xref: /linux/kernel/events/internal.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 #ifndef _KERNEL_EVENTS_INTERNAL_H
2 #define _KERNEL_EVENTS_INTERNAL_H
3 
4 #include <linux/hardirq.h>
5 #include <linux/uaccess.h>
6 
7 /* Buffer handling */
8 
9 #define RING_BUFFER_WRITABLE		0x01
10 
11 struct ring_buffer {
12 	atomic_t			refcount;
13 	struct rcu_head			rcu_head;
14 #ifdef CONFIG_PERF_USE_VMALLOC
15 	struct work_struct		work;
16 	int				page_order;	/* allocation order  */
17 #endif
18 	int				nr_pages;	/* nr of data pages  */
19 	int				writable;	/* are we writable   */
20 
21 	atomic_t			poll;		/* POLL_ for wakeups */
22 
23 	local_t				head;		/* write position    */
24 	local_t				nest;		/* nested writers    */
25 	local_t				events;		/* event limit       */
26 	local_t				wakeup;		/* wakeup stamp      */
27 	local_t				lost;		/* nr records lost   */
28 
29 	long				watermark;	/* wakeup watermark  */
30 	/* poll crap */
31 	spinlock_t			event_lock;
32 	struct list_head		event_list;
33 
34 	struct perf_event_mmap_page	*user_page;
35 	void				*data_pages[0];
36 };
37 
38 extern void rb_free(struct ring_buffer *rb);
39 extern struct ring_buffer *
40 rb_alloc(int nr_pages, long watermark, int cpu, int flags);
41 extern void perf_event_wakeup(struct perf_event *event);
42 
43 extern void
44 perf_event_header__init_id(struct perf_event_header *header,
45 			   struct perf_sample_data *data,
46 			   struct perf_event *event);
47 extern void
48 perf_event__output_id_sample(struct perf_event *event,
49 			     struct perf_output_handle *handle,
50 			     struct perf_sample_data *sample);
51 
52 extern struct page *
53 perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff);
54 
55 #ifdef CONFIG_PERF_USE_VMALLOC
56 /*
57  * Back perf_mmap() with vmalloc memory.
58  *
59  * Required for architectures that have d-cache aliasing issues.
60  */
61 
62 static inline int page_order(struct ring_buffer *rb)
63 {
64 	return rb->page_order;
65 }
66 
67 #else
68 
69 static inline int page_order(struct ring_buffer *rb)
70 {
71 	return 0;
72 }
73 #endif
74 
75 static inline unsigned long perf_data_size(struct ring_buffer *rb)
76 {
77 	return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
78 }
79 
80 #define DEFINE_OUTPUT_COPY(func_name, memcpy_func)			\
81 static inline unsigned int						\
82 func_name(struct perf_output_handle *handle,				\
83 	  const void *buf, unsigned int len)				\
84 {									\
85 	unsigned long size, written;					\
86 									\
87 	do {								\
88 		size = min_t(unsigned long, handle->size, len);		\
89 									\
90 		written = memcpy_func(handle->addr, buf, size);		\
91 									\
92 		len -= written;						\
93 		handle->addr += written;				\
94 		buf += written;						\
95 		handle->size -= written;				\
96 		if (!handle->size) {					\
97 			struct ring_buffer *rb = handle->rb;		\
98 									\
99 			handle->page++;					\
100 			handle->page &= rb->nr_pages - 1;		\
101 			handle->addr = rb->data_pages[handle->page];	\
102 			handle->size = PAGE_SIZE << page_order(rb);	\
103 		}							\
104 	} while (len && written == size);				\
105 									\
106 	return len;							\
107 }
108 
109 static inline int memcpy_common(void *dst, const void *src, size_t n)
110 {
111 	memcpy(dst, src, n);
112 	return n;
113 }
114 
115 DEFINE_OUTPUT_COPY(__output_copy, memcpy_common)
116 
117 #define MEMCPY_SKIP(dst, src, n) (n)
118 
119 DEFINE_OUTPUT_COPY(__output_skip, MEMCPY_SKIP)
120 
121 #ifndef arch_perf_out_copy_user
122 #define arch_perf_out_copy_user __copy_from_user_inatomic
123 #endif
124 
125 DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
126 
127 /* Callchain handling */
128 extern struct perf_callchain_entry *
129 perf_callchain(struct perf_event *event, struct pt_regs *regs);
130 extern int get_callchain_buffers(void);
131 extern void put_callchain_buffers(void);
132 
133 static inline int get_recursion_context(int *recursion)
134 {
135 	int rctx;
136 
137 	if (in_nmi())
138 		rctx = 3;
139 	else if (in_irq())
140 		rctx = 2;
141 	else if (in_softirq())
142 		rctx = 1;
143 	else
144 		rctx = 0;
145 
146 	if (recursion[rctx])
147 		return -1;
148 
149 	recursion[rctx]++;
150 	barrier();
151 
152 	return rctx;
153 }
154 
155 static inline void put_recursion_context(int *recursion, int rctx)
156 {
157 	barrier();
158 	recursion[rctx]--;
159 }
160 
161 #ifdef CONFIG_HAVE_PERF_USER_STACK_DUMP
162 static inline bool arch_perf_have_user_stack_dump(void)
163 {
164 	return true;
165 }
166 
167 #define perf_user_stack_pointer(regs) user_stack_pointer(regs)
168 #else
169 static inline bool arch_perf_have_user_stack_dump(void)
170 {
171 	return false;
172 }
173 
174 #define perf_user_stack_pointer(regs) 0
175 #endif /* CONFIG_HAVE_PERF_USER_STACK_DUMP */
176 
177 #endif /* _KERNEL_EVENTS_INTERNAL_H */
178