diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_events_user.c | 75 |
1 files changed, 67 insertions, 8 deletions
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 2bcae7abfa81..2c0a6ec75548 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -40,17 +40,44 @@ */ #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 +/* + * 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) + static char *register_page_data; static DEFINE_MUTEX(reg_mutex); -static DEFINE_HASHTABLE(register_table, 4); +static DEFINE_HASHTABLE(register_table, 8); static DECLARE_BITMAP(page_bitmap, MAX_EVENTS); /* @@ -72,6 +99,7 @@ struct user_event { int index; int flags; int min_size; + char status; }; /* @@ -106,6 +134,22 @@ static u32 user_event_key(char *name) return jhash(name, strlen(name), 0); } +static __always_inline +void user_event_register_set(struct user_event *user) +{ + int i = user->index; + + 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; + + 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) { @@ -648,7 +692,7 @@ static int destroy_user_event(struct user_event *user) dyn_event_remove(&user->devent); - register_page_data[user->index] = 0; + user_event_register_clear(user); clear_bit(user->index, page_bitmap); hash_del(&user->node); @@ -827,7 +871,12 @@ 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; } /* @@ -1332,7 +1381,17 @@ 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; } /* @@ -1376,7 +1435,7 @@ static long user_events_ioctl_reg(struct file *file, unsigned long uarg) 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; } @@ -1485,7 +1544,7 @@ static int user_status_mmap(struct file *file, struct vm_area_struct *vma) { unsigned long size = vma->vm_end - vma->vm_start; - if (size != MAX_EVENTS) + if (size != MAX_BYTES) return -EINVAL; return remap_pfn_range(vma, vma->vm_start, @@ -1520,7 +1579,7 @@ static int user_seq_show(struct seq_file *m, void *p) mutex_lock(®_mutex); hash_for_each(register_table, i, user, node) { - status = register_page_data[user->index]; + status = user->status; flags = user->flags; seq_printf(m, "%d:%s", user->index, EVENT_NAME(user)); |