[librseq.git] / src / rseq-percpu-alloc.c

// SPDX-License-Identifier: MIT
// SPDX-FileCopyrightText: 2024 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

#include <rseq/percpu-alloc.h>
#include <sys/mman.h>
#include <assert.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <rseq/compiler.h>
#include <errno.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>

#ifdef HAVE_LIBNUMA
# include <numa.h>
# include <numaif.h>
#endif

#include "rseq-alloc-utils.h"

/*
 * rseq-percpu-alloc.c: rseq CPU-Local Storage (CLS) memory allocator.
 *
 * The rseq per-CPU memory allocator allows the application the request
 * memory pools of CPU-Local memory each of containing objects of a
 * given size (rounded to next power of 2), reserving a given virtual
 * address size per CPU, for a given maximum number of CPUs.
 *
 * The per-CPU memory allocator is analogous to TLS (Thread-Local
 * Storage) memory: TLS is Thread-Local Storage, whereas the per-CPU
 * memory allocator provides CPU-Local Storage.
 */

/*
 * Use high bits of per-CPU addresses to index the pool.
 * This leaves the low bits of available to the application for pointer
 * tagging (based on next power of 2 alignment of the allocations).
 */
#if RSEQ_BITS_PER_LONG == 64
# define POOL_INDEX_BITS	16
#else
# define POOL_INDEX_BITS	8
#endif
#define MAX_NR_POOLS		(1UL << POOL_INDEX_BITS)
#define POOL_INDEX_SHIFT	(RSEQ_BITS_PER_LONG - POOL_INDEX_BITS)
#define MAX_POOL_LEN		(1UL << POOL_INDEX_SHIFT)
#define MAX_POOL_LEN_MASK	(MAX_POOL_LEN - 1)

#define POOL_SET_NR_ENTRIES	POOL_INDEX_SHIFT

/*
 * Smallest allocation should hold enough space for a free list pointer.
 */
#if RSEQ_BITS_PER_LONG == 64
# define POOL_SET_MIN_ENTRY	3	/* Smallest item_len=8 */
#else
# define POOL_SET_MIN_ENTRY	2	/* Smallest item_len=4 */
#endif

/*
 * Skip pool index 0 to ensure allocated entries at index 0 do not match
 * a NULL pointer.
 */
#define FIRST_POOL		1

struct free_list_node;

struct free_list_node {
	struct free_list_node *next;
};

/* This lock protects pool create/destroy. */
static pthread_mutex_t pool_lock = PTHREAD_MUTEX_INITIALIZER;

struct rseq_mmap_attr {
	void *(*mmap_func)(void *priv, size_t len);
	int (*munmap_func)(void *priv, void *ptr, size_t len);
	void *mmap_priv;
};

struct rseq_percpu_pool {
	void *base;
	unsigned int index;
	size_t item_len;
	size_t percpu_len;
	int item_order;
	int max_nr_cpus;

	/*
	 * The free list chains freed items on the CPU 0 address range.
	 * We should rethink this decision if false sharing between
	 * malloc/free from other CPUs and data accesses from CPU 0
	 * becomes an issue. This is a NULL-terminated singly-linked
	 * list.
	 */
	struct free_list_node *free_list_head;
	size_t next_unused;
	/* This lock protects allocation/free within the pool. */
	pthread_mutex_t lock;

	struct rseq_mmap_attr mmap_attr;
};

//TODO: the array of pools should grow dynamically on create.
static struct rseq_percpu_pool rseq_percpu_pool[MAX_NR_POOLS];

/*
 * Pool set entries are indexed by item_len rounded to the next power of
 * 2. A pool set can contain NULL pool entries, in which case the next
 * large enough entry will be used for allocation.
 */
struct rseq_percpu_pool_set {
	/* This lock protects add vs malloc/zmalloc within the pool set. */
	pthread_mutex_t lock;
	struct rseq_percpu_pool *entries[POOL_SET_NR_ENTRIES];
};

static
void *__rseq_pool_percpu_ptr(struct rseq_percpu_pool *pool, int cpu, uintptr_t item_offset)
{
	return pool->base + (pool->percpu_len * cpu) + item_offset;
}

void *__rseq_percpu_ptr(void __rseq_percpu *_ptr, int cpu)
{
	uintptr_t ptr = (uintptr_t) _ptr;
	uintptr_t item_offset = ptr & MAX_POOL_LEN_MASK;
	uintptr_t pool_index = ptr >> POOL_INDEX_SHIFT;
	struct rseq_percpu_pool *pool = &rseq_percpu_pool[pool_index];

	assert(cpu >= 0);
	return __rseq_pool_percpu_ptr(pool, cpu, item_offset);
}

static
void rseq_percpu_zero_item(struct rseq_percpu_pool *pool, uintptr_t item_offset)
{
	int i;

	for (i = 0; i < pool->max_nr_cpus; i++) {
		char *p = __rseq_pool_percpu_ptr(pool, i, item_offset);
		memset(p, 0, pool->item_len);
	}
}

#ifdef HAVE_LIBNUMA
int rseq_percpu_pool_init_numa(struct rseq_percpu_pool *pool, int numa_flags)
{
	unsigned long nr_pages, page;
	long ret, page_len;
	int cpu;

	if (!numa_flags)
		return 0;
	page_len = rseq_get_page_len();
	nr_pages = pool->percpu_len >> rseq_get_count_order_ulong(page_len);
	for (cpu = 0; cpu < pool->max_nr_cpus; cpu++) {
		int node = numa_node_of_cpu(cpu);

		/* TODO: batch move_pages() call with an array of pages. */
		for (page = 0; page < nr_pages; page++) {
			void *pageptr = __rseq_pool_percpu_ptr(pool, cpu, page * page_len);
			int status = -EPERM;

			ret = move_pages(0, 1, &pageptr, &node, &status, numa_flags);
			if (ret)
				return ret;
		}
	}
	return 0;
}
#else
void rseq_percpu_pool_init_numa(struct rseq_percpu_pool *pool __attribute__((unused)),
		int numa_flags __attribute__((unused)))
{
	return 0;
}
#endif

static
void *default_mmap_func(void *priv __attribute__((unused)), size_t len)
{
	void *base;

	base = mmap(NULL, len, PROT_READ | PROT_WRITE,
			MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
	if (base == MAP_FAILED)
		return NULL;
	return base;
}

static
int default_munmap_func(void *priv __attribute__((unused)), void *ptr, size_t len)
{
	return munmap(ptr, len);
}

struct rseq_percpu_pool *rseq_percpu_pool_create(size_t item_len,
		size_t percpu_len, int max_nr_cpus,
		const struct rseq_mmap_attr *mmap_attr,
		int flags)
{
	void *(*mmap_func)(void *priv, size_t len);
	int (*munmap_func)(void *priv, void *ptr, size_t len);
	void *mmap_priv;
	struct rseq_percpu_pool *pool;
	void *base;
	unsigned int i;
	int order;

	if (flags) {
		errno = EINVAL;
		return NULL;
	}

	/* Make sure each item is large enough to contain free list pointers. */
	if (item_len < sizeof(void *))
		item_len = sizeof(void *);

	/* Align item_len on next power of two. */
	order = rseq_get_count_order_ulong(item_len);
	if (order < 0) {
		errno = EINVAL;
		return NULL;
	}
	item_len = 1UL << order;

	/* Align percpu_len on page size. */
	percpu_len = rseq_align(percpu_len, rseq_get_page_len());

	if (max_nr_cpus < 0 || item_len > percpu_len ||
			percpu_len > (UINTPTR_MAX >> POOL_INDEX_BITS)) {
		errno = EINVAL;
		return NULL;
	}

	if (mmap_attr) {
		mmap_func = mmap_attr->mmap_func;
		munmap_func = mmap_attr->munmap_func;
		mmap_priv = mmap_attr->mmap_priv;
	} else {
		mmap_func = default_mmap_func;
		munmap_func = default_munmap_func;
		mmap_priv = NULL;
	}
	pthread_mutex_lock(&pool_lock);
	/* Linear scan in array of pools to find empty spot. */
	for (i = FIRST_POOL; i < MAX_NR_POOLS; i++) {
		pool = &rseq_percpu_pool[i];
		if (!pool->base)
			goto found_empty;
	}
	errno = ENOMEM;
	pool = NULL;
	goto end;

found_empty:
	base = mmap_func(mmap_priv, percpu_len * max_nr_cpus);
	if (!base) {
		pool = NULL;
		goto end;
	}
	pthread_mutex_init(&pool->lock, NULL);
	pool->base = base;
	pool->percpu_len = percpu_len;
	pool->max_nr_cpus = max_nr_cpus;
	pool->index = i;
	pool->item_len = item_len;
	pool->item_order = order;
	pool->mmap_attr.mmap_func = mmap_func;
	pool->mmap_attr.munmap_func = munmap_func;
	pool->mmap_attr.mmap_priv = mmap_priv;
end:
	pthread_mutex_unlock(&pool_lock);
	return pool;
}

int rseq_percpu_pool_destroy(struct rseq_percpu_pool *pool)
{
	int ret;

	pthread_mutex_lock(&pool_lock);
	if (!pool->base) {
		errno = ENOENT;
		ret = -1;
		goto end;
	}
	ret = pool->mmap_attr.munmap_func(pool->mmap_attr.mmap_priv, pool->base,
			pool->percpu_len * pool->max_nr_cpus);
	if (ret)
		goto end;
	pthread_mutex_destroy(&pool->lock);
	memset(pool, 0, sizeof(*pool));
end:
	pthread_mutex_unlock(&pool_lock);
	return 0;
}

static
void __rseq_percpu *__rseq_percpu_malloc(struct rseq_percpu_pool *pool, bool zeroed)
{
	struct free_list_node *node;
	uintptr_t item_offset;
	void __rseq_percpu *addr;

	pthread_mutex_lock(&pool->lock);
	/* Get first entry from free list. */
	node = pool->free_list_head;
	if (node != NULL) {
		/* Remove node from free list (update head). */
		pool->free_list_head = node->next;
		item_offset = (uintptr_t) ((void *) node - pool->base);
		addr = (void *) (((uintptr_t) pool->index << POOL_INDEX_SHIFT) | item_offset);
		goto end;
	}
	if (pool->next_unused + pool->item_len > pool->percpu_len) {
		errno = ENOMEM;
		addr = NULL;
		goto end;
	}
	item_offset = pool->next_unused;
	addr = (void *) (((uintptr_t) pool->index << POOL_INDEX_SHIFT) | item_offset);
	pool->next_unused += pool->item_len;
end:
	pthread_mutex_unlock(&pool->lock);
	if (zeroed && addr)
		rseq_percpu_zero_item(pool, item_offset);
	return addr;
}

void __rseq_percpu *rseq_percpu_malloc(struct rseq_percpu_pool *pool)
{
	return __rseq_percpu_malloc(pool, false);
}

void __rseq_percpu *rseq_percpu_zmalloc(struct rseq_percpu_pool *pool)
{
	return __rseq_percpu_malloc(pool, true);
}

void rseq_percpu_free(void __rseq_percpu *_ptr)
{
	uintptr_t ptr = (uintptr_t) _ptr;
	uintptr_t item_offset = ptr & MAX_POOL_LEN_MASK;
	uintptr_t pool_index = ptr >> POOL_INDEX_SHIFT;
	struct rseq_percpu_pool *pool = &rseq_percpu_pool[pool_index];
	struct free_list_node *head, *item;

	pthread_mutex_lock(&pool->lock);
	/* Add ptr to head of free list */
	head = pool->free_list_head;
	/* Free-list is in CPU 0 range. */
	item = (struct free_list_node *)__rseq_pool_percpu_ptr(pool, 0, item_offset);
	item->next = head;
	pool->free_list_head = item;
	pthread_mutex_unlock(&pool->lock);
}

struct rseq_percpu_pool_set *rseq_percpu_pool_set_create(void)
{
	struct rseq_percpu_pool_set *pool_set;

	pool_set = calloc(1, sizeof(struct rseq_percpu_pool_set));
	if (!pool_set)
		return NULL;
	pthread_mutex_init(&pool_set->lock, NULL);
	return pool_set;
}

int rseq_percpu_pool_set_destroy(struct rseq_percpu_pool_set *pool_set)
{
	int order, ret;

	for (order = POOL_SET_MIN_ENTRY; order < POOL_SET_NR_ENTRIES; order++) {
		struct rseq_percpu_pool *pool = pool_set->entries[order];

		if (!pool)
			continue;
		ret = rseq_percpu_pool_destroy(pool);
		if (ret)
			return ret;
		pool_set->entries[order] = NULL;
	}
	pthread_mutex_destroy(&pool_set->lock);
	free(pool_set);
	return 0;
}

/* Ownership of pool is handed over to pool set on success. */
int rseq_percpu_pool_set_add_pool(struct rseq_percpu_pool_set *pool_set, struct rseq_percpu_pool *pool)
{
	size_t item_order = pool->item_order;
	int ret = 0;

	pthread_mutex_lock(&pool_set->lock);
	if (pool_set->entries[item_order]) {
		errno = EBUSY;
		ret = -1;
		goto end;
	}
	pool_set->entries[pool->item_order] = pool;
end:
	pthread_mutex_unlock(&pool_set->lock);
	return ret;
}

static
void __rseq_percpu *__rseq_percpu_pool_set_malloc(struct rseq_percpu_pool_set *pool_set, size_t len, bool zeroed)
{
	int order, min_order = POOL_SET_MIN_ENTRY;
	struct rseq_percpu_pool *pool;
	void __rseq_percpu *addr;

	order = rseq_get_count_order_ulong(len);
	if (order > POOL_SET_MIN_ENTRY)
		min_order = order;
again:
	pthread_mutex_lock(&pool_set->lock);
	/* First smallest present pool where @len fits. */
	for (order = min_order; order < POOL_SET_NR_ENTRIES; order++) {
		pool = pool_set->entries[order];

		if (!pool)
			continue;
		if (pool->item_len >= len)
			goto found;
	}
	pool = NULL;
found:
	pthread_mutex_unlock(&pool_set->lock);
	if (pool) {
		addr = __rseq_percpu_malloc(pool, zeroed);
		if (addr == NULL && errno == ENOMEM) {
			/*
			 * If the allocation failed, try again with a
			 * larger pool.
			 */
			min_order = order + 1;
			goto again;
		}
	} else {
		/* Not found. */
		errno = ENOMEM;
		addr = NULL;
	}
	return addr;
}

void __rseq_percpu *rseq_percpu_pool_set_malloc(struct rseq_percpu_pool_set *pool_set, size_t len)
{
	return __rseq_percpu_pool_set_malloc(pool_set, len, false);
}

void __rseq_percpu *rseq_percpu_pool_set_zmalloc(struct rseq_percpu_pool_set *pool_set, size_t len)
{
	return __rseq_percpu_pool_set_malloc(pool_set, len, true);
}

struct rseq_mmap_attr *rseq_mmap_attr_create(void *(*mmap_func)(void *priv, size_t len),
		int (*munmap_func)(void *priv, void *ptr, size_t len),
		void *mmap_priv)
{
	struct rseq_mmap_attr *attr = calloc(1, sizeof(struct rseq_mmap_attr));

	if (!attr)
		return NULL;
	attr->mmap_func = mmap_func;
	attr->munmap_func = munmap_func;
	attr->mmap_priv = mmap_priv;
	return attr;
}

void rseq_mmap_attr_destroy(struct rseq_mmap_attr *attr)
{
	free(attr);
}
Commit	Line	Data
ef6695f1 MD	1	// SPDX-License-Identifier: MIT
	2	// SPDX-FileCopyrightText: 2024 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	3
	4	#include <rseq/percpu-alloc.h>
	5	#include <sys/mman.h>
	6	#include <assert.h>
	7	#include <string.h>
	8	#include <pthread.h>
	9	#include <unistd.h>
	10	#include <stdlib.h>
	11	#include <rseq/compiler.h>
	12	#include <errno.h>
	13	#include <stdint.h>
	14	#include <stdbool.h>
367e559c MD	15	#include <stdio.h>
	16
	17	#ifdef HAVE_LIBNUMA
	18	# include <numa.h>
	19	# include <numaif.h>
	20	#endif
ef6695f1	21
19be9217 MD	22	#include "rseq-alloc-utils.h"
19be9217 MD	23
ef6695f1	24	/*
8ab16a24	25	* rseq-percpu-alloc.c: rseq CPU-Local Storage (CLS) memory allocator.
ef6695f1	26	*
8ab16a24 MD	27	* The rseq per-CPU memory allocator allows the application the request
8ab16a24 MD	28	* memory pools of CPU-Local memory each of containing objects of a
8aa1462d MD	29	* given size (rounded to next power of 2), reserving a given virtual
8aa1462d MD	30	* address size per CPU, for a given maximum number of CPUs.
8ab16a24 MD	31	*
	32	* The per-CPU memory allocator is analogous to TLS (Thread-Local
	33	* Storage) memory: TLS is Thread-Local Storage, whereas the per-CPU
	34	* memory allocator provides CPU-Local Storage.
ef6695f1 MD	35	*/
ef6695f1 MD	36
72b100a1	37	/*
8ab16a24	38	* Use high bits of per-CPU addresses to index the pool.
72b100a1 MD	39	* This leaves the low bits of available to the application for pointer
	40	* tagging (based on next power of 2 alignment of the allocations).
	41	*/
ef6695f1	42	#if RSEQ_BITS_PER_LONG == 64
72b100a1	43	# define POOL_INDEX_BITS 16
ef6695f1	44	#else
72b100a1	45	# define POOL_INDEX_BITS 8
ef6695f1	46	#endif
72b100a1 MD	47	#define MAX_NR_POOLS (1UL << POOL_INDEX_BITS)
	48	#define POOL_INDEX_SHIFT (RSEQ_BITS_PER_LONG - POOL_INDEX_BITS)
	49	#define MAX_POOL_LEN (1UL << POOL_INDEX_SHIFT)
	50	#define MAX_POOL_LEN_MASK (MAX_POOL_LEN - 1)
ef6695f1	51
72b100a1	52	#define POOL_SET_NR_ENTRIES POOL_INDEX_SHIFT
ef6695f1	53
72b100a1 MD	54	/*
	55	* Smallest allocation should hold enough space for a free list pointer.
	56	*/
ef6695f1 MD	57	#if RSEQ_BITS_PER_LONG == 64
	58	# define POOL_SET_MIN_ENTRY 3 /* Smallest item_len=8 */
	59	#else
	60	# define POOL_SET_MIN_ENTRY 2 /* Smallest item_len=4 */
	61	#endif
	62
bb1552e2 MD	63	/*
	64	* Skip pool index 0 to ensure allocated entries at index 0 do not match
	65	* a NULL pointer.
	66	*/
	67	#define FIRST_POOL 1
	68
ef6695f1 MD	69	struct free_list_node;
	70
	71	struct free_list_node {
	72	struct free_list_node *next;
	73	};
	74
	75	/* This lock protects pool create/destroy. */
	76	static pthread_mutex_t pool_lock = PTHREAD_MUTEX_INITIALIZER;
	77
9bd07c29 MD	78	struct rseq_mmap_attr {
	79	void (mmap_func)(void *priv, size_t len);
	80	int (munmap_func)(void priv, void *ptr, size_t len);
	81	void *mmap_priv;
	82	};
	83
ef6695f1 MD	84	struct rseq_percpu_pool {
	85	void *base;
	86	unsigned int index;
	87	size_t item_len;
	88	size_t percpu_len;
	89	int item_order;
	90	int max_nr_cpus;
	91
	92	/*
8ab16a24	93	* The free list chains freed items on the CPU 0 address range.
ef6695f1	94	* We should rethink this decision if false sharing between
8ab16a24	95	* malloc/free from other CPUs and data accesses from CPU 0
ef6695f1 MD	96	* becomes an issue. This is a NULL-terminated singly-linked
	97	* list.
	98	*/
	99	struct free_list_node *free_list_head;
	100	size_t next_unused;
	101	/* This lock protects allocation/free within the pool. */
	102	pthread_mutex_t lock;
9bd07c29 MD	103
9bd07c29 MD	104	struct rseq_mmap_attr mmap_attr;
ef6695f1 MD	105	};
	106
	107	//TODO: the array of pools should grow dynamically on create.
	108	static struct rseq_percpu_pool rseq_percpu_pool[MAX_NR_POOLS];
	109
	110	/*
	111	* Pool set entries are indexed by item_len rounded to the next power of
	112	* 2. A pool set can contain NULL pool entries, in which case the next
	113	* large enough entry will be used for allocation.
	114	*/
	115	struct rseq_percpu_pool_set {
	116	/* This lock protects add vs malloc/zmalloc within the pool set. */
	117	pthread_mutex_t lock;
	118	struct rseq_percpu_pool *entries[POOL_SET_NR_ENTRIES];
	119	};
	120
367e559c MD	121	static
	122	void __rseq_pool_percpu_ptr(struct rseq_percpu_pool pool, int cpu, uintptr_t item_offset)
	123	{
	124	return pool->base + (pool->percpu_len * cpu) + item_offset;
	125	}
	126
d24ee051	127	void __rseq_percpu_ptr(void __rseq_percpu _ptr, int cpu)
367e559c MD	128	{
367e559c MD	129	uintptr_t ptr = (uintptr_t) _ptr;
72b100a1 MD	130	uintptr_t item_offset = ptr & MAX_POOL_LEN_MASK;
72b100a1 MD	131	uintptr_t pool_index = ptr >> POOL_INDEX_SHIFT;
367e559c MD	132	struct rseq_percpu_pool *pool = &rseq_percpu_pool[pool_index];
	133
	134	assert(cpu >= 0);
	135	return __rseq_pool_percpu_ptr(pool, cpu, item_offset);
	136	}
	137
	138	static
	139	void rseq_percpu_zero_item(struct rseq_percpu_pool *pool, uintptr_t item_offset)
	140	{
	141	int i;
	142
	143	for (i = 0; i < pool->max_nr_cpus; i++) {
	144	char *p = __rseq_pool_percpu_ptr(pool, i, item_offset);
	145	memset(p, 0, pool->item_len);
	146	}
	147	}
	148
	149	#ifdef HAVE_LIBNUMA
9bd07c29	150	int rseq_percpu_pool_init_numa(struct rseq_percpu_pool *pool, int numa_flags)
367e559c MD	151	{
	152	unsigned long nr_pages, page;
	153	long ret, page_len;
	154	int cpu;
	155
	156	if (!numa_flags)
9bd07c29	157	return 0;
367e559c	158	page_len = rseq_get_page_len();
19be9217	159	nr_pages = pool->percpu_len >> rseq_get_count_order_ulong(page_len);
367e559c MD	160	for (cpu = 0; cpu < pool->max_nr_cpus; cpu++) {
	161	int node = numa_node_of_cpu(cpu);
	162
	163	/* TODO: batch move_pages() call with an array of pages. */
	164	for (page = 0; page < nr_pages; page++) {
	165	void pageptr = __rseq_pool_percpu_ptr(pool, cpu, page page_len);
	166	int status = -EPERM;
	167
	168	ret = move_pages(0, 1, &pageptr, &node, &status, numa_flags);
9bd07c29 MD	169	if (ret)
9bd07c29 MD	170	return ret;
367e559c MD	171	}
367e559c MD	172	}
9bd07c29	173	return 0;
367e559c MD	174	}
367e559c MD	175	#else
367e559c MD	176	void rseq_percpu_pool_init_numa(struct rseq_percpu_pool *pool __attribute__((unused)),
	177	int numa_flags __attribute__((unused)))
	178	{
9bd07c29	179	return 0;
367e559c MD	180	}
	181	#endif
	182
9bd07c29 MD	183	static
	184	void default_mmap_func(void priv __attribute__((unused)), size_t len)
	185	{
	186	void *base;
	187
	188	base = mmap(NULL, len, PROT_READ \| PROT_WRITE,
	189	MAP_ANONYMOUS \| MAP_PRIVATE, -1, 0);
	190	if (base == MAP_FAILED)
	191	return NULL;
	192	return base;
	193	}
	194
	195	static
	196	int default_munmap_func(void priv __attribute__((unused)), void ptr, size_t len)
	197	{
	198	return munmap(ptr, len);
	199	}
	200
ef6695f1 MD	201	struct rseq_percpu_pool *rseq_percpu_pool_create(size_t item_len,
ef6695f1 MD	202	size_t percpu_len, int max_nr_cpus,
6b30db4e MD	203	const struct rseq_mmap_attr *mmap_attr,
6b30db4e MD	204	int flags)
ef6695f1	205	{
9bd07c29 MD	206	void (mmap_func)(void *priv, size_t len);
	207	int (munmap_func)(void priv, void *ptr, size_t len);
	208	void *mmap_priv;
ef6695f1 MD	209	struct rseq_percpu_pool *pool;
	210	void *base;
	211	unsigned int i;
	212	int order;
ef6695f1	213
6b30db4e MD	214	if (flags) {
	215	errno = EINVAL;
	216	return NULL;
	217	}
	218
ef6695f1 MD	219	/* Make sure each item is large enough to contain free list pointers. */
	220	if (item_len < sizeof(void *))
	221	item_len = sizeof(void *);
	222
	223	/* Align item_len on next power of two. */
19be9217	224	order = rseq_get_count_order_ulong(item_len);
ef6695f1 MD	225	if (order < 0) {
	226	errno = EINVAL;
	227	return NULL;
	228	}
	229	item_len = 1UL << order;
	230
	231	/* Align percpu_len on page size. */
367e559c	232	percpu_len = rseq_align(percpu_len, rseq_get_page_len());
ef6695f1 MD	233
ef6695f1 MD	234	if (max_nr_cpus < 0 \|\| item_len > percpu_len \|\|
72b100a1	235	percpu_len > (UINTPTR_MAX >> POOL_INDEX_BITS)) {
ef6695f1 MD	236	errno = EINVAL;
	237	return NULL;
	238	}
	239
9bd07c29 MD	240	if (mmap_attr) {
	241	mmap_func = mmap_attr->mmap_func;
	242	munmap_func = mmap_attr->munmap_func;
	243	mmap_priv = mmap_attr->mmap_priv;
	244	} else {
	245	mmap_func = default_mmap_func;
	246	munmap_func = default_munmap_func;
	247	mmap_priv = NULL;
	248	}
ef6695f1 MD	249	pthread_mutex_lock(&pool_lock);
ef6695f1 MD	250	/* Linear scan in array of pools to find empty spot. */
bb1552e2	251	for (i = FIRST_POOL; i < MAX_NR_POOLS; i++) {
ef6695f1 MD	252	pool = &rseq_percpu_pool[i];
	253	if (!pool->base)
	254	goto found_empty;
	255	}
	256	errno = ENOMEM;
	257	pool = NULL;
	258	goto end;
	259
	260	found_empty:
9bd07c29 MD	261	base = mmap_func(mmap_priv, percpu_len * max_nr_cpus);
9bd07c29 MD	262	if (!base) {
ef6695f1 MD	263	pool = NULL;
	264	goto end;
	265	}
ef6695f1 MD	266	pthread_mutex_init(&pool->lock, NULL);
	267	pool->base = base;
	268	pool->percpu_len = percpu_len;
	269	pool->max_nr_cpus = max_nr_cpus;
	270	pool->index = i;
	271	pool->item_len = item_len;
	272	pool->item_order = order;
9bd07c29 MD	273	pool->mmap_attr.mmap_func = mmap_func;
	274	pool->mmap_attr.munmap_func = munmap_func;
	275	pool->mmap_attr.mmap_priv = mmap_priv;
ef6695f1 MD	276	end:
	277	pthread_mutex_unlock(&pool_lock);
	278	return pool;
	279	}
	280
	281	int rseq_percpu_pool_destroy(struct rseq_percpu_pool *pool)
	282	{
	283	int ret;
	284
	285	pthread_mutex_lock(&pool_lock);
	286	if (!pool->base) {
	287	errno = ENOENT;
	288	ret = -1;
	289	goto end;
	290	}
9bd07c29 MD	291	ret = pool->mmap_attr.munmap_func(pool->mmap_attr.mmap_priv, pool->base,
9bd07c29 MD	292	pool->percpu_len * pool->max_nr_cpus);
ef6695f1 MD	293	if (ret)
	294	goto end;
	295	pthread_mutex_destroy(&pool->lock);
	296	memset(pool, 0, sizeof(*pool));
	297	end:
	298	pthread_mutex_unlock(&pool_lock);
	299	return 0;
	300	}
	301
ef6695f1	302	static
d24ee051	303	void __rseq_percpu __rseq_percpu_malloc(struct rseq_percpu_pool pool, bool zeroed)
ef6695f1 MD	304	{
	305	struct free_list_node *node;
	306	uintptr_t item_offset;
d24ee051	307	void __rseq_percpu *addr;
ef6695f1 MD	308
	309	pthread_mutex_lock(&pool->lock);
	310	/* Get first entry from free list. */
	311	node = pool->free_list_head;
	312	if (node != NULL) {
	313	/* Remove node from free list (update head). */
	314	pool->free_list_head = node->next;
	315	item_offset = (uintptr_t) ((void *) node - pool->base);
72b100a1	316	addr = (void *) (((uintptr_t) pool->index << POOL_INDEX_SHIFT) \| item_offset);
ef6695f1 MD	317	goto end;
	318	}
	319	if (pool->next_unused + pool->item_len > pool->percpu_len) {
ea1a3ada	320	errno = ENOMEM;
ef6695f1 MD	321	addr = NULL;
	322	goto end;
	323	}
	324	item_offset = pool->next_unused;
72b100a1	325	addr = (void *) (((uintptr_t) pool->index << POOL_INDEX_SHIFT) \| item_offset);
ef6695f1 MD	326	pool->next_unused += pool->item_len;
	327	end:
	328	pthread_mutex_unlock(&pool->lock);
	329	if (zeroed && addr)
	330	rseq_percpu_zero_item(pool, item_offset);
	331	return addr;
	332	}
	333
d24ee051	334	void __rseq_percpu rseq_percpu_malloc(struct rseq_percpu_pool pool)
ef6695f1 MD	335	{
	336	return __rseq_percpu_malloc(pool, false);
	337	}
	338
d24ee051	339	void __rseq_percpu rseq_percpu_zmalloc(struct rseq_percpu_pool pool)
ef6695f1 MD	340	{
	341	return __rseq_percpu_malloc(pool, true);
	342	}
	343
d24ee051	344	void rseq_percpu_free(void __rseq_percpu *_ptr)
ef6695f1 MD	345	{
ef6695f1 MD	346	uintptr_t ptr = (uintptr_t) _ptr;
72b100a1 MD	347	uintptr_t item_offset = ptr & MAX_POOL_LEN_MASK;
72b100a1 MD	348	uintptr_t pool_index = ptr >> POOL_INDEX_SHIFT;
ef6695f1 MD	349	struct rseq_percpu_pool *pool = &rseq_percpu_pool[pool_index];
	350	struct free_list_node head, item;
	351
	352	pthread_mutex_lock(&pool->lock);
	353	/* Add ptr to head of free list */
	354	head = pool->free_list_head;
8ab16a24	355	/* Free-list is in CPU 0 range. */
ef6695f1 MD	356	item = (struct free_list_node *)__rseq_pool_percpu_ptr(pool, 0, item_offset);
	357	item->next = head;
	358	pool->free_list_head = item;
	359	pthread_mutex_unlock(&pool->lock);
	360	}
	361
	362	struct rseq_percpu_pool_set *rseq_percpu_pool_set_create(void)
	363	{
	364	struct rseq_percpu_pool_set *pool_set;
	365
	366	pool_set = calloc(1, sizeof(struct rseq_percpu_pool_set));
	367	if (!pool_set)
	368	return NULL;
	369	pthread_mutex_init(&pool_set->lock, NULL);
	370	return pool_set;
	371	}
	372
	373	int rseq_percpu_pool_set_destroy(struct rseq_percpu_pool_set *pool_set)
	374	{
	375	int order, ret;
	376
	377	for (order = POOL_SET_MIN_ENTRY; order < POOL_SET_NR_ENTRIES; order++) {
	378	struct rseq_percpu_pool *pool = pool_set->entries[order];
	379
	380	if (!pool)
	381	continue;
	382	ret = rseq_percpu_pool_destroy(pool);
	383	if (ret)
	384	return ret;
	385	pool_set->entries[order] = NULL;
	386	}
	387	pthread_mutex_destroy(&pool_set->lock);
	388	free(pool_set);
	389	return 0;
	390	}
	391
	392	/* Ownership of pool is handed over to pool set on success. */
	393	int rseq_percpu_pool_set_add_pool(struct rseq_percpu_pool_set pool_set, struct rseq_percpu_pool pool)
	394	{
	395	size_t item_order = pool->item_order;
	396	int ret = 0;
	397
	398	pthread_mutex_lock(&pool_set->lock);
	399	if (pool_set->entries[item_order]) {
	400	errno = EBUSY;
	401	ret = -1;
	402	goto end;
	403	}
	404	pool_set->entries[pool->item_order] = pool;
	405	end:
	406	pthread_mutex_unlock(&pool_set->lock);
	407	return ret;
	408	}
	409
	410	static
d24ee051	411	void __rseq_percpu __rseq_percpu_pool_set_malloc(struct rseq_percpu_pool_set pool_set, size_t len, bool zeroed)
ef6695f1 MD	412	{
	413	int order, min_order = POOL_SET_MIN_ENTRY;
	414	struct rseq_percpu_pool *pool;
d24ee051	415	void __rseq_percpu *addr;
ef6695f1	416
d06f5cf5 MD	417	order = rseq_get_count_order_ulong(len);
	418	if (order > POOL_SET_MIN_ENTRY)
	419	min_order = order;
ef6695f1 MD	420	again:
	421	pthread_mutex_lock(&pool_set->lock);
	422	/* First smallest present pool where @len fits. */
	423	for (order = min_order; order < POOL_SET_NR_ENTRIES; order++) {
	424	pool = pool_set->entries[order];
	425
	426	if (!pool)
	427	continue;
	428	if (pool->item_len >= len)
	429	goto found;
	430	}
	431	pool = NULL;
	432	found:
	433	pthread_mutex_unlock(&pool_set->lock);
	434	if (pool) {
	435	addr = __rseq_percpu_malloc(pool, zeroed);
	436	if (addr == NULL && errno == ENOMEM) {
	437	/*
	438	* If the allocation failed, try again with a
	439	* larger pool.
	440	*/
	441	min_order = order + 1;
	442	goto again;
	443	}
	444	} else {
	445	/* Not found. */
	446	errno = ENOMEM;
	447	addr = NULL;
	448	}
	449	return addr;
	450	}
	451
d24ee051	452	void __rseq_percpu rseq_percpu_pool_set_malloc(struct rseq_percpu_pool_set pool_set, size_t len)
ef6695f1 MD	453	{
	454	return __rseq_percpu_pool_set_malloc(pool_set, len, false);
	455	}
	456
d24ee051	457	void __rseq_percpu rseq_percpu_pool_set_zmalloc(struct rseq_percpu_pool_set pool_set, size_t len)
ef6695f1 MD	458	{
	459	return __rseq_percpu_pool_set_malloc(pool_set, len, true);
	460	}
9bd07c29 MD	461
	462	struct rseq_mmap_attr rseq_mmap_attr_create(void (mmap_func)(void priv, size_t len),
	463	int (munmap_func)(void priv, void *ptr, size_t len),
	464	void *mmap_priv)
	465	{
	466	struct rseq_mmap_attr *attr = calloc(1, sizeof(struct rseq_mmap_attr));
	467
	468	if (!attr)
	469	return NULL;
	470	attr->mmap_func = mmap_func;
	471	attr->munmap_func = munmap_func;
	472	attr->mmap_priv = mmap_priv;
	473	return attr;
	474	}
	475
	476	void rseq_mmap_attr_destroy(struct rseq_mmap_attr *attr)
	477	{
	478	free(attr);
	479	}