d63c489b88
cycle_kernel_lock() was added during the big BKL pushdown. It should ensure the serializiation against driver init code. mmapper_open() cannot be called before misc_register() succeeded, but p_buf might be uninitialized. Move the initialization of p_buf before the misc_register() call and get rid of cycle_kernel_lock(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091010153349.682213670@linutronix.de> Cc: Jeff Dike <jdike@addtoit.com>
139 lines
2.9 KiB
C
139 lines
2.9 KiB
C
/*
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* arch/um/drivers/mmapper_kern.c
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*
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* BRIEF MODULE DESCRIPTION
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*
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* Copyright (C) 2000 RidgeRun, Inc.
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* Author: RidgeRun, Inc.
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* Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
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*
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*/
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#include <linux/stddef.h>
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#include <linux/types.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <asm/uaccess.h>
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#include "mem_user.h"
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/* These are set in mmapper_init, which is called at boot time */
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static unsigned long mmapper_size;
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static unsigned long p_buf;
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static char *v_buf;
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static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
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loff_t *ppos)
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{
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return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
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}
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static ssize_t mmapper_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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if (*ppos > mmapper_size)
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return -EINVAL;
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if (count > mmapper_size - *ppos)
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count = mmapper_size - *ppos;
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if (copy_from_user(&v_buf[*ppos], buf, count))
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return -EFAULT;
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return count;
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}
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static int mmapper_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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return -ENOIOCTLCMD;
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}
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static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
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{
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int ret = -EINVAL;
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int size;
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if (vma->vm_pgoff != 0)
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goto out;
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size = vma->vm_end - vma->vm_start;
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if (size > mmapper_size)
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return -EFAULT;
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/*
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* XXX A comment above remap_pfn_range says it should only be
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* called when the mm semaphore is held
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*/
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if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
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vma->vm_page_prot))
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goto out;
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ret = 0;
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out:
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return ret;
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}
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static int mmapper_open(struct inode *inode, struct file *file)
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{
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return 0;
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}
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static int mmapper_release(struct inode *inode, struct file *file)
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{
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return 0;
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}
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static const struct file_operations mmapper_fops = {
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.owner = THIS_MODULE,
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.read = mmapper_read,
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.write = mmapper_write,
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.ioctl = mmapper_ioctl,
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.mmap = mmapper_mmap,
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.open = mmapper_open,
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.release = mmapper_release,
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};
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/*
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* No locking needed - only used (and modified) by below initcall and exitcall.
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*/
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static struct miscdevice mmapper_dev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "mmapper",
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.fops = &mmapper_fops
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};
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static int __init mmapper_init(void)
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{
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int err;
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printk(KERN_INFO "Mapper v0.1\n");
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v_buf = (char *) find_iomem("mmapper", &mmapper_size);
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if (mmapper_size == 0) {
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printk(KERN_ERR "mmapper_init - find_iomem failed\n");
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return -ENODEV;
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}
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p_buf = __pa(v_buf);
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err = misc_register(&mmapper_dev);
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if (err) {
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printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
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err);
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return err;;
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}
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return 0;
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}
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static void mmapper_exit(void)
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{
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misc_deregister(&mmapper_dev);
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}
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module_init(mmapper_init);
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module_exit(mmapper_exit);
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MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
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MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
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