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ARM: dma-mapping: remove custom consistent dma region

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This patch changes dma-mapping subsystem to use generic vmalloc areas
for all consistent dma allocations. This increases the total size limit
of the consistent allocations and removes platform hacks and a lot of
duplicated code.

Atomic allocations are served from special pool preallocated on boot,
because vmalloc areas cannot be reliably created in atomic context.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
This commit is contained in:
Marek Szyprowski 2012-07-30 09:11:33 +02:00
parent 5e6cafc83e
commit e9da6e9905
6 changed files with 188 additions and 330 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/kernel-parameters.txt
View File

@ -526,7 +526,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
coherent_pool=nn[KMG] [ARM,KNL]
Sets the size of memory pool for coherent, atomic dma
allocations if Contiguous Memory Allocator (CMA) is used.
allocations, by default set to 256K.
code_bytes [X86] How many bytes of object code to print
in an oops report.

2
arch/arm/include/asm/dma-mapping.h
View File

@ -226,7 +226,7 @@ static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struc
* DMA region above it's default value of 2MB. It must be called before the
* memory allocator is initialised, i.e. before any core_initcall.
*/
extern void __init init_consistent_dma_size(unsigned long size);
static inline void init_consistent_dma_size(unsigned long size) { }
/*
* For SA-1111, IXP425, and ADI systems the dma-mapping functions are "magic"

488
arch/arm/mm/dma-mapping.c
View File

@ -22,6 +22,7 @@
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/iommu.h>
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <asm/memory.h>
@ -217,115 +218,70 @@ static void __dma_free_buffer(struct page *page, size_t size)
}
#ifdef CONFIG_MMU
#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - consistent_base) >> PAGE_SHIFT)
#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - consistent_base) >> PMD_SHIFT)
/*
* These are the page tables (2MB each) covering uncached, DMA consistent allocations
*/
static pte_t **consistent_pte;
#define DEFAULT_CONSISTENT_DMA_SIZE SZ_2M
static unsigned long consistent_base = CONSISTENT_END - DEFAULT_CONSISTENT_DMA_SIZE;
void __init init_consistent_dma_size(unsigned long size)
{
unsigned long base = CONSISTENT_END - ALIGN(size, SZ_2M);
BUG_ON(consistent_pte); /* Check we're called before DMA region init */
BUG_ON(base < VMALLOC_END);
/* Grow region to accommodate specified size */
if (base < consistent_base)
consistent_base = base;
}
#include "vmregion.h"
static struct arm_vmregion_head consistent_head = {
.vm_lock = __SPIN_LOCK_UNLOCKED(&consistent_head.vm_lock),
.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
.vm_end = CONSISTENT_END,
};
#ifdef CONFIG_HUGETLB_PAGE
#error ARM Coherent DMA allocator does not (yet) support huge TLB
#endif
/*
* Initialise the consistent memory allocation.
*/
static int __init consistent_init(void)
{
int ret = 0;
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
int i = 0;
unsigned long base = consistent_base;
unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;
if (IS_ENABLED(CONFIG_CMA) && !IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
return 0;
consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);
if (!consistent_pte) {
pr_err("%s: no memory\n", __func__);
return -ENOMEM;
}
pr_debug("DMA memory: 0x%08lx - 0x%08lx:\n", base, CONSISTENT_END);
consistent_head.vm_start = base;
do {
pgd = pgd_offset(&init_mm, base);
pud = pud_alloc(&init_mm, pgd, base);
if (!pud) {
pr_err("%s: no pud tables\n", __func__);
ret = -ENOMEM;
break;
}
pmd = pmd_alloc(&init_mm, pud, base);
if (!pmd) {
pr_err("%s: no pmd tables\n", __func__);
ret = -ENOMEM;
break;
}
WARN_ON(!pmd_none(*pmd));
pte = pte_alloc_kernel(pmd, base);
if (!pte) {
pr_err("%s: no pte tables\n", __func__);
ret = -ENOMEM;
break;
}
consistent_pte[i++] = pte;
base += PMD_SIZE;
} while (base < CONSISTENT_END);
return ret;
}
core_initcall(consistent_init);
static void *__alloc_from_contiguous(struct device *dev, size_t size,
pgprot_t prot, struct page **ret_page);
static struct arm_vmregion_head coherent_head = {
.vm_lock = __SPIN_LOCK_UNLOCKED(&coherent_head.vm_lock),
.vm_list = LIST_HEAD_INIT(coherent_head.vm_list),
static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
pgprot_t prot, struct page **ret_page,
const void *caller);
static void *
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
struct vm_struct *area;
unsigned long addr;
/*
* DMA allocation can be mapped to user space, so lets
* set VM_USERMAP flags too.
*/
area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
caller);
if (!area)
return NULL;
addr = (unsigned long)area->addr;
area->phys_addr = __pfn_to_phys(page_to_pfn(page));
if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
vunmap((void *)addr);
return NULL;
}
return (void *)addr;
}
static void __dma_free_remap(void *cpu_addr, size_t size)
{
unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP;
struct vm_struct *area = find_vm_area(cpu_addr);
if (!area || (area->flags & flags) != flags) {
WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
return;
}
unmap_kernel_range((unsigned long)cpu_addr, size);
vunmap(cpu_addr);
}
struct dma_pool {
size_t size;
spinlock_t lock;
unsigned long *bitmap;
unsigned long nr_pages;
void *vaddr;
struct page *page;
};
static size_t coherent_pool_size = DEFAULT_CONSISTENT_DMA_SIZE / 8;
static struct dma_pool atomic_pool = {
.size = SZ_256K,
};
static int __init early_coherent_pool(char *p)
{
coherent_pool_size = memparse(p, &p);
atomic_pool.size = memparse(p, &p);
return 0;
}
early_param("coherent_pool", early_coherent_pool);
@ -333,32 +289,45 @@ early_param("coherent_pool", early_coherent_pool);
/*
* Initialise the coherent pool for atomic allocations.
*/
static int __init coherent_init(void)
static int __init atomic_pool_init(void)
{
struct dma_pool *pool = &atomic_pool;
pgprot_t prot = pgprot_dmacoherent(pgprot_kernel);
size_t size = coherent_pool_size;
unsigned long nr_pages = pool->size >> PAGE_SHIFT;
unsigned long *bitmap;
struct page *page;
void *ptr;
int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
if (!IS_ENABLED(CONFIG_CMA))
return 0;
bitmap = kzalloc(bitmap_size, GFP_KERNEL);
if (!bitmap)
goto no_bitmap;
ptr = __alloc_from_contiguous(NULL, size, prot, &page);
if (IS_ENABLED(CONFIG_CMA))
ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
else
ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
&page, NULL);
if (ptr) {
coherent_head.vm_start = (unsigned long) ptr;
coherent_head.vm_end = (unsigned long) ptr + size;
printk(KERN_INFO "DMA: preallocated %u KiB pool for atomic coherent allocations\n",
(unsigned)size / 1024);
spin_lock_init(&pool->lock);
pool->vaddr = ptr;
pool->page = page;
pool->bitmap = bitmap;
pool->nr_pages = nr_pages;
pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n",
(unsigned)pool->size / 1024);
return 0;
}
printk(KERN_ERR "DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
(unsigned)size / 1024);
kfree(bitmap);
no_bitmap:
pr_err("DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
(unsigned)pool->size / 1024);
return -ENOMEM;
}
/*
* CMA is activated by core_initcall, so we must be called after it.
*/
postcore_initcall(coherent_init);
postcore_initcall(atomic_pool_init);
struct dma_contig_early_reserve {
phys_addr_t base;
@ -406,112 +375,6 @@ void __init dma_contiguous_remap(void)
}
}
static void *
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
struct arm_vmregion *c;
size_t align;
int bit;
if (!consistent_pte) {
pr_err("%s: not initialised\n", __func__);
dump_stack();
return NULL;
}
/*
* Align the virtual region allocation - maximum alignment is
* a section size, minimum is a page size. This helps reduce
* fragmentation of the DMA space, and also prevents allocations
* smaller than a section from crossing a section boundary.
*/
bit = fls(size - 1);
if (bit > SECTION_SHIFT)
bit = SECTION_SHIFT;
align = 1 << bit;
/*
* Allocate a virtual address in the consistent mapping region.
*/
c = arm_vmregion_alloc(&consistent_head, align, size,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM), caller);
if (c) {
pte_t *pte;
int idx = CONSISTENT_PTE_INDEX(c->vm_start);
u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
pte = consistent_pte[idx] + off;
c->priv = page;
do {
BUG_ON(!pte_none(*pte));
set_pte_ext(pte, mk_pte(page, prot), 0);
page++;
pte++;
off++;
if (off >= PTRS_PER_PTE) {
off = 0;
pte = consistent_pte[++idx];
}
} while (size -= PAGE_SIZE);
dsb();
return (void *)c->vm_start;
}
return NULL;
}
static void __dma_free_remap(void *cpu_addr, size_t size)
{
struct arm_vmregion *c;
unsigned long addr;
pte_t *ptep;
int idx;
u32 off;
c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr);
if (!c) {
pr_err("%s: trying to free invalid coherent area: %p\n",
__func__, cpu_addr);
dump_stack();
return;
}
if ((c->vm_end - c->vm_start) != size) {
pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
__func__, c->vm_end - c->vm_start, size);
dump_stack();
size = c->vm_end - c->vm_start;
}
idx = CONSISTENT_PTE_INDEX(c->vm_start);
off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
ptep = consistent_pte[idx] + off;
addr = c->vm_start;
do {
pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
ptep++;
addr += PAGE_SIZE;
off++;
if (off >= PTRS_PER_PTE) {
off = 0;
ptep = consistent_pte[++idx];
}
if (pte_none(pte) || !pte_present(pte))
pr_crit("%s: bad page in kernel page table\n",
__func__);
} while (size -= PAGE_SIZE);
flush_tlb_kernel_range(c->vm_start, c->vm_end);
arm_vmregion_free(&consistent_head, c);
}
static int __dma_update_pte(pte_t *pte, pgtable_t token, unsigned long addr,
void *data)
{
@ -552,16 +415,17 @@ static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
return ptr;
}
static void *__alloc_from_pool(struct device *dev, size_t size,
struct page **ret_page, const void *caller)
static void *__alloc_from_pool(size_t size, struct page **ret_page)
{
struct arm_vmregion *c;
struct dma_pool *pool = &atomic_pool;
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned int pageno;
unsigned long flags;
void *ptr = NULL;
size_t align;
if (!coherent_head.vm_start) {
printk(KERN_ERR "%s: coherent pool not initialised!\n",
__func__);
dump_stack();
if (!pool->vaddr) {
WARN(1, "coherent pool not initialised!\n");
return NULL;
}
@ -571,35 +435,41 @@ static void *__alloc_from_pool(struct device *dev, size_t size,
* size. This helps reduce fragmentation of the DMA space.
*/
align = PAGE_SIZE << get_order(size);
c = arm_vmregion_alloc(&coherent_head, align, size, 0, caller);
if (c) {
void *ptr = (void *)c->vm_start;
struct page *page = virt_to_page(ptr);
*ret_page = page;
return ptr;
spin_lock_irqsave(&pool->lock, flags);
pageno = bitmap_find_next_zero_area(pool->bitmap, pool->nr_pages,
0, count, (1 << align) - 1);
if (pageno < pool->nr_pages) {
bitmap_set(pool->bitmap, pageno, count);
ptr = pool->vaddr + PAGE_SIZE * pageno;
*ret_page = pool->page + pageno;
}
return NULL;
spin_unlock_irqrestore(&pool->lock, flags);
return ptr;
}
static int __free_from_pool(void *cpu_addr, size_t size)
static int __free_from_pool(void *start, size_t size)
{
unsigned long start = (unsigned long)cpu_addr;
unsigned long end = start + size;
struct arm_vmregion *c;
struct dma_pool *pool = &atomic_pool;
unsigned long pageno, count;
unsigned long flags;
if (start < coherent_head.vm_start || end > coherent_head.vm_end)
if (start < pool->vaddr || start > pool->vaddr + pool->size)
return 0;
c = arm_vmregion_find_remove(&coherent_head, (unsigned long)start);
if ((c->vm_end - c->vm_start) != size) {
printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
__func__, c->vm_end - c->vm_start, size);
dump_stack();
size = c->vm_end - c->vm_start;
if (start + size > pool->vaddr + pool->size) {
WARN(1, "freeing wrong coherent size from pool\n");
return 0;
}
arm_vmregion_free(&coherent_head, c);
pageno = (start - pool->vaddr) >> PAGE_SHIFT;
count = size >> PAGE_SHIFT;
spin_lock_irqsave(&pool->lock, flags);
bitmap_clear(pool->bitmap, pageno, count);
spin_unlock_irqrestore(&pool->lock, flags);
return 1;
}
@ -644,7 +514,7 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
#define __get_dma_pgprot(attrs, prot) __pgprot(0)
#define __alloc_remap_buffer(dev, size, gfp, prot, ret, c) NULL
#define __alloc_from_pool(dev, size, ret_page, c) NULL
#define __alloc_from_pool(size, ret_page) NULL
#define __alloc_from_contiguous(dev, size, prot, ret) NULL
#define __free_from_pool(cpu_addr, size) 0
#define __free_from_contiguous(dev, page, size) do { } while (0)
@ -702,10 +572,10 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (arch_is_coherent() || nommu())
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (gfp & GFP_ATOMIC)
addr = __alloc_from_pool(size, &page);
else if (!IS_ENABLED(CONFIG_CMA))
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
else if (gfp & GFP_ATOMIC)
addr = __alloc_from_pool(dev, size, &page, caller);
else
addr = __alloc_from_contiguous(dev, size, prot, &page);
@ -998,9 +868,6 @@ static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
static int __init dma_debug_do_init(void)
{
#ifdef CONFIG_MMU
arm_vmregion_create_proc("dma-mappings", &consistent_head);
#endif
dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
return 0;
}
@ -1117,61 +984,32 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t s
* Create a CPU mapping for a specified pages
*/
static void *
__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot)
__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
struct arm_vmregion *c;
size_t align;
size_t count = size >> PAGE_SHIFT;
int bit;
unsigned int i, nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
struct vm_struct *area;
unsigned long p;
if (!consistent_pte[0]) {
pr_err("%s: not initialised\n", __func__);
dump_stack();
area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
caller);
if (!area)
return NULL;
area->pages = pages;
area->nr_pages = nr_pages;
p = (unsigned long)area->addr;
for (i = 0; i < nr_pages; i++) {
phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i]));
if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot))
goto err;
p += PAGE_SIZE;
}
/*
* Align the virtual region allocation - maximum alignment is
* a section size, minimum is a page size. This helps reduce
* fragmentation of the DMA space, and also prevents allocations
* smaller than a section from crossing a section boundary.
*/
bit = fls(size - 1);
if (bit > SECTION_SHIFT)
bit = SECTION_SHIFT;
align = 1 << bit;
/*
* Allocate a virtual address in the consistent mapping region.
*/
c = arm_vmregion_alloc(&consistent_head, align, size,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM), NULL);
if (c) {
pte_t *pte;
int idx = CONSISTENT_PTE_INDEX(c->vm_start);
int i = 0;
u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
pte = consistent_pte[idx] + off;
c->priv = pages;
do {
BUG_ON(!pte_none(*pte));
set_pte_ext(pte, mk_pte(pages[i], prot), 0);
pte++;
off++;
i++;
if (off >= PTRS_PER_PTE) {
off = 0;
pte = consistent_pte[++idx];
}
} while (i < count);
dsb();
return (void *)c->vm_start;
}
return area->addr;
err:
unmap_kernel_range((unsigned long)area->addr, size);
vunmap(area->addr);
return NULL;
}
@ -1230,6 +1068,16 @@ static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t si
return 0;
}
static struct page **__iommu_get_pages(void *cpu_addr)
{
struct vm_struct *area;
area = find_vm_area(cpu_addr);
if (area && (area->flags & VM_ARM_DMA_CONSISTENT))
return area->pages;
return NULL;
}
static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
{
@ -1248,7 +1096,8 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
if (*handle == DMA_ERROR_CODE)
goto err_buffer;
addr = __iommu_alloc_remap(pages, size, gfp, prot);
addr = __iommu_alloc_remap(pages, size, gfp, prot,
__builtin_return_address(0));
if (!addr)
goto err_mapping;
@ -1265,31 +1114,25 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
struct dma_attrs *attrs)
{
struct arm_vmregion *c;
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
if (c) {
struct page **pages = c->priv;
unsigned long uaddr = vma->vm_start;
unsigned long usize = vma->vm_end - vma->vm_start;
int i = 0;
struct page **pages = __iommu_get_pages(cpu_addr);
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
if (!pages)
return -ENXIO;
do {
int ret;
ret = vm_insert_page(vma, uaddr, pages[i++]);
int ret = vm_insert_page(vma, uaddr, *pages++);
if (ret) {
pr_err("Remapping memory, error: %d\n", ret);
pr_err("Remapping memory failed: %d\n", ret);
return ret;
}
uaddr += PAGE_SIZE;
usize -= PAGE_SIZE;
} while (usize > 0);
}
return 0;
}
@ -1300,16 +1143,19 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs)
{
struct arm_vmregion *c;
struct page **pages = __iommu_get_pages(cpu_addr);
size = PAGE_ALIGN(size);
c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
if (c) {
struct page **pages = c->priv;
__dma_free_remap(cpu_addr, size);
if (!pages) {
WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
return;
}
unmap_kernel_range((unsigned long)cpu_addr, size);
vunmap(cpu_addr);
__iommu_remove_mapping(dev, handle, size);
__iommu_free_buffer(dev, pages, size);
}
}
/*

3
arch/arm/mm/mm.h
View File

@ -59,6 +59,9 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
#define VM_ARM_MTYPE(mt) ((mt) << 20)
#define VM_ARM_MTYPE_MASK (0x1f << 20)
/* consistent regions used by dma_alloc_attrs() */
#define VM_ARM_DMA_CONSISTENT 0x20000000
#endif
#ifdef CONFIG_ZONE_DMA

1
include/linux/vmalloc.h
View File

@ -93,6 +93,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size,
unsigned long start, unsigned long end,
const void *caller);
extern struct vm_struct *remove_vm_area(const void *addr);
extern struct vm_struct *find_vm_area(const void *addr);
extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
struct page ***pages);

10
mm/vmalloc.c
View File

@ -1403,7 +1403,15 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
-1, GFP_KERNEL, caller);
}
static struct vm_struct *find_vm_area(const void *addr)
/**
* find_vm_area - find a continuous kernel virtual area
* @addr: base address
*
* Search for the kernel VM area starting at @addr, and return it.
* It is up to the caller to do all required locking to keep the returned
* pointer valid.
*/
struct vm_struct *find_vm_area(const void *addr)
{
struct vmap_area *va;