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本帖最后由 瀚海书香 于 2013-10-28 15:49 编辑
回复 5# netdoger
Translate userspace virtual address to physical address more complex than kernel mode.
Just follow this:
- /*******************************************************************************
-
- Copyright(c) 2008-2012
- This program is free software; you can redistribute it and/or modify it
- under the terms and conditions of the GNU General Public License,
- version 2, as published by the Free Software Foundation.
- This program is distributed in the hope it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- more details.
- You should have received a copy of the GNU General Public License along with
- this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
- The full GNU General Public License is included in this distribution in
- the file called "COPYING".
- Version: 0.1
- Date: 2012-04-21 10:25:55 CST
- Contact Information:
- Tony <tingw.liu@gmail.com>
- Home, Qingdao, China.
- *******************************************************************************/
- #include <linux/module.h>
- #include <asm/pgtable.h>
- #include <linux/version.h>
- #include <asm/page.h>
- #include <linux/gfp.h>
- #include <linux/page-flags.h>
- #include <linux/sched.h>//find_task_by_vpid
- #include <linux/mm.h>//find_vma
- #include <asm/uaccess.h>
- #include <asm/page.h>
- #include <asm/e820.h>
- #include <asm/pgtable_types.h>
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Tony <tingw.liu@gmail.com>");
- MODULE_DESCRIPTION("CONVERT USER VIRTUAL ADDRESS TO PHYADDRESS");
- static int pid;
- static unsigned long va;
- module_param(pid, int, 0644);
- module_param(va, ulong, 0644);
- static int find_pgd_init(void)
- {
- unsigned long pa=0;
- struct task_struct *pcb_tmp=NULL;
- struct page *ppage = NULL;
- unsigned long pfn = 0;
- pgd_t *pgd_tmp = NULL;
- pud_t *pud_tmp = NULL;
- pmd_t *pmd_tmp = NULL;
- pte_t *pte_tmp = NULL;
- printk(KERN_ALERT "PAGE_OFFSET=0x%lx\n", PAGE_OFFSET);
- printk(KERN_ALERT "PGDIR_SHIFT=%d\n", PGDIR_SHIFT);
- printk(KERN_ALERT "PUD_SHIFT=%d\n", PUD_SHIFT);
- printk(KERN_ALERT "PMD_SHIFT=%d\n", PMD_SHIFT);
- printk(KERN_ALERT "PAGE_SHIFT=%d\n", PAGE_SHIFT);
- printk(KERN_ALERT "PTRS_PRE_PGD=%d\n", PTRS_PER_PGD);
- printk(KERN_ALERT "PTRS_PRE_PUD=%d\n", PTRS_PER_PUD);
- printk(KERN_ALERT "PTRS_PRE_PMD=%d\n", PTRS_PER_PMD);
- printk(KERN_ALERT "PTRS_PRE_PTE=%d\n", PTRS_PER_PTE);
- printk(KERN_ALERT "PAGE_MASK=0x%lx\n", PAGE_MASK);
- if (!(pcb_tmp = pid_task(find_vpid(pid), PIDTYPE_PID))) {
- printk(KERN_ALERT "Can't find the task %d.\n", pid);
- return -1;
- }
- printk(KERN_ALERT "pgd=0x%p\n", pcb_tmp->mm->pgd);
- if (!find_vma(pcb_tmp->mm, va)) {
- printk(KERN_ALERT "virt_addr 0x%p not available.\n", va);
- return -1;
- }
- pgd_tmp = pgd_offset(pcb_tmp->mm, va);
- printk(KERN_ALERT "pgd_tmp=0x%p\n", pgd_tmp);
- printk(KERN_ALERT "pgd_val(*pgd_tmp)=0x%p\n", pgd_val(*pgd_tmp));
- if (pgd_none(*pgd_tmp) || pgd_bad(*pgd_tmp)) {
- printk(KERN_ALERT "Not mapped in pgd.\n");
- return -1;
- }
- pud_tmp = pud_offset(pgd_tmp,va);
- if (pud_none(*pud_tmp) || pud_bad(*pud_tmp)) {
- printk(KERN_ALERT "Not mapped in pud.\n");
- return -1;
- }
- pmd_tmp = pmd_offset(pud_tmp,va);
- if (pmd_none(*pmd_tmp) || pmd_bad(*pmd_tmp)) {
- printk(KERN_ALERT "Not mapped in pmd.\n");
- return -1;
- }
- /*FIXME:
- Do I need to check Large Page ? PSE bit.
- if(pmd_large(*pmd_tmp) == 1){
- pa = (pmd_val(*pmd_tmp) & PMD_MASK) | (va & ~PMD_MASK);
- }
- */
- pte_tmp = pte_offset_kernel(pmd_tmp, va);
- if (!pte_tmp || pte_none(*pte_tmp)) {
- printk(KERN_ALERT "Not mapped in pte.\n");
- return 0;
- }
- if (!pte_present(*pte_tmp)) {
- printk(KERN_ALERT "pte not in RAM,maybe swaped.\n");
- return 0;
- }
- ppage = pte_page(*pte_tmp);
- pfn = page_to_pfn(ppage);
- pa = page_to_phys(ppage);
- pa = pa|(va&~PAGE_MASK);
- printk(KERN_ALERT "virt_addr 0x%lx in RAM is 0x%lx.\n",va,pa);
- printk(KERN_ALERT "content in 0x%lx is 0x%lx.\n",pa,*(unsigned int*)(__va(pa)));
- return 0;
- }
- static void find_pgd_exit(void)
- {
- printk(KERN_ALERT "Goodbey.\n");
- }
- module_init(find_pgd_init);
- module_exit(find_pgd_exit);
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发表于 2013-10-28 09:48
发表于 2013-10-28 10:29
