/* * (C) Copyright 1994 Linus Torvalds * * Changes: * * Modified from Linus source to removing active mappings from any * task.  This is required for implementing the virtual graphics * interface for direct rendering on the SGI - miguel. * * Added a routine to map a vmalloc()ed area into user space, this one * is required by the /dev/shmiq driver - miguel. */#include <linux/stat.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/smp.h>#include <linux/smp_lock.h>#include <linux/shm.h>#include <linux/errno.h>#include <linux/mman.h>#include <linux/module.h>#include <linux/string.h>#include <linux/vmalloc.h>#include <linux/swap.h>#include <asm/system.h>#include <asm/pgalloc.h>#include <asm/page.h>static inline voidremove_mapping_pte_range (pmd_t *pmd, unsigned long address, unsigned long size){	pte_t *pte;	unsigned long end;	if (pmd_none (*pmd))		return;	if (pmd_bad (*pmd)){		printk ("remove_graphics_pte_range: bad pmd (%08lx)\n", pmd_val (*pmd));		pmd_clear (pmd);		return;	}	pte = pte_offset (pmd, address);	address &= ~PMD_MASK;	end = address + size;	if (end > PMD_SIZE)		end = PMD_SIZE;	do {		pte_t entry = *pte;		if (pte_present (entry))			set_pte (pte, pte_modify (entry, PAGE_NONE));		address += PAGE_SIZE;		pte++;	} while (address < end);}static inline voidremove_mapping_pmd_range (pgd_t *pgd, unsigned long address, unsigned long size){	pmd_t *pmd;	unsigned long end;	if (pgd_none (*pgd))		return;	if (pgd_bad (*pgd)){		printk ("remove_graphics_pmd_range: bad pgd (%08lx)\n", pgd_val (*pgd));		pgd_clear (pgd);		return;	}	pmd = pmd_offset (pgd, address);	address &= ~PGDIR_MASK;	end = address + size;	if (end > PGDIR_SIZE)		end = PGDIR_SIZE;	do {		remove_mapping_pte_range (pmd, address, end - address);		address = (address + PMD_SIZE) & PMD_MASK;		pmd++;	} while (address < end);}/* * This routine is called from the page fault handler to remove a * range of active mappings at this point */voidremove_mapping (struct task_struct *task, unsigned long start, unsigned long end){	unsigned long beg = start;	pgd_t *dir;	down_write (&task->mm->mmap_sem);	dir = pgd_offset (task->mm, start);	flush_cache_range (task->mm, beg, end);	while (start < end){		remove_mapping_pmd_range (dir, start, end - start);		start = (start + PGDIR_SIZE) & PGDIR_MASK;		dir++;	}	local_flush_tlb_range (task->mm, beg, end);	up_write (&task->mm->mmap_sem);}EXPORT_SYMBOL(remove_mapping);void *vmalloc_uncached (unsigned long size){	return __vmalloc (size, GFP_KERNEL | __GFP_HIGHMEM,	                  PAGE_KERNEL_UNCACHED);}static inline void free_pte(pte_t page){	if (pte_present(page)) {		struct page *ptpage = pte_page(page);		if ((!VALID_PAGE(ptpage)) || PageReserved(ptpage))			return;		__free_page(ptpage);		if (current->mm->rss <= 0)			return;		current->mm->rss--;		return;	}	swap_free(pte_to_swp_entry(page));}static inline void forget_pte(pte_t page){	if (!pte_none(page)) {		printk("forget_pte: old mapping existed!\n");		free_pte(page);	}}/* * maps a range of vmalloc()ed memory into the requested pages. the old * mappings are removed. */static inline voidvmap_pte_range (pte_t *pte, unsigned long address, unsigned long size, unsigned long vaddr){	unsigned long end;	pgd_t *vdir;	pmd_t *vpmd;	pte_t *vpte;	address &= ~PMD_MASK;	end = address + size;	if (end > PMD_SIZE)		end = PMD_SIZE;	do {		pte_t oldpage = *pte;		struct page * page;		pte_clear(pte);		vdir = pgd_offset_k (vaddr);		vpmd = pmd_offset (vdir, vaddr);		vpte = pte_offset (vpmd, vaddr);		page = pte_page (*vpte);		set_pte(pte, mk_pte(page, PAGE_USERIO));		forget_pte(oldpage);		address += PAGE_SIZE;		vaddr += PAGE_SIZE;		pte++;	} while (address < end);}static inline intvmap_pmd_range (pmd_t *pmd, unsigned long address, unsigned long size, unsigned long vaddr){	unsigned long end;	address &= ~PGDIR_MASK;	end = address + size;	if (end > PGDIR_SIZE)		end = PGDIR_SIZE;	vaddr -= address;	do {		pte_t * pte = pte_alloc(current->mm, pmd, address);		if (!pte)			return -ENOMEM;		vmap_pte_range(pte, address, end - address, address + vaddr);		address = (address + PMD_SIZE) & PMD_MASK;		pmd++;	} while (address < end);	return 0;}intvmap_page_range (unsigned long from, unsigned long size, unsigned long vaddr){	int error = 0;	pgd_t * dir;	unsigned long beg = from;	unsigned long end = from + size;	vaddr -= from;	dir = pgd_offset(current->mm, from);	flush_cache_range(current->mm, beg, end);	while (from < end) {		pmd_t *pmd = pmd_alloc(current->mm, dir, from);		error = -ENOMEM;		if (!pmd)			break;		error = vmap_pmd_range(pmd, from, end - from, vaddr + from);		if (error)			break;		from = (from + PGDIR_SIZE) & PGDIR_MASK;		dir++;	}	local_flush_tlb_range(current->mm, beg, end);	return error;}