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Commit 02568396 authored by Pete Zaitcev's avatar Pete Zaitcev Committed by Greg Kroah-Hartman
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[PATCH] usbmon in 2.6.13: peeking into DMA areas 



This code looks at urb->transfer_dma, maps the page and takes the data.
I am looking for volunteers to contribute architectures other than i386
or to develop an architecure-neutral API for it (or point me that it
was done already).

Signed-off-by: default avatarPete Zaitcev <zaitcev@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d0384200

drivers/usb/mon/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
# Makefile for USB Core files and filesystem

#



usbmon-objs	:= mon_main.o mon_stat.o mon_text.o

usbmon-objs	:= mon_main.o mon_stat.o mon_text.o mon_dma.o



# This does not use CONFIG_USB_MON because we want this to use a tristate.

obj-$(CONFIG_USB)	+= usbmon.o

drivers/usb/mon/mon_dma.c

0 → 100644
+55 −0
Original line number Diff line number Diff line 
/*

 * The USB Monitor, inspired by Dave Harding's USBMon.

 *

 * mon_dma.c: Library which snoops on DMA areas.

 *

 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)

 */

#include <linux/kernel.h>

#include <linux/list.h>

#include <linux/highmem.h>

#include <asm/page.h>



#include <linux/usb.h>	/* Only needed for declarations in usb_mon.h */

#include "usb_mon.h"



#ifdef __i386__		/* CONFIG_ARCH_I386 does not exit */

#define MON_HAS_UNMAP 1



#define phys_to_page(phys)	pfn_to_page((phys) >> PAGE_SHIFT)



char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)

{

	struct page *pg;

	unsigned long flags;

	unsigned char *map;

	unsigned char *ptr;



	/*

	 * On i386, a DMA handle is the "physical" address of a page.

	 * In other words, the bus address is equal to physical address.

	 * There is no IOMMU.

	 */

	pg = phys_to_page(dma_addr);



	/*

	 * We are called from hardware IRQs in case of callbacks.

	 * But we can be called from softirq or process context in case

	 * of submissions. In such case, we need to protect KM_IRQ0.

	 */

	local_irq_save(flags);

	map = kmap_atomic(pg, KM_IRQ0);

	ptr = map + (dma_addr & (PAGE_SIZE-1));

	memcpy(dst, ptr, len);

	kunmap_atomic(map, KM_IRQ0);

	local_irq_restore(flags);

	return 0;

}

#endif /* __i386__ */



#ifndef MON_HAS_UNMAP

char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)

{

	return 'D';

}

#endif

drivers/usb/mon/mon_text.c

+17 −18
Original line number Diff line number Diff line
@@ -91,25 +91,11 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb, 
    int len, char ev_type)

{

	int pipe = urb->pipe;

	unsigned char *data;



	/*

	 * The check to see if it's safe to poke at data has an enormous

	 * number of corner cases, but it seems that the following is

	 * more or less safe.

	 *

	 * We do not even try to look transfer_buffer, because it can

	 * contain non-NULL garbage in case the upper level promised to

	 * set DMA for the HCD.

	 */

	if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)

		return 'D';



	if (len <= 0)

		return 'L';



	if ((data = urb->transfer_buffer) == NULL)

		return 'Z';	/* '0' would be not as pretty. */

	if (len >= DATA_MAX)

		len = DATA_MAX;



	/*

	 * Bulk is easy to shortcut reliably.
@@ -126,8 +112,21 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb, 
		}

	}



	if (len >= DATA_MAX)

		len = DATA_MAX;

	/*

	 * The check to see if it's safe to poke at data has an enormous

	 * number of corner cases, but it seems that the following is

	 * more or less safe.

	 *

	 * We do not even try to look transfer_buffer, because it can

	 * contain non-NULL garbage in case the upper level promised to

	 * set DMA for the HCD.

	 */

	if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)

		return mon_dmapeek(ep->data, urb->transfer_dma, len);



	if (urb->transfer_buffer == NULL)

		return 'Z';	/* '0' would be not as pretty. */



	memcpy(ep->data, urb->transfer_buffer, len);

	return 0;

}

drivers/usb/mon/usb_mon.h

+4 −0
Original line number Diff line number Diff line
@@ -45,6 +45,10 @@ struct mon_reader { 
void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r);

void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r);



/*

 */

extern char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len);



extern struct semaphore mon_lock;



extern struct file_operations mon_fops_text;