linux-hardened/mm/vmalloc.c
Nick Piggin 02b709df81 mm: purge fragmented percpu vmap blocks
Improve handling of fragmented per-CPU vmaps.  We previously don't free
up per-CPU maps until all its addresses have been used and freed.  So
fragmented blocks could fill up vmalloc space even if they actually had
no active vmap regions within them.

Add some logic to allow all CPUs to have these blocks purged in the case
of failure to allocate a new vm area, and also put some logic to trim
such blocks of a current CPU if we hit them in the allocation path (so
as to avoid a large build up of them).

Christoph reported some vmap allocation failures when using the per CPU
vmap APIs in XFS, which cannot be reproduced after this patch and the
previous bug fix.

Cc: linux-mm@kvack.org
Cc: stable@kernel.org
Tested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
--
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02 12:50:47 -08:00

2465 lines
61 KiB
C

/*
* linux/mm/vmalloc.c
*
* Copyright (C) 1993 Linus Torvalds
* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
* SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
* Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
* Numa awareness, Christoph Lameter, SGI, June 2005
*/
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
#include <linux/pfn.h>
#include <linux/kmemleak.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>
#include <asm/shmparam.h>
/*** Page table manipulation functions ***/
static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
{
pte_t *pte;
pte = pte_offset_kernel(pmd, addr);
do {
pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
WARN_ON(!pte_none(ptent) && !pte_present(ptent));
} while (pte++, addr += PAGE_SIZE, addr != end);
}
static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
vunmap_pte_range(pmd, addr, next);
} while (pmd++, addr = next, addr != end);
}
static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
{
pud_t *pud;
unsigned long next;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
vunmap_pmd_range(pud, addr, next);
} while (pud++, addr = next, addr != end);
}
static void vunmap_page_range(unsigned long addr, unsigned long end)
{
pgd_t *pgd;
unsigned long next;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
vunmap_pud_range(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pte_t *pte;
/*
* nr is a running index into the array which helps higher level
* callers keep track of where we're up to.
*/
pte = pte_alloc_kernel(pmd, addr);
if (!pte)
return -ENOMEM;
do {
struct page *page = pages[*nr];
if (WARN_ON(!pte_none(*pte)))
return -EBUSY;
if (WARN_ON(!page))
return -ENOMEM;
set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
(*nr)++;
} while (pte++, addr += PAGE_SIZE, addr != end);
return 0;
}
static int vmap_pmd_range(pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_alloc(&init_mm, pud, addr);
if (!pmd)
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
return -ENOMEM;
} while (pmd++, addr = next, addr != end);
return 0;
}
static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr)
{
pud_t *pud;
unsigned long next;
pud = pud_alloc(&init_mm, pgd, addr);
if (!pud)
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
return -ENOMEM;
} while (pud++, addr = next, addr != end);
return 0;
}
/*
* Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
* will have pfns corresponding to the "pages" array.
*
* Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
*/
static int vmap_page_range_noflush(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages)
{
pgd_t *pgd;
unsigned long next;
unsigned long addr = start;
int err = 0;
int nr = 0;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
if (err)
return err;
} while (pgd++, addr = next, addr != end);
return nr;
}
static int vmap_page_range(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages)
{
int ret;
ret = vmap_page_range_noflush(start, end, prot, pages);
flush_cache_vmap(start, end);
return ret;
}
int is_vmalloc_or_module_addr(const void *x)
{
/*
* ARM, x86-64 and sparc64 put modules in a special place,
* and fall back on vmalloc() if that fails. Others
* just put it in the vmalloc space.
*/
#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
unsigned long addr = (unsigned long)x;
if (addr >= MODULES_VADDR && addr < MODULES_END)
return 1;
#endif
return is_vmalloc_addr(x);
}
/*
* Walk a vmap address to the struct page it maps.
*/
struct page *vmalloc_to_page(const void *vmalloc_addr)
{
unsigned long addr = (unsigned long) vmalloc_addr;
struct page *page = NULL;
pgd_t *pgd = pgd_offset_k(addr);
/*
* XXX we might need to change this if we add VIRTUAL_BUG_ON for
* architectures that do not vmalloc module space
*/
VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
if (!pgd_none(*pgd)) {
pud_t *pud = pud_offset(pgd, addr);
if (!pud_none(*pud)) {
pmd_t *pmd = pmd_offset(pud, addr);
if (!pmd_none(*pmd)) {
pte_t *ptep, pte;
ptep = pte_offset_map(pmd, addr);
pte = *ptep;
if (pte_present(pte))
page = pte_page(pte);
pte_unmap(ptep);
}
}
}
return page;
}
EXPORT_SYMBOL(vmalloc_to_page);
/*
* Map a vmalloc()-space virtual address to the physical page frame number.
*/
unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
{
return page_to_pfn(vmalloc_to_page(vmalloc_addr));
}
EXPORT_SYMBOL(vmalloc_to_pfn);
/*** Global kva allocator ***/
#define VM_LAZY_FREE 0x01
#define VM_LAZY_FREEING 0x02
#define VM_VM_AREA 0x04
struct vmap_area {
unsigned long va_start;
unsigned long va_end;
unsigned long flags;
struct rb_node rb_node; /* address sorted rbtree */
struct list_head list; /* address sorted list */
struct list_head purge_list; /* "lazy purge" list */
void *private;
struct rcu_head rcu_head;
};
static DEFINE_SPINLOCK(vmap_area_lock);
static struct rb_root vmap_area_root = RB_ROOT;
static LIST_HEAD(vmap_area_list);
static unsigned long vmap_area_pcpu_hole;
static struct vmap_area *__find_vmap_area(unsigned long addr)
{
struct rb_node *n = vmap_area_root.rb_node;
while (n) {
struct vmap_area *va;
va = rb_entry(n, struct vmap_area, rb_node);
if (addr < va->va_start)
n = n->rb_left;
else if (addr > va->va_start)
n = n->rb_right;
else
return va;
}
return NULL;
}
static void __insert_vmap_area(struct vmap_area *va)
{
struct rb_node **p = &vmap_area_root.rb_node;
struct rb_node *parent = NULL;
struct rb_node *tmp;
while (*p) {
struct vmap_area *tmp;
parent = *p;
tmp = rb_entry(parent, struct vmap_area, rb_node);
if (va->va_start < tmp->va_end)
p = &(*p)->rb_left;
else if (va->va_end > tmp->va_start)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&va->rb_node, parent, p);
rb_insert_color(&va->rb_node, &vmap_area_root);
/* address-sort this list so it is usable like the vmlist */
tmp = rb_prev(&va->rb_node);
if (tmp) {
struct vmap_area *prev;
prev = rb_entry(tmp, struct vmap_area, rb_node);
list_add_rcu(&va->list, &prev->list);
} else
list_add_rcu(&va->list, &vmap_area_list);
}
static void purge_vmap_area_lazy(void);
/*
* Allocate a region of KVA of the specified size and alignment, within the
* vstart and vend.
*/
static struct vmap_area *alloc_vmap_area(unsigned long size,
unsigned long align,
unsigned long vstart, unsigned long vend,
int node, gfp_t gfp_mask)
{
struct vmap_area *va;
struct rb_node *n;
unsigned long addr;
int purged = 0;
BUG_ON(!size);
BUG_ON(size & ~PAGE_MASK);
va = kmalloc_node(sizeof(struct vmap_area),
gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!va))
return ERR_PTR(-ENOMEM);
retry:
addr = ALIGN(vstart, align);
spin_lock(&vmap_area_lock);
if (addr + size - 1 < addr)
goto overflow;
/* XXX: could have a last_hole cache */
n = vmap_area_root.rb_node;
if (n) {
struct vmap_area *first = NULL;
do {
struct vmap_area *tmp;
tmp = rb_entry(n, struct vmap_area, rb_node);
if (tmp->va_end >= addr) {
if (!first && tmp->va_start < addr + size)
first = tmp;
n = n->rb_left;
} else {
first = tmp;
n = n->rb_right;
}
} while (n);
if (!first)
goto found;
if (first->va_end < addr) {
n = rb_next(&first->rb_node);
if (n)
first = rb_entry(n, struct vmap_area, rb_node);
else
goto found;
}
while (addr + size > first->va_start && addr + size <= vend) {
addr = ALIGN(first->va_end + PAGE_SIZE, align);
if (addr + size - 1 < addr)
goto overflow;
n = rb_next(&first->rb_node);
if (n)
first = rb_entry(n, struct vmap_area, rb_node);
else
goto found;
}
}
found:
if (addr + size > vend) {
overflow:
spin_unlock(&vmap_area_lock);
if (!purged) {
purge_vmap_area_lazy();
purged = 1;
goto retry;
}
if (printk_ratelimit())
printk(KERN_WARNING
"vmap allocation for size %lu failed: "
"use vmalloc=<size> to increase size.\n", size);
kfree(va);
return ERR_PTR(-EBUSY);
}
BUG_ON(addr & (align-1));
va->va_start = addr;
va->va_end = addr + size;
va->flags = 0;
__insert_vmap_area(va);
spin_unlock(&vmap_area_lock);
return va;
}
static void rcu_free_va(struct rcu_head *head)
{
struct vmap_area *va = container_of(head, struct vmap_area, rcu_head);
kfree(va);
}
static void __free_vmap_area(struct vmap_area *va)
{
BUG_ON(RB_EMPTY_NODE(&va->rb_node));
rb_erase(&va->rb_node, &vmap_area_root);
RB_CLEAR_NODE(&va->rb_node);
list_del_rcu(&va->list);
/*
* Track the highest possible candidate for pcpu area
* allocation. Areas outside of vmalloc area can be returned
* here too, consider only end addresses which fall inside
* vmalloc area proper.
*/
if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
call_rcu(&va->rcu_head, rcu_free_va);
}
/*
* Free a region of KVA allocated by alloc_vmap_area
*/
static void free_vmap_area(struct vmap_area *va)
{
spin_lock(&vmap_area_lock);
__free_vmap_area(va);
spin_unlock(&vmap_area_lock);
}
/*
* Clear the pagetable entries of a given vmap_area
*/
static void unmap_vmap_area(struct vmap_area *va)
{
vunmap_page_range(va->va_start, va->va_end);
}
static void vmap_debug_free_range(unsigned long start, unsigned long end)
{
/*
* Unmap page tables and force a TLB flush immediately if
* CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
* bugs similarly to those in linear kernel virtual address
* space after a page has been freed.
*
* All the lazy freeing logic is still retained, in order to
* minimise intrusiveness of this debugging feature.
*
* This is going to be *slow* (linear kernel virtual address
* debugging doesn't do a broadcast TLB flush so it is a lot
* faster).
*/
#ifdef CONFIG_DEBUG_PAGEALLOC
vunmap_page_range(start, end);
flush_tlb_kernel_range(start, end);
#endif
}
/*
* lazy_max_pages is the maximum amount of virtual address space we gather up
* before attempting to purge with a TLB flush.
*
* There is a tradeoff here: a larger number will cover more kernel page tables
* and take slightly longer to purge, but it will linearly reduce the number of
* global TLB flushes that must be performed. It would seem natural to scale
* this number up linearly with the number of CPUs (because vmapping activity
* could also scale linearly with the number of CPUs), however it is likely
* that in practice, workloads might be constrained in other ways that mean
* vmap activity will not scale linearly with CPUs. Also, I want to be
* conservative and not introduce a big latency on huge systems, so go with
* a less aggressive log scale. It will still be an improvement over the old
* code, and it will be simple to change the scale factor if we find that it
* becomes a problem on bigger systems.
*/
static unsigned long lazy_max_pages(void)
{
unsigned int log;
log = fls(num_online_cpus());
return log * (32UL * 1024 * 1024 / PAGE_SIZE);
}
static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
/* for per-CPU blocks */
static void purge_fragmented_blocks_allcpus(void);
/*
* Purges all lazily-freed vmap areas.
*
* If sync is 0 then don't purge if there is already a purge in progress.
* If force_flush is 1, then flush kernel TLBs between *start and *end even
* if we found no lazy vmap areas to unmap (callers can use this to optimise
* their own TLB flushing).
* Returns with *start = min(*start, lowest purged address)
* *end = max(*end, highest purged address)
*/
static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
int sync, int force_flush)
{
static DEFINE_SPINLOCK(purge_lock);
LIST_HEAD(valist);
struct vmap_area *va;
struct vmap_area *n_va;
int nr = 0;
/*
* If sync is 0 but force_flush is 1, we'll go sync anyway but callers
* should not expect such behaviour. This just simplifies locking for
* the case that isn't actually used at the moment anyway.
*/
if (!sync && !force_flush) {
if (!spin_trylock(&purge_lock))
return;
} else
spin_lock(&purge_lock);
if (sync)
purge_fragmented_blocks_allcpus();
rcu_read_lock();
list_for_each_entry_rcu(va, &vmap_area_list, list) {
if (va->flags & VM_LAZY_FREE) {
if (va->va_start < *start)
*start = va->va_start;
if (va->va_end > *end)
*end = va->va_end;
nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
unmap_vmap_area(va);
list_add_tail(&va->purge_list, &valist);
va->flags |= VM_LAZY_FREEING;
va->flags &= ~VM_LAZY_FREE;
}
}
rcu_read_unlock();
if (nr)
atomic_sub(nr, &vmap_lazy_nr);
if (nr || force_flush)
flush_tlb_kernel_range(*start, *end);
if (nr) {
spin_lock(&vmap_area_lock);
list_for_each_entry_safe(va, n_va, &valist, purge_list)
__free_vmap_area(va);
spin_unlock(&vmap_area_lock);
}
spin_unlock(&purge_lock);
}
/*
* Kick off a purge of the outstanding lazy areas. Don't bother if somebody
* is already purging.
*/
static void try_purge_vmap_area_lazy(void)
{
unsigned long start = ULONG_MAX, end = 0;
__purge_vmap_area_lazy(&start, &end, 0, 0);
}
/*
* Kick off a purge of the outstanding lazy areas.
*/
static void purge_vmap_area_lazy(void)
{
unsigned long start = ULONG_MAX, end = 0;
__purge_vmap_area_lazy(&start, &end, 1, 0);
}
/*
* Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been
* called for the correct range previously.
*/
static void free_unmap_vmap_area_noflush(struct vmap_area *va)
{
va->flags |= VM_LAZY_FREE;
atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages()))
try_purge_vmap_area_lazy();
}
/*
* Free and unmap a vmap area
*/
static void free_unmap_vmap_area(struct vmap_area *va)
{
flush_cache_vunmap(va->va_start, va->va_end);
free_unmap_vmap_area_noflush(va);
}
static struct vmap_area *find_vmap_area(unsigned long addr)
{
struct vmap_area *va;
spin_lock(&vmap_area_lock);
va = __find_vmap_area(addr);
spin_unlock(&vmap_area_lock);
return va;
}
static void free_unmap_vmap_area_addr(unsigned long addr)
{
struct vmap_area *va;
va = find_vmap_area(addr);
BUG_ON(!va);
free_unmap_vmap_area(va);
}
/*** Per cpu kva allocator ***/
/*
* vmap space is limited especially on 32 bit architectures. Ensure there is
* room for at least 16 percpu vmap blocks per CPU.
*/
/*
* If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
* to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess
* instead (we just need a rough idea)
*/
#if BITS_PER_LONG == 32
#define VMALLOC_SPACE (128UL*1024*1024)
#else
#define VMALLOC_SPACE (128UL*1024*1024*1024)
#endif
#define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
#define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
#define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
#define VMAP_BBMAP_BITS VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
VMALLOC_PAGES / NR_CPUS / 16))
#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
static bool vmap_initialized __read_mostly = false;
struct vmap_block_queue {
spinlock_t lock;
struct list_head free;
};
struct vmap_block {
spinlock_t lock;
struct vmap_area *va;
struct vmap_block_queue *vbq;
unsigned long free, dirty;
DECLARE_BITMAP(alloc_map, VMAP_BBMAP_BITS);
DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS);
struct list_head free_list;
struct rcu_head rcu_head;
struct list_head purge;
};
/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
/*
* Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
* in the free path. Could get rid of this if we change the API to return a
* "cookie" from alloc, to be passed to free. But no big deal yet.
*/
static DEFINE_SPINLOCK(vmap_block_tree_lock);
static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
/*
* We should probably have a fallback mechanism to allocate virtual memory
* out of partially filled vmap blocks. However vmap block sizing should be
* fairly reasonable according to the vmalloc size, so it shouldn't be a
* big problem.
*/
static unsigned long addr_to_vb_idx(unsigned long addr)
{
addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
addr /= VMAP_BLOCK_SIZE;
return addr;
}
static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
{
struct vmap_block_queue *vbq;
struct vmap_block *vb;
struct vmap_area *va;
unsigned long vb_idx;
int node, err;
node = numa_node_id();
vb = kmalloc_node(sizeof(struct vmap_block),
gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!vb))
return ERR_PTR(-ENOMEM);
va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
VMALLOC_START, VMALLOC_END,
node, gfp_mask);
if (unlikely(IS_ERR(va))) {
kfree(vb);
return ERR_PTR(PTR_ERR(va));
}
err = radix_tree_preload(gfp_mask);
if (unlikely(err)) {
kfree(vb);
free_vmap_area(va);
return ERR_PTR(err);
}
spin_lock_init(&vb->lock);
vb->va = va;
vb->free = VMAP_BBMAP_BITS;
vb->dirty = 0;
bitmap_zero(vb->alloc_map, VMAP_BBMAP_BITS);
bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS);
INIT_LIST_HEAD(&vb->free_list);
vb_idx = addr_to_vb_idx(va->va_start);
spin_lock(&vmap_block_tree_lock);
err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
spin_unlock(&vmap_block_tree_lock);
BUG_ON(err);
radix_tree_preload_end();
vbq = &get_cpu_var(vmap_block_queue);
vb->vbq = vbq;
spin_lock(&vbq->lock);
list_add_rcu(&vb->free_list, &vbq->free);
spin_unlock(&vbq->lock);
put_cpu_var(vmap_block_queue);
return vb;
}
static void rcu_free_vb(struct rcu_head *head)
{
struct vmap_block *vb = container_of(head, struct vmap_block, rcu_head);
kfree(vb);
}
static void free_vmap_block(struct vmap_block *vb)
{
struct vmap_block *tmp;
unsigned long vb_idx;
vb_idx = addr_to_vb_idx(vb->va->va_start);
spin_lock(&vmap_block_tree_lock);
tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
spin_unlock(&vmap_block_tree_lock);
BUG_ON(tmp != vb);
free_unmap_vmap_area_noflush(vb->va);
call_rcu(&vb->rcu_head, rcu_free_vb);
}
static void purge_fragmented_blocks(int cpu)
{
LIST_HEAD(purge);
struct vmap_block *vb;
struct vmap_block *n_vb;
struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
rcu_read_lock();
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
continue;
spin_lock(&vb->lock);
if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
vb->free = 0; /* prevent further allocs after releasing lock */
vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
bitmap_fill(vb->alloc_map, VMAP_BBMAP_BITS);
bitmap_fill(vb->dirty_map, VMAP_BBMAP_BITS);
spin_lock(&vbq->lock);
list_del_rcu(&vb->free_list);
spin_unlock(&vbq->lock);
spin_unlock(&vb->lock);
list_add_tail(&vb->purge, &purge);
} else
spin_unlock(&vb->lock);
}
rcu_read_unlock();
list_for_each_entry_safe(vb, n_vb, &purge, purge) {
list_del(&vb->purge);
free_vmap_block(vb);
}
}
static void purge_fragmented_blocks_thiscpu(void)
{
purge_fragmented_blocks(smp_processor_id());
}
static void purge_fragmented_blocks_allcpus(void)
{
int cpu;
for_each_possible_cpu(cpu)
purge_fragmented_blocks(cpu);
}
static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
{
struct vmap_block_queue *vbq;
struct vmap_block *vb;
unsigned long addr = 0;
unsigned int order;
int purge = 0;
BUG_ON(size & ~PAGE_MASK);
BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
order = get_order(size);
again:
rcu_read_lock();
vbq = &get_cpu_var(vmap_block_queue);
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
int i;
spin_lock(&vb->lock);
if (vb->free < 1UL << order)
goto next;
i = bitmap_find_free_region(vb->alloc_map,
VMAP_BBMAP_BITS, order);
if (i < 0) {
if (vb->free + vb->dirty == VMAP_BBMAP_BITS) {
/* fragmented and no outstanding allocations */
BUG_ON(vb->dirty != VMAP_BBMAP_BITS);
purge = 1;
}
goto next;
}
addr = vb->va->va_start + (i << PAGE_SHIFT);
BUG_ON(addr_to_vb_idx(addr) !=
addr_to_vb_idx(vb->va->va_start));
vb->free -= 1UL << order;
if (vb->free == 0) {
spin_lock(&vbq->lock);
list_del_rcu(&vb->free_list);
spin_unlock(&vbq->lock);
}
spin_unlock(&vb->lock);
break;
next:
spin_unlock(&vb->lock);
}
if (purge)
purge_fragmented_blocks_thiscpu();
put_cpu_var(vmap_block_queue);
rcu_read_unlock();
if (!addr) {
vb = new_vmap_block(gfp_mask);
if (IS_ERR(vb))
return vb;
goto again;
}
return (void *)addr;
}
static void vb_free(const void *addr, unsigned long size)
{
unsigned long offset;
unsigned long vb_idx;
unsigned int order;
struct vmap_block *vb;
BUG_ON(size & ~PAGE_MASK);
BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
order = get_order(size);
offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
vb_idx = addr_to_vb_idx((unsigned long)addr);
rcu_read_lock();
vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
rcu_read_unlock();
BUG_ON(!vb);
spin_lock(&vb->lock);
BUG_ON(bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order));
vb->dirty += 1UL << order;
if (vb->dirty == VMAP_BBMAP_BITS) {
BUG_ON(vb->free);
spin_unlock(&vb->lock);
free_vmap_block(vb);
} else
spin_unlock(&vb->lock);
}
/**
* vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
*
* The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
* to amortize TLB flushing overheads. What this means is that any page you
* have now, may, in a former life, have been mapped into kernel virtual
* address by the vmap layer and so there might be some CPUs with TLB entries
* still referencing that page (additional to the regular 1:1 kernel mapping).
*
* vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
* be sure that none of the pages we have control over will have any aliases
* from the vmap layer.
*/
void vm_unmap_aliases(void)
{
unsigned long start = ULONG_MAX, end = 0;
int cpu;
int flush = 0;
if (unlikely(!vmap_initialized))
return;
for_each_possible_cpu(cpu) {
struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
struct vmap_block *vb;
rcu_read_lock();
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
int i;
spin_lock(&vb->lock);
i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
while (i < VMAP_BBMAP_BITS) {
unsigned long s, e;
int j;
j = find_next_zero_bit(vb->dirty_map,
VMAP_BBMAP_BITS, i);
s = vb->va->va_start + (i << PAGE_SHIFT);
e = vb->va->va_start + (j << PAGE_SHIFT);
vunmap_page_range(s, e);
flush = 1;
if (s < start)
start = s;
if (e > end)
end = e;
i = j;
i = find_next_bit(vb->dirty_map,
VMAP_BBMAP_BITS, i);
}
spin_unlock(&vb->lock);
}
rcu_read_unlock();
}
__purge_vmap_area_lazy(&start, &end, 1, flush);
}
EXPORT_SYMBOL_GPL(vm_unmap_aliases);
/**
* vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
* @mem: the pointer returned by vm_map_ram
* @count: the count passed to that vm_map_ram call (cannot unmap partial)
*/
void vm_unmap_ram(const void *mem, unsigned int count)
{
unsigned long size = count << PAGE_SHIFT;
unsigned long addr = (unsigned long)mem;
BUG_ON(!addr);
BUG_ON(addr < VMALLOC_START);
BUG_ON(addr > VMALLOC_END);
BUG_ON(addr & (PAGE_SIZE-1));
debug_check_no_locks_freed(mem, size);
vmap_debug_free_range(addr, addr+size);
if (likely(count <= VMAP_MAX_ALLOC))
vb_free(mem, size);
else
free_unmap_vmap_area_addr(addr);
}
EXPORT_SYMBOL(vm_unmap_ram);
/**
* vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
* @pages: an array of pointers to the pages to be mapped
* @count: number of pages
* @node: prefer to allocate data structures on this node
* @prot: memory protection to use. PAGE_KERNEL for regular RAM
*
* Returns: a pointer to the address that has been mapped, or %NULL on failure
*/
void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
{
unsigned long size = count << PAGE_SHIFT;
unsigned long addr;
void *mem;
if (likely(count <= VMAP_MAX_ALLOC)) {
mem = vb_alloc(size, GFP_KERNEL);
if (IS_ERR(mem))
return NULL;
addr = (unsigned long)mem;
} else {
struct vmap_area *va;
va = alloc_vmap_area(size, PAGE_SIZE,
VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
if (IS_ERR(va))
return NULL;
addr = va->va_start;
mem = (void *)addr;
}
if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
vm_unmap_ram(mem, count);
return NULL;
}
return mem;
}
EXPORT_SYMBOL(vm_map_ram);
/**
* vm_area_register_early - register vmap area early during boot
* @vm: vm_struct to register
* @align: requested alignment
*
* This function is used to register kernel vm area before
* vmalloc_init() is called. @vm->size and @vm->flags should contain
* proper values on entry and other fields should be zero. On return,
* vm->addr contains the allocated address.
*
* DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
*/
void __init vm_area_register_early(struct vm_struct *vm, size_t align)
{
static size_t vm_init_off __initdata;
unsigned long addr;
addr = ALIGN(VMALLOC_START + vm_init_off, align);
vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
vm->addr = (void *)addr;
vm->next = vmlist;
vmlist = vm;
}
void __init vmalloc_init(void)
{
struct vmap_area *va;
struct vm_struct *tmp;
int i;
for_each_possible_cpu(i) {
struct vmap_block_queue *vbq;
vbq = &per_cpu(vmap_block_queue, i);
spin_lock_init(&vbq->lock);
INIT_LIST_HEAD(&vbq->free);
}
/* Import existing vmlist entries. */
for (tmp = vmlist; tmp; tmp = tmp->next) {
va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
va->flags = tmp->flags | VM_VM_AREA;
va->va_start = (unsigned long)tmp->addr;
va->va_end = va->va_start + tmp->size;
__insert_vmap_area(va);
}
vmap_area_pcpu_hole = VMALLOC_END;
vmap_initialized = true;
}
/**
* map_kernel_range_noflush - map kernel VM area with the specified pages
* @addr: start of the VM area to map
* @size: size of the VM area to map
* @prot: page protection flags to use
* @pages: pages to map
*
* Map PFN_UP(@size) pages at @addr. The VM area @addr and @size
* specify should have been allocated using get_vm_area() and its
* friends.
*
* NOTE:
* This function does NOT do any cache flushing. The caller is
* responsible for calling flush_cache_vmap() on to-be-mapped areas
* before calling this function.
*
* RETURNS:
* The number of pages mapped on success, -errno on failure.
*/
int map_kernel_range_noflush(unsigned long addr, unsigned long size,
pgprot_t prot, struct page **pages)
{
return vmap_page_range_noflush(addr, addr + size, prot, pages);
}
/**
* unmap_kernel_range_noflush - unmap kernel VM area
* @addr: start of the VM area to unmap
* @size: size of the VM area to unmap
*
* Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size
* specify should have been allocated using get_vm_area() and its
* friends.
*
* NOTE:
* This function does NOT do any cache flushing. The caller is
* responsible for calling flush_cache_vunmap() on to-be-mapped areas
* before calling this function and flush_tlb_kernel_range() after.
*/
void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
{
vunmap_page_range(addr, addr + size);
}
/**
* unmap_kernel_range - unmap kernel VM area and flush cache and TLB
* @addr: start of the VM area to unmap
* @size: size of the VM area to unmap
*
* Similar to unmap_kernel_range_noflush() but flushes vcache before
* the unmapping and tlb after.
*/
void unmap_kernel_range(unsigned long addr, unsigned long size)
{
unsigned long end = addr + size;
flush_cache_vunmap(addr, end);
vunmap_page_range(addr, end);
flush_tlb_kernel_range(addr, end);
}
int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
{
unsigned long addr = (unsigned long)area->addr;
unsigned long end = addr + area->size - PAGE_SIZE;
int err;
err = vmap_page_range(addr, end, prot, *pages);
if (err > 0) {
*pages += err;
err = 0;
}
return err;
}
EXPORT_SYMBOL_GPL(map_vm_area);
/*** Old vmalloc interfaces ***/
DEFINE_RWLOCK(vmlist_lock);
struct vm_struct *vmlist;
static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
unsigned long flags, void *caller)
{
struct vm_struct *tmp, **p;
vm->flags = flags;
vm->addr = (void *)va->va_start;
vm->size = va->va_end - va->va_start;
vm->caller = caller;
va->private = vm;
va->flags |= VM_VM_AREA;
write_lock(&vmlist_lock);
for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
if (tmp->addr >= vm->addr)
break;
}
vm->next = *p;
*p = vm;
write_unlock(&vmlist_lock);
}
static struct vm_struct *__get_vm_area_node(unsigned long size,
unsigned long align, unsigned long flags, unsigned long start,
unsigned long end, int node, gfp_t gfp_mask, void *caller)
{
static struct vmap_area *va;
struct vm_struct *area;
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP) {
int bit = fls(size);
if (bit > IOREMAP_MAX_ORDER)
bit = IOREMAP_MAX_ORDER;
else if (bit < PAGE_SHIFT)
bit = PAGE_SHIFT;
align = 1ul << bit;
}
size = PAGE_ALIGN(size);
if (unlikely(!size))
return NULL;
area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!area))
return NULL;
/*
* We always allocate a guard page.
*/
size += PAGE_SIZE;
va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
if (IS_ERR(va)) {
kfree(area);
return NULL;
}
insert_vmalloc_vm(area, va, flags, caller);
return area;
}
struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
unsigned long start, unsigned long end)
{
return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
__builtin_return_address(0));
}
EXPORT_SYMBOL_GPL(__get_vm_area);
struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
unsigned long start, unsigned long end,
void *caller)
{
return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
caller);
}
/**
* get_vm_area - reserve a contiguous kernel virtual area
* @size: size of the area
* @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
*
* Search an area of @size in the kernel virtual mapping area,
* and reserved it for out purposes. Returns the area descriptor
* on success or %NULL on failure.
*/
struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
{
return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
-1, GFP_KERNEL, __builtin_return_address(0));
}
struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
void *caller)
{
return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
-1, GFP_KERNEL, caller);
}
struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags,
int node, gfp_t gfp_mask)
{
return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
node, gfp_mask, __builtin_return_address(0));
}
static struct vm_struct *find_vm_area(const void *addr)
{
struct vmap_area *va;
va = find_vmap_area((unsigned long)addr);
if (va && va->flags & VM_VM_AREA)
return va->private;
return NULL;
}
/**
* remove_vm_area - find and remove a continuous kernel virtual area
* @addr: base address
*
* Search for the kernel VM area starting at @addr, and remove it.
* This function returns the found VM area, but using it is NOT safe
* on SMP machines, except for its size or flags.
*/
struct vm_struct *remove_vm_area(const void *addr)
{
struct vmap_area *va;
va = find_vmap_area((unsigned long)addr);
if (va && va->flags & VM_VM_AREA) {
struct vm_struct *vm = va->private;
struct vm_struct *tmp, **p;
/*
* remove from list and disallow access to this vm_struct
* before unmap. (address range confliction is maintained by
* vmap.)
*/
write_lock(&vmlist_lock);
for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
;
*p = tmp->next;
write_unlock(&vmlist_lock);
vmap_debug_free_range(va->va_start, va->va_end);
free_unmap_vmap_area(va);
vm->size -= PAGE_SIZE;
return vm;
}
return NULL;
}
static void __vunmap(const void *addr, int deallocate_pages)
{
struct vm_struct *area;
if (!addr)
return;
if ((PAGE_SIZE-1) & (unsigned long)addr) {
WARN(1, KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
return;
}
area = remove_vm_area(addr);
if (unlikely(!area)) {
WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
addr);
return;
}
debug_check_no_locks_freed(addr, area->size);
debug_check_no_obj_freed(addr, area->size);
if (deallocate_pages) {
int i;
for (i = 0; i < area->nr_pages; i++) {
struct page *page = area->pages[i];
BUG_ON(!page);
__free_page(page);
}
if (area->flags & VM_VPAGES)
vfree(area->pages);
else
kfree(area->pages);
}
kfree(area);
return;
}
/**
* vfree - release memory allocated by vmalloc()
* @addr: memory base address
*
* Free the virtually continuous memory area starting at @addr, as
* obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
* NULL, no operation is performed.
*
* Must not be called in interrupt context.
*/
void vfree(const void *addr)
{
BUG_ON(in_interrupt());
kmemleak_free(addr);
__vunmap(addr, 1);
}
EXPORT_SYMBOL(vfree);
/**
* vunmap - release virtual mapping obtained by vmap()
* @addr: memory base address
*
* Free the virtually contiguous memory area starting at @addr,
* which was created from the page array passed to vmap().
*
* Must not be called in interrupt context.
*/
void vunmap(const void *addr)
{
BUG_ON(in_interrupt());
might_sleep();
__vunmap(addr, 0);
}
EXPORT_SYMBOL(vunmap);
/**
* vmap - map an array of pages into virtually contiguous space
* @pages: array of page pointers
* @count: number of pages to map
* @flags: vm_area->flags
* @prot: page protection for the mapping
*
* Maps @count pages from @pages into contiguous kernel virtual
* space.
*/
void *vmap(struct page **pages, unsigned int count,
unsigned long flags, pgprot_t prot)
{
struct vm_struct *area;
might_sleep();
if (count > totalram_pages)
return NULL;
area = get_vm_area_caller((count << PAGE_SHIFT), flags,
__builtin_return_address(0));
if (!area)
return NULL;
if (map_vm_area(area, prot, &pages)) {
vunmap(area->addr);
return NULL;
}
return area->addr;
}
EXPORT_SYMBOL(vmap);
static void *__vmalloc_node(unsigned long size, unsigned long align,
gfp_t gfp_mask, pgprot_t prot,
int node, void *caller);
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
pgprot_t prot, int node, void *caller)
{
struct page **pages;
unsigned int nr_pages, array_size, i;
gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
array_size = (nr_pages * sizeof(struct page *));
area->nr_pages = nr_pages;
/* Please note that the recursion is strictly bounded. */
if (array_size > PAGE_SIZE) {
pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
PAGE_KERNEL, node, caller);
area->flags |= VM_VPAGES;
} else {
pages = kmalloc_node(array_size, nested_gfp, node);
}
area->pages = pages;
area->caller = caller;
if (!area->pages) {
remove_vm_area(area->addr);
kfree(area);
return NULL;
}
for (i = 0; i < area->nr_pages; i++) {
struct page *page;
if (node < 0)
page = alloc_page(gfp_mask);
else
page = alloc_pages_node(node, gfp_mask, 0);
if (unlikely(!page)) {
/* Successfully allocated i pages, free them in __vunmap() */
area->nr_pages = i;
goto fail;
}
area->pages[i] = page;
}
if (map_vm_area(area, prot, &pages))
goto fail;
return area->addr;
fail:
vfree(area->addr);
return NULL;
}
void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
{
void *addr = __vmalloc_area_node(area, gfp_mask, prot, -1,
__builtin_return_address(0));
/*
* A ref_count = 3 is needed because the vm_struct and vmap_area
* structures allocated in the __get_vm_area_node() function contain
* references to the virtual address of the vmalloc'ed block.
*/
kmemleak_alloc(addr, area->size - PAGE_SIZE, 3, gfp_mask);
return addr;
}
/**
* __vmalloc_node - allocate virtually contiguous memory
* @size: allocation size
* @align: desired alignment
* @gfp_mask: flags for the page level allocator
* @prot: protection mask for the allocated pages
* @node: node to use for allocation or -1
* @caller: caller's return address
*
* Allocate enough pages to cover @size from the page level
* allocator with @gfp_mask flags. Map them into contiguous
* kernel virtual space, using a pagetable protection of @prot.
*/
static void *__vmalloc_node(unsigned long size, unsigned long align,
gfp_t gfp_mask, pgprot_t prot,
int node, void *caller)
{
struct vm_struct *area;
void *addr;
unsigned long real_size = size;
size = PAGE_ALIGN(size);
if (!size || (size >> PAGE_SHIFT) > totalram_pages)
return NULL;
area = __get_vm_area_node(size, align, VM_ALLOC, VMALLOC_START,
VMALLOC_END, node, gfp_mask, caller);
if (!area)
return NULL;
addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
/*
* A ref_count = 3 is needed because the vm_struct and vmap_area
* structures allocated in the __get_vm_area_node() function contain
* references to the virtual address of the vmalloc'ed block.
*/
kmemleak_alloc(addr, real_size, 3, gfp_mask);
return addr;
}
void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
{
return __vmalloc_node(size, 1, gfp_mask, prot, -1,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__vmalloc);
/**
* vmalloc - allocate virtually contiguous memory
* @size: allocation size
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc(unsigned long size)
{
return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
-1, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc);
/**
* vmalloc_user - allocate zeroed virtually contiguous memory for userspace
* @size: allocation size
*
* The resulting memory area is zeroed so it can be mapped to userspace
* without leaking data.
*/
void *vmalloc_user(unsigned long size)
{
struct vm_struct *area;
void *ret;
ret = __vmalloc_node(size, SHMLBA,
GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
PAGE_KERNEL, -1, __builtin_return_address(0));
if (ret) {
area = find_vm_area(ret);
area->flags |= VM_USERMAP;
}
return ret;
}
EXPORT_SYMBOL(vmalloc_user);
/**
* vmalloc_node - allocate memory on a specific node
* @size: allocation size
* @node: numa node
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc_node(unsigned long size, int node)
{
return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
node, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc_node);
#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
#endif
/**
* vmalloc_exec - allocate virtually contiguous, executable memory
* @size: allocation size
*
* Kernel-internal function to allocate enough pages to cover @size
* the page level allocator and map them into contiguous and
* executable kernel virtual space.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc_exec(unsigned long size)
{
return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
-1, __builtin_return_address(0));
}
#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
#else
#define GFP_VMALLOC32 GFP_KERNEL
#endif
/**
* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
* @size: allocation size
*
* Allocate enough 32bit PA addressable pages to cover @size from the
* page level allocator and map them into contiguous kernel virtual space.
*/
void *vmalloc_32(unsigned long size)
{
return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
-1, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc_32);
/**
* vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
* @size: allocation size
*
* The resulting memory area is 32bit addressable and zeroed so it can be
* mapped to userspace without leaking data.
*/
void *vmalloc_32_user(unsigned long size)
{
struct vm_struct *area;
void *ret;
ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
-1, __builtin_return_address(0));
if (ret) {
area = find_vm_area(ret);
area->flags |= VM_USERMAP;
}
return ret;
}
EXPORT_SYMBOL(vmalloc_32_user);
/*
* small helper routine , copy contents to buf from addr.
* If the page is not present, fill zero.
*/
static int aligned_vread(char *buf, char *addr, unsigned long count)
{
struct page *p;
int copied = 0;
while (count) {
unsigned long offset, length;
offset = (unsigned long)addr & ~PAGE_MASK;
length = PAGE_SIZE - offset;
if (length > count)
length = count;
p = vmalloc_to_page(addr);
/*
* To do safe access to this _mapped_ area, we need
* lock. But adding lock here means that we need to add
* overhead of vmalloc()/vfree() calles for this _debug_
* interface, rarely used. Instead of that, we'll use
* kmap() and get small overhead in this access function.
*/
if (p) {
/*
* we can expect USER0 is not used (see vread/vwrite's
* function description)
*/
void *map = kmap_atomic(p, KM_USER0);
memcpy(buf, map + offset, length);
kunmap_atomic(map, KM_USER0);
} else
memset(buf, 0, length);
addr += length;
buf += length;
copied += length;
count -= length;
}
return copied;
}
static int aligned_vwrite(char *buf, char *addr, unsigned long count)
{
struct page *p;
int copied = 0;
while (count) {
unsigned long offset, length;
offset = (unsigned long)addr & ~PAGE_MASK;
length = PAGE_SIZE - offset;
if (length > count)
length = count;
p = vmalloc_to_page(addr);
/*
* To do safe access to this _mapped_ area, we need
* lock. But adding lock here means that we need to add
* overhead of vmalloc()/vfree() calles for this _debug_
* interface, rarely used. Instead of that, we'll use
* kmap() and get small overhead in this access function.
*/
if (p) {
/*
* we can expect USER0 is not used (see vread/vwrite's
* function description)
*/
void *map = kmap_atomic(p, KM_USER0);
memcpy(map + offset, buf, length);
kunmap_atomic(map, KM_USER0);
}
addr += length;
buf += length;
copied += length;
count -= length;
}
return copied;
}
/**
* vread() - read vmalloc area in a safe way.
* @buf: buffer for reading data
* @addr: vm address.
* @count: number of bytes to be read.
*
* Returns # of bytes which addr and buf should be increased.
* (same number to @count). Returns 0 if [addr...addr+count) doesn't
* includes any intersect with alive vmalloc area.
*
* This function checks that addr is a valid vmalloc'ed area, and
* copy data from that area to a given buffer. If the given memory range
* of [addr...addr+count) includes some valid address, data is copied to
* proper area of @buf. If there are memory holes, they'll be zero-filled.
* IOREMAP area is treated as memory hole and no copy is done.
*
* If [addr...addr+count) doesn't includes any intersects with alive
* vm_struct area, returns 0.
* @buf should be kernel's buffer. Because this function uses KM_USER0,
* the caller should guarantee KM_USER0 is not used.
*
* Note: In usual ops, vread() is never necessary because the caller
* should know vmalloc() area is valid and can use memcpy().
* This is for routines which have to access vmalloc area without
* any informaion, as /dev/kmem.
*
*/
long vread(char *buf, char *addr, unsigned long count)
{
struct vm_struct *tmp;
char *vaddr, *buf_start = buf;
unsigned long buflen = count;
unsigned long n;
/* Don't allow overflow */
if ((unsigned long) addr + count < count)
count = -(unsigned long) addr;
read_lock(&vmlist_lock);
for (tmp = vmlist; count && tmp; tmp = tmp->next) {
vaddr = (char *) tmp->addr;
if (addr >= vaddr + tmp->size - PAGE_SIZE)
continue;
while (addr < vaddr) {
if (count == 0)
goto finished;
*buf = '\0';
buf++;
addr++;
count--;
}
n = vaddr + tmp->size - PAGE_SIZE - addr;
if (n > count)
n = count;
if (!(tmp->flags & VM_IOREMAP))
aligned_vread(buf, addr, n);
else /* IOREMAP area is treated as memory hole */
memset(buf, 0, n);
buf += n;
addr += n;
count -= n;
}
finished:
read_unlock(&vmlist_lock);
if (buf == buf_start)
return 0;
/* zero-fill memory holes */
if (buf != buf_start + buflen)
memset(buf, 0, buflen - (buf - buf_start));
return buflen;
}
/**
* vwrite() - write vmalloc area in a safe way.
* @buf: buffer for source data
* @addr: vm address.
* @count: number of bytes to be read.
*
* Returns # of bytes which addr and buf should be incresed.
* (same number to @count).
* If [addr...addr+count) doesn't includes any intersect with valid
* vmalloc area, returns 0.
*
* This function checks that addr is a valid vmalloc'ed area, and
* copy data from a buffer to the given addr. If specified range of
* [addr...addr+count) includes some valid address, data is copied from
* proper area of @buf. If there are memory holes, no copy to hole.
* IOREMAP area is treated as memory hole and no copy is done.
*
* If [addr...addr+count) doesn't includes any intersects with alive
* vm_struct area, returns 0.
* @buf should be kernel's buffer. Because this function uses KM_USER0,
* the caller should guarantee KM_USER0 is not used.
*
* Note: In usual ops, vwrite() is never necessary because the caller
* should know vmalloc() area is valid and can use memcpy().
* This is for routines which have to access vmalloc area without
* any informaion, as /dev/kmem.
*
* The caller should guarantee KM_USER1 is not used.
*/
long vwrite(char *buf, char *addr, unsigned long count)
{
struct vm_struct *tmp;
char *vaddr;
unsigned long n, buflen;
int copied = 0;
/* Don't allow overflow */
if ((unsigned long) addr + count < count)
count = -(unsigned long) addr;
buflen = count;
read_lock(&vmlist_lock);
for (tmp = vmlist; count && tmp; tmp = tmp->next) {
vaddr = (char *) tmp->addr;
if (addr >= vaddr + tmp->size - PAGE_SIZE)
continue;
while (addr < vaddr) {
if (count == 0)
goto finished;
buf++;
addr++;
count--;
}
n = vaddr + tmp->size - PAGE_SIZE - addr;
if (n > count)
n = count;
if (!(tmp->flags & VM_IOREMAP)) {
aligned_vwrite(buf, addr, n);
copied++;
}
buf += n;
addr += n;
count -= n;
}
finished:
read_unlock(&vmlist_lock);
if (!copied)
return 0;
return buflen;
}
/**
* remap_vmalloc_range - map vmalloc pages to userspace
* @vma: vma to cover (map full range of vma)
* @addr: vmalloc memory
* @pgoff: number of pages into addr before first page to map
*
* Returns: 0 for success, -Exxx on failure
*
* This function checks that addr is a valid vmalloc'ed area, and
* that it is big enough to cover the vma. Will return failure if
* that criteria isn't met.
*
* Similar to remap_pfn_range() (see mm/memory.c)
*/
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
unsigned long pgoff)
{
struct vm_struct *area;
unsigned long uaddr = vma->vm_start;
unsigned long usize = vma->vm_end - vma->vm_start;
if ((PAGE_SIZE-1) & (unsigned long)addr)
return -EINVAL;
area = find_vm_area(addr);
if (!area)
return -EINVAL;
if (!(area->flags & VM_USERMAP))
return -EINVAL;
if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
return -EINVAL;
addr += pgoff << PAGE_SHIFT;
do {
struct page *page = vmalloc_to_page(addr);
int ret;
ret = vm_insert_page(vma, uaddr, page);
if (ret)
return ret;
uaddr += PAGE_SIZE;
addr += PAGE_SIZE;
usize -= PAGE_SIZE;
} while (usize > 0);
/* Prevent "things" like memory migration? VM_flags need a cleanup... */
vma->vm_flags |= VM_RESERVED;
return 0;
}
EXPORT_SYMBOL(remap_vmalloc_range);
/*
* Implement a stub for vmalloc_sync_all() if the architecture chose not to
* have one.
*/
void __attribute__((weak)) vmalloc_sync_all(void)
{
}
static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
{
/* apply_to_page_range() does all the hard work. */
return 0;
}
/**
* alloc_vm_area - allocate a range of kernel address space
* @size: size of the area
*
* Returns: NULL on failure, vm_struct on success
*
* This function reserves a range of kernel address space, and
* allocates pagetables to map that range. No actual mappings
* are created. If the kernel address space is not shared
* between processes, it syncs the pagetable across all
* processes.
*/
struct vm_struct *alloc_vm_area(size_t size)
{
struct vm_struct *area;
area = get_vm_area_caller(size, VM_IOREMAP,
__builtin_return_address(0));
if (area == NULL)
return NULL;
/*
* This ensures that page tables are constructed for this region
* of kernel virtual address space and mapped into init_mm.
*/
if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
area->size, f, NULL)) {
free_vm_area(area);
return NULL;
}
/* Make sure the pagetables are constructed in process kernel
mappings */
vmalloc_sync_all();
return area;
}
EXPORT_SYMBOL_GPL(alloc_vm_area);
void free_vm_area(struct vm_struct *area)
{
struct vm_struct *ret;
ret = remove_vm_area(area->addr);
BUG_ON(ret != area);
kfree(area);
}
EXPORT_SYMBOL_GPL(free_vm_area);
static struct vmap_area *node_to_va(struct rb_node *n)
{
return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
}
/**
* pvm_find_next_prev - find the next and prev vmap_area surrounding @end
* @end: target address
* @pnext: out arg for the next vmap_area
* @pprev: out arg for the previous vmap_area
*
* Returns: %true if either or both of next and prev are found,
* %false if no vmap_area exists
*
* Find vmap_areas end addresses of which enclose @end. ie. if not
* NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
*/
static bool pvm_find_next_prev(unsigned long end,
struct vmap_area **pnext,
struct vmap_area **pprev)
{
struct rb_node *n = vmap_area_root.rb_node;
struct vmap_area *va = NULL;
while (n) {
va = rb_entry(n, struct vmap_area, rb_node);
if (end < va->va_end)
n = n->rb_left;
else if (end > va->va_end)
n = n->rb_right;
else
break;
}
if (!va)
return false;
if (va->va_end > end) {
*pnext = va;
*pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
} else {
*pprev = va;
*pnext = node_to_va(rb_next(&(*pprev)->rb_node));
}
return true;
}
/**
* pvm_determine_end - find the highest aligned address between two vmap_areas
* @pnext: in/out arg for the next vmap_area
* @pprev: in/out arg for the previous vmap_area
* @align: alignment
*
* Returns: determined end address
*
* Find the highest aligned address between *@pnext and *@pprev below
* VMALLOC_END. *@pnext and *@pprev are adjusted so that the aligned
* down address is between the end addresses of the two vmap_areas.
*
* Please note that the address returned by this function may fall
* inside *@pnext vmap_area. The caller is responsible for checking
* that.
*/
static unsigned long pvm_determine_end(struct vmap_area **pnext,
struct vmap_area **pprev,
unsigned long align)
{
const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
unsigned long addr;
if (*pnext)
addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
else
addr = vmalloc_end;
while (*pprev && (*pprev)->va_end > addr) {
*pnext = *pprev;
*pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
}
return addr;
}
/**
* pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
* @offsets: array containing offset of each area
* @sizes: array containing size of each area
* @nr_vms: the number of areas to allocate
* @align: alignment, all entries in @offsets and @sizes must be aligned to this
* @gfp_mask: allocation mask
*
* Returns: kmalloc'd vm_struct pointer array pointing to allocated
* vm_structs on success, %NULL on failure
*
* Percpu allocator wants to use congruent vm areas so that it can
* maintain the offsets among percpu areas. This function allocates
* congruent vmalloc areas for it. These areas tend to be scattered
* pretty far, distance between two areas easily going up to
* gigabytes. To avoid interacting with regular vmallocs, these areas
* are allocated from top.
*
* Despite its complicated look, this allocator is rather simple. It
* does everything top-down and scans areas from the end looking for
* matching slot. While scanning, if any of the areas overlaps with
* existing vmap_area, the base address is pulled down to fit the
* area. Scanning is repeated till all the areas fit and then all
* necessary data structres are inserted and the result is returned.
*/
struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
const size_t *sizes, int nr_vms,
size_t align, gfp_t gfp_mask)
{
const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
struct vmap_area **vas, *prev, *next;
struct vm_struct **vms;
int area, area2, last_area, term_area;
unsigned long base, start, end, last_end;
bool purged = false;
gfp_mask &= GFP_RECLAIM_MASK;
/* verify parameters and allocate data structures */
BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align));
for (last_area = 0, area = 0; area < nr_vms; area++) {
start = offsets[area];
end = start + sizes[area];
/* is everything aligned properly? */
BUG_ON(!IS_ALIGNED(offsets[area], align));
BUG_ON(!IS_ALIGNED(sizes[area], align));
/* detect the area with the highest address */
if (start > offsets[last_area])
last_area = area;
for (area2 = 0; area2 < nr_vms; area2++) {
unsigned long start2 = offsets[area2];
unsigned long end2 = start2 + sizes[area2];
if (area2 == area)
continue;
BUG_ON(start2 >= start && start2 < end);
BUG_ON(end2 <= end && end2 > start);
}
}
last_end = offsets[last_area] + sizes[last_area];
if (vmalloc_end - vmalloc_start < last_end) {
WARN_ON(true);
return NULL;
}
vms = kzalloc(sizeof(vms[0]) * nr_vms, gfp_mask);
vas = kzalloc(sizeof(vas[0]) * nr_vms, gfp_mask);
if (!vas || !vms)
goto err_free;
for (area = 0; area < nr_vms; area++) {
vas[area] = kzalloc(sizeof(struct vmap_area), gfp_mask);
vms[area] = kzalloc(sizeof(struct vm_struct), gfp_mask);
if (!vas[area] || !vms[area])
goto err_free;
}
retry:
spin_lock(&vmap_area_lock);
/* start scanning - we scan from the top, begin with the last area */
area = term_area = last_area;
start = offsets[area];
end = start + sizes[area];
if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
base = vmalloc_end - last_end;
goto found;
}
base = pvm_determine_end(&next, &prev, align) - end;
while (true) {
BUG_ON(next && next->va_end <= base + end);
BUG_ON(prev && prev->va_end > base + end);
/*
* base might have underflowed, add last_end before
* comparing.
*/
if (base + last_end < vmalloc_start + last_end) {
spin_unlock(&vmap_area_lock);
if (!purged) {
purge_vmap_area_lazy();
purged = true;
goto retry;
}
goto err_free;
}
/*
* If next overlaps, move base downwards so that it's
* right below next and then recheck.
*/
if (next && next->va_start < base + end) {
base = pvm_determine_end(&next, &prev, align) - end;
term_area = area;
continue;
}
/*
* If prev overlaps, shift down next and prev and move
* base so that it's right below new next and then
* recheck.
*/
if (prev && prev->va_end > base + start) {
next = prev;
prev = node_to_va(rb_prev(&next->rb_node));
base = pvm_determine_end(&next, &prev, align) - end;
term_area = area;
continue;
}
/*
* This area fits, move on to the previous one. If
* the previous one is the terminal one, we're done.
*/
area = (area + nr_vms - 1) % nr_vms;
if (area == term_area)
break;
start = offsets[area];
end = start + sizes[area];
pvm_find_next_prev(base + end, &next, &prev);
}
found:
/* we've found a fitting base, insert all va's */
for (area = 0; area < nr_vms; area++) {
struct vmap_area *va = vas[area];
va->va_start = base + offsets[area];
va->va_end = va->va_start + sizes[area];
__insert_vmap_area(va);
}
vmap_area_pcpu_hole = base + offsets[last_area];
spin_unlock(&vmap_area_lock);
/* insert all vm's */
for (area = 0; area < nr_vms; area++)
insert_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
pcpu_get_vm_areas);
kfree(vas);
return vms;
err_free:
for (area = 0; area < nr_vms; area++) {
if (vas)
kfree(vas[area]);
if (vms)
kfree(vms[area]);
}
kfree(vas);
kfree(vms);
return NULL;
}
/**
* pcpu_free_vm_areas - free vmalloc areas for percpu allocator
* @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
* @nr_vms: the number of allocated areas
*
* Free vm_structs and the array allocated by pcpu_get_vm_areas().
*/
void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
{
int i;
for (i = 0; i < nr_vms; i++)
free_vm_area(vms[i]);
kfree(vms);
}
#ifdef CONFIG_PROC_FS
static void *s_start(struct seq_file *m, loff_t *pos)
{
loff_t n = *pos;
struct vm_struct *v;
read_lock(&vmlist_lock);
v = vmlist;
while (n > 0 && v) {
n--;
v = v->next;
}
if (!n)
return v;
return NULL;
}
static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
struct vm_struct *v = p;
++*pos;
return v->next;
}
static void s_stop(struct seq_file *m, void *p)
{
read_unlock(&vmlist_lock);
}
static void show_numa_info(struct seq_file *m, struct vm_struct *v)
{
if (NUMA_BUILD) {
unsigned int nr, *counters = m->private;
if (!counters)
return;
memset(counters, 0, nr_node_ids * sizeof(unsigned int));
for (nr = 0; nr < v->nr_pages; nr++)
counters[page_to_nid(v->pages[nr])]++;
for_each_node_state(nr, N_HIGH_MEMORY)
if (counters[nr])
seq_printf(m, " N%u=%u", nr, counters[nr]);
}
}
static int s_show(struct seq_file *m, void *p)
{
struct vm_struct *v = p;
seq_printf(m, "0x%p-0x%p %7ld",
v->addr, v->addr + v->size, v->size);
if (v->caller) {
char buff[KSYM_SYMBOL_LEN];
seq_putc(m, ' ');
sprint_symbol(buff, (unsigned long)v->caller);
seq_puts(m, buff);
}
if (v->nr_pages)
seq_printf(m, " pages=%d", v->nr_pages);
if (v->phys_addr)
seq_printf(m, " phys=%lx", v->phys_addr);
if (v->flags & VM_IOREMAP)
seq_printf(m, " ioremap");
if (v->flags & VM_ALLOC)
seq_printf(m, " vmalloc");
if (v->flags & VM_MAP)
seq_printf(m, " vmap");
if (v->flags & VM_USERMAP)
seq_printf(m, " user");
if (v->flags & VM_VPAGES)
seq_printf(m, " vpages");
show_numa_info(m, v);
seq_putc(m, '\n');
return 0;
}
static const struct seq_operations vmalloc_op = {
.start = s_start,
.next = s_next,
.stop = s_stop,
.show = s_show,
};
static int vmalloc_open(struct inode *inode, struct file *file)
{
unsigned int *ptr = NULL;
int ret;
if (NUMA_BUILD)
ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL);
ret = seq_open(file, &vmalloc_op);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = ptr;
} else
kfree(ptr);
return ret;
}
static const struct file_operations proc_vmalloc_operations = {
.open = vmalloc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int __init proc_vmalloc_init(void)
{
proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
return 0;
}
module_init(proc_vmalloc_init);
#endif