debug.c

linux-2.6.15.6

/*
 *  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 <linux/sysctl.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/debugfs.h>

#include <asm/debug.h>

#define DEBUG_PROLOG_ENTRY -1

#define ALL_AREAS 0 /* copy all debug areas */
#define NO_AREAS  1 /* copy no debug areas */

/* 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_page;                /* act page in given area */
	int    act_entry;               /* last formated entry (offset */
                                        /* relative to beginning of last */
                                        /* formated page) */
	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 timespec *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 pages_per_area,
			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_prolog_pages_fn(debug_info_t * id,
			struct debug_view *view, char *out_buf);
static int debug_input_pages_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_pages_view = {
	"pages",
	&debug_prolog_pages_fn,
	NULL,
	NULL,
	&debug_input_pages_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 dentry *debug_debugfs_root_entry;

/* functions */

/*
 * debug_areas_alloc
 * - Debug areas are implemented as a threedimensonal array:
 *   areas[areanumber][pagenumber][pageoffset]
 */

static debug_entry_t***
debug_areas_alloc(int pages_per_area, int nr_areas)
{
	debug_entry_t*** areas;
	int i,j;

	areas = (debug_entry_t ***) kmalloc(nr_areas *
					sizeof(debug_entry_t**),
					GFP_KERNEL);
	if (!areas)
		goto fail_malloc_areas;
	for (i = 0; i < nr_areas; i++) {
		areas[i] = (debug_entry_t**) kmalloc(pages_per_area *
				sizeof(debug_entry_t*),GFP_KERNEL);
		if (!areas[i]) {
			goto fail_malloc_areas2;
		}
		for(j = 0; j < pages_per_area; j++) {
			areas[i][j] = (debug_entry_t*)kmalloc(PAGE_SIZE,
						GFP_KERNEL);
			if(!areas[i][j]) {
				for(j--; j >=0 ; j--) {
					kfree(areas[i][j]);
				}
				kfree(areas[i]);
				goto fail_malloc_areas2;
			} else {
				memset(areas[i][j],0,PAGE_SIZE);
			}
		}
	}
	return areas;

fail_malloc_areas2:
	for(i--; i >= 0; i--){
		for(j=0; j < pages_per_area;j++){
			kfree(areas[i][j]);
		}
		kfree(areas[i]);
	}
	kfree(areas);
fail_malloc_areas:
	return NULL;

}


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

static debug_info_t*
debug_info_alloc(char *name, int pages_per_area, int nr_areas, int buf_size,
		int level, int mode)
{
	debug_info_t* rc;

	/* alloc everything */

	rc = (debug_info_t*) kmalloc(sizeof(debug_info_t), GFP_KERNEL);
	if(!rc)
		goto fail_malloc_rc;
	rc->active_entries = (int*)kmalloc(nr_areas * sizeof(int), GFP_KERNEL);
	if(!rc->active_entries)
		goto fail_malloc_active_entries;
	memset(rc->active_entries, 0, nr_areas * sizeof(int));
	rc->active_pages = (int*)kmalloc(nr_areas * sizeof(int), GFP_KERNEL);
	if(!rc->active_pages)
		goto fail_malloc_active_pages;
	memset(rc->active_pages, 0, nr_areas * sizeof(int));
	if((mode == ALL_AREAS) && (pages_per_area != 0)){
		rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
		if(!rc->areas)
			goto fail_malloc_areas;
	} else {
		rc->areas = NULL;
	}

	/* initialize members */

	spin_lock_init(&rc->lock);
	rc->pages_per_area = pages_per_area;
	rc->nr_areas       = nr_areas;
	rc->active_area    = 0;
	rc->level          = level;
	rc->buf_size       = buf_size;
	rc->entry_size     = sizeof(debug_entry_t) + buf_size;
	strlcpy(rc->name, name, sizeof(rc->name)-1);
	memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
	memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS *
		sizeof(struct dentry*));
	atomic_set(&(rc->ref_count), 0);

	return rc;

fail_malloc_areas:
	kfree(rc->active_pages);
fail_malloc_active_pages:
	kfree(rc->active_entries);
fail_malloc_active_entries:
	kfree(rc);
fail_malloc_rc:
	return NULL;
}

/*
 * debug_areas_free
 * - free all debug areas
 */

static void
debug_areas_free(debug_info_t* db_info)
{
	int i,j;

	if(!db_info->areas)
		return;
	for (i = 0; i < db_info->nr_areas; i++) {
		for(j = 0; j < db_info->pages_per_area; j++) {
			kfree(db_info->areas[i][j]);
		}
		kfree(db_info->areas[i]);
	}
	kfree(db_info->areas);
	db_info->areas = NULL;
}

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

static void
debug_info_free(debug_info_t* db_info){
	debug_areas_free(db_info);
	kfree(db_info->active_entries);
	kfree(db_info->active_pages);
	kfree(db_info);
}

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

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

        rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
				DEBUG_DEFAULT_LEVEL, ALL_AREAS);
        if(!rc) 
		goto out;

	/* create root directory */
        rc->debugfs_root_entry = debugfs_create_dir(rc->name,
					debug_debugfs_root_entry);

	/* append new element to linked list */
        if (!debug_area_first) {
                /* 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 mode)
{
        int i,j;
        debug_info_t* rc;
        unsigned long flags;

	/* get a consistent copy of the debug areas */
	do {
		rc = debug_info_alloc(in->name, in->pages_per_area,
			in->nr_areas, in->buf_size, in->level, mode);
		spin_lock_irqsave(&in->lock, flags);
		if(!rc)
			goto out;
		/* has something changed in the meantime ? */
		if((rc->pages_per_area == in->pages_per_area) &&
		   (rc->nr_areas == in->nr_areas)) {
			break;
		}
		spin_unlock_irqrestore(&in->lock, flags);
		debug_info_free(rc);
	} while (1);

        if(!rc || (mode == NO_AREAS))
                goto out;

        for(i = 0; i < in->nr_areas; i++){
		for(j = 0; j < in->pages_per_area; j++) {
			memcpy(rc->areas[i][j], in->areas[i][j],PAGE_SIZE);
		}
        }
out:
        spin_unlock_irqrestore(&in->lock, flags);
        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)) {
		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
			if (!db_info->views[i])
				continue;
			debugfs_remove(db_info->debugfs_entries[i]);
		}
		debugfs_remove(db_info->debugfs_root_entry);
		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_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_snap,view,p_info->temp_buf);
		goto out;
	}
	if (!id_snap->areas) /* this is true, if we have a prolog only view */
		goto out;    /* or if 'pages_per_area' is 0 */
	act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area]
				[p_info->act_page] + p_info->act_entry);
                        
	if (act_entry->id.stck == 0LL)
			goto out;  /* empty entry */
	if (view->header_proc)
		len += view->header_proc(id_snap, view, p_info->act_area,
					act_entry, p_info->temp_buf + len);
	if (view->format_proc)
		len += view->format_proc(id_snap, view, p_info->temp_buf + len,
						DEBUG_DATA(act_entry));
out:
        return len;
}

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

static inline int
debug_next_entry(file_private_info_t *p_info)
{
	debug_info_t *id;

	id = p_info->debug_info_snap;
	if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
		p_info->act_entry = 0;
		p_info->act_page  = 0;
		goto out;
	}
	if(!id->areas)
		return 1;
	p_info->act_entry += id->entry_size;
	/* switch to next page, if we reached the end of the page  */
	if (p_info->act_entry > (PAGE_SIZE - id->entry_size)){
		/* next page */
		p_info->act_entry = 0;
		p_info->act_page += 1;
		if((p_info->act_page % id->pages_per_area) == 0) {
			/* next area */
        		p_info->act_area++;
			p_info->act_page=0;
		}
        	if(p_info->act_area >= id->nr_areas)
			return 1;
	}
out:
	return 0;