mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
![Christoph Hellwig](/assets/img/avatar_default.png)
Use lockdep to check for held locks instead of using home grown asserts. Link: https://lore.kernel.org/r/20190828141955.22210-4-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Steven Price <steven.price@arm.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
378 lines
9.2 KiB
C
378 lines
9.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/pagewalk.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/hugetlb.h>
|
|
|
|
static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
pte_t *pte;
|
|
int err = 0;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
|
|
pte = pte_offset_map(pmd, addr);
|
|
for (;;) {
|
|
err = ops->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
|
|
if (err)
|
|
break;
|
|
addr += PAGE_SIZE;
|
|
if (addr == end)
|
|
break;
|
|
pte++;
|
|
}
|
|
|
|
pte_unmap(pte);
|
|
return err;
|
|
}
|
|
|
|
static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
pmd_t *pmd;
|
|
unsigned long next;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
int err = 0;
|
|
|
|
pmd = pmd_offset(pud, addr);
|
|
do {
|
|
again:
|
|
next = pmd_addr_end(addr, end);
|
|
if (pmd_none(*pmd) || !walk->vma) {
|
|
if (ops->pte_hole)
|
|
err = ops->pte_hole(addr, next, walk);
|
|
if (err)
|
|
break;
|
|
continue;
|
|
}
|
|
/*
|
|
* This implies that each ->pmd_entry() handler
|
|
* needs to know about pmd_trans_huge() pmds
|
|
*/
|
|
if (ops->pmd_entry)
|
|
err = ops->pmd_entry(pmd, addr, next, walk);
|
|
if (err)
|
|
break;
|
|
|
|
/*
|
|
* Check this here so we only break down trans_huge
|
|
* pages when we _need_ to
|
|
*/
|
|
if (!ops->pte_entry)
|
|
continue;
|
|
|
|
split_huge_pmd(walk->vma, pmd, addr);
|
|
if (pmd_trans_unstable(pmd))
|
|
goto again;
|
|
err = walk_pte_range(pmd, addr, next, walk);
|
|
if (err)
|
|
break;
|
|
} while (pmd++, addr = next, addr != end);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
pud_t *pud;
|
|
unsigned long next;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
int err = 0;
|
|
|
|
pud = pud_offset(p4d, addr);
|
|
do {
|
|
again:
|
|
next = pud_addr_end(addr, end);
|
|
if (pud_none(*pud) || !walk->vma) {
|
|
if (ops->pte_hole)
|
|
err = ops->pte_hole(addr, next, walk);
|
|
if (err)
|
|
break;
|
|
continue;
|
|
}
|
|
|
|
if (ops->pud_entry) {
|
|
spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma);
|
|
|
|
if (ptl) {
|
|
err = ops->pud_entry(pud, addr, next, walk);
|
|
spin_unlock(ptl);
|
|
if (err)
|
|
break;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
split_huge_pud(walk->vma, pud, addr);
|
|
if (pud_none(*pud))
|
|
goto again;
|
|
|
|
if (ops->pmd_entry || ops->pte_entry)
|
|
err = walk_pmd_range(pud, addr, next, walk);
|
|
if (err)
|
|
break;
|
|
} while (pud++, addr = next, addr != end);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
p4d_t *p4d;
|
|
unsigned long next;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
int err = 0;
|
|
|
|
p4d = p4d_offset(pgd, addr);
|
|
do {
|
|
next = p4d_addr_end(addr, end);
|
|
if (p4d_none_or_clear_bad(p4d)) {
|
|
if (ops->pte_hole)
|
|
err = ops->pte_hole(addr, next, walk);
|
|
if (err)
|
|
break;
|
|
continue;
|
|
}
|
|
if (ops->pmd_entry || ops->pte_entry)
|
|
err = walk_pud_range(p4d, addr, next, walk);
|
|
if (err)
|
|
break;
|
|
} while (p4d++, addr = next, addr != end);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int walk_pgd_range(unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
pgd_t *pgd;
|
|
unsigned long next;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
int err = 0;
|
|
|
|
pgd = pgd_offset(walk->mm, addr);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
if (pgd_none_or_clear_bad(pgd)) {
|
|
if (ops->pte_hole)
|
|
err = ops->pte_hole(addr, next, walk);
|
|
if (err)
|
|
break;
|
|
continue;
|
|
}
|
|
if (ops->pmd_entry || ops->pte_entry)
|
|
err = walk_p4d_range(pgd, addr, next, walk);
|
|
if (err)
|
|
break;
|
|
} while (pgd++, addr = next, addr != end);
|
|
|
|
return err;
|
|
}
|
|
|
|
#ifdef CONFIG_HUGETLB_PAGE
|
|
static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
|
|
unsigned long end)
|
|
{
|
|
unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
|
|
return boundary < end ? boundary : end;
|
|
}
|
|
|
|
static int walk_hugetlb_range(unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
struct vm_area_struct *vma = walk->vma;
|
|
struct hstate *h = hstate_vma(vma);
|
|
unsigned long next;
|
|
unsigned long hmask = huge_page_mask(h);
|
|
unsigned long sz = huge_page_size(h);
|
|
pte_t *pte;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
int err = 0;
|
|
|
|
do {
|
|
next = hugetlb_entry_end(h, addr, end);
|
|
pte = huge_pte_offset(walk->mm, addr & hmask, sz);
|
|
|
|
if (pte)
|
|
err = ops->hugetlb_entry(pte, hmask, addr, next, walk);
|
|
else if (ops->pte_hole)
|
|
err = ops->pte_hole(addr, next, walk);
|
|
|
|
if (err)
|
|
break;
|
|
} while (addr = next, addr != end);
|
|
|
|
return err;
|
|
}
|
|
|
|
#else /* CONFIG_HUGETLB_PAGE */
|
|
static int walk_hugetlb_range(unsigned long addr, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_HUGETLB_PAGE */
|
|
|
|
/*
|
|
* Decide whether we really walk over the current vma on [@start, @end)
|
|
* or skip it via the returned value. Return 0 if we do walk over the
|
|
* current vma, and return 1 if we skip the vma. Negative values means
|
|
* error, where we abort the current walk.
|
|
*/
|
|
static int walk_page_test(unsigned long start, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
struct vm_area_struct *vma = walk->vma;
|
|
const struct mm_walk_ops *ops = walk->ops;
|
|
|
|
if (ops->test_walk)
|
|
return ops->test_walk(start, end, walk);
|
|
|
|
/*
|
|
* vma(VM_PFNMAP) doesn't have any valid struct pages behind VM_PFNMAP
|
|
* range, so we don't walk over it as we do for normal vmas. However,
|
|
* Some callers are interested in handling hole range and they don't
|
|
* want to just ignore any single address range. Such users certainly
|
|
* define their ->pte_hole() callbacks, so let's delegate them to handle
|
|
* vma(VM_PFNMAP).
|
|
*/
|
|
if (vma->vm_flags & VM_PFNMAP) {
|
|
int err = 1;
|
|
if (ops->pte_hole)
|
|
err = ops->pte_hole(start, end, walk);
|
|
return err ? err : 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __walk_page_range(unsigned long start, unsigned long end,
|
|
struct mm_walk *walk)
|
|
{
|
|
int err = 0;
|
|
struct vm_area_struct *vma = walk->vma;
|
|
|
|
if (vma && is_vm_hugetlb_page(vma)) {
|
|
if (walk->ops->hugetlb_entry)
|
|
err = walk_hugetlb_range(start, end, walk);
|
|
} else
|
|
err = walk_pgd_range(start, end, walk);
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* walk_page_range - walk page table with caller specific callbacks
|
|
* @mm: mm_struct representing the target process of page table walk
|
|
* @start: start address of the virtual address range
|
|
* @end: end address of the virtual address range
|
|
* @ops: operation to call during the walk
|
|
* @private: private data for callbacks' usage
|
|
*
|
|
* Recursively walk the page table tree of the process represented by @mm
|
|
* within the virtual address range [@start, @end). During walking, we can do
|
|
* some caller-specific works for each entry, by setting up pmd_entry(),
|
|
* pte_entry(), and/or hugetlb_entry(). If you don't set up for some of these
|
|
* callbacks, the associated entries/pages are just ignored.
|
|
* The return values of these callbacks are commonly defined like below:
|
|
*
|
|
* - 0 : succeeded to handle the current entry, and if you don't reach the
|
|
* end address yet, continue to walk.
|
|
* - >0 : succeeded to handle the current entry, and return to the caller
|
|
* with caller specific value.
|
|
* - <0 : failed to handle the current entry, and return to the caller
|
|
* with error code.
|
|
*
|
|
* Before starting to walk page table, some callers want to check whether
|
|
* they really want to walk over the current vma, typically by checking
|
|
* its vm_flags. walk_page_test() and @ops->test_walk() are used for this
|
|
* purpose.
|
|
*
|
|
* struct mm_walk keeps current values of some common data like vma and pmd,
|
|
* which are useful for the access from callbacks. If you want to pass some
|
|
* caller-specific data to callbacks, @private should be helpful.
|
|
*
|
|
* Locking:
|
|
* Callers of walk_page_range() and walk_page_vma() should hold @mm->mmap_sem,
|
|
* because these function traverse vma list and/or access to vma's data.
|
|
*/
|
|
int walk_page_range(struct mm_struct *mm, unsigned long start,
|
|
unsigned long end, const struct mm_walk_ops *ops,
|
|
void *private)
|
|
{
|
|
int err = 0;
|
|
unsigned long next;
|
|
struct vm_area_struct *vma;
|
|
struct mm_walk walk = {
|
|
.ops = ops,
|
|
.mm = mm,
|
|
.private = private,
|
|
};
|
|
|
|
if (start >= end)
|
|
return -EINVAL;
|
|
|
|
if (!walk.mm)
|
|
return -EINVAL;
|
|
|
|
lockdep_assert_held(&walk.mm->mmap_sem);
|
|
|
|
vma = find_vma(walk.mm, start);
|
|
do {
|
|
if (!vma) { /* after the last vma */
|
|
walk.vma = NULL;
|
|
next = end;
|
|
} else if (start < vma->vm_start) { /* outside vma */
|
|
walk.vma = NULL;
|
|
next = min(end, vma->vm_start);
|
|
} else { /* inside vma */
|
|
walk.vma = vma;
|
|
next = min(end, vma->vm_end);
|
|
vma = vma->vm_next;
|
|
|
|
err = walk_page_test(start, next, &walk);
|
|
if (err > 0) {
|
|
/*
|
|
* positive return values are purely for
|
|
* controlling the pagewalk, so should never
|
|
* be passed to the callers.
|
|
*/
|
|
err = 0;
|
|
continue;
|
|
}
|
|
if (err < 0)
|
|
break;
|
|
}
|
|
if (walk.vma || walk.ops->pte_hole)
|
|
err = __walk_page_range(start, next, &walk);
|
|
if (err)
|
|
break;
|
|
} while (start = next, start < end);
|
|
return err;
|
|
}
|
|
|
|
int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
|
|
void *private)
|
|
{
|
|
struct mm_walk walk = {
|
|
.ops = ops,
|
|
.mm = vma->vm_mm,
|
|
.vma = vma,
|
|
.private = private,
|
|
};
|
|
int err;
|
|
|
|
if (!walk.mm)
|
|
return -EINVAL;
|
|
|
|
lockdep_assert_held(&walk.mm->mmap_sem);
|
|
|
|
err = walk_page_test(vma->vm_start, vma->vm_end, &walk);
|
|
if (err > 0)
|
|
return 0;
|
|
if (err < 0)
|
|
return err;
|
|
return __walk_page_range(vma->vm_start, vma->vm_end, &walk);
|
|
}
|