diff options
Diffstat (limited to 'kernel/trace/trace_events_user.c')
-rw-r--r-- | kernel/trace/trace_events_user.c | 568 |
1 files changed, 426 insertions, 142 deletions
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index a6621c52ce45..ae78c2d53c8a 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -14,6 +14,7 @@ #include <linux/uio.h> #include <linux/ioctl.h> #include <linux/jhash.h> +#include <linux/refcount.h> #include <linux/trace_events.h> #include <linux/tracefs.h> #include <linux/types.h> @@ -39,28 +40,69 @@ */ #define MAX_PAGE_ORDER 0 #define MAX_PAGES (1 << MAX_PAGE_ORDER) -#define MAX_EVENTS (MAX_PAGES * PAGE_SIZE) +#define MAX_BYTES (MAX_PAGES * PAGE_SIZE) +#define MAX_EVENTS (MAX_BYTES * 8) /* Limit how long of an event name plus args within the subsystem. */ #define MAX_EVENT_DESC 512 #define EVENT_NAME(user_event) ((user_event)->tracepoint.name) #define MAX_FIELD_ARRAY_SIZE 1024 -#define MAX_FIELD_ARG_NAME 256 -static char *register_page_data; +/* + * The MAP_STATUS_* macros are used for taking a index and determining the + * appropriate byte and the bit in the byte to set/reset for an event. + * + * The lower 3 bits of the index decide which bit to set. + * The remaining upper bits of the index decide which byte to use for the bit. + * + * This is used when an event has a probe attached/removed to reflect live + * status of the event wanting tracing or not to user-programs via shared + * memory maps. + */ +#define MAP_STATUS_BYTE(index) ((index) >> 3) +#define MAP_STATUS_MASK(index) BIT((index) & 7) + +/* + * Internal bits (kernel side only) to keep track of connected probes: + * These are used when status is requested in text form about an event. These + * bits are compared against an internal byte on the event to determine which + * probes to print out to the user. + * + * These do not reflect the mapped bytes between the user and kernel space. + */ +#define EVENT_STATUS_FTRACE BIT(0) +#define EVENT_STATUS_PERF BIT(1) +#define EVENT_STATUS_OTHER BIT(7) + +/* + * Stores the pages, tables, and locks for a group of events. + * Each logical grouping of events has its own group, with a + * matching page for status checks within user programs. This + * allows for isolation of events to user programs by various + * means. + */ +struct user_event_group { + struct page *pages; + char *register_page_data; + char *system_name; + struct hlist_node node; + struct mutex reg_mutex; + DECLARE_HASHTABLE(register_table, 8); + DECLARE_BITMAP(page_bitmap, MAX_EVENTS); +}; -static DEFINE_MUTEX(reg_mutex); -static DEFINE_HASHTABLE(register_table, 4); -static DECLARE_BITMAP(page_bitmap, MAX_EVENTS); +/* Group for init_user_ns mapping, top-most group */ +static struct user_event_group *init_group; /* * Stores per-event properties, as users register events * within a file a user_event might be created if it does not * already exist. These are globally used and their lifetime * is tied to the refcnt member. These cannot go away until the - * refcnt reaches zero. + * refcnt reaches one. */ struct user_event { + struct user_event_group *group; struct tracepoint tracepoint; struct trace_event_call call; struct trace_event_class class; @@ -68,10 +110,11 @@ struct user_event { struct hlist_node node; struct list_head fields; struct list_head validators; - atomic_t refcnt; + refcount_t refcnt; int index; int flags; int min_size; + char status; }; /* @@ -86,6 +129,11 @@ struct user_event_refs { struct user_event *events[]; }; +struct user_event_file_info { + struct user_event_group *group; + struct user_event_refs *refs; +}; + #define VALIDATOR_ENSURE_NULL (1 << 0) #define VALIDATOR_REL (1 << 1) @@ -98,7 +146,8 @@ struct user_event_validator { typedef void (*user_event_func_t) (struct user_event *user, struct iov_iter *i, void *tpdata, bool *faulted); -static int user_event_parse(char *name, char *args, char *flags, +static int user_event_parse(struct user_event_group *group, char *name, + char *args, char *flags, struct user_event **newuser); static u32 user_event_key(char *name) @@ -106,6 +155,144 @@ static u32 user_event_key(char *name) return jhash(name, strlen(name), 0); } +static void set_page_reservations(char *pages, bool set) +{ + int page; + + for (page = 0; page < MAX_PAGES; ++page) { + void *addr = pages + (PAGE_SIZE * page); + + if (set) + SetPageReserved(virt_to_page(addr)); + else + ClearPageReserved(virt_to_page(addr)); + } +} + +static void user_event_group_destroy(struct user_event_group *group) +{ + if (group->register_page_data) + set_page_reservations(group->register_page_data, false); + + if (group->pages) + __free_pages(group->pages, MAX_PAGE_ORDER); + + kfree(group->system_name); + kfree(group); +} + +static char *user_event_group_system_name(struct user_namespace *user_ns) +{ + char *system_name; + int len = sizeof(USER_EVENTS_SYSTEM) + 1; + + if (user_ns != &init_user_ns) { + /* + * Unexpected at this point: + * We only currently support init_user_ns. + * When we enable more, this will trigger a failure so log. + */ + pr_warn("user_events: Namespace other than init_user_ns!\n"); + return NULL; + } + + system_name = kmalloc(len, GFP_KERNEL); + + if (!system_name) + return NULL; + + snprintf(system_name, len, "%s", USER_EVENTS_SYSTEM); + + return system_name; +} + +static inline struct user_event_group +*user_event_group_from_user_ns(struct user_namespace *user_ns) +{ + if (user_ns == &init_user_ns) + return init_group; + + return NULL; +} + +static struct user_event_group *current_user_event_group(void) +{ + struct user_namespace *user_ns = current_user_ns(); + struct user_event_group *group = NULL; + + while (user_ns) { + group = user_event_group_from_user_ns(user_ns); + + if (group) + break; + + user_ns = user_ns->parent; + } + + return group; +} + +static struct user_event_group +*user_event_group_create(struct user_namespace *user_ns) +{ + struct user_event_group *group; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + + if (!group) + return NULL; + + group->system_name = user_event_group_system_name(user_ns); + + if (!group->system_name) + goto error; + + group->pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER); + + if (!group->pages) + goto error; + + group->register_page_data = page_address(group->pages); + + set_page_reservations(group->register_page_data, true); + + /* Zero all bits beside 0 (which is reserved for failures) */ + bitmap_zero(group->page_bitmap, MAX_EVENTS); + set_bit(0, group->page_bitmap); + + mutex_init(&group->reg_mutex); + hash_init(group->register_table); + + return group; +error: + if (group) + user_event_group_destroy(group); + + return NULL; +}; + +static __always_inline +void user_event_register_set(struct user_event *user) +{ + int i = user->index; + + user->group->register_page_data[MAP_STATUS_BYTE(i)] |= MAP_STATUS_MASK(i); +} + +static __always_inline +void user_event_register_clear(struct user_event *user) +{ + int i = user->index; + + user->group->register_page_data[MAP_STATUS_BYTE(i)] &= ~MAP_STATUS_MASK(i); +} + +static __always_inline __must_check +bool user_event_last_ref(struct user_event *user) +{ + return refcount_read(&user->refcnt) == 1; +} + static __always_inline __must_check size_t copy_nofault(void *addr, size_t bytes, struct iov_iter *i) { @@ -141,7 +328,8 @@ static struct list_head *user_event_get_fields(struct trace_event_call *call) * * Upon success user_event has its ref count increased by 1. */ -static int user_event_parse_cmd(char *raw_command, struct user_event **newuser) +static int user_event_parse_cmd(struct user_event_group *group, + char *raw_command, struct user_event **newuser) { char *name = raw_command; char *args = strpbrk(name, " "); @@ -155,7 +343,7 @@ static int user_event_parse_cmd(char *raw_command, struct user_event **newuser) if (flags) *flags++ = '\0'; - return user_event_parse(name, args, flags, newuser); + return user_event_parse(group, name, args, flags, newuser); } static int user_field_array_size(const char *type) @@ -277,7 +465,7 @@ static int user_event_add_field(struct user_event *user, const char *type, goto add_field; add_validator: - if (strstr(type, "char") != 0) + if (strstr(type, "char") != NULL) validator_flags |= VALIDATOR_ENSURE_NULL; validator = kmalloc(sizeof(*validator), GFP_KERNEL); @@ -458,7 +646,7 @@ static const char *user_field_format(const char *type) return "%d"; if (strcmp(type, "unsigned char") == 0) return "%u"; - if (strstr(type, "char[") != 0) + if (strstr(type, "char[") != NULL) return "%s"; /* Unknown, likely struct, allowed treat as 64-bit */ @@ -479,10 +667,52 @@ static bool user_field_is_dyn_string(const char *type, const char **str_func) return false; check: - return strstr(type, "char") != 0; + return strstr(type, "char") != NULL; } #define LEN_OR_ZERO (len ? len - pos : 0) +static int user_dyn_field_set_string(int argc, const char **argv, int *iout, + char *buf, int len, bool *colon) +{ + int pos = 0, i = *iout; + + *colon = false; + + for (; i < argc; ++i) { + if (i != *iout) + pos += snprintf(buf + pos, LEN_OR_ZERO, " "); + + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", argv[i]); + + if (strchr(argv[i], ';')) { + ++i; + *colon = true; + break; + } + } + + /* Actual set, advance i */ + if (len != 0) + *iout = i; + + return pos + 1; +} + +static int user_field_set_string(struct ftrace_event_field *field, + char *buf, int len, bool colon) +{ + int pos = 0; + + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->type); + pos += snprintf(buf + pos, LEN_OR_ZERO, " "); + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->name); + + if (colon) + pos += snprintf(buf + pos, LEN_OR_ZERO, ";"); + + return pos + 1; +} + static int user_event_set_print_fmt(struct user_event *user, char *buf, int len) { struct ftrace_event_field *field, *next; @@ -600,8 +830,8 @@ static int destroy_user_event(struct user_event *user) dyn_event_remove(&user->devent); - register_page_data[user->index] = 0; - clear_bit(user->index, page_bitmap); + user_event_register_clear(user); + clear_bit(user->index, user->group->page_bitmap); hash_del(&user->node); user_event_destroy_validators(user); @@ -612,16 +842,17 @@ static int destroy_user_event(struct user_event *user) return ret; } -static struct user_event *find_user_event(char *name, u32 *outkey) +static struct user_event *find_user_event(struct user_event_group *group, + char *name, u32 *outkey) { struct user_event *user; u32 key = user_event_key(name); *outkey = key; - hash_for_each_possible(register_table, user, node, key) + hash_for_each_possible(group->register_table, user, node, key) if (!strcmp(EVENT_NAME(user), name)) { - atomic_inc(&user->refcnt); + refcount_inc(&user->refcnt); return user; } @@ -779,7 +1010,12 @@ static void update_reg_page_for(struct user_event *user) rcu_read_unlock_sched(); } - register_page_data[user->index] = status; + if (status) + user_event_register_set(user); + else + user_event_register_clear(user); + + user->status = status; } /* @@ -835,17 +1071,18 @@ static int user_event_reg(struct trace_event_call *call, return ret; inc: - atomic_inc(&user->refcnt); + refcount_inc(&user->refcnt); update_reg_page_for(user); return 0; dec: update_reg_page_for(user); - atomic_dec(&user->refcnt); + refcount_dec(&user->refcnt); return 0; } static int user_event_create(const char *raw_command) { + struct user_event_group *group; struct user_event *user; char *name; int ret; @@ -861,14 +1098,19 @@ static int user_event_create(const char *raw_command) if (!name) return -ENOMEM; - mutex_lock(®_mutex); + group = current_user_event_group(); - ret = user_event_parse_cmd(name, &user); + if (!group) + return -ENOENT; + + mutex_lock(&group->reg_mutex); + + ret = user_event_parse_cmd(group, name, &user); if (!ret) - atomic_dec(&user->refcnt); + refcount_dec(&user->refcnt); - mutex_unlock(®_mutex); + mutex_unlock(&group->reg_mutex); if (ret) kfree(name); @@ -910,14 +1152,14 @@ static bool user_event_is_busy(struct dyn_event *ev) { struct user_event *user = container_of(ev, struct user_event, devent); - return atomic_read(&user->refcnt) != 0; + return !user_event_last_ref(user); } static int user_event_free(struct dyn_event *ev) { struct user_event *user = container_of(ev, struct user_event, devent); - if (atomic_read(&user->refcnt) != 0) + if (!user_event_last_ref(user)) return -EBUSY; return destroy_user_event(user); @@ -926,49 +1168,35 @@ static int user_event_free(struct dyn_event *ev) static bool user_field_match(struct ftrace_event_field *field, int argc, const char **argv, int *iout) { - char *field_name, *arg_name; - int len, pos, i = *iout; + char *field_name = NULL, *dyn_field_name = NULL; bool colon = false, match = false; + int dyn_len, len; - if (i >= argc) + if (*iout >= argc) return false; - len = MAX_FIELD_ARG_NAME; - field_name = kmalloc(len, GFP_KERNEL); - arg_name = kmalloc(len, GFP_KERNEL); - - if (!arg_name || !field_name) - goto out; - - pos = 0; - - for (; i < argc; ++i) { - if (i != *iout) - pos += snprintf(arg_name + pos, len - pos, " "); + dyn_len = user_dyn_field_set_string(argc, argv, iout, dyn_field_name, + 0, &colon); - pos += snprintf(arg_name + pos, len - pos, argv[i]); + len = user_field_set_string(field, field_name, 0, colon); - if (strchr(argv[i], ';')) { - ++i; - colon = true; - break; - } - } + if (dyn_len != len) + return false; - pos = 0; + dyn_field_name = kmalloc(dyn_len, GFP_KERNEL); + field_name = kmalloc(len, GFP_KERNEL); - pos += snprintf(field_name + pos, len - pos, field->type); - pos += snprintf(field_name + pos, len - pos, " "); - pos += snprintf(field_name + pos, len - pos, field->name); + if (!dyn_field_name || !field_name) + goto out; - if (colon) - pos += snprintf(field_name + pos, len - pos, ";"); + user_dyn_field_set_string(argc, argv, iout, dyn_field_name, + dyn_len, &colon); - *iout = i; + user_field_set_string(field, field_name, len, colon); - match = strcmp(arg_name, field_name) == 0; + match = strcmp(dyn_field_name, field_name) == 0; out: - kfree(arg_name); + kfree(dyn_field_name); kfree(field_name); return match; @@ -1036,7 +1264,8 @@ static int user_event_trace_register(struct user_event *user) * The name buffer lifetime is owned by this method for success cases only. * Upon success the returned user_event has its ref count increased by 1. */ -static int user_event_parse(char *name, char *args, char *flags, +static int user_event_parse(struct user_event_group *group, char *name, + char *args, char *flags, struct user_event **newuser) { int ret; @@ -1046,7 +1275,7 @@ static int user_event_parse(char *name, char *args, char *flags, /* Prevent dyn_event from racing */ mutex_lock(&event_mutex); - user = find_user_event(name, &key); + user = find_user_event(group, name, &key); mutex_unlock(&event_mutex); if (user) { @@ -1059,7 +1288,7 @@ static int user_event_parse(char *name, char *args, char *flags, return 0; } - index = find_first_zero_bit(page_bitmap, MAX_EVENTS); + index = find_first_zero_bit(group->page_bitmap, MAX_EVENTS); if (index == MAX_EVENTS) return -EMFILE; @@ -1073,6 +1302,7 @@ static int user_event_parse(char *name, char *args, char *flags, INIT_LIST_HEAD(&user->fields); INIT_LIST_HEAD(&user->validators); + user->group = group; user->tracepoint.name = name; ret = user_event_parse_fields(user, args); @@ -1091,8 +1321,8 @@ static int user_event_parse(char *name, char *args, char *flags, user->call.flags = TRACE_EVENT_FL_TRACEPOINT; user->call.tp = &user->tracepoint; user->call.event.funcs = &user_event_funcs; + user->class.system = group->system_name; - user->class.system = USER_EVENTS_SYSTEM; user->class.fields_array = user_event_fields_array; user->class.get_fields = user_event_get_fields; user->class.reg = user_event_reg; @@ -1110,13 +1340,13 @@ static int user_event_parse(char *name, char *args, char *flags, user->index = index; - /* Ensure we track ref */ - atomic_inc(&user->refcnt); + /* Ensure we track self ref and caller ref (2) */ + refcount_set(&user->refcnt, 2); dyn_event_init(&user->devent, &user_event_dops); dyn_event_add(&user->devent, &user->call); - set_bit(user->index, page_bitmap); - hash_add(register_table, &user->node, key); + set_bit(user->index, group->page_bitmap); + hash_add(group->register_table, &user->node, key); mutex_unlock(&event_mutex); @@ -1134,32 +1364,20 @@ put_user: /* * Deletes a previously created event if it is no longer being used. */ -static int delete_user_event(char *name) +static int delete_user_event(struct user_event_group *group, char *name) { u32 key; - int ret; - struct user_event *user = find_user_event(name, &key); + struct user_event *user = find_user_event(group, name, &key); if (!user) return -ENOENT; - /* Ensure we are the last ref */ - if (atomic_read(&user->refcnt) != 1) { - ret = -EBUSY; - goto put_ref; - } - - ret = destroy_user_event(user); - - if (ret) - goto put_ref; + refcount_dec(&user->refcnt); - return ret; -put_ref: - /* No longer have this ref */ - atomic_dec(&user->refcnt); + if (!user_event_last_ref(user)) + return -EBUSY; - return ret; + return destroy_user_event(user); } /* @@ -1167,6 +1385,7 @@ put_ref: */ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) { + struct user_event_file_info *info = file->private_data; struct user_event_refs *refs; struct user_event *user = NULL; struct tracepoint *tp; @@ -1178,7 +1397,7 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) rcu_read_lock_sched(); - refs = rcu_dereference_sched(file->private_data); + refs = rcu_dereference_sched(info->refs); /* * The refs->events array is protected by RCU, and new items may be @@ -1236,6 +1455,28 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) return ret; } +static int user_events_open(struct inode *node, struct file *file) +{ + struct user_event_group *group; + struct user_event_file_info *info; + + group = current_user_event_group(); + + if (!group) + return -ENOENT; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + + if (!info) + return -ENOMEM; + + info->group = group; + + file->private_data = info; + + return 0; +} + static ssize_t user_events_write(struct file *file, const char __user *ubuf, size_t count, loff_t *ppos) { @@ -1245,7 +1486,8 @@ static ssize_t user_events_write(struct file *file, const char __user *ubuf, if (unlikely(*ppos != 0)) return -EFAULT; - if (unlikely(import_single_range(READ, (char *)ubuf, count, &iov, &i))) + if (unlikely(import_single_range(WRITE, (char __user *)ubuf, + count, &iov, &i))) return -EFAULT; return user_events_write_core(file, &i); @@ -1256,13 +1498,15 @@ static ssize_t user_events_write_iter(struct kiocb *kp, struct iov_iter *i) return user_events_write_core(kp->ki_filp, i); } -static int user_events_ref_add(struct file *file, struct user_event *user) +static int user_events_ref_add(struct user_event_file_info *info, + struct user_event *user) { + struct user_event_group *group = info->group; struct user_event_refs *refs, *new_refs; int i, size, count = 0; - refs = rcu_dereference_protected(file->private_data, - lockdep_is_held(®_mutex)); + refs = rcu_dereference_protected(info->refs, + lockdep_is_held(&group->reg_mutex)); if (refs) { count = refs->count; @@ -1286,9 +1530,9 @@ static int user_events_ref_add(struct file *file, struct user_event *user) new_refs->events[i] = user; - atomic_inc(&user->refcnt); + refcount_inc(&user->refcnt); - rcu_assign_pointer(file->private_data, new_refs); + rcu_assign_pointer(info->refs, new_refs); if (refs) kfree_rcu(refs, rcu); @@ -1309,13 +1553,24 @@ static long user_reg_get(struct user_reg __user *ureg, struct user_reg *kreg) if (size > PAGE_SIZE) return -E2BIG; - return copy_struct_from_user(kreg, sizeof(*kreg), ureg, size); + if (size < offsetofend(struct user_reg, write_index)) + return -EINVAL; + + ret = copy_struct_from_user(kreg, sizeof(*kreg), ureg, size); + + if (ret) + return ret; + + kreg->size = size; + + return 0; } /* * Registers a user_event on behalf of a user process. */ -static long user_events_ioctl_reg(struct file *file, unsigned long uarg) +static long user_events_ioctl_reg(struct user_event_file_info *info, + unsigned long uarg) { struct user_reg __user *ureg = (struct user_reg __user *)uarg; struct user_reg reg; @@ -1336,24 +1591,24 @@ static long user_events_ioctl_reg(struct file *file, unsigned long uarg) return ret; } - ret = user_event_parse_cmd(name, &user); + ret = user_event_parse_cmd(info->group, name, &user); if (ret) { kfree(name); return ret; } - ret = user_events_ref_add(file, user); + ret = user_events_ref_add(info, user); /* No longer need parse ref, ref_add either worked or not */ - atomic_dec(&user->refcnt); + refcount_dec(&user->refcnt); /* Positive number is index and valid */ if (ret < 0) return ret; put_user((u32)ret, &ureg->write_index); - put_user(user->index, &ureg->status_index); + put_user(user->index, &ureg->status_bit); return 0; } @@ -1361,7 +1616,8 @@ static long user_events_ioctl_reg(struct file *file, unsigned long uarg) /* * Deletes a user_event on behalf of a user process. */ -static long user_events_ioctl_del(struct file *file, unsigned long uarg) +static long user_events_ioctl_del(struct user_event_file_info *info, + unsigned long uarg) { void __user *ubuf = (void __user *)uarg; char *name; @@ -1374,7 +1630,7 @@ static long user_events_ioctl_del(struct file *file, unsigned long uarg) /* event_mutex prevents dyn_event from racing */ mutex_lock(&event_mutex); - ret = delete_user_event(name); + ret = delete_user_event(info->group, name); mutex_unlock(&event_mutex); kfree(name); @@ -1388,19 +1644,21 @@ static long user_events_ioctl_del(struct file *file, unsigned long uarg) static long user_events_ioctl(struct file *file, unsigned int cmd, unsigned long uarg) { + struct user_event_file_info *info = file->private_data; + struct user_event_group *group = info->group; long ret = -ENOTTY; switch (cmd) { case DIAG_IOCSREG: - mutex_lock(®_mutex); - ret = user_events_ioctl_reg(file, uarg); - mutex_unlock(®_mutex); + mutex_lock(&group->reg_mutex); + ret = user_events_ioctl_reg(info, uarg); + mutex_unlock(&group->reg_mutex); break; case DIAG_IOCSDEL: - mutex_lock(®_mutex); - ret = user_events_ioctl_del(file, uarg); - mutex_unlock(®_mutex); + mutex_lock(&group->reg_mutex); + ret = user_events_ioctl_del(info, uarg); + mutex_unlock(&group->reg_mutex); break; } @@ -1412,17 +1670,24 @@ static long user_events_ioctl(struct file *file, unsigned int cmd, */ static int user_events_release(struct inode *node, struct file *file) { + struct user_event_file_info *info = file->private_data; + struct user_event_group *group; struct user_event_refs *refs; struct user_event *user; int i; + if (!info) + return -EINVAL; + + group = info->group; + /* * Ensure refs cannot change under any situation by taking the * register mutex during the final freeing of the references. */ - mutex_lock(®_mutex); + mutex_lock(&group->reg_mutex); - refs = file->private_data; + refs = info->refs; if (!refs) goto out; @@ -1436,37 +1701,56 @@ static int user_events_release(struct inode *node, struct file *file) user = refs->events[i]; if (user) - atomic_dec(&user->refcnt); + refcount_dec(&user->refcnt); } out: file->private_data = NULL; - mutex_unlock(®_mutex); + mutex_unlock(&group->reg_mutex); kfree(refs); + kfree(info); return 0; } static const struct file_operations user_data_fops = { + .open = user_events_open, .write = user_events_write, .write_iter = user_events_write_iter, .unlocked_ioctl = user_events_ioctl, .release = user_events_release, }; +static struct user_event_group *user_status_group(struct file *file) +{ + struct seq_file *m = file->private_data; + + if (!m) + return NULL; + + return m->private; +} + /* * Maps the shared page into the user process for checking if event is enabled. */ static int user_status_mmap(struct file *file, struct vm_area_struct *vma) { + char *pages; + struct user_event_group *group = user_status_group(file); unsigned long size = vma->vm_end - vma->vm_start; - if (size != MAX_EVENTS) + if (size != MAX_BYTES) + return -EINVAL; + + if (!group) return -EINVAL; + pages = group->register_page_data; + return remap_pfn_range(vma, vma->vm_start, - virt_to_phys(register_page_data) >> PAGE_SHIFT, + virt_to_phys(pages) >> PAGE_SHIFT, size, vm_get_page_prot(VM_READ)); } @@ -1490,14 +1774,18 @@ static void user_seq_stop(struct seq_file *m, void *p) static int user_seq_show(struct seq_file *m, void *p) { + struct user_event_group *group = m->private; struct user_event *user; char status; int i, active = 0, busy = 0, flags; - mutex_lock(®_mutex); + if (!group) + return -EINVAL; + + mutex_lock(&group->reg_mutex); - hash_for_each(register_table, i, user, node) { - status = register_page_data[user->index]; + hash_for_each(group->register_table, i, user, node) { + status = user->status; flags = user->flags; seq_printf(m, "%d:%s", user->index, EVENT_NAME(user)); @@ -1520,7 +1808,7 @@ static int user_seq_show(struct seq_file *m, void *p) active++; } - mutex_unlock(®_mutex); + mutex_unlock(&group->reg_mutex); seq_puts(m, "\n"); seq_printf(m, "Active: %d\n", active); @@ -1539,7 +1827,24 @@ static const struct seq_operations user_seq_ops = { static int user_status_open(struct inode *node, struct file *file) { - return seq_open(file, &user_seq_ops); + struct user_event_group *group; + int ret; + + group = current_user_event_group(); + + if (!group) + return -ENOENT; + + ret = seq_open(file, &user_seq_ops); + + if (!ret) { + /* Chain group to seq_file */ + struct seq_file *m = file->private_data; + + m->private = group; + } + + return ret; } static const struct file_operations user_status_fops = { @@ -1580,42 +1885,21 @@ err: return -ENODEV; } -static void set_page_reservations(bool set) -{ - int page; - - for (page = 0; page < MAX_PAGES; ++page) { - void *addr = register_page_data + (PAGE_SIZE * page); - - if (set) - SetPageReserved(virt_to_page(addr)); - else - ClearPageReserved(virt_to_page(addr)); - } -} - static int __init trace_events_user_init(void) { - struct page *pages; int ret; - /* Zero all bits beside 0 (which is reserved for failures) */ - bitmap_zero(page_bitmap, MAX_EVENTS); - set_bit(0, page_bitmap); + init_group = user_event_group_create(&init_user_ns); - pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER); - if (!pages) + if (!init_group) return -ENOMEM; - register_page_data = page_address(pages); - - set_page_reservations(true); ret = create_user_tracefs(); if (ret) { pr_warn("user_events could not register with tracefs\n"); - set_page_reservations(false); - __free_pages(pages, MAX_PAGE_ORDER); + user_event_group_destroy(init_group); + init_group = NULL; return ret; } |