Revision 89a8640279f8bb78aaf778d1fc5c4a6778f18064 authored by David Howells on 30 October 2009, 13:13:26 UTC, committed by Linus Torvalds on 31 October 2009, 19:11:37 UTC
Don't pass NULL pointers to fput() in the error handling paths of the NOMMU
do_mmap_pgoff() as it can't handle it.

The following can be used as a test program:

	int main() { static long long a[1024 * 1024 * 20] = { 0 }; return a;}

Without the patch, the code oopses in atomic_long_dec_and_test() as called by
fput() after the kernel complains that it can't allocate that big a chunk of
memory.  With the patch, the kernel just complains about the allocation size
and then the program segfaults during execve() as execve() can't complete the
allocation of all the new ELF program segments.

Reported-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 2e2ec95
Raw File
dsp56k.c
/*
 * The DSP56001 Device Driver, saviour of the Free World(tm)
 *
 * Authors: Fredrik Noring   <noring@nocrew.org>
 *          lars brinkhoff   <lars@nocrew.org>
 *          Tomas Berndtsson <tomas@nocrew.org>
 *
 * First version May 1996
 *
 * History:
 *  97-01-29   Tomas Berndtsson,
 *               Integrated with Linux 2.1.21 kernel sources.
 *  97-02-15   Tomas Berndtsson,
 *               Fixed for kernel 2.1.26
 *
 * BUGS:
 *  Hmm... there must be something here :)
 *
 * Copyright (C) 1996,1997 Fredrik Noring, lars brinkhoff & Tomas Berndtsson
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/slab.h>	/* for kmalloc() and kfree() */
#include <linux/major.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/delay.h>	/* guess what */
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/smp_lock.h>
#include <linux/firmware.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>	/* For put_user and get_user */

#include <asm/atarihw.h>
#include <asm/traps.h>

#include <asm/dsp56k.h>

/* minor devices */
#define DSP56K_DEV_56001        0    /* The only device so far */

#define TIMEOUT    10   /* Host port timeout in number of tries */
#define MAXIO    2048   /* Maximum number of words before sleep */
#define DSP56K_MAX_BINARY_LENGTH (3*64*1024)

#define DSP56K_TX_INT_ON	dsp56k_host_interface.icr |=  DSP56K_ICR_TREQ
#define DSP56K_RX_INT_ON	dsp56k_host_interface.icr |=  DSP56K_ICR_RREQ
#define DSP56K_TX_INT_OFF	dsp56k_host_interface.icr &= ~DSP56K_ICR_TREQ
#define DSP56K_RX_INT_OFF	dsp56k_host_interface.icr &= ~DSP56K_ICR_RREQ

#define DSP56K_TRANSMIT		(dsp56k_host_interface.isr & DSP56K_ISR_TXDE)
#define DSP56K_RECEIVE		(dsp56k_host_interface.isr & DSP56K_ISR_RXDF)

#define handshake(count, maxio, timeout, ENABLE, f) \
{ \
	long i, t, m; \
	while (count > 0) { \
		m = min_t(unsigned long, count, maxio); \
		for (i = 0; i < m; i++) { \
			for (t = 0; t < timeout && !ENABLE; t++) \
				msleep(20); \
			if(!ENABLE) \
				return -EIO; \
			f; \
		} \
		count -= m; \
		if (m == maxio) msleep(20); \
	} \
}

#define tx_wait(n) \
{ \
	int t; \
	for(t = 0; t < n && !DSP56K_TRANSMIT; t++) \
		msleep(10); \
	if(!DSP56K_TRANSMIT) { \
		return -EIO; \
	} \
}

#define rx_wait(n) \
{ \
	int t; \
	for(t = 0; t < n && !DSP56K_RECEIVE; t++) \
		msleep(10); \
	if(!DSP56K_RECEIVE) { \
		return -EIO; \
	} \
}

static struct dsp56k_device {
	unsigned long in_use;
	long maxio, timeout;
	int tx_wsize, rx_wsize;
} dsp56k;

static struct class *dsp56k_class;

static int dsp56k_reset(void)
{
	u_char status;
	
	/* Power down the DSP */
	sound_ym.rd_data_reg_sel = 14;
	status = sound_ym.rd_data_reg_sel & 0xef;
	sound_ym.wd_data = status;
	sound_ym.wd_data = status | 0x10;
  
	udelay(10);
  
	/* Power up the DSP */
	sound_ym.rd_data_reg_sel = 14;
	sound_ym.wd_data = sound_ym.rd_data_reg_sel & 0xef;

	return 0;
}

static int dsp56k_upload(u_char __user *bin, int len)
{
	struct platform_device *pdev;
	const struct firmware *fw;
	const char fw_name[] = "dsp56k/bootstrap.bin";
	int err;
	int i;

	dsp56k_reset();

	pdev = platform_device_register_simple("dsp56k", 0, NULL, 0);
	if (IS_ERR(pdev)) {
		printk(KERN_ERR "Failed to register device for \"%s\"\n",
		       fw_name);
		return -EINVAL;
	}
	err = request_firmware(&fw, fw_name, &pdev->dev);
	platform_device_unregister(pdev);
	if (err) {
		printk(KERN_ERR "Failed to load image \"%s\" err %d\n",
		       fw_name, err);
		return err;
	}
	if (fw->size % 3) {
		printk(KERN_ERR "Bogus length %d in image \"%s\"\n",
		       fw->size, fw_name);
		release_firmware(fw);
		return -EINVAL;
	}
	for (i = 0; i < fw->size; i = i + 3) {
		/* tx_wait(10); */
		dsp56k_host_interface.data.b[1] = fw->data[i];
		dsp56k_host_interface.data.b[2] = fw->data[i + 1];
		dsp56k_host_interface.data.b[3] = fw->data[i + 2];
	}
	release_firmware(fw);
	for (; i < 512; i++) {
		/* tx_wait(10); */
		dsp56k_host_interface.data.b[1] = 0;
		dsp56k_host_interface.data.b[2] = 0;
		dsp56k_host_interface.data.b[3] = 0;
	}
  
	for (i = 0; i < len; i++) {
		tx_wait(10);
		get_user(dsp56k_host_interface.data.b[1], bin++);
		get_user(dsp56k_host_interface.data.b[2], bin++);
		get_user(dsp56k_host_interface.data.b[3], bin++);
	}

	tx_wait(10);
	dsp56k_host_interface.data.l = 3;    /* Magic execute */

	return 0;
}

static ssize_t dsp56k_read(struct file *file, char __user *buf, size_t count,
			   loff_t *ppos)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	int dev = iminor(inode) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
	{

		long n;

		/* Don't do anything if nothing is to be done */
		if (!count) return 0;

		n = 0;
		switch (dsp56k.rx_wsize) {
		case 1:  /* 8 bit */
		{
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.b[3], buf+n++));
			return n;
		}
		case 2:  /* 16 bit */
		{
			short __user *data;

			count /= 2;
			data = (short __user *) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.w[1], data+n++));
			return 2*n;
		}
		case 3:  /* 24 bit */
		{
			count /= 3;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.b[1], buf+n++);
				  put_user(dsp56k_host_interface.data.b[2], buf+n++);
				  put_user(dsp56k_host_interface.data.b[3], buf+n++));
			return 3*n;
		}
		case 4:  /* 32 bit */
		{
			long __user *data;

			count /= 4;
			data = (long __user *) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.l, data+n++));
			return 4*n;
		}
		}
		return -EFAULT;
	}

	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

static ssize_t dsp56k_write(struct file *file, const char __user *buf, size_t count,
			    loff_t *ppos)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	int dev = iminor(inode) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
	{
		long n;

		/* Don't do anything if nothing is to be done */
		if (!count) return 0;

		n = 0;
		switch (dsp56k.tx_wsize) {
		case 1:  /* 8 bit */
		{
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.b[3], buf+n++));
			return n;
		}
		case 2:  /* 16 bit */
		{
			const short __user *data;

			count /= 2;
			data = (const short __user *)buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.w[1], data+n++));
			return 2*n;
		}
		case 3:  /* 24 bit */
		{
			count /= 3;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.b[1], buf+n++);
				  get_user(dsp56k_host_interface.data.b[2], buf+n++);
				  get_user(dsp56k_host_interface.data.b[3], buf+n++));
			return 3*n;
		}
		case 4:  /* 32 bit */
		{
			const long __user *data;

			count /= 4;
			data = (const long __user *)buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.l, data+n++));
			return 4*n;
		}
		}

		return -EFAULT;
	}
	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

static long dsp56k_ioctl(struct file *file, unsigned int cmd,
			 unsigned long arg)
{
	int dev = iminor(file->f_path.dentry->d_inode) & 0x0f;
	void __user *argp = (void __user *)arg;

	switch(dev)
	{
	case DSP56K_DEV_56001:

		switch(cmd) {
		case DSP56K_UPLOAD:
		{
			char __user *bin;
			int r, len;
			struct dsp56k_upload __user *binary = argp;
    
			if(get_user(len, &binary->len) < 0)
				return -EFAULT;
			if(get_user(bin, &binary->bin) < 0)
				return -EFAULT;
		
			if (len == 0) {
				return -EINVAL;      /* nothing to upload?!? */
			}
			if (len > DSP56K_MAX_BINARY_LENGTH) {
				return -EINVAL;
			}
			lock_kernel();
			r = dsp56k_upload(bin, len);
			unlock_kernel();
			if (r < 0) {
				return r;
			}
    
			break;
		}
		case DSP56K_SET_TX_WSIZE:
			if (arg > 4 || arg < 1)
				return -EINVAL;
			lock_kernel();
			dsp56k.tx_wsize = (int) arg;
			unlock_kernel();
			break;
		case DSP56K_SET_RX_WSIZE:
			if (arg > 4 || arg < 1)
				return -EINVAL;
			lock_kernel();
			dsp56k.rx_wsize = (int) arg;
			unlock_kernel();
			break;
		case DSP56K_HOST_FLAGS:
		{
			int dir, out, status;
			struct dsp56k_host_flags __user *hf = argp;
    
			if(get_user(dir, &hf->dir) < 0)
				return -EFAULT;
			if(get_user(out, &hf->out) < 0)
				return -EFAULT;

			lock_kernel();
			if ((dir & 0x1) && (out & 0x1))
				dsp56k_host_interface.icr |= DSP56K_ICR_HF0;
			else if (dir & 0x1)
				dsp56k_host_interface.icr &= ~DSP56K_ICR_HF0;
			if ((dir & 0x2) && (out & 0x2))
				dsp56k_host_interface.icr |= DSP56K_ICR_HF1;
			else if (dir & 0x2)
				dsp56k_host_interface.icr &= ~DSP56K_ICR_HF1;

			status = 0;
			if (dsp56k_host_interface.icr & DSP56K_ICR_HF0) status |= 0x1;
			if (dsp56k_host_interface.icr & DSP56K_ICR_HF1) status |= 0x2;
			if (dsp56k_host_interface.isr & DSP56K_ISR_HF2) status |= 0x4;
			if (dsp56k_host_interface.isr & DSP56K_ISR_HF3) status |= 0x8;
			unlock_kernel();
			return put_user(status, &hf->status);
		}
		case DSP56K_HOST_CMD:
			if (arg > 31 || arg < 0)
				return -EINVAL;
			lock_kernel();
			dsp56k_host_interface.cvr = (u_char)((arg & DSP56K_CVR_HV_MASK) |
							     DSP56K_CVR_HC);
			unlock_kernel();
			break;
		default:
			return -EINVAL;
		}
		return 0;

	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

/* As of 2.1.26 this should be dsp56k_poll,
 * but how do I then check device minor number?
 * Do I need this function at all???
 */
#if 0
static unsigned int dsp56k_poll(struct file *file, poll_table *wait)
{
	int dev = iminor(file->f_path.dentry->d_inode) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
		/* poll_wait(file, ???, wait); */
		return POLLIN | POLLRDNORM | POLLOUT;

	default:
		printk("DSP56k driver: Unknown minor device: %d\n", dev);
		return 0;
	}
}
#endif

static int dsp56k_open(struct inode *inode, struct file *file)
{
	int dev = iminor(inode) & 0x0f;
	int ret = 0;

	lock_kernel();
	switch(dev)
	{
	case DSP56K_DEV_56001:

		if (test_and_set_bit(0, &dsp56k.in_use)) {
			ret = -EBUSY;
			goto out;
		}

		dsp56k.timeout = TIMEOUT;
		dsp56k.maxio = MAXIO;
		dsp56k.rx_wsize = dsp56k.tx_wsize = 4; 

		DSP56K_TX_INT_OFF;
		DSP56K_RX_INT_OFF;

		/* Zero host flags */
		dsp56k_host_interface.icr &= ~DSP56K_ICR_HF0;
		dsp56k_host_interface.icr &= ~DSP56K_ICR_HF1;

		break;

	default:
		ret = -ENODEV;
	}
out:
	unlock_kernel();
	return ret;
}

static int dsp56k_release(struct inode *inode, struct file *file)
{
	int dev = iminor(inode) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
		clear_bit(0, &dsp56k.in_use);
		break;
	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}

	return 0;
}

static const struct file_operations dsp56k_fops = {
	.owner		= THIS_MODULE,
	.read		= dsp56k_read,
	.write		= dsp56k_write,
	.unlocked_ioctl	= dsp56k_ioctl,
	.open		= dsp56k_open,
	.release	= dsp56k_release,
};


/****** Init and module functions ******/

static char banner[] __initdata = KERN_INFO "DSP56k driver installed\n";

static int __init dsp56k_init_driver(void)
{
	int err = 0;

	if(!MACH_IS_ATARI || !ATARIHW_PRESENT(DSP56K)) {
		printk("DSP56k driver: Hardware not present\n");
		return -ENODEV;
	}

	if(register_chrdev(DSP56K_MAJOR, "dsp56k", &dsp56k_fops)) {
		printk("DSP56k driver: Unable to register driver\n");
		return -ENODEV;
	}
	dsp56k_class = class_create(THIS_MODULE, "dsp56k");
	if (IS_ERR(dsp56k_class)) {
		err = PTR_ERR(dsp56k_class);
		goto out_chrdev;
	}
	device_create(dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
		      "dsp56k");

	printk(banner);
	goto out;

out_chrdev:
	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
out:
	return err;
}
module_init(dsp56k_init_driver);

static void __exit dsp56k_cleanup_driver(void)
{
	device_destroy(dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
	class_destroy(dsp56k_class);
	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
}
module_exit(dsp56k_cleanup_driver);

MODULE_LICENSE("GPL");
MODULE_FIRMWARE("dsp56k/bootstrap.bin");
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