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android-kvm / linux / 7c51f7bbf057f82aeba3390c39ef61b244181c09 / . / mm / vmalloc.c
blob: 6b783baf12a14323361c53196f8e2a2645dc1142 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
* Improving global KVA allocator, Uladzislau Rezki, Sony, May 2019
*/
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/sched/signal.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/set_memory.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/rbtree.h>
#include <linux/xarray.h>
#include <linux/io.h>
#include <linux/rcupdate.h>
#include <linux/pfn.h>
#include <linux/kmemleak.h>
#include <linux/atomic.h>
#include <linux/compiler.h>
#include <linux/memcontrol.h>
#include <linux/llist.h>
#include <linux/uio.h>
#include <linux/bitops.h>
#include <linux/rbtree_augmented.h>
#include <linux/overflow.h>
#include <linux/pgtable.h>
#include <linux/hugetlb.h>
#include <linux/sched/mm.h>
#include <asm/tlbflush.h>
#include <asm/shmparam.h>
#include <linux/page_owner.h>
#define CREATE_TRACE_POINTS
#include <trace/events/vmalloc.h>
#include "internal.h"
#include "pgalloc-track.h"
#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
static unsigned int __ro_after_init ioremap_max_page_shift = BITS_PER_LONG - 1;
static int __init set_nohugeiomap(char *str)
{
ioremap_max_page_shift = PAGE_SHIFT;
return 0;
}
early_param("nohugeiomap", set_nohugeiomap);
#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
static const unsigned int ioremap_max_page_shift = PAGE_SHIFT;
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
static bool __ro_after_init vmap_allow_huge = true;
static int __init set_nohugevmalloc(char *str)
{
vmap_allow_huge = false;
return 0;
}
early_param("nohugevmalloc", set_nohugevmalloc);
#else /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
static const bool vmap_allow_huge = false;
#endif /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
bool is_vmalloc_addr(const void *x)
{
unsigned long addr = (unsigned long)kasan_reset_tag(x);
return addr >= VMALLOC_START && addr < VMALLOC_END;
}
EXPORT_SYMBOL(is_vmalloc_addr);
struct vfree_deferred {
struct llist_head list;
struct work_struct wq;
};
static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
/*** Page table manipulation functions ***/
static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift, pgtbl_mod_mask *mask)
{
pte_t *pte;
u64 pfn;
struct page *page;
unsigned long size = PAGE_SIZE;
pfn = phys_addr >> PAGE_SHIFT;
pte = pte_alloc_kernel_track(pmd, addr, mask);
if (!pte)
return -ENOMEM;
do {
if (!pte_none(ptep_get(pte))) {
if (pfn_valid(pfn)) {
page = pfn_to_page(pfn);
dump_page(page, "remapping already mapped page");
}
BUG();
}
#ifdef CONFIG_HUGETLB_PAGE
size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
if (size != PAGE_SIZE) {
pte_t entry = pfn_pte(pfn, prot);
entry = arch_make_huge_pte(entry, ilog2(size), 0);
set_huge_pte_at(&init_mm, addr, pte, entry, size);
pfn += PFN_DOWN(size);
continue;
}
#endif
set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
} while (pte += PFN_DOWN(size), addr += size, addr != end);
*mask |= PGTBL_PTE_MODIFIED;
return 0;
}
static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
if (max_page_shift < PMD_SHIFT)
return 0;
if (!arch_vmap_pmd_supported(prot))
return 0;
if ((end - addr) != PMD_SIZE)
return 0;
if (!IS_ALIGNED(addr, PMD_SIZE))
return 0;
if (!IS_ALIGNED(phys_addr, PMD_SIZE))
return 0;
if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
return 0;
return pmd_set_huge(pmd, phys_addr, prot);
}
static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift, pgtbl_mod_mask *mask)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
if (!pmd)
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot,
max_page_shift)) {
*mask |= PGTBL_PMD_MODIFIED;
continue;
}
if (vmap_pte_range(pmd, addr, next, phys_addr, prot, max_page_shift, mask))
return -ENOMEM;
} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
if (max_page_shift < PUD_SHIFT)
return 0;
if (!arch_vmap_pud_supported(prot))
return 0;
if ((end - addr) != PUD_SIZE)
return 0;
if (!IS_ALIGNED(addr, PUD_SIZE))
return 0;
if (!IS_ALIGNED(phys_addr, PUD_SIZE))
return 0;
if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
return 0;
return pud_set_huge(pud, phys_addr, prot);
}
static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift, pgtbl_mod_mask *mask)
{
pud_t *pud;
unsigned long next;
pud = pud_alloc_track(&init_mm, p4d, addr, mask);
if (!pud)
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot,
max_page_shift)) {
*mask |= PGTBL_PUD_MODIFIED;
continue;
}
if (vmap_pmd_range(pud, addr, next, phys_addr, prot,
max_page_shift, mask))
return -ENOMEM;
} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
if (max_page_shift < P4D_SHIFT)
return 0;
if (!arch_vmap_p4d_supported(prot))
return 0;
if ((end - addr) != P4D_SIZE)
return 0;
if (!IS_ALIGNED(addr, P4D_SIZE))
return 0;
if (!IS_ALIGNED(phys_addr, P4D_SIZE))
return 0;
if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
return 0;
return p4d_set_huge(p4d, phys_addr, prot);
}
static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift, pgtbl_mod_mask *mask)
{
p4d_t *p4d;
unsigned long next;
p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
if (!p4d)
return -ENOMEM;
do {
next = p4d_addr_end(addr, end);
if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot,
max_page_shift)) {
*mask |= PGTBL_P4D_MODIFIED;
continue;
}
if (vmap_pud_range(p4d, addr, next, phys_addr, prot,
max_page_shift, mask))
return -ENOMEM;
} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
static int vmap_range_noflush(unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
pgd_t *pgd;
unsigned long start;
unsigned long next;
int err;
pgtbl_mod_mask mask = 0;
might_sleep();
BUG_ON(addr >= end);
start = addr;
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
err = vmap_p4d_range(pgd, addr, next, phys_addr, prot,
max_page_shift, &mask);
if (err)
break;
} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
arch_sync_kernel_mappings(start, end);
return err;
}
int vmap_page_range(unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot)
{
int err;
err = vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot),
ioremap_max_page_shift);
flush_cache_vmap(addr, end);
if (!err)
err = kmsan_ioremap_page_range(addr, end, phys_addr, prot,
ioremap_max_page_shift);
return err;
}
int ioremap_page_range(unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot)
{
struct vm_struct *area;
area = find_vm_area((void *)addr);
if (!area || !(area->flags & VM_IOREMAP)) {
WARN_ONCE(1, "vm_area at addr %lx is not marked as VM_IOREMAP\n", addr);
return -EINVAL;
}
if (addr != (unsigned long)area->addr ||
(void *)end != area->addr + get_vm_area_size(area)) {
WARN_ONCE(1, "ioremap request [%lx,%lx) doesn't match vm_area [%lx, %lx)\n",
addr, end, (long)area->addr,
(long)area->addr + get_vm_area_size(area));
return -ERANGE;
}
return vmap_page_range(addr, end, phys_addr, prot);
}
static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
pgtbl_mod_mask *mask)
{
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);
*mask |= PGTBL_PTE_MODIFIED;
}
static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
pgtbl_mod_mask *mask)
{
pmd_t *pmd;
unsigned long next;
int cleared;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
cleared = pmd_clear_huge(pmd);
if (cleared || pmd_bad(*pmd))
*mask |= PGTBL_PMD_MODIFIED;
if (cleared)
continue;
if (pmd_none_or_clear_bad(pmd))
continue;
vunmap_pte_range(pmd, addr, next, mask);
cond_resched();
} while (pmd++, addr = next, addr != end);
}
static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
pgtbl_mod_mask *mask)
{
pud_t *pud;
unsigned long next;
int cleared;
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
cleared = pud_clear_huge(pud);
if (cleared || pud_bad(*pud))
*mask |= PGTBL_PUD_MODIFIED;
if (cleared)
continue;
if (pud_none_or_clear_bad(pud))
continue;
vunmap_pmd_range(pud, addr, next, mask);
} while (pud++, addr = next, addr != end);
}
static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
pgtbl_mod_mask *mask)
{
p4d_t *p4d;
unsigned long next;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
p4d_clear_huge(p4d);
if (p4d_bad(*p4d))
*mask |= PGTBL_P4D_MODIFIED;
if (p4d_none_or_clear_bad(p4d))
continue;
vunmap_pud_range(p4d, addr, next, mask);
} while (p4d++, addr = next, addr != end);
}
/*
* vunmap_range_noflush is similar to vunmap_range, but does not
* flush caches or TLBs.
*
* The caller is responsible for calling flush_cache_vmap() before calling
* this function, and flush_tlb_kernel_range after it has returned
* successfully (and before the addresses are expected to cause a page fault
* or be re-mapped for something else, if TLB flushes are being delayed or
* coalesced).
*
* This is an internal function only. Do not use outside mm/.
*/
void __vunmap_range_noflush(unsigned long start, unsigned long end)
{
unsigned long next;
pgd_t *pgd;
unsigned long addr = start;
pgtbl_mod_mask mask = 0;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
if (pgd_bad(*pgd))
mask |= PGTBL_PGD_MODIFIED;
if (pgd_none_or_clear_bad(pgd))
continue;
vunmap_p4d_range(pgd, addr, next, &mask);
} while (pgd++, addr = next, addr != end);
if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
arch_sync_kernel_mappings(start, end);
}
void vunmap_range_noflush(unsigned long start, unsigned long end)
{
kmsan_vunmap_range_noflush(start, end);
__vunmap_range_noflush(start, end);
}
/**
* vunmap_range - unmap kernel virtual addresses
* @addr: start of the VM area to unmap
* @end: end of the VM area to unmap (non-inclusive)
*
* Clears any present PTEs in the virtual address range, flushes TLBs and
* caches. Any subsequent access to the address before it has been re-mapped
* is a kernel bug.
*/
void vunmap_range(unsigned long addr, unsigned long end)
{
flush_cache_vunmap(addr, end);
vunmap_range_noflush(addr, end);
flush_tlb_kernel_range(addr, end);
}
static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
pgtbl_mod_mask *mask)
{
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_track(pmd, addr, mask);
if (!pte)
return -ENOMEM;
do {
struct page *page = pages[*nr];
if (WARN_ON(!pte_none(ptep_get(pte))))
return -EBUSY;
if (WARN_ON(!page))
return -ENOMEM;
if (WARN_ON(!pfn_valid(page_to_pfn(page))))
return -EINVAL;
set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
(*nr)++;
} while (pte++, addr += PAGE_SIZE, addr != end);
*mask |= PGTBL_PTE_MODIFIED;
return 0;
}
static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
pgtbl_mod_mask *mask)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
if (!pmd)
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask))
return -ENOMEM;
} while (pmd++, addr = next, addr != end);
return 0;
}
static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
pgtbl_mod_mask *mask)
{
pud_t *pud;
unsigned long next;
pud = pud_alloc_track(&init_mm, p4d, addr, mask);
if (!pud)
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask))
return -ENOMEM;
} while (pud++, addr = next, addr != end);
return 0;
}
static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
pgtbl_mod_mask *mask)
{
p4d_t *p4d;
unsigned long next;
p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
if (!p4d)
return -ENOMEM;
do {
next = p4d_addr_end(addr, end);
if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask))
return -ENOMEM;
} while (p4d++, addr = next, addr != end);
return 0;
}
static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages)
{
unsigned long start = addr;
pgd_t *pgd;
unsigned long next;
int err = 0;
int nr = 0;
pgtbl_mod_mask mask = 0;
BUG_ON(addr >= end);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
if (pgd_bad(*pgd))
mask |= PGTBL_PGD_MODIFIED;
err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
if (err)
return err;
} while (pgd++, addr = next, addr != end);
if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
arch_sync_kernel_mappings(start, end);
return 0;
}
/*
* vmap_pages_range_noflush is similar to vmap_pages_range, but does not
* flush caches.
*
* The caller is responsible for calling flush_cache_vmap() after this
* function returns successfully and before the addresses are accessed.
*
* This is an internal function only. Do not use outside mm/.
*/
int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
unsigned int i, nr = (end - addr) >> PAGE_SHIFT;
WARN_ON(page_shift < PAGE_SHIFT);
if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) ||
page_shift == PAGE_SHIFT)
return vmap_small_pages_range_noflush(addr, end, prot, pages);
for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) {
int err;
err = vmap_range_noflush(addr, addr + (1UL << page_shift),
page_to_phys(pages[i]), prot,
page_shift);
if (err)
return err;
addr += 1UL << page_shift;
}
return 0;
}
int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
int ret = kmsan_vmap_pages_range_noflush(addr, end, prot, pages,
page_shift);
if (ret)
return ret;
return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
}
/**
* vmap_pages_range - map pages to a kernel virtual address
* @addr: start of the VM area to map
* @end: end of the VM area to map (non-inclusive)
* @prot: page protection flags to use
* @pages: pages to map (always PAGE_SIZE pages)
* @page_shift: maximum shift that the pages may be mapped with, @pages must
* be aligned and contiguous up to at least this shift.
*
* RETURNS:
* 0 on success, -errno on failure.
*/
static int vmap_pages_range(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
int err;
err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
flush_cache_vmap(addr, end);
return err;
}
static int check_sparse_vm_area(struct vm_struct *area, unsigned long start,
unsigned long end)
{
might_sleep();
if (WARN_ON_ONCE(area->flags & VM_FLUSH_RESET_PERMS))
return -EINVAL;
if (WARN_ON_ONCE(area->flags & VM_NO_GUARD))
return -EINVAL;
if (WARN_ON_ONCE(!(area->flags & VM_SPARSE)))
return -EINVAL;
if ((end - start) >> PAGE_SHIFT > totalram_pages())
return -E2BIG;
if (start < (unsigned long)area->addr ||
(void *)end > area->addr + get_vm_area_size(area))
return -ERANGE;
return 0;
}
/**
* vm_area_map_pages - map pages inside given sparse vm_area
* @area: vm_area
* @start: start address inside vm_area
* @end: end address inside vm_area
* @pages: pages to map (always PAGE_SIZE pages)
*/
int vm_area_map_pages(struct vm_struct *area, unsigned long start,
unsigned long end, struct page **pages)
{
int err;
err = check_sparse_vm_area(area, start, end);
if (err)
return err;
return vmap_pages_range(start, end, PAGE_KERNEL, pages, PAGE_SHIFT);
}
/**
* vm_area_unmap_pages - unmap pages inside given sparse vm_area
* @area: vm_area
* @start: start address inside vm_area
* @end: end address inside vm_area
*/
void vm_area_unmap_pages(struct vm_struct *area, unsigned long start,
unsigned long end)
{
if (check_sparse_vm_area(area, start, end))
return;
vunmap_range(start, end);
}
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_EXECMEM) && defined(MODULES_VADDR)
unsigned long addr = (unsigned long)kasan_reset_tag(x);
if (addr >= MODULES_VADDR && addr < MODULES_END)
return 1;
#endif
return is_vmalloc_addr(x);
}
EXPORT_SYMBOL_GPL(is_vmalloc_or_module_addr);
/*
* Walk a vmap address to the struct page it maps. Huge vmap mappings will
* return the tail page that corresponds to the base page address, which
* matches small vmap mappings.
*/
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);
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
/*
* 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))
return NULL;
if (WARN_ON_ONCE(pgd_leaf(*pgd)))
return NULL; /* XXX: no allowance for huge pgd */
if (WARN_ON_ONCE(pgd_bad(*pgd)))
return NULL;
p4d = p4d_offset(pgd, addr);
if (p4d_none(*p4d))
return NULL;
if (p4d_leaf(*p4d))
return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT);
if (WARN_ON_ONCE(p4d_bad(*p4d)))
return NULL;
pud = pud_offset(p4d, addr);
if (pud_none(*pud))
return NULL;
if (pud_leaf(*pud))
return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
if (WARN_ON_ONCE(pud_bad(*pud)))
return NULL;
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd))
return NULL;
if (pmd_leaf(*pmd))
return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
if (WARN_ON_ONCE(pmd_bad(*pmd)))
return NULL;
ptep = pte_offset_kernel(pmd, addr);
pte = ptep_get(ptep);
if (pte_present(pte))
page = pte_page(pte);
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 DEBUG_AUGMENT_PROPAGATE_CHECK 0
#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
static DEFINE_SPINLOCK(free_vmap_area_lock);
static bool vmap_initialized __read_mostly;
/*
* This kmem_cache is used for vmap_area objects. Instead of
* allocating from slab we reuse an object from this cache to
* make things faster. Especially in "no edge" splitting of
* free block.
*/
static struct kmem_cache *vmap_area_cachep;
/*
* This linked list is used in pair with free_vmap_area_root.
* It gives O(1) access to prev/next to perform fast coalescing.
*/
static LIST_HEAD(free_vmap_area_list);
/*
* This augment red-black tree represents the free vmap space.
* All vmap_area objects in this tree are sorted by va->va_start
* address. It is used for allocation and merging when a vmap
* object is released.
*
* Each vmap_area node contains a maximum available free block
* of its sub-tree, right or left. Therefore it is possible to
* find a lowest match of free area.
*/
static struct rb_root free_vmap_area_root = RB_ROOT;
/*
* Preload a CPU with one object for "no edge" split case. The
* aim is to get rid of allocations from the atomic context, thus
* to use more permissive allocation masks.
*/
static DEFINE_PER_CPU(struct vmap_area *, ne_fit_preload_node);
/*
* This structure defines a single, solid model where a list and
* rb-tree are part of one entity protected by the lock. Nodes are
* sorted in ascending order, thus for O(1) access to left/right
* neighbors a list is used as well as for sequential traversal.
*/
struct rb_list {
struct rb_root root;
struct list_head head;
spinlock_t lock;
};
/*
* A fast size storage contains VAs up to 1M size. A pool consists
* of linked between each other ready to go VAs of certain sizes.
* An index in the pool-array corresponds to number of pages + 1.
*/
#define MAX_VA_SIZE_PAGES 256
struct vmap_pool {
struct list_head head;
unsigned long len;
};
/*
* An effective vmap-node logic. Users make use of nodes instead
* of a global heap. It allows to balance an access and mitigate
* contention.
*/
static struct vmap_node {
/* Simple size segregated storage. */
struct vmap_pool pool[MAX_VA_SIZE_PAGES];
spinlock_t pool_lock;
bool skip_populate;
/* Bookkeeping data of this node. */
struct rb_list busy;
struct rb_list lazy;
/*
* Ready-to-free areas.
*/
struct list_head purge_list;
struct work_struct purge_work;
unsigned long nr_purged;
} single;
/*
* Initial setup consists of one single node, i.e. a balancing
* is fully disabled. Later on, after vmap is initialized these
* parameters are updated based on a system capacity.
*/
static struct vmap_node *vmap_nodes = &single;
static __read_mostly unsigned int nr_vmap_nodes = 1;
static __read_mostly unsigned int vmap_zone_size = 1;
static inline unsigned int
addr_to_node_id(unsigned long addr)
{
return (addr / vmap_zone_size) % nr_vmap_nodes;
}
static inline struct vmap_node *
addr_to_node(unsigned long addr)
{
return &vmap_nodes[addr_to_node_id(addr)];
}
static inline struct vmap_node *
id_to_node(unsigned int id)
{
return &vmap_nodes[id % nr_vmap_nodes];
}
/*
* We use the value 0 to represent "no node", that is why
* an encoded value will be the node-id incremented by 1.
* It is always greater then 0. A valid node_id which can
* be encoded is [0:nr_vmap_nodes - 1]. If a passed node_id
* is not valid 0 is returned.
*/
static unsigned int
encode_vn_id(unsigned int node_id)
{
/* Can store U8_MAX [0:254] nodes. */
if (node_id < nr_vmap_nodes)
return (node_id + 1) << BITS_PER_BYTE;
/* Warn and no node encoded. */
WARN_ONCE(1, "Encode wrong node id (%u)\n", node_id);
return 0;
}
/*
* Returns an encoded node-id, the valid range is within
* [0:nr_vmap_nodes-1] values. Otherwise nr_vmap_nodes is
* returned if extracted data is wrong.
*/
static unsigned int
decode_vn_id(unsigned int val)
{
unsigned int node_id = (val >> BITS_PER_BYTE) - 1;
/* Can store U8_MAX [0:254] nodes. */
if (node_id < nr_vmap_nodes)
return node_id;
/* If it was _not_ zero, warn. */
WARN_ONCE(node_id != UINT_MAX,
"Decode wrong node id (%d)\n", node_id);
return nr_vmap_nodes;
}
static bool
is_vn_id_valid(unsigned int node_id)
{
if (node_id < nr_vmap_nodes)
return true;
return false;
}
static __always_inline unsigned long
va_size(struct vmap_area *va)
{
return (va->va_end - va->va_start);
}
static __always_inline unsigned long
get_subtree_max_size(struct rb_node *node)
{
struct vmap_area *va;
va = rb_entry_safe(node, struct vmap_area, rb_node);
return va ? va->subtree_max_size : 0;
}
RB_DECLARE_CALLBACKS_MAX(static, free_vmap_area_rb_augment_cb,
struct vmap_area, rb_node, unsigned long, subtree_max_size, va_size)
static void reclaim_and_purge_vmap_areas(void);
static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
static void drain_vmap_area_work(struct work_struct *work);
static DECLARE_WORK(drain_vmap_work, drain_vmap_area_work);
static atomic_long_t nr_vmalloc_pages;
unsigned long vmalloc_nr_pages(void)
{
return atomic_long_read(&nr_vmalloc_pages);
}
static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root)
{
struct rb_node *n = root->rb_node;
addr = (unsigned long)kasan_reset_tag((void *)addr);
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_end)
n = n->rb_right;
else
return va;
}
return NULL;
}
/* Look up the first VA which satisfies addr < va_end, NULL if none. */
static struct vmap_area *
__find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root)
{
struct vmap_area *va = NULL;
struct rb_node *n = root->rb_node;
addr = (unsigned long)kasan_reset_tag((void *)addr);
while (n) {
struct vmap_area *tmp;
tmp = rb_entry(n, struct vmap_area, rb_node);
if (tmp->va_end > addr) {
va = tmp;
if (tmp->va_start <= addr)
break;
n = n->rb_left;
} else
n = n->rb_right;
}
return va;
}
/*
* Returns a node where a first VA, that satisfies addr < va_end, resides.
* If success, a node is locked. A user is responsible to unlock it when a
* VA is no longer needed to be accessed.
*
* Returns NULL if nothing found.
*/
static struct vmap_node *
find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va)
{
unsigned long va_start_lowest;
struct vmap_node *vn;
int i;
repeat:
for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) {
vn = &vmap_nodes[i];
spin_lock(&vn->busy.lock);
*va = __find_vmap_area_exceed_addr(addr, &vn->busy.root);
if (*va)
if (!va_start_lowest || (*va)->va_start < va_start_lowest)
va_start_lowest = (*va)->va_start;
spin_unlock(&vn->busy.lock);
}
/*
* Check if found VA exists, it might have gone away. In this case we
* repeat the search because a VA has been removed concurrently and we
* need to proceed to the next one, which is a rare case.
*/
if (va_start_lowest) {
vn = addr_to_node(va_start_lowest);
spin_lock(&vn->busy.lock);
*va = __find_vmap_area(va_start_lowest, &vn->busy.root);
if (*va)
return vn;
spin_unlock(&vn->busy.lock);
goto repeat;
}
return NULL;
}
/*
* This function returns back addresses of parent node
* and its left or right link for further processing.
*
* Otherwise NULL is returned. In that case all further
* steps regarding inserting of conflicting overlap range
* have to be declined and actually considered as a bug.
*/
static __always_inline struct rb_node **
find_va_links(struct vmap_area *va,
struct rb_root *root, struct rb_node *from,
struct rb_node **parent)
{
struct vmap_area *tmp_va;
struct rb_node **link;
if (root) {
link = &root->rb_node;
if (unlikely(!*link)) {
*parent = NULL;
return link;
}
} else {
link = &from;
}
/*
* Go to the bottom of the tree. When we hit the last point
* we end up with parent rb_node and correct direction, i name
* it link, where the new va->rb_node will be attached to.
*/
do {
tmp_va = rb_entry(*link, struct vmap_area, rb_node);
/*
* During the traversal we also do some sanity check.
* Trigger the BUG() if there are sides(left/right)
* or full overlaps.
*/
if (va->va_end <= tmp_va->va_start)
link = &(*link)->rb_left;
else if (va->va_start >= tmp_va->va_end)
link = &(*link)->rb_right;
else {
WARN(1, "vmalloc bug: 0x%lx-0x%lx overlaps with 0x%lx-0x%lx\n",
va->va_start, va->va_end, tmp_va->va_start, tmp_va->va_end);
return NULL;
}
} while (*link);
*parent = &tmp_va->rb_node;
return link;
}
static __always_inline struct list_head *
get_va_next_sibling(struct rb_node *parent, struct rb_node **link)
{
struct list_head *list;
if (unlikely(!parent))
/*
* The red-black tree where we try to find VA neighbors
* before merging or inserting is empty, i.e. it means
* there is no free vmap space. Normally it does not
* happen but we handle this case anyway.
*/
return NULL;
list = &rb_entry(parent, struct vmap_area, rb_node)->list;
return (&parent->rb_right == link ? list->next : list);
}
static __always_inline void
__link_va(struct vmap_area *va, struct rb_root *root,
struct rb_node *parent, struct rb_node **link,
struct list_head *head, bool augment)
{
/*
* VA is still not in the list, but we can
* identify its future previous list_head node.
*/
if (likely(parent)) {
head = &rb_entry(parent, struct vmap_area, rb_node)->list;
if (&parent->rb_right != link)
head = head->prev;
}
/* Insert to the rb-tree */
rb_link_node(&va->rb_node, parent, link);
if (augment) {
/*
* Some explanation here. Just perform simple insertion
* to the tree. We do not set va->subtree_max_size to
* its current size before calling rb_insert_augmented().
* It is because we populate the tree from the bottom
* to parent levels when the node _is_ in the tree.
*
* Therefore we set subtree_max_size to zero after insertion,
* to let __augment_tree_propagate_from() puts everything to
* the correct order later on.
*/
rb_insert_augmented(&va->rb_node,
root, &free_vmap_area_rb_augment_cb);
va->subtree_max_size = 0;
} else {
rb_insert_color(&va->rb_node, root);
}
/* Address-sort this list */
list_add(&va->list, head);
}
static __always_inline void
link_va(struct vmap_area *va, struct rb_root *root,
struct rb_node *parent, struct rb_node **link,
struct list_head *head)
{
__link_va(va, root, parent, link, head, false);
}
static __always_inline void
link_va_augment(struct vmap_area *va, struct rb_root *root,
struct rb_node *parent, struct rb_node **link,
struct list_head *head)
{
__link_va(va, root, parent, link, head, true);
}
static __always_inline void
__unlink_va(struct vmap_area *va, struct rb_root *root, bool augment)
{
if (WARN_ON(RB_EMPTY_NODE(&va->rb_node)))
return;
if (augment)
rb_erase_augmented(&va->rb_node,
root, &free_vmap_area_rb_augment_cb);
else
rb_erase(&va->rb_node, root);
list_del_init(&va->list);
RB_CLEAR_NODE(&va->rb_node);
}
static __always_inline void
unlink_va(struct vmap_area *va, struct rb_root *root)
{
__unlink_va(va, root, false);
}
static __always_inline void
unlink_va_augment(struct vmap_area *va, struct rb_root *root)
{
__unlink_va(va, root, true);
}
#if DEBUG_AUGMENT_PROPAGATE_CHECK
/*
* Gets called when remove the node and rotate.
*/
static __always_inline unsigned long
compute_subtree_max_size(struct vmap_area *va)
{
return max3(va_size(va),
get_subtree_max_size(va->rb_node.rb_left),
get_subtree_max_size(va->rb_node.rb_right));
}
static void
augment_tree_propagate_check(void)
{
struct vmap_area *va;
unsigned long computed_size;
list_for_each_entry(va, &free_vmap_area_list, list) {
computed_size = compute_subtree_max_size(va);
if (computed_size != va->subtree_max_size)
pr_emerg("tree is corrupted: %lu, %lu\n",
va_size(va), va->subtree_max_size);
}
}
#endif
/*
* This function populates subtree_max_size from bottom to upper
* levels starting from VA point. The propagation must be done
* when VA size is modified by changing its va_start/va_end. Or
* in case of newly inserting of VA to the tree.
*
* It means that __augment_tree_propagate_from() must be called:
* - After VA has been inserted to the tree(free path);
* - After VA has been shrunk(allocation path);
* - After VA has been increased(merging path).
*
* Please note that, it does not mean that upper parent nodes
* and their subtree_max_size are recalculated all the time up
* to the root node.
*
* 4--8
* /\
* / \
* / \
* 2--2 8--8
*
* For example if we modify the node 4, shrinking it to 2, then
* no any modification is required. If we shrink the node 2 to 1
* its subtree_max_size is updated only, and set to 1. If we shrink
* the node 8 to 6, then its subtree_max_size is set to 6 and parent
* node becomes 4--6.
*/
static __always_inline void
augment_tree_propagate_from(struct vmap_area *va)
{
/*
* Populate the tree from bottom towards the root until
* the calculated maximum available size of checked node
* is equal to its current one.
*/
free_vmap_area_rb_augment_cb_propagate(&va->rb_node, NULL);
#if DEBUG_AUGMENT_PROPAGATE_CHECK
augment_tree_propagate_check();
#endif
}
static void
insert_vmap_area(struct vmap_area *va,
struct rb_root *root, struct list_head *head)
{
struct rb_node **link;
struct rb_node *parent;
link = find_va_links(va, root, NULL, &parent);
if (link)
link_va(va, root, parent, link, head);
}
static void
insert_vmap_area_augment(struct vmap_area *va,
struct rb_node *from, struct rb_root *root,
struct list_head *head)
{
struct rb_node **link;
struct rb_node *parent;
if (from)
link = find_va_links(va, NULL, from, &parent);
else
link = find_va_links(va, root, NULL, &parent);
if (link) {
link_va_augment(va, root, parent, link, head);
augment_tree_propagate_from(va);
}
}
/*
* Merge de-allocated chunk of VA memory with previous
* and next free blocks. If coalesce is not done a new
* free area is inserted. If VA has been merged, it is
* freed.
*
* Please note, it can return NULL in case of overlap
* ranges, followed by WARN() report. Despite it is a
* buggy behaviour, a system can be alive and keep
* ongoing.
*/
static __always_inline struct vmap_area *
__merge_or_add_vmap_area(struct vmap_area *va,
struct rb_root *root, struct list_head *head, bool augment)
{
struct vmap_area *sibling;
struct list_head *next;
struct rb_node **link;
struct rb_node *parent;
bool merged = false;
/*
* Find a place in the tree where VA potentially will be
* inserted, unless it is merged with its sibling/siblings.
*/
link = find_va_links(va, root, NULL, &parent);
if (!link)
return NULL;
/*
* Get next node of VA to check if merging can be done.
*/
next = get_va_next_sibling(parent, link);
if (unlikely(next == NULL))
goto insert;
/*
* start end
* | |
* |<------VA------>|<-----Next----->|
* | |
* start end
*/
if (next != head) {
sibling = list_entry(next, struct vmap_area, list);
if (sibling->va_start == va->va_end) {
sibling->va_start = va->va_start;
/* Free vmap_area object. */
kmem_cache_free(vmap_area_cachep, va);
/* Point to the new merged area. */
va = sibling;
merged = true;
}
}
/*
* start end
* | |
* |<-----Prev----->|<------VA------>|
* | |
* start end
*/
if (next->prev != head) {
sibling = list_entry(next->prev, struct vmap_area, list);
if (sibling->va_end == va->va_start) {
/*
* If both neighbors are coalesced, it is important
* to unlink the "next" node first, followed by merging
* with "previous" one. Otherwise the tree might not be
* fully populated if a sibling's augmented value is
* "normalized" because of rotation operations.
*/
if (merged)
__unlink_va(va, root, augment);
sibling->va_end = va->va_end;
/* Free vmap_area object. */
kmem_cache_free(vmap_area_cachep, va);
/* Point to the new merged area. */
va = sibling;
merged = true;
}
}
insert:
if (!merged)
__link_va(va, root, parent, link, head, augment);
return va;
}
static __always_inline struct vmap_area *
merge_or_add_vmap_area(struct vmap_area *va,
struct rb_root *root, struct list_head *head)
{
return __merge_or_add_vmap_area(va, root, head, false);
}
static __always_inline struct vmap_area *
merge_or_add_vmap_area_augment(struct vmap_area *va,
struct rb_root *root, struct list_head *head)
{
va = __merge_or_add_vmap_area(va, root, head, true);
if (va)
augment_tree_propagate_from(va);
return va;
}
static __always_inline bool
is_within_this_va(struct vmap_area *va, unsigned long size,
unsigned long align, unsigned long vstart)
{
unsigned long nva_start_addr;
if (va->va_start > vstart)
nva_start_addr = ALIGN(va->va_start, align);
else
nva_start_addr = ALIGN(vstart, align);
/* Can be overflowed due to big size or alignment. */
if (nva_start_addr + size < nva_start_addr ||
nva_start_addr < vstart)
return false;
return (nva_start_addr + size <= va->va_end);
}
/*
* Find the first free block(lowest start address) in the tree,
* that will accomplish the request corresponding to passing
* parameters. Please note, with an alignment bigger than PAGE_SIZE,
* a search length is adjusted to account for worst case alignment
* overhead.
*/
static __always_inline struct vmap_area *
find_vmap_lowest_match(struct rb_root *root, unsigned long size,
unsigned long align, unsigned long vstart, bool adjust_search_size)
{
struct vmap_area *va;
struct rb_node *node;
unsigned long length;
/* Start from the root. */
node = root->rb_node;
/* Adjust the search size for alignment overhead. */
length = adjust_search_size ? size + align - 1 : size;
while (node) {
va = rb_entry(node, struct vmap_area, rb_node);
if (get_subtree_max_size(node->rb_left) >= length &&
vstart < va->va_start) {
node = node->rb_left;
} else {
if (is_within_this_va(va, size, align, vstart))
return va;
/*
* Does not make sense to go deeper towards the right
* sub-tree if it does not have a free block that is
* equal or bigger to the requested search length.
*/
if (get_subtree_max_size(node->rb_right) >= length) {
node = node->rb_right;
continue;
}
/*
* OK. We roll back and find the first right sub-tree,
* that will satisfy the search criteria. It can happen
* due to "vstart" restriction or an alignment overhead
* that is bigger then PAGE_SIZE.
*/
while ((node = rb_parent(node))) {
va = rb_entry(node, struct vmap_area, rb_node);
if (is_within_this_va(va, size, align, vstart))
return va;
if (get_subtree_max_size(node->rb_right) >= length &&
vstart <= va->va_start) {
/*
* Shift the vstart forward. Please note, we update it with
* parent's start address adding "1" because we do not want
* to enter same sub-tree after it has already been checked
* and no suitable free block found there.
*/
vstart = va->va_start + 1;
node = node->rb_right;
break;
}
}
}
}
return NULL;
}
#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
#include <linux/random.h>
static struct vmap_area *
find_vmap_lowest_linear_match(struct list_head *head, unsigned long size,
unsigned long align, unsigned long vstart)
{
struct vmap_area *va;
list_for_each_entry(va, head, list) {
if (!is_within_this_va(va, size, align, vstart))
continue;
return va;
}
return NULL;
}
static void
find_vmap_lowest_match_check(struct rb_root *root, struct list_head *head,
unsigned long size, unsigned long align)
{
struct vmap_area *va_1, *va_2;
unsigned long vstart;
unsigned int rnd;
get_random_bytes(&rnd, sizeof(rnd));
vstart = VMALLOC_START + rnd;
va_1 = find_vmap_lowest_match(root, size, align, vstart, false);
va_2 = find_vmap_lowest_linear_match(head, size, align, vstart);
if (va_1 != va_2)
pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
va_1, va_2, vstart);
}
#endif
enum fit_type {
NOTHING_FIT = 0,
FL_FIT_TYPE = 1, /* full fit */
LE_FIT_TYPE = 2, /* left edge fit */
RE_FIT_TYPE = 3, /* right edge fit */
NE_FIT_TYPE = 4 /* no edge fit */
};
static __always_inline enum fit_type
classify_va_fit_type(struct vmap_area *va,
unsigned long nva_start_addr, unsigned long size)
{
enum fit_type type;
/* Check if it is within VA. */
if (nva_start_addr < va->va_start ||
nva_start_addr + size > va->va_end)
return NOTHING_FIT;
/* Now classify. */
if (va->va_start == nva_start_addr) {
if (va->va_end == nva_start_addr + size)
type = FL_FIT_TYPE;
else
type = LE_FIT_TYPE;
} else if (va->va_end == nva_start_addr + size) {
type = RE_FIT_TYPE;
} else {
type = NE_FIT_TYPE;
}
return type;
}
static __always_inline int
va_clip(struct rb_root *root, struct list_head *head,
struct vmap_area *va, unsigned long nva_start_addr,
unsigned long size)
{
struct vmap_area *lva = NULL;
enum fit_type type = classify_va_fit_type(va, nva_start_addr, size);
if (type == FL_FIT_TYPE) {
/*
* No need to split VA, it fully fits.
*
* | |
* V NVA V
* |---------------|
*/
unlink_va_augment(va, root);
kmem_cache_free(vmap_area_cachep, va);
} else if (type == LE_FIT_TYPE) {
/*
* Split left edge of fit VA.
*
* | |
* V NVA V R
* |-------|-------|
*/
va->va_start += size;
} else if (type == RE_FIT_TYPE) {
/*
* Split right edge of fit VA.
*
* | |
* L V NVA V
* |-------|-------|
*/
va->va_end = nva_start_addr;
} else if (type == NE_FIT_TYPE) {
/*
* Split no edge of fit VA.
*
* | |
* L V NVA V R
* |---|-------|---|
*/
lva = __this_cpu_xchg(ne_fit_preload_node, NULL);
if (unlikely(!lva)) {
/*
* For percpu allocator we do not do any pre-allocation
* and leave it as it is. The reason is it most likely
* never ends up with NE_FIT_TYPE splitting. In case of
* percpu allocations offsets and sizes are aligned to
* fixed align request, i.e. RE_FIT_TYPE and FL_FIT_TYPE
* are its main fitting cases.
*
* There are a few exceptions though, as an example it is
* a first allocation (early boot up) when we have "one"
* big free space that has to be split.
*
* Also we can hit this path in case of regular "vmap"
* allocations, if "this" current CPU was not preloaded.
* See the comment in alloc_vmap_area() why. If so, then
* GFP_NOWAIT is used instead to get an extra object for
* split purpose. That is rare and most time does not
* occur.
*
* What happens if an allocation gets failed. Basically,
* an "overflow" path is triggered to purge lazily freed
* areas to free some memory, then, the "retry" path is
* triggered to repeat one more time. See more details
* in alloc_vmap_area() function.
*/
lva = kmem_cache_alloc(vmap_area_cachep, GFP_NOWAIT);
if (!lva)
return -1;
}
/*
* Build the remainder.
*/
lva->va_start = va->va_start;
lva->va_end = nva_start_addr;
/*
* Shrink this VA to remaining size.
*/
va->va_start = nva_start_addr + size;
} else {
return -1;
}
if (type != FL_FIT_TYPE) {
augment_tree_propagate_from(va);
if (lva) /* type == NE_FIT_TYPE */
insert_vmap_area_augment(lva, &va->rb_node, root, head);
}
return 0;
}
static unsigned long
va_alloc(struct vmap_area *va,
struct rb_root *root, struct list_head *head,
unsigned long size, unsigned long align,
unsigned long vstart, unsigned long vend)
{
unsigned long nva_start_addr;
int ret;
if (va->va_start > vstart)
nva_start_addr = ALIGN(va->va_start, align);
else
nva_start_addr = ALIGN(vstart, align);
/* Check the "vend" restriction. */
if (nva_start_addr + size > vend)
return vend;
/* Update the free vmap_area. */
ret = va_clip(root, head, va, nva_start_addr, size);
if (WARN_ON_ONCE(ret))
return vend;
return nva_start_addr;
}
/*
* Returns a start address of the newly allocated area, if success.
* Otherwise a vend is returned that indicates failure.
*/
static __always_inline unsigned long
__alloc_vmap_area(struct rb_root *root, struct list_head *head,
unsigned long size, unsigned long align,
unsigned long vstart, unsigned long vend)
{
bool adjust_search_size = true;
unsigned long nva_start_addr;
struct vmap_area *va;
/*
* Do not adjust when:
* a) align <= PAGE_SIZE, because it does not make any sense.
* All blocks(their start addresses) are at least PAGE_SIZE
* aligned anyway;
* b) a short range where a requested size corresponds to exactly
* specified [vstart:vend] interval and an alignment > PAGE_SIZE.
* With adjusted search length an allocation would not succeed.
*/
if (align <= PAGE_SIZE || (align > PAGE_SIZE && (vend - vstart) == size))
adjust_search_size = false;
va = find_vmap_lowest_match(root, size, align, vstart, adjust_search_size);
if (unlikely(!va))
return vend;
nva_start_addr = va_alloc(va, root, head, size, align, vstart, vend);
if (nva_start_addr == vend)
return vend;
#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
find_vmap_lowest_match_check(root, head, size, align);
#endif
return nva_start_addr;
}
/*
* Free a region of KVA allocated by alloc_vmap_area
*/
static void free_vmap_area(struct vmap_area *va)
{
struct vmap_node *vn = addr_to_node(va->va_start);
/*
* Remove from the busy tree/list.
*/
spin_lock(&vn->busy.lock);
unlink_va(va, &vn->busy.root);
spin_unlock(&vn->busy.lock);
/*
* Insert/Merge it back to the free tree/list.
*/
spin_lock(&free_vmap_area_lock);
merge_or_add_vmap_area_augment(va, &free_vmap_area_root, &free_vmap_area_list);
spin_unlock(&free_vmap_area_lock);
}
static inline void
preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node)
{
struct vmap_area *va = NULL, *tmp;
/*
* Preload this CPU with one extra vmap_area object. It is used
* when fit type of free area is NE_FIT_TYPE. It guarantees that
* a CPU that does an allocation is preloaded.
*
* We do it in non-atomic context, thus it allows us to use more
* permissive allocation masks to be more stable under low memory
* condition and high memory pressure.
*/
if (!this_cpu_read(ne_fit_preload_node))
va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
spin_lock(lock);
tmp = NULL;
if (va && !__this_cpu_try_cmpxchg(ne_fit_preload_node, &tmp, va))
kmem_cache_free(vmap_area_cachep, va);
}
static struct vmap_pool *
size_to_va_pool(struct vmap_node *vn, unsigned long size)
{
unsigned int idx = (size - 1) / PAGE_SIZE;
if (idx < MAX_VA_SIZE_PAGES)
return &vn->pool[idx];
return NULL;
}
static bool
node_pool_add_va(struct vmap_node *n, struct vmap_area *va)
{
struct vmap_pool *vp;
vp = size_to_va_pool(n, va_size(va));
if (!vp)
return false;
spin_lock(&n->pool_lock);
list_add(&va->list, &vp->head);
WRITE_ONCE(vp->len, vp->len + 1);
spin_unlock(&n->pool_lock);
return true;
}
static struct vmap_area *
node_pool_del_va(struct vmap_node *vn, unsigned long size,
unsigned long align, unsigned long vstart,
unsigned long vend)
{
struct vmap_area *va = NULL;
struct vmap_pool *vp;
int err = 0;
vp = size_to_va_pool(vn, size);
if (!vp || list_empty(&vp->head))
return NULL;
spin_lock(&vn->pool_lock);
if (!list_empty(&vp->head)) {
va = list_first_entry(&vp->head, struct vmap_area, list);
if (IS_ALIGNED(va->va_start, align)) {
/*
* Do some sanity check and emit a warning
* if one of below checks detects an error.
*/
err |= (va_size(va) != size);
err |= (va->va_start < vstart);
err |= (va->va_end > vend);
if (!WARN_ON_ONCE(err)) {
list_del_init(&va->list);
WRITE_ONCE(vp->len, vp->len - 1);
} else {
va = NULL;
}
} else {
list_move_tail(&va->list, &vp->head);
va = NULL;
}
}
spin_unlock(&vn->pool_lock);
return va;
}
static struct vmap_area *
node_alloc(unsigned long size, unsigned long align,
unsigned long vstart, unsigned long vend,
unsigned long *addr, unsigned int *vn_id)
{
struct vmap_area *va;
*vn_id = 0;
*addr = vend;
/*
* Fallback to a global heap if not vmalloc or there
* is only one node.
*/
if (vstart != VMALLOC_START || vend != VMALLOC_END ||
nr_vmap_nodes == 1)
return NULL;
*vn_id = raw_smp_processor_id() % nr_vmap_nodes;
va = node_pool_del_va(id_to_node(*vn_id), size, align, vstart, vend);
*vn_id = encode_vn_id(*vn_id);
if (va)
*addr = va->va_start;
return va;
}
static inline void setup_vmalloc_vm(struct vm_struct *vm,
struct vmap_area *va, unsigned long flags, const void *caller)
{
vm->flags = flags;
vm->addr = (void *)va->va_start;
vm->size = va->va_end - va->va_start;
vm->caller = caller;
va->vm = vm;
}
/*
* Allocate a region of KVA of the specified size and alignment, within the
* vstart and vend. If vm is passed in, the two will also be bound.
*/
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,
unsigned long va_flags, struct vm_struct *vm)
{
struct vmap_node *vn;
struct vmap_area *va;
unsigned long freed;
unsigned long addr;
unsigned int vn_id;
int purged = 0;
int ret;
if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
return ERR_PTR(-EINVAL);
if (unlikely(!vmap_initialized))
return ERR_PTR(-EBUSY);
might_sleep();
/*
* If a VA is obtained from a global heap(if it fails here)
* it is anyway marked with this "vn_id" so it is returned
* to this pool's node later. Such way gives a possibility
* to populate pools based on users demand.
*
* On success a ready to go VA is returned.
*/
va = node_alloc(size, align, vstart, vend, &addr, &vn_id);
if (!va) {
gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
if (unlikely(!va))
return ERR_PTR(-ENOMEM);
/*
* Only scan the relevant parts containing pointers to other objects
* to avoid false negatives.
*/
kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask);
}
retry:
if (addr == vend) {
preload_this_cpu_lock(&free_vmap_area_lock, gfp_mask, node);
addr = __alloc_vmap_area(&free_vmap_area_root, &free_vmap_area_list,
size, align, vstart, vend);
spin_unlock(&free_vmap_area_lock);
}
trace_alloc_vmap_area(addr, size, align, vstart, vend, addr == vend);
/*
* If an allocation fails, the "vend" address is
* returned. Therefore trigger the overflow path.
*/
if (unlikely(addr == vend))
goto overflow;
va->va_start = addr;
va->va_end = addr + size;
va->vm = NULL;
va->flags = (va_flags | vn_id);
if (vm) {
vm->addr = (void *)va->va_start;
vm->size = va->va_end - va->va_start;
va->vm = vm;
}
vn = addr_to_node(va->va_start);
spin_lock(&vn->busy.lock);
insert_vmap_area(va, &vn->busy.root, &vn->busy.head);
spin_unlock(&vn->busy.lock);
BUG_ON(!IS_ALIGNED(va->va_start, align));
BUG_ON(va->va_start < vstart);
BUG_ON(va->va_end > vend);
ret = kasan_populate_vmalloc(addr, size);
if (ret) {
free_vmap_area(va);
return ERR_PTR(ret);
}
return va;
overflow:
if (!purged) {
reclaim_and_purge_vmap_areas();
purged = 1;
goto retry;
}
freed = 0;
blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
if (freed > 0) {
purged = 0;
goto retry;
}
if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
pr_warn("vmalloc_node_range for size %lu failed: Address range restricted to %#lx - %#lx\n",
size, vstart, vend);
kmem_cache_free(vmap_area_cachep, va);
return ERR_PTR(-EBUSY);
}
int register_vmap_purge_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&vmap_notify_list, nb);
}
EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
int unregister_vmap_purge_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
/*
* 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_long_t vmap_lazy_nr = ATOMIC_LONG_INIT(0);
/*
* Serialize vmap purging. There is no actual critical section protected
* by this lock, but we want to avoid concurrent calls for performance
* reasons and to make the pcpu_get_vm_areas more deterministic.
*/
static DEFINE_MUTEX(vmap_purge_lock);
/* for per-CPU blocks */
static void purge_fragmented_blocks_allcpus(void);
static cpumask_t purge_nodes;
static void
reclaim_list_global(struct list_head *head)
{
struct vmap_area *va, *n;
if (list_empty(head))
return;
spin_lock(&free_vmap_area_lock);
list_for_each_entry_safe(va, n, head, list)
merge_or_add_vmap_area_augment(va,
&free_vmap_area_root, &free_vmap_area_list);
spin_unlock(&free_vmap_area_lock);
}
static void
decay_va_pool_node(struct vmap_node *vn, bool full_decay)
{
struct vmap_area *va, *nva;
struct list_head decay_list;
struct rb_root decay_root;
unsigned long n_decay;
int i;
decay_root = RB_ROOT;
INIT_LIST_HEAD(&decay_list);
for (i = 0; i < MAX_VA_SIZE_PAGES; i++) {
struct list_head tmp_list;
if (list_empty(&vn->pool[i].head))
continue;
INIT_LIST_HEAD(&tmp_list);
/* Detach the pool, so no-one can access it. */
spin_lock(&vn->pool_lock);
list_replace_init(&vn->pool[i].head, &tmp_list);
spin_unlock(&vn->pool_lock);
if (full_decay)
WRITE_ONCE(vn->pool[i].len, 0);
/* Decay a pool by ~25% out of left objects. */
n_decay = vn->pool[i].len >> 2;
list_for_each_entry_safe(va, nva, &tmp_list, list) {
list_del_init(&va->list);
merge_or_add_vmap_area(va, &decay_root, &decay_list);
if (!full_decay) {
WRITE_ONCE(vn->pool[i].len, vn->pool[i].len - 1);
if (!--n_decay)
break;
}
}
/*
* Attach the pool back if it has been partly decayed.
* Please note, it is supposed that nobody(other contexts)
* can populate the pool therefore a simple list replace
* operation takes place here.
*/
if (!full_decay && !list_empty(&tmp_list)) {
spin_lock(&vn->pool_lock);
list_replace_init(&tmp_list, &vn->pool[i].head);
spin_unlock(&vn->pool_lock);
}
}
reclaim_list_global(&decay_list);
}
static void purge_vmap_node(struct work_struct *work)
{
struct vmap_node *vn = container_of(work,
struct vmap_node, purge_work);
struct vmap_area *va, *n_va;
LIST_HEAD(local_list);
vn->nr_purged = 0;
list_for_each_entry_safe(va, n_va, &vn->purge_list, list) {
unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
unsigned long orig_start = va->va_start;
unsigned long orig_end = va->va_end;
unsigned int vn_id = decode_vn_id(va->flags);
list_del_init(&va->list);
if (is_vmalloc_or_module_addr((void *)orig_start))
kasan_release_vmalloc(orig_start, orig_end,
va->va_start, va->va_end);
atomic_long_sub(nr, &vmap_lazy_nr);
vn->nr_purged++;
if (is_vn_id_valid(vn_id) && !vn->skip_populate)
if (node_pool_add_va(vn, va))
continue;
/* Go back to global. */
list_add(&va->list, &local_list);
}
reclaim_list_global(&local_list);
}
/*
* Purges all lazily-freed vmap areas.
*/
static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end,
bool full_pool_decay)
{
unsigned long nr_purged_areas = 0;
unsigned int nr_purge_helpers;
unsigned int nr_purge_nodes;
struct vmap_node *vn;
int i;
lockdep_assert_held(&vmap_purge_lock);
/*
* Use cpumask to mark which node has to be processed.
*/
purge_nodes = CPU_MASK_NONE;
for (i = 0; i < nr_vmap_nodes; i++) {
vn = &vmap_nodes[i];
INIT_LIST_HEAD(&vn->purge_list);
vn->skip_populate = full_pool_decay;
decay_va_pool_node(vn, full_pool_decay);
if (RB_EMPTY_ROOT(&vn->lazy.root))
continue;
spin_lock(&vn->lazy.lock);
WRITE_ONCE(vn->lazy.root.rb_node, NULL);
list_replace_init(&vn->lazy.head, &vn->purge_list);
spin_unlock(&vn->lazy.lock);
start = min(start, list_first_entry(&vn->purge_list,
struct vmap_area, list)->va_start);
end = max(end, list_last_entry(&vn->purge_list,
struct vmap_area, list)->va_end);
cpumask_set_cpu(i, &purge_nodes);
}
nr_purge_nodes = cpumask_weight(&purge_nodes);
if (nr_purge_nodes > 0) {
flush_tlb_kernel_range(start, end);
/* One extra worker is per a lazy_max_pages() full set minus one. */
nr_purge_helpers = atomic_long_read(&vmap_lazy_nr) / lazy_max_pages();
nr_purge_helpers = clamp(nr_purge_helpers, 1U, nr_purge_nodes) - 1;
for_each_cpu(i, &purge_nodes) {
vn = &vmap_nodes[i];
if (nr_purge_helpers > 0) {
INIT_WORK(&vn->purge_work, purge_vmap_node);
if (cpumask_test_cpu(i, cpu_online_mask))
schedule_work_on(i, &vn->purge_work);
else
schedule_work(&vn->purge_work);
nr_purge_helpers--;
} else {
vn->purge_work.func = NULL;
purge_vmap_node(&vn->purge_work);
nr_purged_areas += vn->nr_purged;
}
}
for_each_cpu(i, &purge_nodes) {
vn = &vmap_nodes[i];
if (vn->purge_work.func) {
flush_work(&vn->purge_work);
nr_purged_areas += vn->nr_purged;
}
}
}
trace_purge_vmap_area_lazy(start, end, nr_purged_areas);
return nr_purged_areas > 0;
}
/*
* Reclaim vmap areas by purging fragmented blocks and purge_vmap_area_list.
*/
static void reclaim_and_purge_vmap_areas(void)
{
mutex_lock(&vmap_purge_lock);
purge_fragmented_blocks_allcpus();
__purge_vmap_area_lazy(ULONG_MAX, 0, true);
mutex_unlock(&vmap_purge_lock);
}
static void drain_vmap_area_work(struct work_struct *work)
{
mutex_lock(&vmap_purge_lock);
__purge_vmap_area_lazy(ULONG_MAX, 0, false);
mutex_unlock(&vmap_purge_lock);
}
/*
* Free a vmap area, caller ensuring that the area has been unmapped,
* unlinked and flush_cache_vunmap had been called for the correct
* range previously.
*/
static void free_vmap_area_noflush(struct vmap_area *va)
{
unsigned long nr_lazy_max = lazy_max_pages();
unsigned long va_start = va->va_start;
unsigned int vn_id = decode_vn_id(va->flags);
struct vmap_node *vn;
unsigned long nr_lazy;
if (WARN_ON_ONCE(!list_empty(&va->list)))
return;
nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
PAGE_SHIFT, &vmap_lazy_nr);
/*
* If it was request by a certain node we would like to
* return it to that node, i.e. its pool for later reuse.
*/
vn = is_vn_id_valid(vn_id) ?
id_to_node(vn_id):addr_to_node(va->va_start);
spin_lock(&vn->lazy.lock);
insert_vmap_area(va, &vn->lazy.root, &vn->lazy.head);
spin_unlock(&vn->lazy.lock);
trace_free_vmap_area_noflush(va_start, nr_lazy, nr_lazy_max);
/* After this point, we may free va at any time */
if (unlikely(nr_lazy > nr_lazy_max))
schedule_work(&drain_vmap_work);
}
/*
* 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);
vunmap_range_noflush(va->va_start, va->va_end);
if (debug_pagealloc_enabled_static())
flush_tlb_kernel_range(va->va_start, va->va_end);
free_vmap_area_noflush(va);
}
struct vmap_area *find_vmap_area(unsigned long addr)
{
struct vmap_node *vn;
struct vmap_area *va;
int i, j;
if (unlikely(!vmap_initialized))
return NULL;
/*
* An addr_to_node_id(addr) converts an address to a node index
* where a VA is located. If VA spans several zones and passed
* addr is not the same as va->va_start, what is not common, we
* may need to scan extra nodes. See an example:
*
* <----va---->
* -|-----|-----|-----|-----|-
* 1 2 0 1
*
* VA resides in node 1 whereas it spans 1, 2 an 0. If passed
* addr is within 2 or 0 nodes we should do extra work.
*/
i = j = addr_to_node_id(addr);
do {
vn = &vmap_nodes[i];
spin_lock(&vn->busy.lock);
va = __find_vmap_area(addr, &vn->busy.root);
spin_unlock(&vn->busy.lock);
if (va)
return va;
} while ((i = (i + 1) % nr_vmap_nodes) != j);
return NULL;
}
static struct vmap_area *find_unlink_vmap_area(unsigned long addr)
{
struct vmap_node *vn;
struct vmap_area *va;
int i, j;
/*
* Check the comment in the find_vmap_area() about the loop.
*/
i = j = addr_to_node_id(addr);
do {
vn = &vmap_nodes[i];
spin_lock(&vn->busy.lock);
va = __find_vmap_area(addr, &vn->busy.root);
if (va)
unlink_va(va, &vn->busy.root);
spin_unlock(&vn->busy.lock);
if (va)
return va;
} while ((i = (i + 1) % nr_vmap_nodes) != j);
return NULL;
}
/*** 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 / roundup_pow_of_two(NR_CPUS) / 16))
#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
/*
* Purge threshold to prevent overeager purging of fragmented blocks for
* regular operations: Purge if vb->free is less than 1/4 of the capacity.
*/
#define VMAP_PURGE_THRESHOLD (VMAP_BBMAP_BITS / 4)
#define VMAP_RAM 0x1 /* indicates vm_map_ram area*/
#define VMAP_BLOCK 0x2 /* mark out the vmap_block sub-type*/
#define VMAP_FLAGS_MASK 0x3
struct vmap_block_queue {
spinlock_t lock;
struct list_head free;
/*
* An xarray requires an extra memory dynamically to
* be allocated. If it is an issue, we can use rb-tree
* instead.
*/
struct xarray vmap_blocks;
};
struct vmap_block {
spinlock_t lock;
struct vmap_area *va;
unsigned long free, dirty;
DECLARE_BITMAP(used_map, VMAP_BBMAP_BITS);
unsigned long dirty_min, dirty_max; /*< dirty range */
struct list_head free_list;
struct rcu_head rcu_head;
struct list_head purge;
unsigned int cpu;
};
/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
/*
* In order to fast access to any "vmap_block" associated with a
* specific address, we use a hash.
*
* A per-cpu vmap_block_queue is used in both ways, to serialize
* an access to free block chains among CPUs(alloc path) and it
* also acts as a vmap_block hash(alloc/free paths). It means we
* overload it, since we already have the per-cpu array which is
* used as a hash table. When used as a hash a 'cpu' passed to
* per_cpu() is not actually a CPU but rather a hash index.
*
* A hash function is addr_to_vb_xa() which hashes any address
* to a specific index(in a hash) it belongs to. This then uses a
* per_cpu() macro to access an array with generated index.
*
* An example:
*
* CPU_1 CPU_2 CPU_0
* | | |
* V V V
* 0 10 20 30 40 50 60
* |------|------|------|------|------|------|...<vmap address space>
* CPU0 CPU1 CPU2 CPU0 CPU1 CPU2
*
* - CPU_1 invokes vm_unmap_ram(6), 6 belongs to CPU0 zone, thus
* it access: CPU0/INDEX0 -> vmap_blocks -> xa_lock;
*
* - CPU_2 invokes vm_unmap_ram(11), 11 belongs to CPU1 zone, thus
* it access: CPU1/INDEX1 -> vmap_blocks -> xa_lock;
*
* - CPU_0 invokes vm_unmap_ram(20), 20 belongs to CPU2 zone, thus
* it access: CPU2/INDEX2 -> vmap_blocks -> xa_lock.
*
* This technique almost always avoids lock contention on insert/remove,
* however xarray spinlocks protect against any contention that remains.
*/
static struct xarray *
addr_to_vb_xa(unsigned long addr)
{
int index = (addr / VMAP_BLOCK_SIZE) % nr_cpu_ids;
/*
* Please note, nr_cpu_ids points on a highest set
* possible bit, i.e. we never invoke cpumask_next()
* if an index points on it which is nr_cpu_ids - 1.
*/
if (!cpu_possible(index))
index = cpumask_next(index, cpu_possible_mask);
return &per_cpu(vmap_block_queue, index).vmap_blocks;
}
/*
* 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 void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
{
unsigned long addr;
addr = va_start + (pages_off << PAGE_SHIFT);
BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
return (void *)addr;
}
/**
* new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
* block. Of course pages number can't exceed VMAP_BBMAP_BITS
* @order: how many 2^order pages should be occupied in newly allocated block
* @gfp_mask: flags for the page level allocator
*
* Return: virtual address in a newly allocated block or ERR_PTR(-errno)
*/
static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
{
struct vmap_block_queue *vbq;
struct vmap_block *vb;
struct vmap_area *va;
struct xarray *xa;
unsigned long vb_idx;
int node, err;
void *vaddr;
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,
VMAP_RAM|VMAP_BLOCK, NULL);
if (IS_ERR(va)) {
kfree(vb);
return ERR_CAST(va);
}
vaddr = vmap_block_vaddr(va->va_start, 0);
spin_lock_init(&vb->lock);
vb->va = va;
/* At least something should be left free */
BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
bitmap_zero(vb->used_map, VMAP_BBMAP_BITS);
vb->free = VMAP_BBMAP_BITS - (1UL << order);
vb->dirty = 0;
vb->dirty_min = VMAP_BBMAP_BITS;
vb->dirty_max = 0;
bitmap_set(vb->used_map, 0, (1UL << order));
INIT_LIST_HEAD(&vb->free_list);
xa = addr_to_vb_xa(va->va_start);
vb_idx = addr_to_vb_idx(va->va_start);
err = xa_insert(xa, vb_idx, vb, gfp_mask);
if (err) {
kfree(vb);
free_vmap_area(va);
return ERR_PTR(err);
}
/*
* list_add_tail_rcu could happened in another core
* rather than vb->cpu due to task migration, which
* is safe as list_add_tail_rcu will ensure the list's
* integrity together with list_for_each_rcu from read
* side.
*/
vb->cpu = raw_smp_processor_id();
vbq = per_cpu_ptr(&vmap_block_queue, vb->cpu);
spin_lock(&vbq->lock);
list_add_tail_rcu(&vb->free_list, &vbq->free);
spin_unlock(&vbq->lock);
return vaddr;
}
static void free_vmap_block(struct vmap_block *vb)
{
struct vmap_node *vn;
struct vmap_block *tmp;
struct xarray *xa;
xa = addr_to_vb_xa(vb->va->va_start);
tmp = xa_erase(xa, addr_to_vb_idx(vb->va->va_start));
BUG_ON(tmp != vb);
vn = addr_to_node(vb->va->va_start);
spin_lock(&vn->busy.lock);
unlink_va(vb->va, &vn->busy.root);
spin_unlock(&vn->busy.lock);
free_vmap_area_noflush(vb->va);
kfree_rcu(vb, rcu_head);
}
static bool purge_fragmented_block(struct vmap_block *vb,
struct list_head *purge_list, bool force_purge)
{
struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, vb->cpu);
if (vb->free + vb->dirty != VMAP_BBMAP_BITS ||
vb->dirty == VMAP_BBMAP_BITS)
return false;
/* Don't overeagerly purge usable blocks unless requested */
if (!(force_purge || vb->free < VMAP_PURGE_THRESHOLD))
return false;
/* prevent further allocs after releasing lock */
WRITE_ONCE(vb->free, 0);
/* prevent purging it again */
WRITE_ONCE(vb->dirty, VMAP_BBMAP_BITS);
vb->dirty_min = 0;
vb->dirty_max = VMAP_BBMAP_BITS;
spin_lock(&vbq->lock);
list_del_rcu(&vb->free_list);
spin_unlock(&vbq->lock);
list_add_tail(&vb->purge, purge_list);
return true;
}
static void free_purged_blocks(struct list_head *purge_list)
{
struct vmap_block *vb, *n_vb;
list_for_each_entry_safe(vb, n_vb, purge_list, purge) {
list_del(&vb->purge);
free_vmap_block(vb);
}
}
static void purge_fragmented_blocks(int cpu)
{
LIST_HEAD(purge);
struct vmap_block *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) {
unsigned long free = READ_ONCE(vb->free);
unsigned long dirty = READ_ONCE(vb->dirty);
if (free + dirty != VMAP_BBMAP_BITS ||
dirty == VMAP_BBMAP_BITS)
continue;
spin_lock(&vb->lock);
purge_fragmented_block(vb, &purge, true);
spin_unlock(&vb->lock);
}
rcu_read_unlock();
free_purged_blocks(&purge);
}
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;
void *vaddr = NULL;
unsigned int order;
BUG_ON(offset_in_page(size));
BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
if (WARN_ON(size == 0)) {
/*
* Allocating 0 bytes isn't what caller wants since
* get_order(0) returns funny result. Just warn and terminate
* early.
*/
return ERR_PTR(-EINVAL);
}
order = get_order(size);
rcu_read_lock();
vbq = raw_cpu_ptr(&vmap_block_queue);
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
unsigned long pages_off;
if (READ_ONCE(vb->free) < (1UL << order))
continue;
spin_lock(&vb->lock);
if (vb->free < (1UL << order)) {
spin_unlock(&vb->lock);
continue;
}
pages_off = VMAP_BBMAP_BITS - vb->free;
vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
WRITE_ONCE(vb->free, vb->free - (1UL << order));
bitmap_set(vb->used_map, pages_off, (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;
}
rcu_read_unlock();
/* Allocate new block if nothing was found */
if (!vaddr)
vaddr = new_vmap_block(order, gfp_mask);
return vaddr;
}
static void vb_free(unsigned long addr, unsigned long size)
{
unsigned long offset;
unsigned int order;
struct vmap_block *vb;
struct xarray *xa;
BUG_ON(offset_in_page(size));
BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
flush_cache_vunmap(addr, addr + size);
order = get_order(size);
offset = (addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT;
xa = addr_to_vb_xa(addr);
vb = xa_load(xa, addr_to_vb_idx(addr));
spin_lock(&vb->lock);
bitmap_clear(vb->used_map, offset, (1UL << order));
spin_unlock(&vb->lock);
vunmap_range_noflush(addr, addr + size);
if (debug_pagealloc_enabled_static())
flush_tlb_kernel_range(addr, addr + size);
spin_lock(&vb->lock);
/* Expand the not yet TLB flushed dirty range */
vb->dirty_min = min(vb->dirty_min, offset);
vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
WRITE_ONCE(vb->dirty, 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);
}
static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush)
{
LIST_HEAD(purge_list);
int cpu;
if (unlikely(!vmap_initialized))
return;
mutex_lock(&vmap_purge_lock);
for_each_possible_cpu(cpu) {
struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
struct vmap_block *vb;
unsigned long idx;
rcu_read_lock();
xa_for_each(&vbq->vmap_blocks, idx, vb) {
spin_lock(&vb->lock);
/*
* Try to purge a fragmented block first. If it's
* not purgeable, check whether there is dirty
* space to be flushed.
*/
if (!purge_fragmented_block(vb, &purge_list, false) &&
vb->dirty_max && vb->dirty != VMAP_BBMAP_BITS) {
unsigned long va_start = vb->va->va_start;
unsigned long s, e;
s = va_start + (vb->dirty_min << PAGE_SHIFT);
e = va_start + (vb->dirty_max << PAGE_SHIFT);
start = min(s, start);
end = max(e, end);
/* Prevent that this is flushed again */
vb->dirty_min = VMAP_BBMAP_BITS;
vb->dirty_max = 0;
flush = 1;
}
spin_unlock(&vb->lock);
}
rcu_read_unlock();
}
free_purged_blocks(&purge_list);
if (!__purge_vmap_area_lazy(start, end, false) && flush)
flush_tlb_kernel_range(start, end);
mutex_unlock(&vmap_purge_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 flush = 0;
_vm_unmap_aliases(start, end, 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 = (unsigned long)count << PAGE_SHIFT;
unsigned long addr = (unsigned long)kasan_reset_tag(mem);
struct vmap_area *va;
might_sleep();
BUG_ON(!addr);
BUG_ON(addr < VMALLOC_START);
BUG_ON(addr > VMALLOC_END);
BUG_ON(!PAGE_ALIGNED(addr));
kasan_poison_vmalloc(mem, size);
if (likely(count <= VMAP_MAX_ALLOC)) {
debug_check_no_locks_freed(mem, size);
vb_free(addr, size);
return;
}
va = find_unlink_vmap_area(addr);
if (WARN_ON_ONCE(!va))
return;
debug_check_no_locks_freed((void *)va->va_start,
(va->va_end - va->va_start));
free_unmap_vmap_area(va);
}
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
*
* If you use this function for less than VMAP_MAX_ALLOC pages, it could be
* faster than vmap so it's good. But if you mix long-life and short-life
* objects with vm_map_ram(), it could consume lots of address space through
* fragmentation (especially on a 32bit machine). You could see failures in
* the end. Please use this function for short-lived objects.
*
* 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)
{
unsigned long size = (unsigned long)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, VMAP_RAM,
NULL);
if (IS_ERR(va))
return NULL;
addr = va->va_start;
mem = (void *)addr;
}
if (vmap_pages_range(addr, addr + size, PAGE_KERNEL,
pages, PAGE_SHIFT) < 0) {
vm_unmap_ram(mem, count);
return NULL;
}
/*
* Mark the pages as accessible, now that they are mapped.
* With hardware tag-based KASAN, marking is skipped for
* non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
*/
mem = kasan_unpoison_vmalloc(mem, size, KASAN_VMALLOC_PROT_NORMAL);
return mem;
}
EXPORT_SYMBOL(vm_map_ram);
static struct vm_struct *vmlist __initdata;
static inline unsigned int vm_area_page_order(struct vm_struct *vm)
{
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
return vm->page_order;
#else
return 0;
#endif
}
static inline void set_vm_area_page_order(struct vm_struct *vm, unsigned int order)
{
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
vm->page_order = order;
#else
BUG_ON(order != 0);
#endif
}
/**
* vm_area_add_early - add vmap area early during boot
* @vm: vm_struct to add
*
* This function is used to add fixed kernel vm area to vmlist before
* vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags
* should contain proper values and the other fields should be zero.
*
* DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
*/
void __init vm_area_add_early(struct vm_struct *vm)
{
struct vm_struct *tmp, **p;
BUG_ON(vmap_initialized);
for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
if (tmp->addr >= vm->addr) {
BUG_ON(tmp->addr < vm->addr + vm->size);
break;
} else
BUG_ON(tmp->addr + tmp->size > vm->addr);
}
vm->next = *p;
*p = vm;
}
/**
* 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)
{
unsigned long addr = ALIGN(VMALLOC_START, align);
struct vm_struct *cur, **p;
BUG_ON(vmap_initialized);
for (p = &vmlist; (cur = *p) != NULL; p = &cur->next) {
if ((unsigned long)cur->addr - addr >= vm->size)
break;
addr = ALIGN((unsigned long)cur->addr + cur->size, align);
}
BUG_ON(addr > VMALLOC_END - vm->size);
vm->addr = (void *)addr;
vm->next = *p;
*p = vm;
kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
}
static void clear_vm_uninitialized_flag(struct vm_struct *vm)
{
/*
* Before removing VM_UNINITIALIZED,
* we should make sure that vm has proper values.
* Pair with smp_rmb() in show_numa_info().
*/
smp_wmb();
vm->flags &= ~VM_UNINITIALIZED;
}
static struct vm_struct *__get_vm_area_node(unsigned long size,
unsigned long align, unsigned long shift, unsigned long flags,
unsigned long start, unsigned long end, int node,
gfp_t gfp_mask, const void *caller)
{
struct vmap_area *va;
struct vm_struct *area;
unsigned long requested_size = size;
BUG_ON(in_interrupt());
size = ALIGN(size, 1ul << shift);
if (unlikely(!size))
return NULL;
if (flags & VM_IOREMAP)
align = 1ul << clamp_t(int, get_count_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!area))
return NULL;
if (!(flags & VM_NO_GUARD))
size += PAGE_SIZE;
area->flags = flags;
area->caller = caller;
va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area);
if (IS_ERR(va)) {
kfree(area);
return NULL;
}
/*
* Mark pages for non-VM_ALLOC mappings as accessible. Do it now as a
* best-effort approach, as they can be mapped outside of vmalloc code.
* For VM_ALLOC mappings, the pages are marked as accessible after
* getting mapped in __vmalloc_node_range().
* With hardware tag-based KASAN, marking is skipped for
* non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
*/
if (!(flags & VM_ALLOC))
area->addr = kasan_unpoison_vmalloc(area->addr, requested_size,
KASAN_VMALLOC_PROT_NORMAL);
return area;
}
struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
unsigned long start, unsigned long end,
const void *caller)
{
return __get_vm_area_node(size, 1, PAGE_SHIFT, flags, start, end,
NUMA_NO_NODE, 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.
*
* Return: 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, PAGE_SHIFT, flags,
VMALLOC_START, VMALLOC_END,
NUMA_NO_NODE, GFP_KERNEL,
__builtin_return_address(0));
}
struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
const void *caller)
{
return __get_vm_area_node(size, 1, PAGE_SHIFT, flags,
VMALLOC_START, VMALLOC_END,
NUMA_NO_NODE, GFP_KERNEL, caller);
}