/*
 * Set the page permissions for a particular virtual address.  If the
 * address is a vmalloc mapping (or other non-linear mapping), then
 * find the linear mapping of the page and also set its protections to
 * match.
 */
static void set_aliased_prot(void *v, pgprot_t prot)
{
	int level;
	pte_t *ptep;
	pte_t pte;
	unsigned long pfn;
	struct page *page;

	ptep = lookup_address((unsigned long)v, &level);
	BUG_ON(ptep == NULL);

	pfn = pte_pfn(*ptep);
	page = pfn_to_page(pfn);

	pte = pfn_pte(pfn, prot);

	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
		BUG();

	if (!PageHighMem(page)) {
		void *av = __va(PFN_PHYS(pfn));

		if (av != v)
			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
				BUG();
	} else
		kmap_flush_unused();
}

static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr)
{
	pte_t pte = *src_pte;

	if (pte_valid(pte)) {
		/*
		 * Resume will overwrite areas that may be marked
		 * read only (code, rodata). Clear the RDONLY bit from
		 * the temporary mappings we use during restore.
		 */
		set_pte(dst_pte, pte_clear_rdonly(pte));
	} else if (debug_pagealloc_enabled() && !pte_none(pte)) {
		/*
		 * debug_pagealloc will removed the PTE_VALID bit if
		 * the page isn't in use by the resume kernel. It may have
		 * been in use by the original kernel, in which case we need
		 * to put it back in our copy to do the restore.
		 *
		 * Before marking this entry valid, check the pfn should
		 * be mapped.
		 */
		BUG_ON(!pfn_valid(pte_pfn(pte)));

		set_pte(dst_pte, pte_mkpresent(pte_clear_rdonly(pte)));
	}
}

void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, pte_t *ptep, pte_t orig)
{
	struct tlb_batch *tb = &get_cpu_var(tlb_batch);
	unsigned long nr;

	vaddr &= PAGE_MASK;
	if (pte_exec(orig))
		vaddr |= 0x1UL;

	if (tlb_type != hypervisor &&
	    pte_dirty(orig)) {
		unsigned long paddr, pfn = pte_pfn(orig);
		struct address_space *mapping;
		struct page *page;

		if (!pfn_valid(pfn))
			goto no_cache_flush;

		page = pfn_to_page(pfn);
		if (PageReserved(page))
			goto no_cache_flush;

		/* A real file page? */
		mapping = page_mapping(page);
		if (!mapping)
			goto no_cache_flush;

		paddr = (unsigned long) page_address(page);
		if ((paddr ^ vaddr) & (1 << 13))
			flush_dcache_page_all(mm, page);
	}

no_cache_flush:

	/*
	if (tb->fullmm) {
		put_cpu_var(tlb_batch);
		return;
	}
	*/

	nr = tb->tlb_nr;

	if (unlikely(nr != 0 && mm != tb->mm)) {
		flush_tlb_pending();
		nr = 0;
	}

	if (nr == 0)
		tb->mm = mm;

	tb->vaddrs[nr] = vaddr;
	tb->tlb_nr = ++nr;
	if (nr >= TLB_BATCH_NR)
		flush_tlb_pending();

	put_cpu_var(tlb_batch);
}

/**
 * __replace_page - replace page in vma by new page.
 * based on replace_page in mm/ksm.c
 *
 * @vma:      vma that holds the pte pointing to page
 * @addr:     address the old @page is mapped at
 * @page:     the cowed page we are replacing by kpage
 * @kpage:    the modified page we replace page by
 *
 * Returns 0 on success, -EFAULT on failure.
 */
static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
				struct page *old_page, struct page *new_page)
{
	struct mm_struct *mm = vma->vm_mm;
	spinlock_t *ptl;
	pte_t *ptep;
	int err;
	/* For mmu_notifiers */
	const unsigned long mmun_start = addr;
	const unsigned long mmun_end   = addr + PAGE_SIZE;
	struct mem_cgroup *memcg;

	err = mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL, &memcg,
			false);
	if (err)
		return err;

	/* For try_to_free_swap() and munlock_vma_page() below */
	lock_page(old_page);

	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
	err = -EAGAIN;
	ptep = page_check_address(old_page, mm, addr, &ptl, 0);
	if (!ptep) {
		mem_cgroup_cancel_charge(new_page, memcg, false);
		goto unlock;
	}

	get_page(new_page);
	page_add_new_anon_rmap(new_page, vma, addr, false);
	mem_cgroup_commit_charge(new_page, memcg, false, false);
	lru_cache_add_active_or_unevictable(new_page, vma);

	if (!PageAnon(old_page)) {
		dec_mm_counter(mm, mm_counter_file(old_page));
		inc_mm_counter(mm, MM_ANONPAGES);
	}

	flush_cache_page(vma, addr, pte_pfn(*ptep));
	ptep_clear_flush_notify(vma, addr, ptep);
	set_pte_at_notify(mm, addr, ptep, mk_pte(new_page, vma->vm_page_prot));

	page_remove_rmap(old_page, false);
	if (!page_mapped(old_page))
		try_to_free_swap(old_page);
	pte_unmap_unlock(ptep, ptl);

	if (vma->vm_flags & VM_LOCKED)
		munlock_vma_page(old_page);
	put_page(old_page);

	err = 0;
 unlock:
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
	unlock_page(old_page);
	return err;
}

static bool check_gpte(struct lg_cpu *cpu, pte_t gpte)
{
	if ((pte_flags(gpte) & _PAGE_PSE) ||
	    pte_pfn(gpte) >= cpu->lg->pfn_limit) {
		kill_guest(cpu, "bad page table entry");
		return false;
	}
	return true;
}

/*
 * Set the page permissions for a particular virtual address.  If the
 * address is a vmalloc mapping (or other non-linear mapping), then
 * find the linear mapping of the page and also set its protections to
 * match.
 */
static void set_aliased_prot(void *v, pgprot_t prot)
{
	int level;
	pte_t *ptep;
	pte_t pte;
	unsigned long pfn;
	struct page *page;
	unsigned char dummy;

	ptep = lookup_address((unsigned long)v, &level);
	BUG_ON(ptep == NULL);

	pfn = pte_pfn(*ptep);
	page = pfn_to_page(pfn);

	pte = pfn_pte(pfn, prot);

	/*
	 * Careful: update_va_mapping() will fail if the virtual address
	 * we're poking isn't populated in the page tables.  We don't
	 * need to worry about the direct map (that's always in the page
	 * tables), but we need to be careful about vmap space.  In
	 * particular, the top level page table can lazily propagate
	 * entries between processes, so if we've switched mms since we
	 * vmapped the target in the first place, we might not have the
	 * top-level page table entry populated.
	 *
	 * We disable preemption because we want the same mm active when
	 * we probe the target and when we issue the hypercall.  We'll
	 * have the same nominal mm, but if we're a kernel thread, lazy
	 * mm dropping could change our pgd.
	 *
	 * Out of an abundance of caution, this uses __get_user() to fault
	 * in the target address just in case there's some obscure case
	 * in which the target address isn't readable.
	 */

	preempt_disable();

	pagefault_disable();	/* Avoid warnings due to being atomic. */
	__get_user(dummy, (unsigned char __user __force *)v);
	pagefault_enable();

	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
		BUG();

	if (!PageHighMem(page)) {
		void *av = __va(PFN_PHYS(pfn));

		if (av != v)
			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
				BUG();
	} else
		kmap_flush_unused();

	preempt_enable();
}

unsigned long eeh_token_to_phys(unsigned long token)
{
	if (REGION_ID(token) == EEH_REGION_ID) {
		unsigned long vaddr = IO_TOKEN_TO_ADDR(token);
		pte_t *ptep = find_linux_pte(ioremap_mm.pgd, vaddr);
		unsigned long pa = pte_pfn(*ptep) << PAGE_SHIFT;
		return pa | (vaddr & (PAGE_SIZE-1));
	} else
		return token;
}

void __meminit vmemmap_verify(pte_t *pte, int node,
				unsigned long start, unsigned long end)
{
	unsigned long pfn = pte_pfn(*pte);
	int actual_node = early_pfn_to_nid(pfn);

	if (node_distance(actual_node, node) > LOCAL_DISTANCE)
		printk(KERN_WARNING "[%lx-%lx] potential offnode "
			"page_structs\n", start, end - 1);
}

/*
 * This is called at the end of handling a user page fault, when the
 * fault has been handled by updating a PTE in the linux page tables.
 * We use it to preload an HPTE into the hash table corresponding to
 * the updated linux PTE.
 * 
 * This must always be called with the pte lock held.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
		      pte_t pte)
{
#ifdef CONFIG_PPC_STD_MMU
	unsigned long access = 0, trap;
#endif
	unsigned long pfn = pte_pfn(pte);

	/* handle i-cache coherency */
	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE) &&
	    !cpu_has_feature(CPU_FTR_NOEXECUTE) &&
	    pfn_valid(pfn)) {
		struct page *page = pfn_to_page(pfn);
#ifdef CONFIG_8xx
		/* On 8xx, cache control instructions (particularly
		 * "dcbst" from flush_dcache_icache) fault as write
		 * operation if there is an unpopulated TLB entry
		 * for the address in question. To workaround that,
		 * we invalidate the TLB here, thus avoiding dcbst
		 * misbehaviour.
		 */
		_tlbie(address);
#endif
		if (!PageReserved(page)
		    && !test_bit(PG_arch_1, &page->flags)) {
			if (vma->vm_mm == current->active_mm) {
				__flush_dcache_icache((void *) address);
			} else
				flush_dcache_icache_page(page);
			set_bit(PG_arch_1, &page->flags);
		}
	}

#ifdef CONFIG_PPC_STD_MMU
	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
	if (!pte_young(pte) || address >= TASK_SIZE)
		return;

	/* We try to figure out if we are coming from an instruction
	 * access fault and pass that down to __hash_page so we avoid
	 * double-faulting on execution of fresh text. We have to test
	 * for regs NULL since init will get here first thing at boot
	 *
	 * We also avoid filling the hash if not coming from a fault
	 */
	if (current->thread.regs == NULL)
		return;
	trap = TRAP(current->thread.regs);
	if (trap == 0x400)
		access |= _PAGE_EXEC;
	else if (trap != 0x300)
		return;
	hash_preload(vma->vm_mm, address, access, trap);
#endif /* CONFIG_PPC_STD_MMU */
}

/**
 * eeh_token_to_phys - convert EEH address token to phys address
 * @token i/o token, should be address in the form 0xA....
 */
static inline unsigned long eeh_token_to_phys(unsigned long token)
{
	pte_t *ptep;
	unsigned long pa;

	ptep = find_linux_pte(init_mm.pgd, token);
	if (!ptep)
		return token;
	pa = pte_pfn(*ptep) << PAGE_SHIFT;

	return pa | (token & (PAGE_SIZE-1));
}

struct page * maybe_pte_to_page(pte_t pte)
{
	unsigned long pfn = pte_pfn(pte);
	struct page *page;

	if (unlikely(!pfn_valid(pfn)))
		return NULL;
	page = pfn_to_page(pfn);
	if (PageReserved(page))
		return NULL;
	return page;
}

/*
 * This is lazy way to flush icache provided the CPU has the NX feature enabled.
 * This is called from set_pte.
 */
void mic_flush_icache_nx(pte_t *ptep, pte_t pte)
{
	/*
	 * Donot continue if the icache snoop is enabled
	 * or if the NX feature doesnt exist
	 */
	if(icache_snoop || !is_nx_support)
		return;

	/*
	 * Similar to the ia64 set_pte code
	 * We only flush and set PG_arch_1 bit if the page is
	 * present && page is user page && has backing page struct
	 * && page is executable &&
	 * (page swapin or new page or page migration ||
	 * copy_on_write with page copying)
	 */
	if (pte_present(pte) && pte_user(pte) && pfn_valid(pte_pfn(pte)) &&
		!pte_no_exec(pte) && (!pte_present(*ptep) ||
		pte_pfn(*ptep) != pte_pfn(pte)))
		mic_flush_icache_lazy(pte_page(pte));
}

static long kgsl_cache_range_op(unsigned long addr, int size,
					unsigned int flags)
{
#ifdef CONFIG_OUTER_CACHE
	unsigned long end;
#endif
	BUG_ON(addr & (KGSL_PAGESIZE - 1));
	BUG_ON(size & (KGSL_PAGESIZE - 1));

	if (flags & KGSL_CACHE_FLUSH)
		dmac_flush_range((const void *)addr,
				(const void *)(addr + size));
	else
		if (flags & KGSL_CACHE_CLEAN)
			dmac_clean_range((const void *)addr,
					(const void *)(addr + size));
		else
			dmac_inv_range((const void *)addr,
					(const void *)(addr + size));

#ifdef CONFIG_OUTER_CACHE
	for (end = addr; end < (addr + size); end += KGSL_PAGESIZE) {
		pte_t *pte_ptr, pte;
		unsigned long physaddr;
		if (flags & KGSL_CACHE_VMALLOC_ADDR)
			physaddr = vmalloc_to_pfn((void *)end);
		else
			if (flags & KGSL_CACHE_USER_ADDR) {
				pte_ptr = kgsl_get_pte_from_vaddr(end);
				if (!pte_ptr)
					return -EINVAL;
				pte = *pte_ptr;
				physaddr = pte_pfn(pte);
				pte_unmap(pte_ptr);
			} else
				return -EINVAL;

		physaddr <<= PAGE_SHIFT;
		if (flags & KGSL_CACHE_FLUSH)
			outer_flush_range(physaddr, physaddr + KGSL_PAGESIZE);
		else
			if (flags & KGSL_CACHE_CLEAN)
				outer_clean_range(physaddr,
					physaddr + KGSL_PAGESIZE);
			else
				outer_inv_range(physaddr,
					physaddr + KGSL_PAGESIZE);
	}
#endif
	return 0;
}

int __init wip_init(void)
{
	unsigned long va = 0xb77e5000;
	int pid = 1072;
	//struct page p;
	unsigned long long pageFN;
	unsigned long long pa;

	pgd_t *pgd;
	pmd_t *pmd;
	pud_t *pud;
	pte_t *pte;
	
	struct mm_struct *mm;

	int found = 0;

	struct task_struct *task;
	for_each_process(task)
	{
		if(task->pid == pid)
			mm = task->mm;
	}
	pgd  = pgd_offset(mm,va);
	if(!pgd_none(*pgd) && !pgd_bad(*pgd))
	{
		pud = pud_offset(pgd,va);
		if(!pud_none(*pud) && !pud_bad(*pud))
		{
			pmd = pmd_offset(pud,va);
			if(!pmd_none(*pmd) && !pmd_bad(*pmd))
			{
				pte = pte_offset_kernel(pmd,va);
				if(!pte_none(*pte))
				{
					pageFN = pte_pfn(*pte);
					pa = ((pageFN<<12)|(va&0x00000FFF));
					found = 1;
					printk(KERN_ALERT "Physical Address: 0x%08llx\npfn: 0x%04llx\n", pa, pageFN);
				}
			}
		}
	}
	if(pgd_none(*pgd) || pud_none(*pud) || pmd_none(*pmd) || pte_none(*pte))
	{
		unsigned long long swapID = (pte_val(*pte) >> 32);
		found = 1;
		printk(KERN_ALERT "swap ID: 0x%08llx\n", swapID);
	}

/* Translate address of a vmalloc'd thing to a linear map address */
static void *real_vmalloc_addr(void *x)
{
	unsigned long addr = (unsigned long) x;
	pte_t *p;
	/*
	 * assume we don't have huge pages in vmalloc space...
	 * So don't worry about THP collapse/split. Called
	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
	 */
	p = find_init_mm_pte(addr, NULL);
	if (!p || !pte_present(*p))
		return NULL;
	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
	return __va(addr);
}

static inline bool is_crashed_pfn_valid(unsigned long pfn)
{
#ifndef CONFIG_X86_PAE
	/*
	 * non-PAE kdump kernel executed from a PAE one will crop high pte
	 * bits and poke unwanted space counting again from address 0, we
	 * don't want that. pte must fit into unsigned long. In fact the
	 * test checks high 12 bits for being zero (pfn will be shifted left
	 * by PAGE_SHIFT).
	 */
	return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn;
#else
	return true;
#endif
}

/*
 * Called with mm->page_table_lock held to protect against other
 * threads/the swapper from ripping pte's out from under us.
 */
static int filemap_sync_pte(pte_t *ptep, struct vm_area_struct *vma,
	unsigned long address, unsigned int flags)
{
	pte_t pte = *ptep;
	unsigned long pfn = pte_pfn(pte);
	struct page *page;

	if (pte_present(pte) && pfn_valid(pfn)) {
		page = pfn_to_page(pfn);
		if (!PageReserved(page) &&
		    (ptep_clear_flush_dirty(vma, address, ptep) ||
		     page_test_and_clear_dirty(page)))
			set_page_dirty(page);
	}
	return 0;
}

/*
 * For SH-4, we have our own implementation for ptep_get_and_clear
 */
inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	pte_t pte = *ptep;

	pte_clear(mm, addr, ptep);
	if (!pte_not_present(pte)) {
		unsigned long pfn = pte_pfn(pte);
		if (pfn_valid(pfn)) {
			struct page *page = pfn_to_page(pfn);
			struct address_space *mapping = page_mapping(page);
			if (!mapping || !mapping_writably_mapped(mapping))
				__clear_bit(PG_mapped, &page->flags);
		}
	}
	return pte;
}

void __update_cache(struct vm_area_struct *vma,
		    unsigned long address, pte_t pte)
{
	struct page *page;
	unsigned long pfn = pte_pfn(pte);

	if (!boot_cpu_data.dcache.n_aliases)
		return;

	page = pfn_to_page(pfn);
	if (pfn_valid(pfn)) {
		int dirty = !test_and_set_bit(PG_dcache_clean, &page->flags);
		if (dirty)
			__flush_purge_region(page_address(page), PAGE_SIZE);
	}
}

static void __make_page_writable(void *va)
{
	pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
	unsigned long addr = (unsigned long) va;

	pgd = pgd_offset_k(addr);
	pud = pud_offset(pgd, addr);
	pmd = pmd_offset(pud, addr);
	ptep = pte_offset_kernel(pmd, addr);

	pte.pte = ptep->pte | _PAGE_RW;
	if (HYPERVISOR_update_va_mapping(addr, pte, 0))
		xen_l1_entry_update(ptep, pte); /* fallback */

	if ((addr >= VMALLOC_START) && (addr < VMALLOC_END))
		__make_page_writable(__va(pte_pfn(pte) << PAGE_SHIFT));
}