Commit 02568396 authored by Pete Zaitcev's avatar Pete Zaitcev Committed by Greg Kroah-Hartman

[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
......@@ -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
/*
* 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
......@@ -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;
}
......
......@@ -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;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment