Message-ID: <153724635419.7866.6301500459081173494.stgit@kernel>
Date:   Tue, 18 Sep 2018 06:52:34 +0200
From:   Mauricio Vasquez B <mauricio.vasquez@...ito.it>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org
Cc:     Yonghong Song <yhs@...com>
Subject: [RFC PATCH bpf-next v3 1/7] bpf: rename stack trace map

In the following patches queue and stack maps (FIFO and LIFO
datastructures) will be implemented.  In order to avoid confusion and
a possible name clash rename stackmap.c to stacktracemap.c and
stack_map_ops to stack_trace_map_ops

Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@...ito.it>
---
 include/linux/bpf_types.h  |    2 
 kernel/bpf/Makefile        |    2 
 kernel/bpf/stackmap.c      |  624 --------------------------------------------
 kernel/bpf/stacktracemap.c |  624 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 626 insertions(+), 626 deletions(-)
 delete mode 100644 kernel/bpf/stackmap.c
 create mode 100644 kernel/bpf/stacktracemap.c

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index cd26c090e7c0..33f7f574b983 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -49,7 +49,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_HASH, htab_lru_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_PERCPU_HASH, htab_lru_percpu_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_LPM_TRIE, trie_map_ops)
 #ifdef CONFIG_PERF_EVENTS
-BPF_MAP_TYPE(BPF_MAP_TYPE_STACK_TRACE, stack_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_STACK_TRACE, stack_trace_map_ops)
 #endif
 BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY_OF_MAPS, array_of_maps_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 0488b8258321..e656bce87c8f 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -20,7 +20,7 @@ endif
 endif
 endif
 ifeq ($(CONFIG_PERF_EVENTS),y)
-obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
+obj-$(CONFIG_BPF_SYSCALL) += stacktracemap.o
 endif
 obj-$(CONFIG_CGROUP_BPF) += cgroup.o
 ifeq ($(CONFIG_INET),y)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
deleted file mode 100644
index 8061a439ef18..000000000000
--- a/kernel/bpf/stackmap.c
+++ /dev/null
@@ -1,624 +0,0 @@
-/* Copyright (c) 2016 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- */
-#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(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;
-	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);
-	if (cost >= U32_MAX - PAGE_SIZE)
-		return ERR_PTR(-E2BIG);
-
-	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
-	if (!smap)
-		return ERR_PTR(-ENOMEM);
-
-	err = -E2BIG;
-	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
-	if (cost >= U32_MAX - PAGE_SIZE)
-		goto free_smap;
-
-	bpf_map_init_from_attr(&smap->map, attr);
-	smap->map.value_size = value_size;
-	smap->n_buckets = n_buckets;
-	smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
-
-	err = bpf_map_precharge_memlock(smap->map.pages);
-	if (err)
-		goto free_smap;
-
-	err = get_callchain_buffers(sysctl_perf_event_max_stack);
-	if (err)
-		goto free_smap;
-
-	err = prealloc_elems_and_freelist(smap);
-	if (err)
-		goto put_buffers;
-
-	return &smap->map;
-
-put_buffers:
-	put_callchain_buffers();
-free_smap:
-	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 == BPF_BUILD_ID_SIZE) {
-			memcpy(build_id,
-			       note_start + note_offs +
-			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
-			       BPF_BUILD_ID_SIZE);
-			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 = page_address(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:
-	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 (in_nmi()) {
-		work = this_cpu_ptr(&up_read_work);
-		if (work->irq_work.flags & IRQ_WORK_BUSY)
-			/* cannot queue more up_read, fallback */
-			irq_work_busy = true;
-	}
-
-	/*
-	 * We cannot do up_read() in nmi context. To do build_id lookup
-	 * in nmi context, 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];
-		}
-		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];
-			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);
-	}
-}
-
-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 NULL;
-}
-
-/* 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_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);
diff --git a/kernel/bpf/stacktracemap.c b/kernel/bpf/stacktracemap.c
new file mode 100644
index 000000000000..bb41e293418d
--- /dev/null
+++ b/kernel/bpf/stacktracemap.c
@@ -0,0 +1,624 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#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(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;
+	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);
+	if (cost >= U32_MAX - PAGE_SIZE)
+		return ERR_PTR(-E2BIG);
+
+	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
+	if (!smap)
+		return ERR_PTR(-ENOMEM);
+
+	err = -E2BIG;
+	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
+	if (cost >= U32_MAX - PAGE_SIZE)
+		goto free_smap;
+
+	bpf_map_init_from_attr(&smap->map, attr);
+	smap->map.value_size = value_size;
+	smap->n_buckets = n_buckets;
+	smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
+
+	err = bpf_map_precharge_memlock(smap->map.pages);
+	if (err)
+		goto free_smap;
+
+	err = get_callchain_buffers(sysctl_perf_event_max_stack);
+	if (err)
+		goto free_smap;
+
+	err = prealloc_elems_and_freelist(smap);
+	if (err)
+		goto put_buffers;
+
+	return &smap->map;
+
+put_buffers:
+	put_callchain_buffers();
+free_smap:
+	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 == BPF_BUILD_ID_SIZE) {
+			memcpy(build_id,
+			       note_start + note_offs +
+			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
+			       BPF_BUILD_ID_SIZE);
+			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 = page_address(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:
+	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 (in_nmi()) {
+		work = this_cpu_ptr(&up_read_work);
+		if (work->irq_work.flags & IRQ_WORK_BUSY)
+			/* cannot queue more up_read, fallback */
+			irq_work_busy = true;
+	}
+
+	/*
+	 * We cannot do up_read() in nmi context. To do build_id lookup
+	 * in nmi context, 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];
+		}
+		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];
+			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);
+	}
+}
+
+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 NULL;
+}
+
+/* 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);

Powered by blists - more mailing lists