Revision bbcd53c960713507ae764bf81970651b5577b95a authored by David Hildenbrand on 07 May 2021, 01:05:55 UTC, committed by Linus Torvalds on 07 May 2021, 07:26:34 UTC
Patch series "drivers/char: remove /dev/kmem for good". Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and memory ballooning, I started questioning the existence of /dev/kmem. Comparing it with the /proc/kcore implementation, it does not seem to be able to deal with things like a) Pages unmapped from the direct mapping (e.g., to be used by secretmem) -> kern_addr_valid(). virt_addr_valid() is not sufficient. b) Special cases like gart aperture memory that is not to be touched -> mem_pfn_is_ram() Unless I am missing something, it's at least broken in some cases and might fault/crash the machine. Looks like its existence has been questioned before in 2005 and 2010 [1], after ~11 additional years, it might make sense to revive the discussion. CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by mistake?). All distributions disable it: in Ubuntu it has been disabled for more than 10 years, in Debian since 2.6.31, in Fedora at least starting with FC3, in RHEL starting with RHEL4, in SUSE starting from 15sp2, and OpenSUSE has it disabled as well. 1) /dev/kmem was popular for rootkits [2] before it got disabled basically everywhere. Ubuntu documents [3] "There is no modern user of /dev/kmem any more beyond attackers using it to load kernel rootkits.". RHEL documents in a BZ [5] "it served no practical purpose other than to serve as a potential security problem or to enable binary module drivers to access structures/functions they shouldn't be touching" 2) /proc/kcore is a decent interface to have a controlled way to read kernel memory for debugging puposes. (will need some extensions to deal with memory offlining/unplug, memory ballooning, and poisoned pages, though) 3) It might be useful for corner case debugging [1]. KDB/KGDB might be a better fit, especially, to write random memory; harder to shoot yourself into the foot. 4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems to be incompatible with 64bit [1]. For educational purposes, /proc/kcore might be used to monitor value updates -- or older kernels can be used. 5) It's broken on arm64, and therefore, completely disabled there. Looks like it's essentially unused and has been replaced by better suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's just remove it. [1] https://lwn.net/Articles/147901/ [2] https://www.linuxjournal.com/article/10505 [3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled [4] https://sourceforge.net/projects/kme/ [5] https://bugzilla.redhat.com/show_bug.cgi?id=154796 Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Alexander A. Klimov" <grandmaster@al2klimov.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Brian Cain <bcain@codeaurora.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Chris Zankel <chris@zankel.net> Cc: Corentin Labbe <clabbe@baylibre.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Greentime Hu <green.hu@gmail.com> Cc: Gregory Clement <gregory.clement@bootlin.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Hillf Danton <hdanton@sina.com> Cc: huang ying <huang.ying.caritas@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: James Troup <james.troup@canonical.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <kasong@redhat.com> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: openrisc@lists.librecores.org Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Paul Mackerras <paulus@samba.org> Cc: "Pavel Machek (CIP)" <pavel@denx.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Pierre Morel <pmorel@linux.ibm.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Rich Felker <dalias@libc.org> Cc: Robert Richter <rric@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Cc: sparclinux@vger.kernel.org Cc: Stafford Horne <shorne@gmail.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Theodore Dubois <tblodt@icloud.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: William Cohen <wcohen@redhat.com> Cc: Xiaoming Ni <nixiaoming@huawei.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent cb152a1
genalloc.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Basic general purpose allocator for managing special purpose
* memory, for example, memory that is not managed by the regular
* kmalloc/kfree interface. Uses for this includes on-device special
* memory, uncached memory etc.
*
* It is safe to use the allocator in NMI handlers and other special
* unblockable contexts that could otherwise deadlock on locks. This
* is implemented by using atomic operations and retries on any
* conflicts. The disadvantage is that there may be livelocks in
* extreme cases. For better scalability, one allocator can be used
* for each CPU.
*
* The lockless operation only works if there is enough memory
* available. If new memory is added to the pool a lock has to be
* still taken. So any user relying on locklessness has to ensure
* that sufficient memory is preallocated.
*
* The basic atomic operation of this allocator is cmpxchg on long.
* On architectures that don't have NMI-safe cmpxchg implementation,
* the allocator can NOT be used in NMI handler. So code uses the
* allocator in NMI handler should depend on
* CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
*
* Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
*/
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/bitmap.h>
#include <linux/rculist.h>
#include <linux/interrupt.h>
#include <linux/genalloc.h>
#include <linux/of_device.h>
#include <linux/vmalloc.h>
static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
{
return chunk->end_addr - chunk->start_addr + 1;
}
static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
{
unsigned long val, nval;
nval = *addr;
do {
val = nval;
if (val & mask_to_set)
return -EBUSY;
cpu_relax();
} while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
return 0;
}
static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
{
unsigned long val, nval;
nval = *addr;
do {
val = nval;
if ((val & mask_to_clear) != mask_to_clear)
return -EBUSY;
cpu_relax();
} while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
return 0;
}
/*
* bitmap_set_ll - set the specified number of bits at the specified position
* @map: pointer to a bitmap
* @start: a bit position in @map
* @nr: number of bits to set
*
* Set @nr bits start from @start in @map lock-lessly. Several users
* can set/clear the same bitmap simultaneously without lock. If two
* users set the same bit, one user will return remain bits, otherwise
* return 0.
*/
static unsigned long
bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
{
unsigned long *p = map + BIT_WORD(start);
const unsigned long size = start + nr;
int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
while (nr >= bits_to_set) {
if (set_bits_ll(p, mask_to_set))
return nr;
nr -= bits_to_set;
bits_to_set = BITS_PER_LONG;
mask_to_set = ~0UL;
p++;
}
if (nr) {
mask_to_set &= BITMAP_LAST_WORD_MASK(size);
if (set_bits_ll(p, mask_to_set))
return nr;
}
return 0;
}
/*
* bitmap_clear_ll - clear the specified number of bits at the specified position
* @map: pointer to a bitmap
* @start: a bit position in @map
* @nr: number of bits to set
*
* Clear @nr bits start from @start in @map lock-lessly. Several users
* can set/clear the same bitmap simultaneously without lock. If two
* users clear the same bit, one user will return remain bits,
* otherwise return 0.
*/
static unsigned long
bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
{
unsigned long *p = map + BIT_WORD(start);
const unsigned long size = start + nr;
int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
while (nr >= bits_to_clear) {
if (clear_bits_ll(p, mask_to_clear))
return nr;
nr -= bits_to_clear;
bits_to_clear = BITS_PER_LONG;
mask_to_clear = ~0UL;
p++;
}
if (nr) {
mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
if (clear_bits_ll(p, mask_to_clear))
return nr;
}
return 0;
}
/**
* gen_pool_create - create a new special memory pool
* @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
* @nid: node id of the node the pool structure should be allocated on, or -1
*
* Create a new special memory pool that can be used to manage special purpose
* memory not managed by the regular kmalloc/kfree interface.
*/
struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
{
struct gen_pool *pool;
pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
if (pool != NULL) {
spin_lock_init(&pool->lock);
INIT_LIST_HEAD(&pool->chunks);
pool->min_alloc_order = min_alloc_order;
pool->algo = gen_pool_first_fit;
pool->data = NULL;
pool->name = NULL;
}
return pool;
}
EXPORT_SYMBOL(gen_pool_create);
/**
* gen_pool_add_owner- add a new chunk of special memory to the pool
* @pool: pool to add new memory chunk to
* @virt: virtual starting address of memory chunk to add to pool
* @phys: physical starting address of memory chunk to add to pool
* @size: size in bytes of the memory chunk to add to pool
* @nid: node id of the node the chunk structure and bitmap should be
* allocated on, or -1
* @owner: private data the publisher would like to recall at alloc time
*
* Add a new chunk of special memory to the specified pool.
*
* Returns 0 on success or a -ve errno on failure.
*/
int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
size_t size, int nid, void *owner)
{
struct gen_pool_chunk *chunk;
unsigned long nbits = size >> pool->min_alloc_order;
unsigned long nbytes = sizeof(struct gen_pool_chunk) +
BITS_TO_LONGS(nbits) * sizeof(long);
chunk = vzalloc_node(nbytes, nid);
if (unlikely(chunk == NULL))
return -ENOMEM;
chunk->phys_addr = phys;
chunk->start_addr = virt;
chunk->end_addr = virt + size - 1;
chunk->owner = owner;
atomic_long_set(&chunk->avail, size);
spin_lock(&pool->lock);
list_add_rcu(&chunk->next_chunk, &pool->chunks);
spin_unlock(&pool->lock);
return 0;
}
EXPORT_SYMBOL(gen_pool_add_owner);
/**
* gen_pool_virt_to_phys - return the physical address of memory
* @pool: pool to allocate from
* @addr: starting address of memory
*
* Returns the physical address on success, or -1 on error.
*/
phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
{
struct gen_pool_chunk *chunk;
phys_addr_t paddr = -1;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
paddr = chunk->phys_addr + (addr - chunk->start_addr);
break;
}
}
rcu_read_unlock();
return paddr;
}
EXPORT_SYMBOL(gen_pool_virt_to_phys);
/**
* gen_pool_destroy - destroy a special memory pool
* @pool: pool to destroy
*
* Destroy the specified special memory pool. Verifies that there are no
* outstanding allocations.
*/
void gen_pool_destroy(struct gen_pool *pool)
{
struct list_head *_chunk, *_next_chunk;
struct gen_pool_chunk *chunk;
int order = pool->min_alloc_order;
unsigned long bit, end_bit;
list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
list_del(&chunk->next_chunk);
end_bit = chunk_size(chunk) >> order;
bit = find_next_bit(chunk->bits, end_bit, 0);
BUG_ON(bit < end_bit);
vfree(chunk);
}
kfree_const(pool->name);
kfree(pool);
}
EXPORT_SYMBOL(gen_pool_destroy);
/**
* gen_pool_alloc_algo_owner - allocate special memory from the pool
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @algo: algorithm passed from caller
* @data: data passed to algorithm
* @owner: optionally retrieve the chunk owner
*
* Allocate the requested number of bytes from the specified pool.
* Uses the pool allocation function (with first-fit algorithm by default).
* Can not be used in NMI handler on architectures without
* NMI-safe cmpxchg implementation.
*/
unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
genpool_algo_t algo, void *data, void **owner)
{
struct gen_pool_chunk *chunk;
unsigned long addr = 0;
int order = pool->min_alloc_order;
unsigned long nbits, start_bit, end_bit, remain;
#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
BUG_ON(in_nmi());
#endif
if (owner)
*owner = NULL;
if (size == 0)
return 0;
nbits = (size + (1UL << order) - 1) >> order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
if (size > atomic_long_read(&chunk->avail))
continue;
start_bit = 0;
end_bit = chunk_size(chunk) >> order;
retry:
start_bit = algo(chunk->bits, end_bit, start_bit,
nbits, data, pool, chunk->start_addr);
if (start_bit >= end_bit)
continue;
remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
if (remain) {
remain = bitmap_clear_ll(chunk->bits, start_bit,
nbits - remain);
BUG_ON(remain);
goto retry;
}
addr = chunk->start_addr + ((unsigned long)start_bit << order);
size = nbits << order;
atomic_long_sub(size, &chunk->avail);
if (owner)
*owner = chunk->owner;
break;
}
rcu_read_unlock();
return addr;
}
EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
/**
* gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: dma-view physical address return value. Use %NULL if unneeded.
*
* Allocate the requested number of bytes from the specified pool.
* Uses the pool allocation function (with first-fit algorithm by default).
* Can not be used in NMI handler on architectures without
* NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated memory, or %NULL on failure
*/
void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
{
return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data);
}
EXPORT_SYMBOL(gen_pool_dma_alloc);
/**
* gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA
* usage with the given pool algorithm
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: DMA-view physical address return value. Use %NULL if unneeded.
* @algo: algorithm passed from caller
* @data: data passed to algorithm
*
* Allocate the requested number of bytes from the specified pool. Uses the
* given pool allocation function. Can not be used in NMI handler on
* architectures without NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated memory, or %NULL on failure
*/
void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
dma_addr_t *dma, genpool_algo_t algo, void *data)
{
unsigned long vaddr;
if (!pool)
return NULL;
vaddr = gen_pool_alloc_algo(pool, size, algo, data);
if (!vaddr)
return NULL;
if (dma)
*dma = gen_pool_virt_to_phys(pool, vaddr);
return (void *)vaddr;
}
EXPORT_SYMBOL(gen_pool_dma_alloc_algo);
/**
* gen_pool_dma_alloc_align - allocate special memory from the pool for DMA
* usage with the given alignment
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: DMA-view physical address return value. Use %NULL if unneeded.
* @align: alignment in bytes for starting address
*
* Allocate the requested number bytes from the specified pool, with the given
* alignment restriction. Can not be used in NMI handler on architectures
* without NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated memory, or %NULL on failure
*/
void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
dma_addr_t *dma, int align)
{
struct genpool_data_align data = { .align = align };
return gen_pool_dma_alloc_algo(pool, size, dma,
gen_pool_first_fit_align, &data);
}
EXPORT_SYMBOL(gen_pool_dma_alloc_align);
/**
* gen_pool_dma_zalloc - allocate special zeroed memory from the pool for
* DMA usage
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: dma-view physical address return value. Use %NULL if unneeded.
*
* Allocate the requested number of zeroed bytes from the specified pool.
* Uses the pool allocation function (with first-fit algorithm by default).
* Can not be used in NMI handler on architectures without
* NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated zeroed memory, or %NULL on failure
*/
void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
{
return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data);
}
EXPORT_SYMBOL(gen_pool_dma_zalloc);
/**
* gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for
* DMA usage with the given pool algorithm
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: DMA-view physical address return value. Use %NULL if unneeded.
* @algo: algorithm passed from caller
* @data: data passed to algorithm
*
* Allocate the requested number of zeroed bytes from the specified pool. Uses
* the given pool allocation function. Can not be used in NMI handler on
* architectures without NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated zeroed memory, or %NULL on failure
*/
void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
dma_addr_t *dma, genpool_algo_t algo, void *data)
{
void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data);
if (vaddr)
memset(vaddr, 0, size);
return vaddr;
}
EXPORT_SYMBOL(gen_pool_dma_zalloc_algo);
/**
* gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for
* DMA usage with the given alignment
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
* @dma: DMA-view physical address return value. Use %NULL if unneeded.
* @align: alignment in bytes for starting address
*
* Allocate the requested number of zeroed bytes from the specified pool,
* with the given alignment restriction. Can not be used in NMI handler on
* architectures without NMI-safe cmpxchg implementation.
*
* Return: virtual address of the allocated zeroed memory, or %NULL on failure
*/
void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
dma_addr_t *dma, int align)
{
struct genpool_data_align data = { .align = align };
return gen_pool_dma_zalloc_algo(pool, size, dma,
gen_pool_first_fit_align, &data);
}
EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
/**
* gen_pool_free_owner - free allocated special memory back to the pool
* @pool: pool to free to
* @addr: starting address of memory to free back to pool
* @size: size in bytes of memory to free
* @owner: private data stashed at gen_pool_add() time
*
* Free previously allocated special memory back to the specified
* pool. Can not be used in NMI handler on architectures without
* NMI-safe cmpxchg implementation.
*/
void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
void **owner)
{
struct gen_pool_chunk *chunk;
int order = pool->min_alloc_order;
unsigned long start_bit, nbits, remain;
#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
BUG_ON(in_nmi());
#endif
if (owner)
*owner = NULL;
nbits = (size + (1UL << order) - 1) >> order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
BUG_ON(addr + size - 1 > chunk->end_addr);
start_bit = (addr - chunk->start_addr) >> order;
remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
BUG_ON(remain);
size = nbits << order;
atomic_long_add(size, &chunk->avail);
if (owner)
*owner = chunk->owner;
rcu_read_unlock();
return;
}
}
rcu_read_unlock();
BUG();
}
EXPORT_SYMBOL(gen_pool_free_owner);
/**
* gen_pool_for_each_chunk - call func for every chunk of generic memory pool
* @pool: the generic memory pool
* @func: func to call
* @data: additional data used by @func
*
* Call @func for every chunk of generic memory pool. The @func is
* called with rcu_read_lock held.
*/
void gen_pool_for_each_chunk(struct gen_pool *pool,
void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
void *data)
{
struct gen_pool_chunk *chunk;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
func(pool, chunk, data);
rcu_read_unlock();
}
EXPORT_SYMBOL(gen_pool_for_each_chunk);
/**
* gen_pool_has_addr - checks if an address falls within the range of a pool
* @pool: the generic memory pool
* @start: start address
* @size: size of the region
*
* Check if the range of addresses falls within the specified pool. Returns
* true if the entire range is contained in the pool and false otherwise.
*/
bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
size_t size)
{
bool found = false;
unsigned long end = start + size - 1;
struct gen_pool_chunk *chunk;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
if (start >= chunk->start_addr && start <= chunk->end_addr) {
if (end <= chunk->end_addr) {
found = true;
break;
}
}
}
rcu_read_unlock();
return found;
}
EXPORT_SYMBOL(gen_pool_has_addr);
/**
* gen_pool_avail - get available free space of the pool
* @pool: pool to get available free space
*
* Return available free space of the specified pool.
*/
size_t gen_pool_avail(struct gen_pool *pool)
{
struct gen_pool_chunk *chunk;
size_t avail = 0;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
avail += atomic_long_read(&chunk->avail);
rcu_read_unlock();
return avail;
}
EXPORT_SYMBOL_GPL(gen_pool_avail);
/**
* gen_pool_size - get size in bytes of memory managed by the pool
* @pool: pool to get size
*
* Return size in bytes of memory managed by the pool.
*/
size_t gen_pool_size(struct gen_pool *pool)
{
struct gen_pool_chunk *chunk;
size_t size = 0;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
size += chunk_size(chunk);
rcu_read_unlock();
return size;
}
EXPORT_SYMBOL_GPL(gen_pool_size);
/**
* gen_pool_set_algo - set the allocation algorithm
* @pool: pool to change allocation algorithm
* @algo: custom algorithm function
* @data: additional data used by @algo
*
* Call @algo for each memory allocation in the pool.
* If @algo is NULL use gen_pool_first_fit as default
* memory allocation function.
*/
void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
{
rcu_read_lock();
pool->algo = algo;
if (!pool->algo)
pool->algo = gen_pool_first_fit;
pool->data = data;
rcu_read_unlock();
}
EXPORT_SYMBOL(gen_pool_set_algo);
/**
* gen_pool_first_fit - find the first available region
* of memory matching the size requirement (no alignment constraint)
* @map: The address to base the search on
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: additional data - unused
* @pool: pool to find the fit region memory from
* @start_addr: not used in this function
*/
unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
unsigned long start, unsigned int nr, void *data,
struct gen_pool *pool, unsigned long start_addr)
{
return bitmap_find_next_zero_area(map, size, start, nr, 0);
}
EXPORT_SYMBOL(gen_pool_first_fit);
/**
* gen_pool_first_fit_align - find the first available region
* of memory matching the size requirement (alignment constraint)
* @map: The address to base the search on
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: data for alignment
* @pool: pool to get order from
* @start_addr: start addr of alloction chunk
*/
unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
unsigned long start, unsigned int nr, void *data,
struct gen_pool *pool, unsigned long start_addr)
{
struct genpool_data_align *alignment;
unsigned long align_mask, align_off;
int order;
alignment = data;
order = pool->min_alloc_order;
align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
align_off = (start_addr & (alignment->align - 1)) >> order;
return bitmap_find_next_zero_area_off(map, size, start, nr,
align_mask, align_off);
}
EXPORT_SYMBOL(gen_pool_first_fit_align);
/**
* gen_pool_fixed_alloc - reserve a specific region
* @map: The address to base the search on
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: data for alignment
* @pool: pool to get order from
* @start_addr: not used in this function
*/
unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
unsigned long start, unsigned int nr, void *data,
struct gen_pool *pool, unsigned long start_addr)
{
struct genpool_data_fixed *fixed_data;
int order;
unsigned long offset_bit;
unsigned long start_bit;
fixed_data = data;
order = pool->min_alloc_order;
offset_bit = fixed_data->offset >> order;
if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
return size;
start_bit = bitmap_find_next_zero_area(map, size,
start + offset_bit, nr, 0);
if (start_bit != offset_bit)
start_bit = size;
return start_bit;
}
EXPORT_SYMBOL(gen_pool_fixed_alloc);
/**
* gen_pool_first_fit_order_align - find the first available region
* of memory matching the size requirement. The region will be aligned
* to the order of the size specified.
* @map: The address to base the search on
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: additional data - unused
* @pool: pool to find the fit region memory from
* @start_addr: not used in this function
*/
unsigned long gen_pool_first_fit_order_align(unsigned long *map,
unsigned long size, unsigned long start,
unsigned int nr, void *data, struct gen_pool *pool,
unsigned long start_addr)
{
unsigned long align_mask = roundup_pow_of_two(nr) - 1;
return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
}
EXPORT_SYMBOL(gen_pool_first_fit_order_align);
/**
* gen_pool_best_fit - find the best fitting region of memory
* matching the size requirement (no alignment constraint)
* @map: The address to base the search on
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: additional data - unused
* @pool: pool to find the fit region memory from
* @start_addr: not used in this function
*
* Iterate over the bitmap to find the smallest free region
* which we can allocate the memory.
*/
unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
unsigned long start, unsigned int nr, void *data,
struct gen_pool *pool, unsigned long start_addr)
{
unsigned long start_bit = size;
unsigned long len = size + 1;
unsigned long index;
index = bitmap_find_next_zero_area(map, size, start, nr, 0);
while (index < size) {
unsigned long next_bit = find_next_bit(map, size, index + nr);
if ((next_bit - index) < len) {
len = next_bit - index;
start_bit = index;
if (len == nr)
return start_bit;
}
index = bitmap_find_next_zero_area(map, size,
next_bit + 1, nr, 0);
}
return start_bit;
}
EXPORT_SYMBOL(gen_pool_best_fit);
static void devm_gen_pool_release(struct device *dev, void *res)
{
gen_pool_destroy(*(struct gen_pool **)res);
}
static int devm_gen_pool_match(struct device *dev, void *res, void *data)
{
struct gen_pool **p = res;
/* NULL data matches only a pool without an assigned name */
if (!data && !(*p)->name)
return 1;
if (!data || !(*p)->name)
return 0;
return !strcmp((*p)->name, data);
}
/**
* gen_pool_get - Obtain the gen_pool (if any) for a device
* @dev: device to retrieve the gen_pool from
* @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
*
* Returns the gen_pool for the device if one is present, or NULL.
*/
struct gen_pool *gen_pool_get(struct device *dev, const char *name)
{
struct gen_pool **p;
p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
(void *)name);
if (!p)
return NULL;
return *p;
}
EXPORT_SYMBOL_GPL(gen_pool_get);
/**
* devm_gen_pool_create - managed gen_pool_create
* @dev: device that provides the gen_pool
* @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
* @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
* @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
*
* Create a new special memory pool that can be used to manage special purpose
* memory not managed by the regular kmalloc/kfree interface. The pool will be
* automatically destroyed by the device management code.
*/
struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
int nid, const char *name)
{
struct gen_pool **ptr, *pool;
const char *pool_name = NULL;
/* Check that genpool to be created is uniquely addressed on device */
if (gen_pool_get(dev, name))
return ERR_PTR(-EINVAL);
if (name) {
pool_name = kstrdup_const(name, GFP_KERNEL);
if (!pool_name)
return ERR_PTR(-ENOMEM);
}
ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
goto free_pool_name;
pool = gen_pool_create(min_alloc_order, nid);
if (!pool)
goto free_devres;
*ptr = pool;
pool->name = pool_name;
devres_add(dev, ptr);
return pool;
free_devres:
devres_free(ptr);
free_pool_name:
kfree_const(pool_name);
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(devm_gen_pool_create);
#ifdef CONFIG_OF
/**
* of_gen_pool_get - find a pool by phandle property
* @np: device node
* @propname: property name containing phandle(s)
* @index: index into the phandle array
*
* Returns the pool that contains the chunk starting at the physical
* address of the device tree node pointed at by the phandle property,
* or NULL if not found.
*/
struct gen_pool *of_gen_pool_get(struct device_node *np,
const char *propname, int index)
{
struct platform_device *pdev;
struct device_node *np_pool, *parent;
const char *name = NULL;
struct gen_pool *pool = NULL;
np_pool = of_parse_phandle(np, propname, index);
if (!np_pool)
return NULL;
pdev = of_find_device_by_node(np_pool);
if (!pdev) {
/* Check if named gen_pool is created by parent node device */
parent = of_get_parent(np_pool);
pdev = of_find_device_by_node(parent);
of_node_put(parent);
of_property_read_string(np_pool, "label", &name);
if (!name)
name = np_pool->name;
}
if (pdev)
pool = gen_pool_get(&pdev->dev, name);
of_node_put(np_pool);
return pool;
}
EXPORT_SYMBOL_GPL(of_gen_pool_get);
#endif /* CONFIG_OF */
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