1 // SPDX-License-Identifier: GPL-2.0
16 void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,  in perf_mmap__init()  argument
19 	map->fd = -1;  in perf_mmap__init()
20 	map->overwrite = overwrite;  in perf_mmap__init()
21 	map->unmap_cb  = unmap_cb;  in perf_mmap__init()
22 	refcount_set(&map->refcnt, 0);  in perf_mmap__init()
24 		prev->next = map;  in perf_mmap__init()
27 size_t perf_mmap__mmap_len(struct perf_mmap *map)  in perf_mmap__mmap_len()  argument
29 	return map->mask + 1 + page_size;  in perf_mmap__mmap_len()
32 int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,  in perf_mmap__mmap()  argument
33 		    int fd, int cpu)  in perf_mmap__mmap()
35 	map->prev = 0;  in perf_mmap__mmap()
36 	map->mask = mp->mask;  in perf_mmap__mmap()
37 	map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,  in perf_mmap__mmap()
39 	if (map->base == MAP_FAILED) {  in perf_mmap__mmap()
40 		map->base = NULL;  in perf_mmap__mmap()
41 		return -1;  in perf_mmap__mmap()
44 	map->fd  = fd;  in perf_mmap__mmap()
45 	map->cpu = cpu;  in perf_mmap__mmap()
49 void perf_mmap__munmap(struct perf_mmap *map)  in perf_mmap__munmap()  argument
51 	if (map && map->base != NULL) {  in perf_mmap__munmap()
52 		munmap(map->base, perf_mmap__mmap_len(map));  in perf_mmap__munmap()
53 		map->base = NULL;  in perf_mmap__munmap()
54 		map->fd = -1;  in perf_mmap__munmap()
55 		refcount_set(&map->refcnt, 0);  in perf_mmap__munmap()
57 	if (map && map->unmap_cb)  in perf_mmap__munmap()
58 		map->unmap_cb(map);  in perf_mmap__munmap()
61 void perf_mmap__get(struct perf_mmap *map)  in perf_mmap__get()  argument
63 	refcount_inc(&map->refcnt);  in perf_mmap__get()
66 void perf_mmap__put(struct perf_mmap *map)  in perf_mmap__put()  argument
68 	BUG_ON(map->base && refcount_read(&map->refcnt) == 0);  in perf_mmap__put()
70 	if (refcount_dec_and_test(&map->refcnt))  in perf_mmap__put()
71 		perf_mmap__munmap(map);  in perf_mmap__put()
76 	ring_buffer_write_tail(md->base, tail);  in perf_mmap__write_tail()
79 u64 perf_mmap__read_head(struct perf_mmap *map)  in perf_mmap__read_head()  argument
81 	return ring_buffer_read_head(map->base);  in perf_mmap__read_head()
84 static bool perf_mmap__empty(struct perf_mmap *map)  in perf_mmap__empty()  argument
86 	struct perf_event_mmap_page *pc = map->base;  in perf_mmap__empty()
88 	return perf_mmap__read_head(map) == map->prev && !pc->aux_size;  in perf_mmap__empty()
91 void perf_mmap__consume(struct perf_mmap *map)  in perf_mmap__consume()  argument
93 	if (!map->overwrite) {  in perf_mmap__consume()
94 		u64 old = map->prev;  in perf_mmap__consume()
96 		perf_mmap__write_tail(map, old);  in perf_mmap__consume()
99 	if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))  in perf_mmap__consume()
100 		perf_mmap__put(map);  in perf_mmap__consume()
103 static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)  in overwrite_rb_find_range()  argument
107 	int size = mask + 1;  in overwrite_rb_find_range()
110 	pheader = (struct perf_event_header *)(buf + (*start & mask));  in overwrite_rb_find_range()
112 		if (evt_head - *start >= (unsigned int)size) {  in overwrite_rb_find_range()
114 			if (evt_head - *start > (unsigned int)size)  in overwrite_rb_find_range()
115 				evt_head -= pheader->size;  in overwrite_rb_find_range()
120 		pheader = (struct perf_event_header *)(buf + (evt_head & mask));  in overwrite_rb_find_range()
122 		if (pheader->size == 0) {  in overwrite_rb_find_range()
128 		evt_head += pheader->size;  in overwrite_rb_find_range()
132 	return -1;  in overwrite_rb_find_range()
138 static int __perf_mmap__read_init(struct perf_mmap *md)  in __perf_mmap__read_init()
141 	u64 old = md->prev;  in __perf_mmap__read_init()
142 	unsigned char *data = md->base + page_size;  in __perf_mmap__read_init()
145 	md->start = md->overwrite ? head : old;  in __perf_mmap__read_init()
146 	md->end = md->overwrite ? old : head;  in __perf_mmap__read_init()
148 	if ((md->end - md->start) < md->flush)  in __perf_mmap__read_init()
149 		return -EAGAIN;  in __perf_mmap__read_init()
151 	size = md->end - md->start;  in __perf_mmap__read_init()
152 	if (size > (unsigned long)(md->mask) + 1) {  in __perf_mmap__read_init()
153 		if (!md->overwrite) {  in __perf_mmap__read_init()
156 			md->prev = head;  in __perf_mmap__read_init()
158 			return -EAGAIN;  in __perf_mmap__read_init()
165 		if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))  in __perf_mmap__read_init()
166 			return -EINVAL;  in __perf_mmap__read_init()
172 int perf_mmap__read_init(struct perf_mmap *map)  in perf_mmap__read_init()  argument
177 	if (!refcount_read(&map->refcnt))  in perf_mmap__read_init()
178 		return -ENOENT;  in perf_mmap__read_init()
180 	return __perf_mmap__read_init(map);  in perf_mmap__read_init()
186  * The last perf_mmap__read() will set tail to map->core.prev.
187  * Need to correct the map->core.prev to head which is the end of next read.
189 void perf_mmap__read_done(struct perf_mmap *map)  in perf_mmap__read_done()  argument
194 	if (!refcount_read(&map->refcnt))  in perf_mmap__read_done()
197 	map->prev = perf_mmap__read_head(map);  in perf_mmap__read_done()
201 static union perf_event *perf_mmap__read(struct perf_mmap *map,  in perf_mmap__read()  argument
204 	unsigned char *data = map->base + page_size;  in perf_mmap__read()
206 	int diff = end - *startp;  in perf_mmap__read()
208 	if (diff >= (int)sizeof(event->header)) {  in perf_mmap__read()
211 		event = (union perf_event *)&data[*startp & map->mask];  in perf_mmap__read()
212 		size = event->header.size;  in perf_mmap__read()
214 		if (size < sizeof(event->header) || diff < (int)size)  in perf_mmap__read()
218 		 * Event straddles the mmap boundary -- header should always  in perf_mmap__read()
221 		if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {  in perf_mmap__read()
222 			unsigned int offset = *startp;  in perf_mmap__read()
223 			unsigned int len = min(sizeof(*event), size), cpy;  in perf_mmap__read()
224 			void *dst = map->event_copy;  in perf_mmap__read()
227 				cpy = min(map->mask + 1 - (offset & map->mask), len);  in perf_mmap__read()
228 				memcpy(dst, &data[offset & map->mask], cpy);  in perf_mmap__read()
231 				len -= cpy;  in perf_mmap__read()
234 			event = (union perf_event *)map->event_copy;  in perf_mmap__read()
255 union perf_event *perf_mmap__read_event(struct perf_mmap *map)  in perf_mmap__read_event()  argument
262 	if (!refcount_read(&map->refcnt))  in perf_mmap__read_event()
265 	/* non-overwirte doesn't pause the ringbuffer */  in perf_mmap__read_event()
266 	if (!map->overwrite)  in perf_mmap__read_event()
267 		map->end = perf_mmap__read_head(map);  in perf_mmap__read_event()
269 	event = perf_mmap__read(map, &map->start, map->end);  in perf_mmap__read_event()
271 	if (!map->overwrite)  in perf_mmap__read_event()
272 		map->prev = map->start;  in perf_mmap__read_event()