mres,
		    ("invalid page replacement, old=%p, ret=%p", *mres, mret));
		vm_page_lock(mret);
		vm_page_free(mret);
		vm_page_unlock(mret);
#endif
		*mres = page;
	}

	page->valid = VM_PAGE_BITS_ALL;

	return VM_PAGER_OK;
}

static struct cdev_pager_ops contigmem_cdev_pager_ops = {
	.cdev_pg_ctor = contigmem_cdev_pager_ctor,
	.cdev_pg_dtor = contigmem_cdev_pager_dtor,
	.cdev_pg_fault = contigmem_cdev_pager_fault,
};

static int
	(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
		struct vm_object **obj, int nprot)
{

	// Testing if this is called when file is opened
	printf("contigmem_mmap_single called \n");

	// struct contigmem_vm_handle *vmh;
	// uint64_t buffer_index;

	// /*
	//  * The buffer index is encoded in the offset.  Divide the offset by
	//  *  PAGE_SIZE to get the index of the buffer requested by the user
	//  *  app.
	//  */
	// buffer_index = *offset / PAGE_SIZE;
	// if (buffer_index >= contigmem_num_buffers)
	// 	return EINVAL;

	// if (size > contigmem_buffer_size)
	// 	return EINVAL;

	// vmh = malloc(sizeof(*vmh), M_CONTIGMEM, M_NOWAIT | M_ZERO);
	// if (vmh == NULL)
	// 	return ENOMEM;
	// vmh->buffer_index = buffer_index;

	// *offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index].addr);
	// *obj = cdev_pager_allocate(vmh, OBJT_DEVICE, &contigmem_cdev_pager_ops,
	// 		size, nprot, *offset, curthread->td_ucred);

	size = __builtin_align_up(size, _Alignof(max_align_t));

   // printf("%d \n", sz);
   // printf("%d Malloc counter\n", MallocCounter);

   	MallocCounter -= size;
   	obj = &ptr[MallocCounter];
   	obj = cheri_setbounds(obj, sz);

	return 0;
}


// SAMPLE SYSCALL IMPLEMENTATION
// /*-
//  * SPDX-License-Identifier: BSD-2-Clause
//  *
//  * Copyright (c) 1999 Assar Westerlund
//  * All rights reserved.
//  *
//  * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
//  */

// #include <sys/param.h>
// #include <sys/proc.h>
// #include <sys/module.h>
// #include <sys/sysproto.h>
// #include <sys/sysent.h>
// #include <sys/kernel.h>
// #include <sys/systm.h>

// /*
//  * The function for implementing the syscall.
//  */
// static int
// hello(struct thread *td, void *arg)
// {

// 	printf("hello kernel\n");
// 	return (0);
// }

// /*
//  * The `sysent' for the new syscall
//  */
// static struct sysent hello_sysent = {
// 	.sy_narg = 0,
// 	.sy_call = hello
// };

// /*
//  * The offset in sysent where the syscall is allocated.
//  */
// static int offset = NO_SYSCALL;

// /*
//  * The function called at load/unload.
//  */
// static int
// load(struct module *module, int cmd, void *arg)
// {
// 	int error = 0;

// 	switch (cmd) {
// 	case MOD_LOAD :
// 		printf("syscall loaded at %d\n", offset);
// 		break;
// 	case MOD_UNLOAD :
// 		printf("syscall unloaded from %d\n", offset);
// 		break;
// 	default :
// 		error = EOPNOTSUPP;
// 		break;
// 	}
// 	return (error);
// }

// SYSCALL_MODULE(syscall, &offset, &hello_sysent, load, NULL);