[mirror_ubuntu-jammy-kernel.git] / kernel / bpf / stackmap.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Facebook
 */
#include <linux/bpf.h>
#include <linux/jhash.h>
#include <linux/filter.h>
#include <linux/stacktrace.h>
#include <linux/perf_event.h>
#include <linux/elf.h>
#include <linux/pagemap.h>
#include <linux/irq_work.h>
#include "percpu_freelist.h"

#define STACK_CREATE_FLAG_MASK					\
	(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY |	\
	 BPF_F_STACK_BUILD_ID)

struct stack_map_bucket {
	struct pcpu_freelist_node fnode;
	u32 hash;
	u32 nr;
	u64 data[];
};

struct bpf_stack_map {
	struct bpf_map map;
	void *elems;
	struct pcpu_freelist freelist;
	u32 n_buckets;
	struct stack_map_bucket *buckets[];
};

/* irq_work to run up_read() for build_id lookup in nmi context */
struct stack_map_irq_work {
	struct irq_work irq_work;
	struct rw_semaphore *sem;
};

static void do_up_read(struct irq_work *entry)
{
	struct stack_map_irq_work *work;

	work = container_of(entry, struct stack_map_irq_work, irq_work);
	up_read_non_owner(work->sem);
	work->sem = NULL;
}

static DEFINE_PER_CPU(struct stack_map_irq_work, up_read_work);

static inline bool stack_map_use_build_id(struct bpf_map *map)
{
	return (map->map_flags & BPF_F_STACK_BUILD_ID);
}

static inline int stack_map_data_size(struct bpf_map *map)
{
	return stack_map_use_build_id(map) ?
		sizeof(struct bpf_stack_build_id) : sizeof(u64);
}

static int prealloc_elems_and_freelist(struct bpf_stack_map *smap)
{
	u32 elem_size = sizeof(struct stack_map_bucket) + smap->map.value_size;
	int err;

	smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries,
					 smap->map.numa_node);
	if (!smap->elems)
		return -ENOMEM;

	err = pcpu_freelist_init(&smap->freelist);
	if (err)
		goto free_elems;

	pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size,
			       smap->map.max_entries);
	return 0;

free_elems:
	bpf_map_area_free(smap->elems);
	return err;
}

/* Called from syscall */
static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
{
	u32 value_size = attr->value_size;
	struct bpf_stack_map *smap;
	struct bpf_map_memory mem;
	u64 cost, n_buckets;
	int err;

	if (!capable(CAP_SYS_ADMIN))
		return ERR_PTR(-EPERM);

	if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
		return ERR_PTR(-EINVAL);

	/* check sanity of attributes */
	if (attr->max_entries == 0 || attr->key_size != 4 ||
	    value_size < 8 || value_size % 8)
		return ERR_PTR(-EINVAL);

	BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64));
	if (attr->map_flags & BPF_F_STACK_BUILD_ID) {
		if (value_size % sizeof(struct bpf_stack_build_id) ||
		    value_size / sizeof(struct bpf_stack_build_id)
		    > sysctl_perf_event_max_stack)
			return ERR_PTR(-EINVAL);
	} else if (value_size / 8 > sysctl_perf_event_max_stack)
		return ERR_PTR(-EINVAL);

	/* hash table size must be power of 2 */
	n_buckets = roundup_pow_of_two(attr->max_entries);

	cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
	err = bpf_map_charge_init(&mem, cost);
	if (err)
		return ERR_PTR(err);

	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
	if (!smap) {
		bpf_map_charge_finish(&mem);
		return ERR_PTR(-ENOMEM);
	}

	bpf_map_init_from_attr(&smap->map, attr);
	smap->map.value_size = value_size;
	smap->n_buckets = n_buckets;

	err = get_callchain_buffers(sysctl_perf_event_max_stack);
	if (err)
		goto free_charge;

	err = prealloc_elems_and_freelist(smap);
	if (err)
		goto put_buffers;

	bpf_map_charge_move(&smap->map.memory, &mem);

	return &smap->map;

put_buffers:
	put_callchain_buffers();
free_charge:
	bpf_map_charge_finish(&mem);
	bpf_map_area_free(smap);
	return ERR_PTR(err);
}

#define BPF_BUILD_ID 3
/*
 * Parse build id from the note segment. This logic can be shared between
 * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
 * identical.
 */
static inline int stack_map_parse_build_id(void *page_addr,
					   unsigned char *build_id,
					   void *note_start,
					   Elf32_Word note_size)
{
	Elf32_Word note_offs = 0, new_offs;

	/* check for overflow */
	if (note_start < page_addr || note_start + note_size < note_start)
		return -EINVAL;

	/* only supports note that fits in the first page */
	if (note_start + note_size > page_addr + PAGE_SIZE)
		return -EINVAL;

	while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
		Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);

		if (nhdr->n_type == BPF_BUILD_ID &&
		    nhdr->n_namesz == sizeof("GNU") &&
		    nhdr->n_descsz > 0 &&
		    nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
			memcpy(build_id,
			       note_start + note_offs +
			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
			       nhdr->n_descsz);
			memset(build_id + nhdr->n_descsz, 0,
			       BPF_BUILD_ID_SIZE - nhdr->n_descsz);
			return 0;
		}
		new_offs = note_offs + sizeof(Elf32_Nhdr) +
			ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
		if (new_offs <= note_offs)  /* overflow */
			break;
		note_offs = new_offs;
	}
	return -EINVAL;
}

/* Parse build ID from 32-bit ELF */
static int stack_map_get_build_id_32(void *page_addr,
				     unsigned char *build_id)
{
	Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
	Elf32_Phdr *phdr;
	int i;

	/* only supports phdr that fits in one page */
	if (ehdr->e_phnum >
	    (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
		return -EINVAL;

	phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));

	for (i = 0; i < ehdr->e_phnum; ++i)
		if (phdr[i].p_type == PT_NOTE)
			return stack_map_parse_build_id(page_addr, build_id,
					page_addr + phdr[i].p_offset,
					phdr[i].p_filesz);
	return -EINVAL;
}

/* Parse build ID from 64-bit ELF */
static int stack_map_get_build_id_64(void *page_addr,
				     unsigned char *build_id)
{
	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
	Elf64_Phdr *phdr;
	int i;

	/* only supports phdr that fits in one page */
	if (ehdr->e_phnum >
	    (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
		return -EINVAL;

	phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));

	for (i = 0; i < ehdr->e_phnum; ++i)
		if (phdr[i].p_type == PT_NOTE)
			return stack_map_parse_build_id(page_addr, build_id,
					page_addr + phdr[i].p_offset,
					phdr[i].p_filesz);
	return -EINVAL;
}

/* Parse build ID of ELF file mapped to vma */
static int stack_map_get_build_id(struct vm_area_struct *vma,
				  unsigned char *build_id)
{
	Elf32_Ehdr *ehdr;
	struct page *page;
	void *page_addr;
	int ret;

	/* only works for page backed storage  */
	if (!vma->vm_file)
		return -EINVAL;

	page = find_get_page(vma->vm_file->f_mapping, 0);
	if (!page)
		return -EFAULT;	/* page not mapped */

	ret = -EINVAL;
	page_addr = kmap_atomic(page);
	ehdr = (Elf32_Ehdr *)page_addr;

	/* compare magic x7f "ELF" */
	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	/* only support executable file and shared object file */
	if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
		goto out;

	if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
		ret = stack_map_get_build_id_32(page_addr, build_id);
	else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
		ret = stack_map_get_build_id_64(page_addr, build_id);
out:
	kunmap_atomic(page_addr);
	put_page(page);
	return ret;
}

static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
					  u64 *ips, u32 trace_nr, bool user)
{
	int i;
	struct vm_area_struct *vma;
	bool irq_work_busy = false;
	struct stack_map_irq_work *work = NULL;

	if (irqs_disabled()) {
		work = this_cpu_ptr(&up_read_work);
		if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
			/* cannot queue more up_read, fallback */
			irq_work_busy = true;
	}

	/*
	 * We cannot do up_read() when the irq is disabled, because of
	 * risk to deadlock with rq_lock. To do build_id lookup when the
	 * irqs are disabled, we need to run up_read() in irq_work. We use
	 * a percpu variable to do the irq_work. If the irq_work is
	 * already used by another lookup, we fall back to report ips.
	 *
	 * Same fallback is used for kernel stack (!user) on a stackmap
	 * with build_id.
	 */
	if (!user || !current || !current->mm || irq_work_busy ||
	    down_read_trylock(&current->mm->mmap_sem) == 0) {
		/* cannot access current->mm, fall back to ips */
		for (i = 0; i < trace_nr; i++) {
			id_offs[i].status = BPF_STACK_BUILD_ID_IP;
			id_offs[i].ip = ips[i];
			memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
		}
		return;
	}

	for (i = 0; i < trace_nr; i++) {
		vma = find_vma(current->mm, ips[i]);
		if (!vma || stack_map_get_build_id(vma, id_offs[i].build_id)) {
			/* per entry fall back to ips */
			id_offs[i].status = BPF_STACK_BUILD_ID_IP;
			id_offs[i].ip = ips[i];
			memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
			continue;
		}
		id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
			- vma->vm_start;
		id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
	}

	if (!work) {
		up_read(&current->mm->mmap_sem);
	} else {
		work->sem = &current->mm->mmap_sem;
		irq_work_queue(&work->irq_work);
		/*
		 * The irq_work will release the mmap_sem with
		 * up_read_non_owner(). The rwsem_release() is called
		 * here to release the lock from lockdep's perspective.
		 */
		rwsem_release(&current->mm->mmap_sem.dep_map, _RET_IP_);
	}
}

BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
	   u64, flags)
{
	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
	struct perf_callchain_entry *trace;
	struct stack_map_bucket *bucket, *new_bucket, *old_bucket;
	u32 max_depth = map->value_size / stack_map_data_size(map);
	/* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */
	u32 init_nr = sysctl_perf_event_max_stack - max_depth;
	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
	u32 hash, id, trace_nr, trace_len;
	bool user = flags & BPF_F_USER_STACK;
	bool kernel = !user;
	u64 *ips;
	bool hash_matches;

	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
			       BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
		return -EINVAL;

	trace = get_perf_callchain(regs, init_nr, kernel, user,
				   sysctl_perf_event_max_stack, false, false);

	if (unlikely(!trace))
		/* couldn't fetch the stack trace */
		return -EFAULT;

	/* get_perf_callchain() guarantees that trace->nr >= init_nr
	 * and trace-nr <= sysctl_perf_event_max_stack, so trace_nr <= max_depth
	 */
	trace_nr = trace->nr - init_nr;

	if (trace_nr <= skip)
		/* skipping more than usable stack trace */
		return -EFAULT;

	trace_nr -= skip;
	trace_len = trace_nr * sizeof(u64);
	ips = trace->ip + skip + init_nr;
	hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0);
	id = hash & (smap->n_buckets - 1);
	bucket = READ_ONCE(smap->buckets[id]);

	hash_matches = bucket && bucket->hash == hash;
	/* fast cmp */
	if (hash_matches && flags & BPF_F_FAST_STACK_CMP)
		return id;

	if (stack_map_use_build_id(map)) {
		/* for build_id+offset, pop a bucket before slow cmp */
		new_bucket = (struct stack_map_bucket *)
			pcpu_freelist_pop(&smap->freelist);
		if (unlikely(!new_bucket))
			return -ENOMEM;
		new_bucket->nr = trace_nr;
		stack_map_get_build_id_offset(
			(struct bpf_stack_build_id *)new_bucket->data,
			ips, trace_nr, user);
		trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
		if (hash_matches && bucket->nr == trace_nr &&
		    memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
			pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
			return id;
		}
		if (bucket && !(flags & BPF_F_REUSE_STACKID)) {
			pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
			return -EEXIST;
		}
	} else {
		if (hash_matches && bucket->nr == trace_nr &&
		    memcmp(bucket->data, ips, trace_len) == 0)
			return id;
		if (bucket && !(flags & BPF_F_REUSE_STACKID))
			return -EEXIST;

		new_bucket = (struct stack_map_bucket *)
			pcpu_freelist_pop(&smap->freelist);
		if (unlikely(!new_bucket))
			return -ENOMEM;
		memcpy(new_bucket->data, ips, trace_len);
	}

	new_bucket->hash = hash;
	new_bucket->nr = trace_nr;

	old_bucket = xchg(&smap->buckets[id], new_bucket);
	if (old_bucket)
		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
	return id;
}

const struct bpf_func_proto bpf_get_stackid_proto = {
	.func		= bpf_get_stackid,
	.gpl_only	= true,
	.ret_type	= RET_INTEGER,
	.arg1_type	= ARG_PTR_TO_CTX,
	.arg2_type	= ARG_CONST_MAP_PTR,
	.arg3_type	= ARG_ANYTHING,
};

BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size,
	   u64, flags)
{
	u32 init_nr, trace_nr, copy_len, elem_size, num_elem;
	bool user_build_id = flags & BPF_F_USER_BUILD_ID;
	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
	bool user = flags & BPF_F_USER_STACK;
	struct perf_callchain_entry *trace;
	bool kernel = !user;
	int err = -EINVAL;
	u64 *ips;

	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
			       BPF_F_USER_BUILD_ID)))
		goto clear;
	if (kernel && user_build_id)
		goto clear;

	elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
					    : sizeof(u64);
	if (unlikely(size % elem_size))
		goto clear;

	num_elem = size / elem_size;
	if (sysctl_perf_event_max_stack < num_elem)
		init_nr = 0;
	else
		init_nr = sysctl_perf_event_max_stack - num_elem;
	trace = get_perf_callchain(regs, init_nr, kernel, user,
				   sysctl_perf_event_max_stack, false, false);
	if (unlikely(!trace))
		goto err_fault;

	trace_nr = trace->nr - init_nr;
	if (trace_nr < skip)
		goto err_fault;

	trace_nr -= skip;
	trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
	copy_len = trace_nr * elem_size;
	ips = trace->ip + skip + init_nr;
	if (user && user_build_id)
		stack_map_get_build_id_offset(buf, ips, trace_nr, user);
	else
		memcpy(buf, ips, copy_len);

	if (size > copy_len)
		memset(buf + copy_len, 0, size - copy_len);
	return copy_len;

err_fault:
	err = -EFAULT;
clear:
	memset(buf, 0, size);
	return err;
}

const struct bpf_func_proto bpf_get_stack_proto = {
	.func		= bpf_get_stack,
	.gpl_only	= true,
	.ret_type	= RET_INTEGER,
	.arg1_type	= ARG_PTR_TO_CTX,
	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
	.arg4_type	= ARG_ANYTHING,
};

/* Called from eBPF program */
static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
{
	return ERR_PTR(-EOPNOTSUPP);
}

/* Called from syscall */
int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
{
	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
	struct stack_map_bucket *bucket, *old_bucket;
	u32 id = *(u32 *)key, trace_len;

	if (unlikely(id >= smap->n_buckets))
		return -ENOENT;

	bucket = xchg(&smap->buckets[id], NULL);
	if (!bucket)
		return -ENOENT;

	trace_len = bucket->nr * stack_map_data_size(map);
	memcpy(value, bucket->data, trace_len);
	memset(value + trace_len, 0, map->value_size - trace_len);

	old_bucket = xchg(&smap->buckets[id], bucket);
	if (old_bucket)
		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
	return 0;
}

static int stack_map_get_next_key(struct bpf_map *map, void *key,
				  void *next_key)
{
	struct bpf_stack_map *smap = container_of(map,
						  struct bpf_stack_map, map);
	u32 id;

	WARN_ON_ONCE(!rcu_read_lock_held());

	if (!key) {
		id = 0;
	} else {
		id = *(u32 *)key;
		if (id >= smap->n_buckets || !smap->buckets[id])
			id = 0;
		else
			id++;
	}

	while (id < smap->n_buckets && !smap->buckets[id])
		id++;

	if (id >= smap->n_buckets)
		return -ENOENT;

	*(u32 *)next_key = id;
	return 0;
}

static int stack_map_update_elem(struct bpf_map *map, void *key, void *value,
				 u64 map_flags)
{
	return -EINVAL;
}

/* Called from syscall or from eBPF program */
static int stack_map_delete_elem(struct bpf_map *map, void *key)
{
	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
	struct stack_map_bucket *old_bucket;
	u32 id = *(u32 *)key;

	if (unlikely(id >= smap->n_buckets))
		return -E2BIG;

	old_bucket = xchg(&smap->buckets[id], NULL);
	if (old_bucket) {
		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
		return 0;
	} else {
		return -ENOENT;
	}
}

/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
static void stack_map_free(struct bpf_map *map)
{
	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);

	/* wait for bpf programs to complete before freeing stack map */
	synchronize_rcu();

	bpf_map_area_free(smap->elems);
	pcpu_freelist_destroy(&smap->freelist);
	bpf_map_area_free(smap);
	put_callchain_buffers();
}

const struct bpf_map_ops stack_trace_map_ops = {
	.map_alloc = stack_map_alloc,
	.map_free = stack_map_free,
	.map_get_next_key = stack_map_get_next_key,
	.map_lookup_elem = stack_map_lookup_elem,
	.map_update_elem = stack_map_update_elem,
	.map_delete_elem = stack_map_delete_elem,
	.map_check_btf = map_check_no_btf,
};

static int __init stack_map_init(void)
{
	int cpu;
	struct stack_map_irq_work *work;

	for_each_possible_cpu(cpu) {
		work = per_cpu_ptr(&up_read_work, cpu);
		init_irq_work(&work->irq_work, do_up_read);
	}
	return 0;
}
subsys_initcall(stack_map_init);
Commit	Line	Data
25763b3c	1	// SPDX-License-Identifier: GPL-2.0-only
d5a3b1f6	2	/* Copyright (c) 2016 Facebook
d5a3b1f6 AS	3	*/
	4	#include <linux/bpf.h>
	5	#include <linux/jhash.h>
	6	#include <linux/filter.h>
d5a3b1f6 AS	7	#include <linux/stacktrace.h>
d5a3b1f6 AS	8	#include <linux/perf_event.h>
615755a7 SL	9	#include <linux/elf.h>
615755a7 SL	10	#include <linux/pagemap.h>
bae77c5e	11	#include <linux/irq_work.h>
557c0c6e	12	#include "percpu_freelist.h"
d5a3b1f6	13
615755a7 SL	14	#define STACK_CREATE_FLAG_MASK \
	15	(BPF_F_NUMA_NODE \| BPF_F_RDONLY \| BPF_F_WRONLY \| \
	16	BPF_F_STACK_BUILD_ID)
6e71b04a	17
d5a3b1f6	18	struct stack_map_bucket {
557c0c6e	19	struct pcpu_freelist_node fnode;
d5a3b1f6 AS	20	u32 hash;
d5a3b1f6 AS	21	u32 nr;
615755a7	22	u64 data[];
d5a3b1f6 AS	23	};
	24
	25	struct bpf_stack_map {
	26	struct bpf_map map;
557c0c6e AS	27	void *elems;
557c0c6e AS	28	struct pcpu_freelist freelist;
d5a3b1f6	29	u32 n_buckets;
557c0c6e	30	struct stack_map_bucket *buckets[];
d5a3b1f6 AS	31	};
d5a3b1f6 AS	32
bae77c5e SL	33	/* irq_work to run up_read() for build_id lookup in nmi context */
	34	struct stack_map_irq_work {
	35	struct irq_work irq_work;
	36	struct rw_semaphore *sem;
	37	};
	38
	39	static void do_up_read(struct irq_work *entry)
	40	{
	41	struct stack_map_irq_work *work;
	42
	43	work = container_of(entry, struct stack_map_irq_work, irq_work);
3defaf2f	44	up_read_non_owner(work->sem);
bae77c5e SL	45	work->sem = NULL;
	46	}
	47
	48	static DEFINE_PER_CPU(struct stack_map_irq_work, up_read_work);
	49
615755a7 SL	50	static inline bool stack_map_use_build_id(struct bpf_map *map)
	51	{
	52	return (map->map_flags & BPF_F_STACK_BUILD_ID);
	53	}
	54
	55	static inline int stack_map_data_size(struct bpf_map *map)
	56	{
	57	return stack_map_use_build_id(map) ?
	58	sizeof(struct bpf_stack_build_id) : sizeof(u64);
	59	}
	60
557c0c6e AS	61	static int prealloc_elems_and_freelist(struct bpf_stack_map *smap)
	62	{
	63	u32 elem_size = sizeof(struct stack_map_bucket) + smap->map.value_size;
	64	int err;
	65
96eabe7a MKL	66	smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries,
96eabe7a MKL	67	smap->map.numa_node);
557c0c6e AS	68	if (!smap->elems)
	69	return -ENOMEM;
	70
	71	err = pcpu_freelist_init(&smap->freelist);
	72	if (err)
	73	goto free_elems;
	74
	75	pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size,
	76	smap->map.max_entries);
	77	return 0;
	78
	79	free_elems:
d407bd25	80	bpf_map_area_free(smap->elems);
557c0c6e AS	81	return err;
	82	}
	83
d5a3b1f6 AS	84	/* Called from syscall */
	85	static struct bpf_map stack_map_alloc(union bpf_attr attr)
	86	{
	87	u32 value_size = attr->value_size;
	88	struct bpf_stack_map *smap;
b936ca64	89	struct bpf_map_memory mem;
d5a3b1f6 AS	90	u64 cost, n_buckets;
	91	int err;
	92
	93	if (!capable(CAP_SYS_ADMIN))
	94	return ERR_PTR(-EPERM);
	95
6e71b04a	96	if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
823707b6 AS	97	return ERR_PTR(-EINVAL);
823707b6 AS	98
d5a3b1f6 AS	99	/* check sanity of attributes */
d5a3b1f6 AS	100	if (attr->max_entries == 0 \|\| attr->key_size != 4 \|\|
615755a7 SL	101	value_size < 8 \|\| value_size % 8)
	102	return ERR_PTR(-EINVAL);
	103
	104	BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64));
	105	if (attr->map_flags & BPF_F_STACK_BUILD_ID) {
	106	if (value_size % sizeof(struct bpf_stack_build_id) \|\|
	107	value_size / sizeof(struct bpf_stack_build_id)
	108	> sysctl_perf_event_max_stack)
	109	return ERR_PTR(-EINVAL);
	110	} else if (value_size / 8 > sysctl_perf_event_max_stack)
d5a3b1f6 AS	111	return ERR_PTR(-EINVAL);
	112
	113	/* hash table size must be power of 2 */
	114	n_buckets = roundup_pow_of_two(attr->max_entries);
	115
	116	cost = n_buckets * sizeof(struct stack_map_bucket ) + sizeof(smap);
b936ca64	117	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
c85d6913	118	err = bpf_map_charge_init(&mem, cost);
b936ca64 RG	119	if (err)
	120	return ERR_PTR(err);
	121
96eabe7a	122	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
b936ca64 RG	123	if (!smap) {
b936ca64 RG	124	bpf_map_charge_finish(&mem);
d407bd25	125	return ERR_PTR(-ENOMEM);
b936ca64	126	}
d5a3b1f6	127
bd475643	128	bpf_map_init_from_attr(&smap->map, attr);
d5a3b1f6	129	smap->map.value_size = value_size;
d5a3b1f6	130	smap->n_buckets = n_buckets;
557c0c6e	131
97c79a38	132	err = get_callchain_buffers(sysctl_perf_event_max_stack);
d5a3b1f6	133	if (err)
b936ca64	134	goto free_charge;
d5a3b1f6	135
557c0c6e AS	136	err = prealloc_elems_and_freelist(smap);
	137	if (err)
	138	goto put_buffers;
	139
b936ca64 RG	140	bpf_map_charge_move(&smap->map.memory, &mem);
b936ca64 RG	141
d5a3b1f6 AS	142	return &smap->map;
d5a3b1f6 AS	143
557c0c6e AS	144	put_buffers:
557c0c6e AS	145	put_callchain_buffers();
b936ca64 RG	146	free_charge:
b936ca64 RG	147	bpf_map_charge_finish(&mem);
d407bd25	148	bpf_map_area_free(smap);
d5a3b1f6 AS	149	return ERR_PTR(err);
	150	}
	151
615755a7 SL	152	#define BPF_BUILD_ID 3
	153	/*
	154	* Parse build id from the note segment. This logic can be shared between
	155	* 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
	156	* identical.
	157	*/
	158	static inline int stack_map_parse_build_id(void *page_addr,
	159	unsigned char *build_id,
	160	void *note_start,
	161	Elf32_Word note_size)
	162	{
	163	Elf32_Word note_offs = 0, new_offs;
	164
	165	/* check for overflow */
	166	if (note_start < page_addr \|\| note_start + note_size < note_start)
	167	return -EINVAL;
	168
	169	/* only supports note that fits in the first page */
	170	if (note_start + note_size > page_addr + PAGE_SIZE)
	171	return -EINVAL;
	172
	173	while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
	174	Elf32_Nhdr nhdr = (Elf32_Nhdr )(note_start + note_offs);
	175
	176	if (nhdr->n_type == BPF_BUILD_ID &&
	177	nhdr->n_namesz == sizeof("GNU") &&
0b698005 SF	178	nhdr->n_descsz > 0 &&
0b698005 SF	179	nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
615755a7 SL	180	memcpy(build_id,
	181	note_start + note_offs +
	182	ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
0b698005 SF	183	nhdr->n_descsz);
	184	memset(build_id + nhdr->n_descsz, 0,
	185	BPF_BUILD_ID_SIZE - nhdr->n_descsz);
615755a7 SL	186	return 0;
	187	}
	188	new_offs = note_offs + sizeof(Elf32_Nhdr) +
	189	ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
	190	if (new_offs <= note_offs) /* overflow */
	191	break;
	192	note_offs = new_offs;
	193	}
	194	return -EINVAL;
	195	}
	196
	197	/* Parse build ID from 32-bit ELF */
	198	static int stack_map_get_build_id_32(void *page_addr,
	199	unsigned char *build_id)
	200	{
	201	Elf32_Ehdr ehdr = (Elf32_Ehdr )page_addr;
	202	Elf32_Phdr *phdr;
	203	int i;
	204
	205	/* only supports phdr that fits in one page */
	206	if (ehdr->e_phnum >
	207	(PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
	208	return -EINVAL;
	209
	210	phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
	211
	212	for (i = 0; i < ehdr->e_phnum; ++i)
	213	if (phdr[i].p_type == PT_NOTE)
	214	return stack_map_parse_build_id(page_addr, build_id,
	215	page_addr + phdr[i].p_offset,
	216	phdr[i].p_filesz);
	217	return -EINVAL;
	218	}
	219
	220	/* Parse build ID from 64-bit ELF */
	221	static int stack_map_get_build_id_64(void *page_addr,
	222	unsigned char *build_id)
	223	{
	224	Elf64_Ehdr ehdr = (Elf64_Ehdr )page_addr;
	225	Elf64_Phdr *phdr;
	226	int i;
	227
	228	/* only supports phdr that fits in one page */
	229	if (ehdr->e_phnum >
	230	(PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
	231	return -EINVAL;
	232
	233	phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
	234
	235	for (i = 0; i < ehdr->e_phnum; ++i)
	236	if (phdr[i].p_type == PT_NOTE)
	237	return stack_map_parse_build_id(page_addr, build_id,
	238	page_addr + phdr[i].p_offset,
	239	phdr[i].p_filesz);
	240	return -EINVAL;
	241	}
	242
	243	/* Parse build ID of ELF file mapped to vma */
	244	static int stack_map_get_build_id(struct vm_area_struct *vma,
	245	unsigned char *build_id)
	246	{
	247	Elf32_Ehdr *ehdr;
	248	struct page *page;
	249	void *page_addr;
250	int ret;
251
252	/* only works for page backed storage */
253	if (!vma->vm_file)
254	return -EINVAL;
255
256	page = find_get_page(vma->vm_file->f_mapping, 0);
257	if (!page)
258	return -EFAULT; /* page not mapped */
259
260	ret = -EINVAL;
beaf3d19	261	page_addr = kmap_atomic(page);
615755a7 SL	262	ehdr = (Elf32_Ehdr *)page_addr;
	263
	264	/* compare magic x7f "ELF" */
	265	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
	266	goto out;
	267
	268	/* only support executable file and shared object file */
	269	if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
	270	goto out;
	271
	272	if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
	273	ret = stack_map_get_build_id_32(page_addr, build_id);
	274	else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
	275	ret = stack_map_get_build_id_64(page_addr, build_id);
	276	out:
beaf3d19	277	kunmap_atomic(page_addr);
615755a7 SL	278	put_page(page);
	279	return ret;
	280	}
	281
5f412632	282	static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
615755a7 SL	283	u64 *ips, u32 trace_nr, bool user)
	284	{
	285	int i;
	286	struct vm_area_struct *vma;
bae77c5e	287	bool irq_work_busy = false;
dc3b8ae9	288	struct stack_map_irq_work *work = NULL;
bae77c5e	289
eac9153f	290	if (irqs_disabled()) {
bae77c5e	291	work = this_cpu_ptr(&up_read_work);
153bedba	292	if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
bae77c5e SL	293	/* cannot queue more up_read, fallback */
	294	irq_work_busy = true;
	295	}
615755a7 SL	296
615755a7 SL	297	/*
eac9153f SL	298	* We cannot do up_read() when the irq is disabled, because of
	299	* risk to deadlock with rq_lock. To do build_id lookup when the
	300	* irqs are disabled, we need to run up_read() in irq_work. We use
bae77c5e SL	301	* a percpu variable to do the irq_work. If the irq_work is
bae77c5e SL	302	* already used by another lookup, we fall back to report ips.
615755a7 SL	303	*
	304	* Same fallback is used for kernel stack (!user) on a stackmap
	305	* with build_id.
	306	*/
bae77c5e	307	if (!user \|\| !current \|\| !current->mm \|\| irq_work_busy \|\|
615755a7 SL	308	down_read_trylock(&current->mm->mmap_sem) == 0) {
	309	/* cannot access current->mm, fall back to ips */
	310	for (i = 0; i < trace_nr; i++) {
	311	id_offs[i].status = BPF_STACK_BUILD_ID_IP;
	312	id_offs[i].ip = ips[i];
4af396ae	313	memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
615755a7 SL	314	}
	315	return;
	316	}
	317
	318	for (i = 0; i < trace_nr; i++) {
	319	vma = find_vma(current->mm, ips[i]);
	320	if (!vma \|\| stack_map_get_build_id(vma, id_offs[i].build_id)) {
	321	/* per entry fall back to ips */
	322	id_offs[i].status = BPF_STACK_BUILD_ID_IP;
	323	id_offs[i].ip = ips[i];
4af396ae	324	memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
615755a7 SL	325	continue;
	326	}
	327	id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
	328	- vma->vm_start;
	329	id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
	330	}
bae77c5e	331
dc3b8ae9	332	if (!work) {
bae77c5e SL	333	up_read(&current->mm->mmap_sem);
	334	} else {
	335	work->sem = &current->mm->mmap_sem;
	336	irq_work_queue(&work->irq_work);
3defaf2f AS	337	/*
	338	* The irq_work will release the mmap_sem with
	339	* up_read_non_owner(). The rwsem_release() is called
	340	* here to release the lock from lockdep's perspective.
	341	*/
5facae4f	342	rwsem_release(&current->mm->mmap_sem.dep_map, _RET_IP_);
bae77c5e	343	}
615755a7 SL	344	}
615755a7 SL	345
f3694e00 DB	346	BPF_CALL_3(bpf_get_stackid, struct pt_regs , regs, struct bpf_map , map,
f3694e00 DB	347	u64, flags)
d5a3b1f6	348	{
d5a3b1f6 AS	349	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
	350	struct perf_callchain_entry *trace;
	351	struct stack_map_bucket bucket, new_bucket, *old_bucket;
615755a7	352	u32 max_depth = map->value_size / stack_map_data_size(map);
c5dfd78e ACM	353	/* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */
c5dfd78e ACM	354	u32 init_nr = sysctl_perf_event_max_stack - max_depth;
d5a3b1f6 AS	355	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
	356	u32 hash, id, trace_nr, trace_len;
	357	bool user = flags & BPF_F_USER_STACK;
	358	bool kernel = !user;
	359	u64 *ips;
615755a7	360	bool hash_matches;
d5a3b1f6 AS	361
	362	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK \| BPF_F_USER_STACK \|
	363	BPF_F_FAST_STACK_CMP \| BPF_F_REUSE_STACKID)))
	364	return -EINVAL;
	365
cfbcf468 ACM	366	trace = get_perf_callchain(regs, init_nr, kernel, user,
cfbcf468 ACM	367	sysctl_perf_event_max_stack, false, false);
d5a3b1f6 AS	368
	369	if (unlikely(!trace))
	370	/* couldn't fetch the stack trace */
	371	return -EFAULT;
	372
	373	/* get_perf_callchain() guarantees that trace->nr >= init_nr
c5dfd78e	374	* and trace-nr <= sysctl_perf_event_max_stack, so trace_nr <= max_depth
d5a3b1f6 AS	375	*/
	376	trace_nr = trace->nr - init_nr;
	377
	378	if (trace_nr <= skip)
	379	/* skipping more than usable stack trace */
	380	return -EFAULT;
	381
	382	trace_nr -= skip;
	383	trace_len = trace_nr * sizeof(u64);
	384	ips = trace->ip + skip + init_nr;
	385	hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0);
	386	id = hash & (smap->n_buckets - 1);
557c0c6e	387	bucket = READ_ONCE(smap->buckets[id]);
d5a3b1f6	388
615755a7 SL	389	hash_matches = bucket && bucket->hash == hash;
	390	/* fast cmp */
	391	if (hash_matches && flags & BPF_F_FAST_STACK_CMP)
	392	return id;
	393
	394	if (stack_map_use_build_id(map)) {
	395	/* for build_id+offset, pop a bucket before slow cmp */
	396	new_bucket = (struct stack_map_bucket *)
	397	pcpu_freelist_pop(&smap->freelist);
	398	if (unlikely(!new_bucket))
	399	return -ENOMEM;
5f412632 YS	400	new_bucket->nr = trace_nr;
	401	stack_map_get_build_id_offset(
	402	(struct bpf_stack_build_id *)new_bucket->data,
	403	ips, trace_nr, user);
615755a7 SL	404	trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
	405	if (hash_matches && bucket->nr == trace_nr &&
	406	memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
	407	pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
d5a3b1f6	408	return id;
615755a7 SL	409	}
	410	if (bucket && !(flags & BPF_F_REUSE_STACKID)) {
	411	pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
	412	return -EEXIST;
	413	}
	414	} else {
	415	if (hash_matches && bucket->nr == trace_nr &&
	416	memcmp(bucket->data, ips, trace_len) == 0)
d5a3b1f6	417	return id;
615755a7 SL	418	if (bucket && !(flags & BPF_F_REUSE_STACKID))
	419	return -EEXIST;
	420
	421	new_bucket = (struct stack_map_bucket *)
	422	pcpu_freelist_pop(&smap->freelist);
	423	if (unlikely(!new_bucket))
	424	return -ENOMEM;
	425	memcpy(new_bucket->data, ips, trace_len);
d5a3b1f6 AS	426	}
d5a3b1f6 AS	427
d5a3b1f6 AS	428	new_bucket->hash = hash;
	429	new_bucket->nr = trace_nr;
	430
	431	old_bucket = xchg(&smap->buckets[id], new_bucket);
	432	if (old_bucket)
557c0c6e	433	pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
d5a3b1f6 AS	434	return id;
	435	}
	436
	437	const struct bpf_func_proto bpf_get_stackid_proto = {
	438	.func = bpf_get_stackid,
	439	.gpl_only = true,
	440	.ret_type = RET_INTEGER,
	441	.arg1_type = ARG_PTR_TO_CTX,
	442	.arg2_type = ARG_CONST_MAP_PTR,
	443	.arg3_type = ARG_ANYTHING,
	444	};
	445
c195651e YS	446	BPF_CALL_4(bpf_get_stack, struct pt_regs , regs, void , buf, u32, size,
	447	u64, flags)
	448	{
	449	u32 init_nr, trace_nr, copy_len, elem_size, num_elem;
	450	bool user_build_id = flags & BPF_F_USER_BUILD_ID;
	451	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
	452	bool user = flags & BPF_F_USER_STACK;
	453	struct perf_callchain_entry *trace;
	454	bool kernel = !user;
	455	int err = -EINVAL;
	456	u64 *ips;
	457
	458	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK \| BPF_F_USER_STACK \|
	459	BPF_F_USER_BUILD_ID)))
	460	goto clear;
	461	if (kernel && user_build_id)
	462	goto clear;
	463
	464	elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
	465	: sizeof(u64);
	466	if (unlikely(size % elem_size))
	467	goto clear;
	468
	469	num_elem = size / elem_size;
	470	if (sysctl_perf_event_max_stack < num_elem)
	471	init_nr = 0;
	472	else
	473	init_nr = sysctl_perf_event_max_stack - num_elem;
	474	trace = get_perf_callchain(regs, init_nr, kernel, user,
	475	sysctl_perf_event_max_stack, false, false);
	476	if (unlikely(!trace))
	477	goto err_fault;
	478
	479	trace_nr = trace->nr - init_nr;
	480	if (trace_nr < skip)
	481	goto err_fault;
	482
	483	trace_nr -= skip;
	484	trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
	485	copy_len = trace_nr * elem_size;
	486	ips = trace->ip + skip + init_nr;
	487	if (user && user_build_id)
	488	stack_map_get_build_id_offset(buf, ips, trace_nr, user);
	489	else
	490	memcpy(buf, ips, copy_len);
	491
	492	if (size > copy_len)
	493	memset(buf + copy_len, 0, size - copy_len);
	494	return copy_len;
	495
	496	err_fault:
	497	err = -EFAULT;
	498	clear:
	499	memset(buf, 0, size);
	500	return err;
	501	}
	502
	503	const struct bpf_func_proto bpf_get_stack_proto = {
	504	.func = bpf_get_stack,
	505	.gpl_only = true,
	506	.ret_type = RET_INTEGER,
	507	.arg1_type = ARG_PTR_TO_CTX,
	508	.arg2_type = ARG_PTR_TO_UNINIT_MEM,
	509	.arg3_type = ARG_CONST_SIZE_OR_ZERO,
510	.arg4_type = ARG_ANYTHING,
511	};
512
557c0c6e	513	/* Called from eBPF program */
d5a3b1f6	514	static void stack_map_lookup_elem(struct bpf_map map, void *key)
557c0c6e	515	{
3b4a63f6	516	return ERR_PTR(-EOPNOTSUPP);
557c0c6e AS	517	}
	518
	519	/* Called from syscall */
	520	int bpf_stackmap_copy(struct bpf_map map, void key, void *value)
d5a3b1f6 AS	521	{
d5a3b1f6 AS	522	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
557c0c6e AS	523	struct stack_map_bucket bucket, old_bucket;
557c0c6e AS	524	u32 id = (u32 )key, trace_len;
d5a3b1f6 AS	525
d5a3b1f6 AS	526	if (unlikely(id >= smap->n_buckets))
557c0c6e AS	527	return -ENOENT;
	528
	529	bucket = xchg(&smap->buckets[id], NULL);
	530	if (!bucket)
	531	return -ENOENT;
	532
615755a7 SL	533	trace_len = bucket->nr * stack_map_data_size(map);
615755a7 SL	534	memcpy(value, bucket->data, trace_len);
557c0c6e AS	535	memset(value + trace_len, 0, map->value_size - trace_len);
	536
	537	old_bucket = xchg(&smap->buckets[id], bucket);
	538	if (old_bucket)
	539	pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
	540	return 0;
d5a3b1f6 AS	541	}
d5a3b1f6 AS	542
16f07c55 YS	543	static int stack_map_get_next_key(struct bpf_map map, void key,
16f07c55 YS	544	void *next_key)
d5a3b1f6	545	{
16f07c55 YS	546	struct bpf_stack_map *smap = container_of(map,
	547	struct bpf_stack_map, map);
	548	u32 id;
	549
	550	WARN_ON_ONCE(!rcu_read_lock_held());
	551
	552	if (!key) {
	553	id = 0;
	554	} else {
	555	id = (u32 )key;
	556	if (id >= smap->n_buckets \|\| !smap->buckets[id])
	557	id = 0;
	558	else
	559	id++;
	560	}
	561
	562	while (id < smap->n_buckets && !smap->buckets[id])
	563	id++;
	564
	565	if (id >= smap->n_buckets)
	566	return -ENOENT;
	567
	568	(u32 )next_key = id;
	569	return 0;
d5a3b1f6 AS	570	}
	571
	572	static int stack_map_update_elem(struct bpf_map map, void key, void *value,
	573	u64 map_flags)
	574	{
	575	return -EINVAL;
	576	}
	577
	578	/* Called from syscall or from eBPF program */
	579	static int stack_map_delete_elem(struct bpf_map map, void key)
	580	{
	581	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
	582	struct stack_map_bucket *old_bucket;
	583	u32 id = (u32 )key;
	584
	585	if (unlikely(id >= smap->n_buckets))
	586	return -E2BIG;
	587
	588	old_bucket = xchg(&smap->buckets[id], NULL);
	589	if (old_bucket) {
557c0c6e	590	pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
d5a3b1f6 AS	591	return 0;
	592	} else {
	593	return -ENOENT;
	594	}
	595	}
	596
	597	/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
	598	static void stack_map_free(struct bpf_map *map)
	599	{
	600	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
d5a3b1f6	601
557c0c6e	602	/* wait for bpf programs to complete before freeing stack map */
d5a3b1f6 AS	603	synchronize_rcu();
d5a3b1f6 AS	604
d407bd25	605	bpf_map_area_free(smap->elems);
557c0c6e	606	pcpu_freelist_destroy(&smap->freelist);
d407bd25	607	bpf_map_area_free(smap);
d5a3b1f6 AS	608	put_callchain_buffers();
	609	}
	610
14499160	611	const struct bpf_map_ops stack_trace_map_ops = {
d5a3b1f6 AS	612	.map_alloc = stack_map_alloc,
	613	.map_free = stack_map_free,
	614	.map_get_next_key = stack_map_get_next_key,
	615	.map_lookup_elem = stack_map_lookup_elem,
	616	.map_update_elem = stack_map_update_elem,
	617	.map_delete_elem = stack_map_delete_elem,
e8d2bec0	618	.map_check_btf = map_check_no_btf,
d5a3b1f6	619	};
bae77c5e SL	620
	621	static int __init stack_map_init(void)
	622	{
	623	int cpu;
	624	struct stack_map_irq_work *work;
	625
	626	for_each_possible_cpu(cpu) {
	627	work = per_cpu_ptr(&up_read_work, cpu);
	628	init_irq_work(&work->irq_work, do_up_read);
	629	}
	630	return 0;
	631	}
	632	subsys_initcall(stack_map_init);