96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
160 lines
3.3 KiB
C
160 lines
3.3 KiB
C
/*
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* Generic /dev/nvram driver for architectures providing some
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* "generic" hooks, that is :
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*
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* nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size
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*
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* Note that an additional hook is supported for PowerMac only
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* for getting the nvram "partition" informations
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*
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*/
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#define NVRAM_VERSION "1.1"
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/fcntl.h>
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#include <linux/init.h>
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#include <linux/mutex.h>
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#include <linux/pagemap.h>
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#include <linux/uaccess.h>
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#include <asm/nvram.h>
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#ifdef CONFIG_PPC_PMAC
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#include <asm/machdep.h>
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#endif
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#define NVRAM_SIZE 8192
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static DEFINE_MUTEX(nvram_mutex);
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static ssize_t nvram_len;
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static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
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{
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return generic_file_llseek_size(file, offset, origin,
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MAX_LFS_FILESIZE, nvram_len);
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}
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static ssize_t read_nvram(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned int i;
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char __user *p = buf;
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if (!access_ok(buf, count))
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return -EFAULT;
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if (*ppos >= nvram_len)
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return 0;
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for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)
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if (__put_user(nvram_read_byte(i), p))
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return -EFAULT;
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*ppos = i;
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return p - buf;
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}
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static ssize_t write_nvram(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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unsigned int i;
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const char __user *p = buf;
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char c;
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if (!access_ok(buf, count))
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return -EFAULT;
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if (*ppos >= nvram_len)
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return 0;
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for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {
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if (__get_user(c, p))
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return -EFAULT;
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nvram_write_byte(c, i);
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}
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*ppos = i;
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return p - buf;
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}
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static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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switch(cmd) {
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#ifdef CONFIG_PPC_PMAC
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case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
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printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
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case IOC_NVRAM_GET_OFFSET: {
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int part, offset;
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if (!machine_is(powermac))
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return -EINVAL;
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if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
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return -EFAULT;
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if (part < pmac_nvram_OF || part > pmac_nvram_NR)
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return -EINVAL;
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offset = pmac_get_partition(part);
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if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
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return -EFAULT;
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break;
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}
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#endif /* CONFIG_PPC_PMAC */
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case IOC_NVRAM_SYNC:
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nvram_sync();
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static long nvram_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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int ret;
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mutex_lock(&nvram_mutex);
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ret = nvram_ioctl(file, cmd, arg);
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mutex_unlock(&nvram_mutex);
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return ret;
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}
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const struct file_operations nvram_fops = {
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.owner = THIS_MODULE,
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.llseek = nvram_llseek,
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.read = read_nvram,
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.write = write_nvram,
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.unlocked_ioctl = nvram_unlocked_ioctl,
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};
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static struct miscdevice nvram_dev = {
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NVRAM_MINOR,
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"nvram",
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&nvram_fops
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};
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int __init nvram_init(void)
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{
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int ret = 0;
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printk(KERN_INFO "Generic non-volatile memory driver v%s\n",
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NVRAM_VERSION);
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ret = misc_register(&nvram_dev);
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if (ret != 0)
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goto out;
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nvram_len = nvram_get_size();
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if (nvram_len < 0)
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nvram_len = NVRAM_SIZE;
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out:
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return ret;
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}
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void __exit nvram_cleanup(void)
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{
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misc_deregister( &nvram_dev );
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}
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module_init(nvram_init);
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module_exit(nvram_cleanup);
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MODULE_LICENSE("GPL");
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