debug.c

优龙2410linux2.6.8内核源代码

/*
 *  arch/s390/kernel/debug.c
 *   S/390 debug facility
 *
 *    Copyright (C) 1999, 2000 IBM Deutschland Entwicklung GmbH,
 *                             IBM Corporation
 *    Author(s): Michael Holzheu ([e-mail]),
 *               Holger Smolinski ([e-mail])
 *
 *    Bugreports to: <[e-mail]>
 */

#include <linux/config.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>

#include <linux/module.h>
#include <linux/init.h>

#include <asm/debug.h>

#define MIN(a,b) (((a)<(b))?(a):(b))
#define DEBUG_PROLOG_ENTRY -1

/* typedefs */

typedef struct file_private_info {
	loff_t offset;			/* offset of last read in file */
	int    act_area;                /* number of last formated area */
	int    act_entry;               /* last formated entry (offset */
                                        /* relative to beginning of last */
                                        /* formated area) */ 
	size_t act_entry_offset;        /* up to this offset we copied */
					/* in last read the last formated */
					/* entry to userland */
	char   temp_buf[2048];		/* buffer for output */
	debug_info_t *debug_info_org;   /* original debug information */
	debug_info_t *debug_info_snap;	/* snapshot of debug information */
	struct debug_view *view;	/* used view of debug info */
} file_private_info_t;

typedef struct
{
	char *string;
	/* 
	 * This assumes that all args are converted into longs 
	 * on L/390 this is the case for all types of parameter 
	 * except of floats, and long long (32 bit) 
         *
         */
	long args[0];
} debug_sprintf_entry_t;


extern void tod_to_timeval(uint64_t todval, struct timeval *xtime);

/* internal function prototyes */

static int debug_init(void);
static ssize_t debug_output(struct file *file, char __user *user_buf,
			    size_t user_len, loff_t * offset);
static ssize_t debug_input(struct file *file, const char __user *user_buf,
			   size_t user_len, loff_t * offset);
static int debug_open(struct inode *inode, struct file *file);
static int debug_close(struct inode *inode, struct file *file);
static debug_info_t*  debug_info_create(char *name, int page_order, int nr_areas, int buf_size);
static void debug_info_get(debug_info_t *);
static void debug_info_put(debug_info_t *);
static int debug_prolog_level_fn(debug_info_t * id,
				 struct debug_view *view, char *out_buf);
static int debug_input_level_fn(debug_info_t * id, struct debug_view *view,
				struct file *file, const char __user *user_buf,
				size_t user_buf_size, loff_t * offset);
static int debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
                                struct file *file, const char __user *user_buf,
                                size_t user_buf_size, loff_t * offset);
static int debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
                                char *out_buf, const char *in_buf);
static int debug_raw_format_fn(debug_info_t * id,
				 struct debug_view *view, char *out_buf,
				 const char *in_buf);
static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
                         int area, debug_entry_t * entry, char *out_buf);

static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
				   char *out_buf, debug_sprintf_entry_t *curr_event);

/* globals */

struct debug_view debug_raw_view = {
	"raw",
	NULL,
	&debug_raw_header_fn,
	&debug_raw_format_fn,
	NULL,
	NULL
};

struct debug_view debug_hex_ascii_view = {
	"hex_ascii",
	NULL,
	&debug_dflt_header_fn,
	&debug_hex_ascii_format_fn,
	NULL,
	NULL
};

struct debug_view debug_level_view = {
	"level",
	&debug_prolog_level_fn,
	NULL,
	NULL,
	&debug_input_level_fn,
	NULL
};

struct debug_view debug_flush_view = {
        "flush",
        NULL,
        NULL,
        NULL,
        &debug_input_flush_fn,
        NULL
};

struct debug_view debug_sprintf_view = {
	"sprintf",
	NULL,
	&debug_dflt_header_fn,
	(debug_format_proc_t*)&debug_sprintf_format_fn,
	NULL,
	NULL
};


unsigned int debug_feature_version = __DEBUG_FEATURE_VERSION;

/* static globals */

static debug_info_t *debug_area_first = NULL;
static debug_info_t *debug_area_last = NULL;
DECLARE_MUTEX(debug_lock);

static int initialized;

static struct file_operations debug_file_ops = {
	.owner	 = THIS_MODULE,
	.read    = debug_output,
	.write   = debug_input,	
	.open    = debug_open,
	.release = debug_close,
};

static struct proc_dir_entry *debug_proc_root_entry;

/* functions */

/*
 * debug_info_alloc
 * - alloc new debug-info
 */

static debug_info_t*  debug_info_alloc(char *name, int page_order,
                                        int nr_areas, int buf_size)
{
	debug_info_t* rc;
	int i;

	/* alloc everything */

	rc = (debug_info_t*) kmalloc(sizeof(debug_info_t), GFP_ATOMIC);
	if(!rc)
		goto fail_malloc_rc;
	rc->active_entry = (int*)kmalloc(nr_areas * sizeof(int), GFP_ATOMIC);
	if(!rc->active_entry)
		goto fail_malloc_active_entry;
	memset(rc->active_entry, 0, nr_areas * sizeof(int));
	rc->areas = (debug_entry_t **) kmalloc(nr_areas *
						sizeof(debug_entry_t *),
						GFP_ATOMIC);
	if (!rc->areas)
		goto fail_malloc_areas;
	for (i = 0; i < nr_areas; i++) {
		rc->areas[i] = (debug_entry_t *) __get_free_pages(GFP_ATOMIC,
								page_order);
		if (!rc->areas[i]) {
			for (i--; i >= 0; i--) {
				free_pages((unsigned long) rc->areas[i],
						page_order);
			}
			goto fail_malloc_areas2;
		} else {
			memset(rc->areas[i], 0, PAGE_SIZE << page_order);
		}
	}

	/* initialize members */

	spin_lock_init(&rc->lock);
	rc->page_order  = page_order;
	rc->nr_areas    = nr_areas;
	rc->active_area = 0;
	rc->level       = DEBUG_DEFAULT_LEVEL;
	rc->buf_size    = buf_size;
	rc->entry_size  = sizeof(debug_entry_t) + buf_size;
	strlcpy(rc->name, name, sizeof(rc->name));
	memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
#ifdef CONFIG_PROC_FS
	memset(rc->proc_entries, 0 ,DEBUG_MAX_VIEWS *
		sizeof(struct proc_dir_entry*));
#endif /* CONFIG_PROC_FS */
	atomic_set(&(rc->ref_count), 0);

	return rc;

fail_malloc_areas2:
	kfree(rc->areas);
fail_malloc_areas:
	kfree(rc->active_entry);
fail_malloc_active_entry:
	kfree(rc);
fail_malloc_rc:
	return NULL;
}

/*
 * debug_info_free
 * - free memory debug-info
 */

static void debug_info_free(debug_info_t* db_info){
	int i;
	for (i = 0; i < db_info->nr_areas; i++) {
		free_pages((unsigned long) db_info->areas[i],
		db_info->page_order);
	}
	kfree(db_info->areas);
	kfree(db_info->active_entry);
	kfree(db_info);
}

/*
 * debug_info_create
 * - create new debug-info
 */

static debug_info_t*  debug_info_create(char *name, int page_order, 
                                        int nr_areas, int buf_size)
{
	debug_info_t* rc;

        rc = debug_info_alloc(name, page_order, nr_areas, buf_size);
        if(!rc) 
		goto out;


	/* create proc rood directory */
        rc->proc_root_entry = proc_mkdir(rc->name, debug_proc_root_entry);

	/* append new element to linked list */
        if (debug_area_first == NULL) {
                /* first element in list */
                debug_area_first = rc;
                rc->prev = NULL;
        } else {
                /* append element to end of list */
                debug_area_last->next = rc;
                rc->prev = debug_area_last;
        }
        debug_area_last = rc;
        rc->next = NULL;

	debug_info_get(rc);
out:
	return rc;
}

/*
 * debug_info_copy
 * - copy debug-info
 */

static debug_info_t* debug_info_copy(debug_info_t* in)
{
        int i;
        debug_info_t* rc;
        rc = debug_info_alloc(in->name, in->page_order, 
                                in->nr_areas, in->buf_size);
        if(!rc)
                goto out;

        for(i = 0; i < in->nr_areas; i++){
                memcpy(rc->areas[i],in->areas[i], PAGE_SIZE << in->page_order);
        }
out:
        return rc;
}

/*
 * debug_info_get
 * - increments reference count for debug-info
 */

static void debug_info_get(debug_info_t * db_info)
{
	if (db_info)
		atomic_inc(&db_info->ref_count);
}

/*
 * debug_info_put:
 * - decreases reference count for debug-info and frees it if necessary
 */

static void debug_info_put(debug_info_t *db_info)
{
	int i;

	if (!db_info)
		return;
	if (atomic_dec_and_test(&db_info->ref_count)) {
#ifdef DEBUG
		printk(KERN_INFO "debug: freeing debug area %p (%s)\n",
		       db_info, db_info->name);
#endif
		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
			if (db_info->views[i] == NULL)
				continue;
#ifdef CONFIG_PROC_FS
			remove_proc_entry(db_info->proc_entries[i]->name,
					  db_info->proc_root_entry);
#endif
		}
#ifdef CONFIG_PROC_FS
		remove_proc_entry(db_info->proc_root_entry->name,
				  debug_proc_root_entry);
#endif
		if(db_info == debug_area_first)
			debug_area_first = db_info->next;
		if(db_info == debug_area_last)
			debug_area_last = db_info->prev;
		if(db_info->prev) db_info->prev->next = db_info->next;
		if(db_info->next) db_info->next->prev = db_info->prev;
		debug_info_free(db_info);
	}
}

/*
 * debug_format_entry:
 * - format one debug entry and return size of formated data
 */

static int debug_format_entry(file_private_info_t *p_info)
{
	debug_info_t *id_org    = p_info->debug_info_org;
	debug_info_t *id_snap   = p_info->debug_info_snap;
	struct debug_view *view = p_info->view;
	debug_entry_t *act_entry;
	size_t len = 0;
	if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
		/* print prolog */
        	if (view->prolog_proc)
                	len += view->prolog_proc(id_org, view,p_info->temp_buf);
		goto out;
	}

	act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area] +
					p_info->act_entry);
                        
	if (act_entry->id.stck == 0LL)
			goto out;  /* empty entry */
	if (view->header_proc)
		len += view->header_proc(id_org, view, p_info->act_area, 
					act_entry, p_info->temp_buf + len);
	if (view->format_proc)
		len += view->format_proc(id_org, view, p_info->temp_buf + len,
						DEBUG_DATA(act_entry));
      out:
        return len;
}

/*
 * debug_next_entry:
 * - goto next entry in p_info
 */

extern inline int debug_next_entry(file_private_info_t *p_info)
{
	debug_info_t *id = p_info->debug_info_snap;
	if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
		p_info->act_entry = 0;
		goto out;
	}
	if ((p_info->act_entry += id->entry_size)
		> ((PAGE_SIZE << (id->page_order)) 
		- id->entry_size)){

		/* next area */
		p_info->act_entry = 0;
        	p_info->act_area++;
        	if(p_info->act_area >= id->nr_areas)
			return 1;
	}
out:
	return 0;	
}

/*
 * debug_output:
 * - called for user read()
 * - copies formated debug entries to the user buffer
 */

static ssize_t debug_output(struct file *file,		/* file descriptor */
			    char __user *user_buf,	/* user buffer */
			    size_t  len,		/* length of buffer */
			    loff_t *offset)	      /* offset in the file */
{
	size_t count = 0;
	size_t entry_offset, size = 0;
	file_private_info_t *p_info;

	p_info = ((file_private_info_t *) file->private_data);
	if (*offset != p_info->offset) 
		return -EPIPE;
	if(p_info->act_area >= p_info->debug_info_snap->nr_areas)
		return 0;

	entry_offset = p_info->act_entry_offset;

	while(count < len){
		size = debug_format_entry(p_info);
		size = MIN((len - count), (size - entry_offset));

		if(size){
			if (copy_to_user(user_buf + count, 
					p_info->temp_buf + entry_offset, size))
			return -EFAULT;
		}
		count += size;
		entry_offset = 0;
		if(count != len)
			if(debug_next_entry(p_info)) 
				goto out;
	}
out:
	p_info->offset           = *offset + count;
	p_info->act_entry_offset = size;	
	*offset = p_info->offset;
	return count;
}

/*
 * debug_input:
 * - called for user write()
 * - calls input function of view
 */

static ssize_t debug_input(struct file *file,
			   const char __user *user_buf, size_t length,
			   loff_t *offset)
{
	int rc = 0;
	file_private_info_t *p_info;

	down(&debug_lock);
	p_info = ((file_private_info_t *) file->private_data);
	if (p_info->view->input_proc)
		rc = p_info->view->input_proc(p_info->debug_info_org,
					      p_info->view, file, user_buf,
					      length, offset);
	else
		rc = -EPERM;
	up(&debug_lock);
	return rc;		/* number of input characters */
}

/*
 * debug_open:
 * - called for user open()
 * - copies formated output to private_data area of the file
 *   handle
 */

static int debug_open(struct inode *inode, struct file *file)
{
	int i = 0, rc = 0;
	file_private_info_t *p_info;
	debug_info_t *debug_info, *debug_info_snapshot;

#ifdef DEBUG
	printk("debug_open\n");
#endif
	down(&debug_lock);

	/* find debug log and view */

	debug_info = debug_area_first;
	while(debug_info != NULL){
		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
			if (debug_info->views[i] == NULL)
				continue;
			else if (debug_info->proc_entries[i] ==
				 PDE(file->f_dentry->d_inode)) {
				goto found;	/* found view ! */
			}
		}
		debug_info = debug_info->next;
	}
	/* no entry found */
	rc = -EINVAL;
	goto out;

      found:

	/* make snapshot of current debug areas to get it consistent */

	debug_info_snapshot = debug_info_copy(debug_info);

	if(!debug_info_snapshot){
#ifdef DEBUG
		printk(KERN_ERR "debug_open: debug_info_copy failed (out of mem)\n");
#endif
		rc = -ENOMEM;
		goto out;
	}

	if ((file->private_data =
	     kmalloc(sizeof(file_private_info_t), GFP_ATOMIC)) == 0) {
#ifdef DEBUG
		printk(KERN_ERR "debug_open: kmalloc failed\n");
#endif
		debug_info_free(debug_info_snapshot);	
		rc = -ENOMEM;
		goto out;
	}
	p_info = (file_private_info_t *) file->private_data;
	p_info->offset = 0;
	p_info->debug_info_snap = debug_info_snapshot;
	p_info->debug_info_org  = debug_info;
	p_info->view = debug_info->views[i];
	p_info->act_area = 0;
	p_info->act_entry = DEBUG_PROLOG_ENTRY;
	p_info->act_entry_offset = 0;

	debug_info_get(debug_info);

      out:
	up(&debug_lock);
	return rc;
}

/*
 * debug_close:
 * - called for user close()
 * - deletes  private_data area of the file handle
 */

static int debug_close(struct inode *inode, struct file *file)
{
	file_private_info_t *p_info;
#ifdef DEBUG
	printk("debug_close\n");
#endif
	p_info = (file_private_info_t *) file->private_data;
	debug_info_free(p_info->debug_info_snap);
	debug_info_put(p_info->debug_info_org);
	kfree(file->private_data);
	return 0;		/* success */
}

/*
 * debug_register:
 * - creates and initializes debug area for the caller
 * - returns handle for debug area
 */

debug_info_t *debug_register
    (char *name, int page_order, int nr_areas, int buf_size) 
{
	debug_info_t *rc = NULL;

	if (!initialized)
		BUG();
	down(&debug_lock);

        /* create new debug_info */

	rc = debug_info_create(name, page_order, nr_areas, buf_size);
	if(!rc) 
		goto out;
	debug_register_view(rc, &debug_level_view);
        debug_register_view(rc, &debug_flush_view);
#ifdef DEBUG
	printk(KERN_INFO
	       "debug: reserved %d areas of %d pages for debugging %s\n",
	       nr_areas, 1 << page_order, rc->name);
#endif
      out:
        if (rc == NULL){
		printk(KERN_ERR "debug: debug_register failed for %s\n",name);
        }