diff options
Diffstat (limited to 'arch/s390/kernel/debug.c')
| -rw-r--r-- | arch/s390/kernel/debug.c | 1574 |
1 files changed, 1574 insertions, 0 deletions
diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c new file mode 100644 index 0000000000..a85e0c3e70 --- /dev/null +++ b/arch/s390/kernel/debug.c @@ -0,0 +1,1574 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * S/390 debug facility + * + * Copyright IBM Corp. 1999, 2020 + * + * Author(s): Michael Holzheu (holzheu@de.ibm.com), + * Holger Smolinski (Holger.Smolinski@de.ibm.com) + * + * Bugreports to: <Linux390@de.ibm.com> + */ + +#define KMSG_COMPONENT "s390dbf" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/stddef.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/string.h> +#include <linux/sysctl.h> +#include <linux/uaccess.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/minmax.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[]; +} debug_sprintf_entry_t; + +/* 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(const char *name, int pages_per_area, + int nr_areas, int buf_size, umode_t mode); +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_sprintf_format_fn(debug_info_t *id, struct debug_view *view, + char *out_buf, const char *inbuf); +static void debug_areas_swap(debug_info_t *a, debug_info_t *b); +static void debug_events_append(debug_info_t *dest, debug_info_t *src); + +/* globals */ + +struct debug_view debug_hex_ascii_view = { + "hex_ascii", + NULL, + &debug_dflt_header_fn, + &debug_hex_ascii_format_fn, + NULL, + NULL +}; +EXPORT_SYMBOL(debug_hex_ascii_view); + +static struct debug_view debug_level_view = { + "level", + &debug_prolog_level_fn, + NULL, + NULL, + &debug_input_level_fn, + NULL +}; + +static struct debug_view debug_pages_view = { + "pages", + &debug_prolog_pages_fn, + NULL, + NULL, + &debug_input_pages_fn, + NULL +}; + +static 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_sprintf_format_fn, + NULL, + NULL +}; +EXPORT_SYMBOL(debug_sprintf_view); + +/* used by dump analysis tools to determine version of debug feature */ +static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION; + +/* static globals */ + +static debug_info_t *debug_area_first; +static debug_info_t *debug_area_last; +static DEFINE_MUTEX(debug_mutex); + +static int initialized; +static int debug_critical; + +static const struct file_operations debug_file_ops = { + .owner = THIS_MODULE, + .read = debug_output, + .write = debug_input, + .open = debug_open, + .release = debug_close, + .llseek = no_llseek, +}; + +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 = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL); + if (!areas) + goto fail_malloc_areas; + for (i = 0; i < nr_areas; i++) { + /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */ + areas[i] = kmalloc_array(pages_per_area, + sizeof(debug_entry_t *), + GFP_KERNEL | __GFP_NOWARN); + if (!areas[i]) + goto fail_malloc_areas2; + for (j = 0; j < pages_per_area; j++) { + areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!areas[i][j]) { + for (j--; j >= 0 ; j--) + kfree(areas[i][j]); + kfree(areas[i]); + goto fail_malloc_areas2; + } + } + } + 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(const char *name, int pages_per_area, + int nr_areas, int buf_size, int level, + int mode) +{ + debug_info_t *rc; + + /* alloc everything */ + rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL); + if (!rc) + goto fail_malloc_rc; + rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL); + if (!rc->active_entries) + goto fail_malloc_active_entries; + rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL); + if (!rc->active_pages) + goto fail_malloc_active_pages; + 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; + strscpy(rc->name, name, sizeof(rc->name)); + memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *)); + memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *)); + refcount_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(const char *name, int pages_per_area, + int nr_areas, int buf_size, umode_t mode) +{ + 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; + + rc->mode = mode & ~S_IFMT; + refcount_set(&rc->ref_count, 1); +out: + return rc; +} + +/* + * debug_info_copy + * - copy debug-info + */ +static debug_info_t *debug_info_copy(debug_info_t *in, int mode) +{ + unsigned long flags; + debug_info_t *rc; + int i, j; + + /* 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 (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) + refcount_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) +{ + if (!db_info) + return; + if (refcount_dec_and_test(&db_info->ref_count)) + 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->clock == 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; +} + +/* + * 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; + 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) { + int formatted_line_residue; + int formatted_line_size; + int user_buf_residue; + size_t copy_size; + + formatted_line_size = debug_format_entry(p_info); + formatted_line_residue = formatted_line_size - entry_offset; + user_buf_residue = len-count; + copy_size = min(user_buf_residue, formatted_line_residue); + if (copy_size) { + if (copy_to_user(user_buf + count, p_info->temp_buf + + entry_offset, copy_size)) + return -EFAULT; + count += copy_size; + entry_offset += copy_size; + } + if (copy_size == formatted_line_residue) { + entry_offset = 0; + if (debug_next_entry(p_info)) + goto out; + } + } +out: + p_info->offset = *offset + count; + p_info->act_entry_offset = entry_offset; + *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) +{ + file_private_info_t *p_info; + int rc = 0; + + mutex_lock(&debug_mutex); + 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; + } + mutex_unlock(&debug_mutex); + 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) +{ + debug_info_t *debug_info, *debug_info_snapshot; + file_private_info_t *p_info; + int i, rc = 0; + + mutex_lock(&debug_mutex); + debug_info = file_inode(file)->i_private; + /* find debug view */ + for (i = 0; i < DEBUG_MAX_VIEWS; i++) { + if (!debug_info->views[i]) + continue; + else if (debug_info->debugfs_entries[i] == file->f_path.dentry) + goto found; /* found view ! */ + } + /* no entry found */ + rc = -EINVAL; + goto out; + +found: + + /* Make snapshot of current debug areas to get it consistent. */ + /* To copy all the areas is only needed, if we have a view which */ + /* formats the debug areas. */ + + if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc) + debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS); + else + debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS); + + if (!debug_info_snapshot) { + rc = -ENOMEM; + goto out; + } + p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL); + if (!p_info) { + debug_info_free(debug_info_snapshot); + rc = -ENOMEM; + goto out; + } + 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_page = 0; + p_info->act_entry = DEBUG_PROLOG_ENTRY; + p_info->act_entry_offset = 0; + file->private_data = p_info; + debug_info_get(debug_info); + nonseekable_open(inode, file); +out: + mutex_unlock(&debug_mutex); + 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; + + p_info = (file_private_info_t *) file->private_data; + if (p_info->debug_info_snap) + debug_info_free(p_info->debug_info_snap); + debug_info_put(p_info->debug_info_org); + kfree(file->private_data); + return 0; /* success */ +} + +/* Create debugfs entries and add to internal list. */ +static void _debug_register(debug_info_t *id) +{ + /* create root directory */ + id->debugfs_root_entry = debugfs_create_dir(id->name, + debug_debugfs_root_entry); + + /* append new element to linked list */ + if (!debug_area_first) { + /* first element in list */ + debug_area_first = id; + id->prev = NULL; + } else { + /* append element to end of list */ + debug_area_last->next = id; + id->prev = debug_area_last; + } + debug_area_last = id; + id->next = NULL; + + debug_register_view(id, &debug_level_view); + debug_register_view(id, &debug_flush_view); + debug_register_view(id, &debug_pages_view); +} + +/** + * debug_register_mode() - creates and initializes debug area. + * + * @name: Name of debug log (e.g. used for debugfs entry) + * @pages_per_area: Number of pages, which will be allocated per area + * @nr_areas: Number of debug areas + * @buf_size: Size of data area in each debug entry + * @mode: File mode for debugfs files. E.g. S_IRWXUGO + * @uid: User ID for debugfs files. Currently only 0 is supported. + * @gid: Group ID for debugfs files. Currently only 0 is supported. + * + * Return: + * - Handle for generated debug area + * - %NULL if register failed + * + * Allocates memory for a debug log. + * Must not be called within an interrupt handler. + */ +debug_info_t *debug_register_mode(const char *name, int pages_per_area, + int nr_areas, int buf_size, umode_t mode, + uid_t uid, gid_t gid) +{ + debug_info_t *rc = NULL; + + /* Since debugfs currently does not support uid/gid other than root, */ + /* we do not allow gid/uid != 0 until we get support for that. */ + if ((uid != 0) || (gid != 0)) + pr_warn("Root becomes the owner of all s390dbf files in sysfs\n"); + BUG_ON(!initialized); + + /* create new debug_info */ + rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode); + if (rc) { + mutex_lock(&debug_mutex); + _debug_register(rc); + mutex_unlock(&debug_mutex); + } else { + pr_err("Registering debug feature %s failed\n", name); + } + return rc; +} +EXPORT_SYMBOL(debug_register_mode); + +/** + * debug_register() - creates and initializes debug area with default file mode. + * + * @name: Name of debug log (e.g. used for debugfs entry) + * @pages_per_area: Number of pages, which will be allocated per area + * @nr_areas: Number of debug areas + * @buf_size: Size of data area in each debug entry + * + * Return: + * - Handle for generated debug area + * - %NULL if register failed + * + * Allocates memory for a debug log. + * The debugfs file mode access permissions are read and write for user. + * Must not be called within an interrupt handler. + */ +debug_info_t *debug_register(const char *name, int pages_per_area, + int nr_areas, int buf_size) +{ + return debug_register_mode(name, pages_per_area, nr_areas, buf_size, + S_IRUSR | S_IWUSR, 0, 0); +} +EXPORT_SYMBOL(debug_register); + +/** + * debug_register_static() - registers a static debug area + * + * @id: Handle for static debug area + * @pages_per_area: Number of pages per area + * @nr_areas: Number of debug areas + * + * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO. + * + * Note: This function is called automatically via an initcall generated by + * DEFINE_STATIC_DEBUG_INFO. + */ +void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas) +{ + unsigned long flags; + debug_info_t *copy; + + if (!initialized) { + pr_err("Tried to register debug feature %s too early\n", + id->name); + return; + } + + copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size, + id->level, ALL_AREAS); + if (!copy) { + pr_err("Registering debug feature %s failed\n", id->name); + + /* Clear pointers to prevent tracing into released initdata. */ + spin_lock_irqsave(&id->lock, flags); + id->areas = NULL; + id->active_pages = NULL; + id->active_entries = NULL; + spin_unlock_irqrestore(&id->lock, flags); + + return; + } + + /* Replace static trace area with dynamic copy. */ + spin_lock_irqsave(&id->lock, flags); + debug_events_append(copy, id); + debug_areas_swap(id, copy); + spin_unlock_irqrestore(&id->lock, flags); + + /* Clear pointers to initdata and discard copy. */ + copy->areas = NULL; + copy->active_pages = NULL; + copy->active_entries = NULL; + debug_info_free(copy); + + mutex_lock(&debug_mutex); + _debug_register(id); + mutex_unlock(&debug_mutex); +} + +/* Remove debugfs entries and remove from internal list. */ +static void _debug_unregister(debug_info_t *id) +{ + int i; + + for (i = 0; i < DEBUG_MAX_VIEWS; i++) { + if (!id->views[i]) + continue; + debugfs_remove(id->debugfs_entries[i]); + } + debugfs_remove(id->debugfs_root_entry); + if (id == debug_area_first) + debug_area_first = id->next; + if (id == debug_area_last) + debug_area_last = id->prev; + if (id->prev) + id->prev->next = id->next; + if (id->next) + id->next->prev = id->prev; +} + +/** + * debug_unregister() - give back debug area. + * + * @id: handle for debug log + * + * Return: + * none + */ +void debug_unregister(debug_info_t *id) +{ + if (!id) + return; + mutex_lock(&debug_mutex); + _debug_unregister(id); + mutex_unlock(&debug_mutex); + + debug_info_put(id); +} +EXPORT_SYMBOL(debug_unregister); + +/* + * debug_set_size: + * - set area size (number of pages) and number of areas + */ +static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area) +{ + debug_info_t *new_id; + unsigned long flags; + + if (!id || (nr_areas <= 0) || (pages_per_area < 0)) + return -EINVAL; + + new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size, + id->level, ALL_AREAS); + if (!new_id) { + pr_info("Allocating memory for %i pages failed\n", + pages_per_area); + return -ENOMEM; + } + + spin_lock_irqsave(&id->lock, flags); + debug_events_append(new_id, id); + debug_areas_swap(new_id, id); + debug_info_free(new_id); + spin_unlock_irqrestore(&id->lock, flags); + pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area); + + return 0; +} + +/** + * debug_set_level() - Sets new actual debug level if new_level is valid. + * + * @id: handle for debug log + * @new_level: new debug level + * + * Return: + * none + */ +void debug_set_level(debug_info_t *id, int new_level) +{ + unsigned long flags; + + if (!id) + return; + + if (new_level == DEBUG_OFF_LEVEL) { + pr_info("%s: switched off\n", id->name); + } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) { + pr_info("%s: level %i is out of range (%i - %i)\n", + id->name, new_level, 0, DEBUG_MAX_LEVEL); + return; + } + + spin_lock_irqsave(&id->lock, flags); + id->level = new_level; + spin_unlock_irqrestore(&id->lock, flags); +} +EXPORT_SYMBOL(debug_set_level); + +/* + * proceed_active_entry: + * - set active entry to next in the ring buffer + */ +static inline void proceed_active_entry(debug_info_t *id) +{ + if ((id->active_entries[id->active_area] += id->entry_size) + > (PAGE_SIZE - id->entry_size)) { + id->active_entries[id->active_area] = 0; + id->active_pages[id->active_area] = + (id->active_pages[id->active_area] + 1) % + id->pages_per_area; + } +} + +/* + * proceed_active_area: + * - set active area to next in the ring buffer + */ +static inline void proceed_active_area(debug_info_t *id) +{ + id->active_area++; + id->active_area = id->active_area % id->nr_areas; +} + +/* + * get_active_entry: + */ +static inline debug_entry_t *get_active_entry(debug_info_t *id) +{ + return (debug_entry_t *) (((char *) id->areas[id->active_area] + [id->active_pages[id->active_area]]) + + id->active_entries[id->active_area]); +} + +/* Swap debug areas of a and b. */ +static void debug_areas_swap(debug_info_t *a, debug_info_t *b) +{ + swap(a->nr_areas, b->nr_areas); + swap(a->pages_per_area, b->pages_per_area); + swap(a->areas, b->areas); + swap(a->active_area, b->active_area); + swap(a->active_pages, b->active_pages); + swap(a->active_entries, b->active_entries); +} + +/* Append all debug events in active area from source to destination log. */ +static void debug_events_append(debug_info_t *dest, debug_info_t *src) +{ + debug_entry_t *from, *to, *last; + + if (!src->areas || !dest->areas) + return; + + /* Loop over all entries in src, starting with oldest. */ + from = get_active_entry(src); + last = from; + do { + if (from->clock != 0LL) { + to = get_active_entry(dest); + memset(to, 0, dest->entry_size); + memcpy(to, from, min(src->entry_size, + dest->entry_size)); + proceed_active_entry(dest); + } + + proceed_active_entry(src); + from = get_active_entry(src); + } while (from != last); +} + +/* + * debug_finish_entry: + * - set timestamp, caller address, cpu number etc. + */ + +static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active, + int level, int exception) +{ + unsigned long timestamp; + union tod_clock clk; + + store_tod_clock_ext(&clk); + timestamp = clk.us; + timestamp -= TOD_UNIX_EPOCH >> 12; + active->clock = timestamp; + active->cpu = smp_processor_id(); + active->caller = __builtin_return_address(0); + active->exception = exception; + active->level = level; + proceed_active_entry(id); + if (exception) + proceed_active_area(id); +} + +static int debug_stoppable = 1; +static int debug_active = 1; + +#define CTL_S390DBF_STOPPABLE 5678 +#define CTL_S390DBF_ACTIVE 5679 + +/* + * proc handler for the running debug_active sysctl + * always allow read, allow write only if debug_stoppable is set or + * if debug_active is already off + */ +static int s390dbf_procactive(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + if (!write || debug_stoppable || !debug_active) + return proc_dointvec(table, write, buffer, lenp, ppos); + else + return 0; +} + +static struct ctl_table s390dbf_table[] = { + { + .procname = "debug_stoppable", + .data = &debug_stoppable, + .maxlen = sizeof(int), + .mode = S_IRUGO | S_IWUSR, + .proc_handler = proc_dointvec, + }, + { + .procname = "debug_active", + .data = &debug_active, + .maxlen = sizeof(int), + .mode = S_IRUGO | S_IWUSR, + .proc_handler = s390dbf_procactive, + }, + { } +}; + +static struct ctl_table_header *s390dbf_sysctl_header; + +/** + * debug_stop_all() - stops the debug feature if stopping is allowed. + * + * Return: + * - none + * + * Currently used in case of a kernel oops. + */ +void debug_stop_all(void) +{ + if (debug_stoppable) + debug_active = 0; +} +EXPORT_SYMBOL(debug_stop_all); + +/** + * debug_set_critical() - event/exception functions try lock instead of spin. + * + * Return: + * - none + * + * Currently used in case of stopping all CPUs but the current one. + * Once in this state, functions to write a debug entry for an + * event or exception no longer spin on the debug area lock, + * but only try to get it and fail if they do not get the lock. + */ +void debug_set_critical(void) +{ + debug_critical = 1; +} + +/* + * debug_event_common: + * - write debug entry with given size + */ +debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf, + int len) +{ + debug_entry_t *active; + unsigned long flags; + + if (!debug_active || !id->areas) + return NULL; + if (debug_critical) { + if (!spin_trylock_irqsave(&id->lock, flags)) + return NULL; + } else { + spin_lock_irqsave(&id->lock, flags); + } + do { + active = get_active_entry(id); + memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size)); + if (len < id->buf_size) + memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len); + debug_finish_entry(id, active, level, 0); + len -= id->buf_size; + buf += id->buf_size; + } while (len > 0); + + spin_unlock_irqrestore(&id->lock, flags); + return active; +} +EXPORT_SYMBOL(debug_event_common); + +/* + * debug_exception_common: + * - write debug entry with given size and switch to next debug area + */ +debug_entry_t *debug_exception_common(debug_info_t *id, int level, + const void *buf, int len) +{ + debug_entry_t *active; + unsigned long flags; + + if (!debug_active || !id->areas) + return NULL; + if (debug_critical) { + if (!spin_trylock_irqsave(&id->lock, flags)) + return NULL; + } else { + spin_lock_irqsave(&id->lock, flags); + } + do { + active = get_active_entry(id); + memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size)); + if (len < id->buf_size) + memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len); + debug_finish_entry(id, active, level, len <= id->buf_size); + len -= id->buf_size; + buf += id->buf_size; + } while (len > 0); + + spin_unlock_irqrestore(&id->lock, flags); + return active; +} +EXPORT_SYMBOL(debug_exception_common); + +/* + * counts arguments in format string for sprintf view + */ +static inline int debug_count_numargs(char *string) +{ + int numargs = 0; + + while (*string) { + if (*string++ == '%') + numargs++; + } + return numargs; +} + +/* + * debug_sprintf_event: + */ +debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...) +{ + debug_sprintf_entry_t *curr_event; + debug_entry_t *active; + unsigned long flags; + int numargs, idx; + va_list ap; + + if (!debug_active || !id->areas) + return NULL; + numargs = debug_count_numargs(string); + + if (debug_critical) { + if (!spin_trylock_irqsave(&id->lock, flags)) + return NULL; + } else { + spin_lock_irqsave(&id->lock, flags); + } + active = get_active_entry(id); + curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active); + va_start(ap, string); + curr_event->string = string; + for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++) + curr_event->args[idx] = va_arg(ap, long); + va_end(ap); + debug_finish_entry(id, active, level, 0); + spin_unlock_irqrestore(&id->lock, flags); + + return active; +} +EXPORT_SYMBOL(__debug_sprintf_event); + +/* + * debug_sprintf_exception: + */ +debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...) +{ + debug_sprintf_entry_t *curr_event; + debug_entry_t *active; + unsigned long flags; + int numargs, idx; + va_list ap; + + if (!debug_active || !id->areas) + return NULL; + + numargs = debug_count_numargs(string); + + if (debug_critical) { + if (!spin_trylock_irqsave(&id->lock, flags)) + return NULL; + } else { + spin_lock_irqsave(&id->lock, flags); + } + active = get_active_entry(id); + curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active); + va_start(ap, string); + curr_event->string = string; + for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++) + curr_event->args[idx] = va_arg(ap, long); + va_end(ap); + debug_finish_entry(id, active, level, 1); + spin_unlock_irqrestore(&id->lock, flags); + + return active; +} +EXPORT_SYMBOL(__debug_sprintf_exception); + +/** + * debug_register_view() - registers new debug view and creates debugfs + * dir entry + * + * @id: handle for debug log + * @view: pointer to debug view struct + * + * Return: + * - 0 : ok + * - < 0: Error + */ +int debug_register_view(debug_info_t *id, struct debug_view *view) +{ + unsigned long flags; + struct dentry *pde; + umode_t mode; + int rc = 0; + int i; + + if (!id) + goto out; + mode = (id->mode | S_IFREG) & ~S_IXUGO; + if (!(view->prolog_proc || view->format_proc || view->header_proc)) + mode &= ~(S_IRUSR | S_IRGRP | S_IROTH); + if (!view->input_proc) + mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH); + pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry, + id, &debug_file_ops); + spin_lock_irqsave(&id->lock, flags); + for (i = 0; i < DEBUG_MAX_VIEWS; i++) { + if (!id->views[i]) + break; + } + if (i == DEBUG_MAX_VIEWS) { + rc = -1; + } else { + id->views[i] = view; + id->debugfs_entries[i] = pde; + } + spin_unlock_irqrestore(&id->lock, flags); + if (rc) { + pr_err("Registering view %s/%s would exceed the maximum " + "number of views %i\n", id->name, view->name, i); + debugfs_remove(pde); + } +out: + return rc; +} +EXPORT_SYMBOL(debug_register_view); + +/** + * debug_unregister_view() - unregisters debug view and removes debugfs + * dir entry + * + * @id: handle for debug log + * @view: pointer to debug view struct + * + * Return: + * - 0 : ok + * - < 0: Error + */ +int debug_unregister_view(debug_info_t *id, struct debug_view *view) +{ + struct dentry *dentry = NULL; + unsigned long flags; + int i, rc = 0; + + if (!id) + goto out; + spin_lock_irqsave(&id->lock, flags); + for (i = 0; i < DEBUG_MAX_VIEWS; i++) { + if (id->views[i] == view) + break; + } + if (i == DEBUG_MAX_VIEWS) { + rc = -1; + } else { + dentry = id->debugfs_entries[i]; + id->views[i] = NULL; + id->debugfs_entries[i] = NULL; + } + spin_unlock_irqrestore(&id->lock, flags); + debugfs_remove(dentry); +out: + return rc; +} +EXPORT_SYMBOL(debug_unregister_view); + +static inline char *debug_get_user_string(const char __user *user_buf, + size_t user_len) +{ + char *buffer; + + buffer = kmalloc(user_len + 1, GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + if (copy_from_user(buffer, user_buf, user_len) != 0) { + kfree(buffer); + return ERR_PTR(-EFAULT); + } + /* got the string, now strip linefeed. */ + if (buffer[user_len - 1] == '\n') + buffer[user_len - 1] = 0; + else + buffer[user_len] = 0; + return buffer; +} + +static inline int debug_get_uint(char *buf) +{ + int rc; + + buf = skip_spaces(buf); + rc = simple_strtoul(buf, &buf, 10); + if (*buf) + rc = -EINVAL; + return rc; +} + +/* + * functions for debug-views + *********************************** +*/ + +/* + * prints out actual debug level + */ + +static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view, + char *out_buf) +{ + return sprintf(out_buf, "%i\n", id->pages_per_area); +} + +/* + * reads new size (number of pages per debug area) + */ + +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_len, loff_t *offset) +{ + int rc, new_pages; + char *str; + + if (user_len > 0x10000) + user_len = 0x10000; + if (*offset != 0) { + rc = -EPIPE; + goto out; + } + str = debug_get_user_string(user_buf, user_len); + if (IS_ERR(str)) { + rc = PTR_ERR(str); + goto out; + } + new_pages = debug_get_uint(str); + if (new_pages < 0) { + rc = -EINVAL; + goto free_str; + } + rc = debug_set_size(id, id->nr_areas, new_pages); + if (rc != 0) { + rc = -EINVAL; + goto free_str; + } + rc = user_len; +free_str: + kfree(str); +out: + *offset += user_len; + return rc; /* number of input characters */ +} + +/* + * prints out actual debug level + */ +static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view, + char *out_buf) +{ + int rc = 0; + + if (id->level == DEBUG_OFF_LEVEL) + rc = sprintf(out_buf, "-\n"); + else + rc = sprintf(out_buf, "%i\n", id->level); + return rc; +} + +/* + * reads new debug level + */ +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_len, loff_t *offset) +{ + int rc, new_level; + char *str; + + if (user_len > 0x10000) + user_len = 0x10000; + if (*offset != 0) { + rc = -EPIPE; + goto out; + } + str = debug_get_user_string(user_buf, user_len); + if (IS_ERR(str)) { + rc = PTR_ERR(str); + goto out; + } + if (str[0] == '-') { + debug_set_level(id, DEBUG_OFF_LEVEL); + rc = user_len; + goto free_str; + } else { + new_level = debug_get_uint(str); + } + if (new_level < 0) { + pr_warn("%s is not a valid level for a debug feature\n", str); + rc = -EINVAL; + } else { + debug_set_level(id, new_level); + rc = user_len; + } +free_str: + kfree(str); +out: + *offset += user_len; + return rc; /* number of input characters */ +} + +/* + * flushes debug areas + */ +static void debug_flush(debug_info_t *id, int area) +{ + unsigned long flags; + int i, j; + + if (!id || !id->areas) + return; + spin_lock_irqsave(&id->lock, flags); + if (area == DEBUG_FLUSH_ALL) { + id->active_area = 0; + memset(id->active_entries, 0, id->nr_areas * sizeof(int)); + for (i = 0; i < id->nr_areas; i++) { + id->active_pages[i] = 0; + for (j = 0; j < id->pages_per_area; j++) + memset(id->areas[i][j], 0, PAGE_SIZE); + } + } else if (area >= 0 && area < id->nr_areas) { + id->active_entries[area] = 0; + id->active_pages[area] = 0; + for (i = 0; i < id->pages_per_area; i++) + memset(id->areas[area][i], 0, PAGE_SIZE); + } + spin_unlock_irqrestore(&id->lock, flags); +} + +/* + * view function: flushes debug areas + */ +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_len, loff_t *offset) +{ + char input_buf[1]; + int rc = user_len; + + if (user_len > 0x10000) + user_len = 0x10000; + if (*offset != 0) { + rc = -EPIPE; + goto out; + } + if (copy_from_user(input_buf, user_buf, 1)) { + rc = -EFAULT; + goto out; + } + if (input_buf[0] == '-') { + debug_flush(id, DEBUG_FLUSH_ALL); + goto out; + } + if (isdigit(input_buf[0])) { + int area = ((int) input_buf[0] - (int) '0'); + + debug_flush(id, area); + goto out; + } + + pr_info("Flushing debug data failed because %c is not a valid " + "area\n", input_buf[0]); + +out: + *offset += user_len; + return rc; /* number of input characters */ +} + +/* + * prints debug data in hex/ascii format + */ +static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view, + char *out_buf, const char *in_buf) +{ + int i, rc = 0; + + for (i = 0; i < id->buf_size; i++) + rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]); + rc += sprintf(out_buf + rc, "| "); + for (i = 0; i < id->buf_size; i++) { + unsigned char c = in_buf[i]; + + if (isascii(c) && isprint(c)) + rc += sprintf(out_buf + rc, "%c", c); + else + rc += sprintf(out_buf + rc, "."); + } + rc += sprintf(out_buf + rc, "\n"); + return rc; +} + +/* + * prints header for debug entry + */ +int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view, + int area, debug_entry_t *entry, char *out_buf) +{ + unsigned long sec, usec; + unsigned long caller; + unsigned int level; + char *except_str; + int rc = 0; + + level = entry->level; + sec = entry->clock; + usec = do_div(sec, USEC_PER_SEC); + + if (entry->exception) + except_str = "*"; + else + except_str = "-"; + caller = (unsigned long) entry->caller; + rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ", + area, sec, usec, level, except_str, + entry->cpu, (void *)caller); + return rc; +} +EXPORT_SYMBOL(debug_dflt_header_fn); + +/* + * prints debug data sprintf-formated: + * debug_sprinf_event/exception calls must be used together with this view + */ + +#define DEBUG_SPRINTF_MAX_ARGS 10 + +static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view, + char *out_buf, const char *inbuf) +{ + debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf; + int num_longs, num_used_args = 0, i, rc = 0; + int index[DEBUG_SPRINTF_MAX_ARGS]; + + /* count of longs fit into one entry */ + num_longs = id->buf_size / sizeof(long); + + if (num_longs < 1) + goto out; /* bufsize of entry too small */ + if (num_longs == 1) { + /* no args, we use only the string */ + strcpy(out_buf, curr_event->string); + rc = strlen(curr_event->string); + goto out; + } + + /* number of arguments used for sprintf (without the format string) */ + num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1)); + + memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int)); + + for (i = 0; i < num_used_args; i++) + index[i] = i; + + rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]], + curr_event->args[index[1]], curr_event->args[index[2]], + curr_event->args[index[3]], curr_event->args[index[4]], + curr_event->args[index[5]], curr_event->args[index[6]], + curr_event->args[index[7]], curr_event->args[index[8]], + curr_event->args[index[9]]); +out: + return rc; +} + +/* + * debug_init: + * - is called exactly once to initialize the debug feature + */ +static int __init debug_init(void) +{ + s390dbf_sysctl_header = register_sysctl("s390dbf", s390dbf_table); + mutex_lock(&debug_mutex); + debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL); + initialized = 1; + mutex_unlock(&debug_mutex); + return 0; +} +postcore_initcall(debug_init); 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