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linux/fs/proc/task_mmu.c
Linus Torvalds 7a3fad30fd Random number generator updates for Linux 6.11-rc1. 
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Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings
2024-07-24 10:29:50 -07:00

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// SPDX-License-Identifier: GPL-2.0
#include <linux/pagewalk.h>
#include <linux/mm_inline.h>
#include <linux/hugetlb.h>
#include <linux/huge_mm.h>
#include <linux/mount.h>
#include <linux/ksm.h>
#include <linux/seq_file.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/mempolicy.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/sched/mm.h>
#include <linux/swapops.h>
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/shmem_fs.h>
#include <linux/uaccess.h>
#include <linux/pkeys.h>
#include <linux/minmax.h>
#include <linux/overflow.h>
#include <linux/buildid.h>
#include <asm/elf.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include "internal.h"
#define SEQ_PUT_DEC(str, val) \
seq_put_decimal_ull_width(m, str, (val) << (PAGE_SHIFT-10), 8)
void task_mem(struct seq_file *m, struct mm_struct *mm)
{
unsigned long text, lib, swap, anon, file, shmem;
unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
anon = get_mm_counter(mm, MM_ANONPAGES);
file = get_mm_counter(mm, MM_FILEPAGES);
shmem = get_mm_counter(mm, MM_SHMEMPAGES);
/*
* Note: to minimize their overhead, mm maintains hiwater_vm and
* hiwater_rss only when about to *lower* total_vm or rss. Any
* collector of these hiwater stats must therefore get total_vm
* and rss too, which will usually be the higher. Barriers? not
* worth the effort, such snapshots can always be inconsistent.
*/
hiwater_vm = total_vm = mm->total_vm;
if (hiwater_vm < mm->hiwater_vm)
hiwater_vm = mm->hiwater_vm;
hiwater_rss = total_rss = anon + file + shmem;
if (hiwater_rss < mm->hiwater_rss)
hiwater_rss = mm->hiwater_rss;
/* split executable areas between text and lib */
text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
text = min(text, mm->exec_vm << PAGE_SHIFT);
lib = (mm->exec_vm << PAGE_SHIFT) - text;
swap = get_mm_counter(mm, MM_SWAPENTS);
SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
SEQ_PUT_DEC(" kB\nRssFile:\t", file);
SEQ_PUT_DEC(" kB\nRssShmem:\t", shmem);
SEQ_PUT_DEC(" kB\nVmData:\t", mm->data_vm);
SEQ_PUT_DEC(" kB\nVmStk:\t", mm->stack_vm);
seq_put_decimal_ull_width(m,
" kB\nVmExe:\t", text >> 10, 8);
seq_put_decimal_ull_width(m,
" kB\nVmLib:\t", lib >> 10, 8);
seq_put_decimal_ull_width(m,
" kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
seq_puts(m, " kB\n");
hugetlb_report_usage(m, mm);
}
#undef SEQ_PUT_DEC
unsigned long task_vsize(struct mm_struct *mm)
{
return PAGE_SIZE * mm->total_vm;
}
unsigned long task_statm(struct mm_struct *mm,
unsigned long *shared, unsigned long *text,
unsigned long *data, unsigned long *resident)
{
*shared = get_mm_counter(mm, MM_FILEPAGES) +
get_mm_counter(mm, MM_SHMEMPAGES);
*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
>> PAGE_SHIFT;
*data = mm->data_vm + mm->stack_vm;
*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
return mm->total_vm;
}
#ifdef CONFIG_NUMA
/*
* Save get_task_policy() for show_numa_map().
*/
static void hold_task_mempolicy(struct proc_maps_private *priv)
{
struct task_struct *task = priv->task;
task_lock(task);
priv->task_mempolicy = get_task_policy(task);
mpol_get(priv->task_mempolicy);
task_unlock(task);
}
static void release_task_mempolicy(struct proc_maps_private *priv)
{
mpol_put(priv->task_mempolicy);
}
#else
static void hold_task_mempolicy(struct proc_maps_private *priv)
{
}
static void release_task_mempolicy(struct proc_maps_private *priv)
{
}
#endif
static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
loff_t *ppos)
{
struct vm_area_struct *vma = vma_next(&priv->iter);
if (vma) {
*ppos = vma->vm_start;
} else {
*ppos = -2UL;
vma = get_gate_vma(priv->mm);
}
return vma;
}
static void *m_start(struct seq_file *m, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
unsigned long last_addr = *ppos;
struct mm_struct *mm;
/* See m_next(). Zero at the start or after lseek. */
if (last_addr == -1UL)
return NULL;
priv->task = get_proc_task(priv->inode);
if (!priv->task)
return ERR_PTR(-ESRCH);
mm = priv->mm;
if (!mm || !mmget_not_zero(mm)) {
put_task_struct(priv->task);
priv->task = NULL;
return NULL;
}
if (mmap_read_lock_killable(mm)) {
mmput(mm);
put_task_struct(priv->task);
priv->task = NULL;
return ERR_PTR(-EINTR);
}
vma_iter_init(&priv->iter, mm, last_addr);
hold_task_mempolicy(priv);
if (last_addr == -2UL)
return get_gate_vma(mm);
return proc_get_vma(priv, ppos);
}
static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
{
if (*ppos == -2UL) {
*ppos = -1UL;
return NULL;
}
return proc_get_vma(m->private, ppos);
}
static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct mm_struct *mm = priv->mm;
if (!priv->task)
return;
release_task_mempolicy(priv);
mmap_read_unlock(mm);
mmput(mm);
put_task_struct(priv->task);
priv->task = NULL;
}
static int proc_maps_open(struct inode *inode, struct file *file,
const struct seq_operations *ops, int psize)
{
struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
if (!priv)
return -ENOMEM;
priv->inode = inode;
priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
if (IS_ERR(priv->mm)) {
int err = PTR_ERR(priv->mm);
seq_release_private(inode, file);
return err;
}
return 0;
}
static int proc_map_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
struct proc_maps_private *priv = seq->private;
if (priv->mm)
mmdrop(priv->mm);
return seq_release_private(inode, file);
}
static int do_maps_open(struct inode *inode, struct file *file,
const struct seq_operations *ops)
{
return proc_maps_open(inode, file, ops,
sizeof(struct proc_maps_private));
}
static void get_vma_name(struct vm_area_struct *vma,
const struct path **path,
const char **name,
const char **name_fmt)
{
struct anon_vma_name *anon_name = vma->vm_mm ? anon_vma_name(vma) : NULL;
*name = NULL;
*path = NULL;
*name_fmt = NULL;
/*
* Print the dentry name for named mappings, and a
* special [heap] marker for the heap:
*/
if (vma->vm_file) {
/*
* If user named this anon shared memory via
* prctl(PR_SET_VMA ..., use the provided name.
*/
if (anon_name) {
*name_fmt = "[anon_shmem:%s]";
*name = anon_name->name;
} else {
*path = file_user_path(vma->vm_file);
}
return;
}
if (vma->vm_ops && vma->vm_ops->name) {
*name = vma->vm_ops->name(vma);
if (*name)
return;
}
*name = arch_vma_name(vma);
if (*name)
return;
if (!vma->vm_mm) {
*name = "[vdso]";
return;
}
if (vma_is_initial_heap(vma)) {
*name = "[heap]";
return;
}
if (vma_is_initial_stack(vma)) {
*name = "[stack]";
return;
}
if (anon_name) {
*name_fmt = "[anon:%s]";
*name = anon_name->name;
return;
}
}
static void show_vma_header_prefix(struct seq_file *m,
unsigned long start, unsigned long end,
vm_flags_t flags, unsigned long long pgoff,
dev_t dev, unsigned long ino)
{
seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
seq_put_hex_ll(m, NULL, start, 8);
seq_put_hex_ll(m, "-", end, 8);
seq_putc(m, ' ');
seq_putc(m, flags & VM_READ ? 'r' : '-');
seq_putc(m, flags & VM_WRITE ? 'w' : '-');
seq_putc(m, flags & VM_EXEC ? 'x' : '-');
seq_putc(m, flags & VM_MAYSHARE ? 's' : 'p');
seq_put_hex_ll(m, " ", pgoff, 8);
seq_put_hex_ll(m, " ", MAJOR(dev), 2);
seq_put_hex_ll(m, ":", MINOR(dev), 2);
seq_put_decimal_ull(m, " ", ino);
seq_putc(m, ' ');
}
static void
show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
{
const struct path *path;
const char *name_fmt, *name;
vm_flags_t flags = vma->vm_flags;
unsigned long ino = 0;
unsigned long long pgoff = 0;
unsigned long start, end;
dev_t dev = 0;
if (vma->vm_file) {
const struct inode *inode = file_user_inode(vma->vm_file);
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
}
start = vma->vm_start;
end = vma->vm_end;
show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
get_vma_name(vma, &path, &name, &name_fmt);
if (path) {
seq_pad(m, ' ');
seq_path(m, path, "\n");
} else if (name_fmt) {
seq_pad(m, ' ');
seq_printf(m, name_fmt, name);
} else if (name) {
seq_pad(m, ' ');
seq_puts(m, name);
}
seq_putc(m, '\n');
}
static int show_map(struct seq_file *m, void *v)
{
show_map_vma(m, v);
return 0;
}
static const struct seq_operations proc_pid_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_map
};
static int pid_maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_maps_op);
}
#define PROCMAP_QUERY_VMA_FLAGS ( \
PROCMAP_QUERY_VMA_READABLE | \
PROCMAP_QUERY_VMA_WRITABLE | \
PROCMAP_QUERY_VMA_EXECUTABLE | \
PROCMAP_QUERY_VMA_SHARED \
)
#define PROCMAP_QUERY_VALID_FLAGS_MASK ( \
PROCMAP_QUERY_COVERING_OR_NEXT_VMA | \
PROCMAP_QUERY_FILE_BACKED_VMA | \
PROCMAP_QUERY_VMA_FLAGS \
)
static int query_vma_setup(struct mm_struct *mm)
{
return mmap_read_lock_killable(mm);
}
static void query_vma_teardown(struct mm_struct *mm, struct vm_area_struct *vma)
{
mmap_read_unlock(mm);
}
static struct vm_area_struct *query_vma_find_by_addr(struct mm_struct *mm, unsigned long addr)
{
return find_vma(mm, addr);
}
static struct vm_area_struct *query_matching_vma(struct mm_struct *mm,
unsigned long addr, u32 flags)
{
struct vm_area_struct *vma;
next_vma:
vma = query_vma_find_by_addr(mm, addr);
if (!vma)
goto no_vma;
/* user requested only file-backed VMA, keep iterating */
if ((flags & PROCMAP_QUERY_FILE_BACKED_VMA) && !vma->vm_file)
goto skip_vma;
/* VMA permissions should satisfy query flags */
if (flags & PROCMAP_QUERY_VMA_FLAGS) {
u32 perm = 0;
if (flags & PROCMAP_QUERY_VMA_READABLE)
perm |= VM_READ;
if (flags & PROCMAP_QUERY_VMA_WRITABLE)
perm |= VM_WRITE;
if (flags & PROCMAP_QUERY_VMA_EXECUTABLE)
perm |= VM_EXEC;
if (flags & PROCMAP_QUERY_VMA_SHARED)
perm |= VM_MAYSHARE;
if ((vma->vm_flags & perm) != perm)
goto skip_vma;
}
/* found covering VMA or user is OK with the matching next VMA */
if ((flags & PROCMAP_QUERY_COVERING_OR_NEXT_VMA) || vma->vm_start <= addr)
return vma;
skip_vma:
/*
* If the user needs closest matching VMA, keep iterating.
*/
addr = vma->vm_end;
if (flags & PROCMAP_QUERY_COVERING_OR_NEXT_VMA)
goto next_vma;
no_vma:
return ERR_PTR(-ENOENT);
}
static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
{
struct procmap_query karg;
struct vm_area_struct *vma;
struct mm_struct *mm;
const char *name = NULL;
char build_id_buf[BUILD_ID_SIZE_MAX], *name_buf = NULL;
__u64 usize;
int err;
if (copy_from_user(&usize, (void __user *)uarg, sizeof(usize)))
return -EFAULT;
/* argument struct can never be that large, reject abuse */
if (usize > PAGE_SIZE)
return -E2BIG;
/* argument struct should have at least query_flags and query_addr fields */
if (usize < offsetofend(struct procmap_query, query_addr))
return -EINVAL;
err = copy_struct_from_user(&karg, sizeof(karg), uarg, usize);
if (err)
return err;
/* reject unknown flags */
if (karg.query_flags & ~PROCMAP_QUERY_VALID_FLAGS_MASK)
return -EINVAL;
/* either both buffer address and size are set, or both should be zero */
if (!!karg.vma_name_size != !!karg.vma_name_addr)
return -EINVAL;
if (!!karg.build_id_size != !!karg.build_id_addr)
return -EINVAL;
mm = priv->mm;
if (!mm || !mmget_not_zero(mm))
return -ESRCH;
err = query_vma_setup(mm);
if (err) {
mmput(mm);
return err;
}
vma = query_matching_vma(mm, karg.query_addr, karg.query_flags);
if (IS_ERR(vma)) {
err = PTR_ERR(vma);
vma = NULL;
goto out;
}
karg.vma_start = vma->vm_start;
karg.vma_end = vma->vm_end;
karg.vma_flags = 0;
if (vma->vm_flags & VM_READ)
karg.vma_flags |= PROCMAP_QUERY_VMA_READABLE;
if (vma->vm_flags & VM_WRITE)
karg.vma_flags |= PROCMAP_QUERY_VMA_WRITABLE;
if (vma->vm_flags & VM_EXEC)
karg.vma_flags |= PROCMAP_QUERY_VMA_EXECUTABLE;
if (vma->vm_flags & VM_MAYSHARE)
karg.vma_flags |= PROCMAP_QUERY_VMA_SHARED;
karg.vma_page_size = vma_kernel_pagesize(vma);
if (vma->vm_file) {
const struct inode *inode = file_user_inode(vma->vm_file);
karg.vma_offset = ((__u64)vma->vm_pgoff) << PAGE_SHIFT;
karg.dev_major = MAJOR(inode->i_sb->s_dev);
karg.dev_minor = MINOR(inode->i_sb->s_dev);
karg.inode = inode->i_ino;
} else {
karg.vma_offset = 0;
karg.dev_major = 0;
karg.dev_minor = 0;
karg.inode = 0;
}
if (karg.build_id_size) {
__u32 build_id_sz;
err = build_id_parse(vma, build_id_buf, &build_id_sz);
if (err) {
karg.build_id_size = 0;
} else {
if (karg.build_id_size < build_id_sz) {
err = -ENAMETOOLONG;
goto out;
}
karg.build_id_size = build_id_sz;
}
}
if (karg.build_id_size) {
__u32 build_id_sz;
err = build_id_parse(vma, build_id_buf, &build_id_sz);
if (err) {
karg.build_id_size = 0;
} else {
if (karg.build_id_size < build_id_sz) {
err = -ENAMETOOLONG;
goto out;
}
karg.build_id_size = build_id_sz;
}
}
if (karg.vma_name_size) {
size_t name_buf_sz = min_t(size_t, PATH_MAX, karg.vma_name_size);
const struct path *path;
const char *name_fmt;
size_t name_sz = 0;
get_vma_name(vma, &path, &name, &name_fmt);
if (path || name_fmt || name) {
name_buf = kmalloc(name_buf_sz, GFP_KERNEL);
if (!name_buf) {
err = -ENOMEM;
goto out;
}
}
if (path) {
name = d_path(path, name_buf, name_buf_sz);
if (IS_ERR(name)) {
err = PTR_ERR(name);
goto out;
}
name_sz = name_buf + name_buf_sz - name;
} else if (name || name_fmt) {
name_sz = 1 + snprintf(name_buf, name_buf_sz, name_fmt ?: "%s", name);
name = name_buf;
}
if (name_sz > name_buf_sz) {
err = -ENAMETOOLONG;
goto out;
}
karg.vma_name_size = name_sz;
}
/* unlock vma or mmap_lock, and put mm_struct before copying data to user */
query_vma_teardown(mm, vma);
mmput(mm);
if (karg.vma_name_size && copy_to_user(u64_to_user_ptr(karg.vma_name_addr),
name, karg.vma_name_size)) {
kfree(name_buf);
return -EFAULT;
}
kfree(name_buf);
if (karg.build_id_size && copy_to_user(u64_to_user_ptr(karg.build_id_addr),
build_id_buf, karg.build_id_size))
return -EFAULT;
if (copy_to_user(uarg, &karg, min_t(size_t, sizeof(karg), usize)))
return -EFAULT;
return 0;
out:
query_vma_teardown(mm, vma);
mmput(mm);
kfree(name_buf);
return err;
}
static long procfs_procmap_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct seq_file *seq = file->private_data;
struct proc_maps_private *priv = seq->private;
switch (cmd) {
case PROCMAP_QUERY:
return do_procmap_query(priv, (void __user *)arg);
default:
return -ENOIOCTLCMD;
}
}
const struct file_operations proc_pid_maps_operations = {
.open = pid_maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = proc_map_release,
.unlocked_ioctl = procfs_procmap_ioctl,
.compat_ioctl = compat_ptr_ioctl,
};
/*
* Proportional Set Size(PSS): my share of RSS.
*
* PSS of a process is the count of pages it has in memory, where each
* page is divided by the number of processes sharing it. So if a
* process has 1000 pages all to itself, and 1000 shared with one other
* process, its PSS will be 1500.
*
* To keep (accumulated) division errors low, we adopt a 64bit
* fixed-point pss counter to minimize division errors. So (pss >>
* PSS_SHIFT) would be the real byte count.
*
* A shift of 12 before division means (assuming 4K page size):
* - 1M 3-user-pages add up to 8KB errors;
* - supports mapcount up to 2^24, or 16M;
* - supports PSS up to 2^52 bytes, or 4PB.
*/
#define PSS_SHIFT 12
#ifdef CONFIG_PROC_PAGE_MONITOR
struct mem_size_stats {
unsigned long resident;
unsigned long shared_clean;
unsigned long shared_dirty;
unsigned long private_clean;
unsigned long private_dirty;
unsigned long referenced;
unsigned long anonymous;
unsigned long lazyfree;
unsigned long anonymous_thp;
unsigned long shmem_thp;
unsigned long file_thp;
unsigned long swap;
unsigned long shared_hugetlb;
unsigned long private_hugetlb;
unsigned long ksm;
u64 pss;
u64 pss_anon;
u64 pss_file;
u64 pss_shmem;
u64 pss_dirty;
u64 pss_locked;
u64 swap_pss;
};
static void smaps_page_accumulate(struct mem_size_stats *mss,
struct folio *folio, unsigned long size, unsigned long pss,
bool dirty, bool locked, bool private)
{
mss->pss += pss;
if (folio_test_anon(folio))
mss->pss_anon += pss;
else if (folio_test_swapbacked(folio))
mss->pss_shmem += pss;
else
mss->pss_file += pss;
if (locked)
mss->pss_locked += pss;
if (dirty || folio_test_dirty(folio)) {
mss->pss_dirty += pss;
if (private)
mss->private_dirty += size;
else
mss->shared_dirty += size;
} else {
if (private)
mss->private_clean += size;
else
mss->shared_clean += size;
}
}
static void smaps_account(struct mem_size_stats *mss, struct page *page,
bool compound, bool young, bool dirty, bool locked,
bool present)
{
struct folio *folio = page_folio(page);
int i, nr = compound ? compound_nr(page) : 1;
unsigned long size = nr * PAGE_SIZE;
/*
* First accumulate quantities that depend only on |size| and the type
* of the compound page.
*/
if (folio_test_anon(folio)) {
mss->anonymous += size;
if (!folio_test_swapbacked(folio) && !dirty &&
!folio_test_dirty(folio))
mss->lazyfree += size;
}
if (folio_test_ksm(folio))
mss->ksm += size;
mss->resident += size;
/* Accumulate the size in pages that have been accessed. */
if (young || folio_test_young(folio) || folio_test_referenced(folio))
mss->referenced += size;
/*
* Then accumulate quantities that may depend on sharing, or that may
* differ page-by-page.
*
* refcount == 1 for present entries guarantees that the folio is mapped
* exactly once. For large folios this implies that exactly one
* PTE/PMD/... maps (a part of) this folio.
*
* Treat all non-present entries (where relying on the mapcount and
* refcount doesn't make sense) as "maybe shared, but not sure how
* often". We treat device private entries as being fake-present.
*
* Note that it would not be safe to read the mapcount especially for
* pages referenced by migration entries, even with the PTL held.
*/
if (folio_ref_count(folio) == 1 || !present) {
smaps_page_accumulate(mss, folio, size, size << PSS_SHIFT,
dirty, locked, present);
return;
}
/*
* We obtain a snapshot of the mapcount. Without holding the folio lock
* this snapshot can be slightly wrong as we cannot always read the
* mapcount atomically.
*/
for (i = 0; i < nr; i++, page++) {
int mapcount = folio_precise_page_mapcount(folio, page);
unsigned long pss = PAGE_SIZE << PSS_SHIFT;
if (mapcount >= 2)
pss /= mapcount;
smaps_page_accumulate(mss, folio, PAGE_SIZE, pss,
dirty, locked, mapcount < 2);
}
}
#ifdef CONFIG_SHMEM
static int smaps_pte_hole(unsigned long addr, unsigned long end,
__always_unused int depth, struct mm_walk *walk)
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
mss->swap += shmem_partial_swap_usage(walk->vma->vm_file->f_mapping,
linear_page_index(vma, addr),
linear_page_index(vma, end));
return 0;
}
#else
#define smaps_pte_hole NULL
#endif /* CONFIG_SHMEM */
static void smaps_pte_hole_lookup(unsigned long addr, struct mm_walk *walk)
{
#ifdef CONFIG_SHMEM
if (walk->ops->pte_hole) {
/* depth is not used */
smaps_pte_hole(addr, addr + PAGE_SIZE, 0, walk);
}
#endif
}
static void smaps_pte_entry(pte_t *pte, unsigned long addr,
struct mm_walk *walk)
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
bool locked = !!(vma->vm_flags & VM_LOCKED);
struct page *page = NULL;
bool present = false, young = false, dirty = false;
pte_t ptent = ptep_get(pte);
if (pte_present(ptent)) {
page = vm_normal_page(vma, addr, ptent);
young = pte_young(ptent);
dirty = pte_dirty(ptent);
present = true;
} else if (is_swap_pte(ptent)) {
swp_entry_t swpent = pte_to_swp_entry(ptent);
if (!non_swap_entry(swpent)) {
int mapcount;
mss->swap += PAGE_SIZE;
mapcount = swp_swapcount(swpent);
if (mapcount >= 2) {
u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
do_div(pss_delta, mapcount);
mss->swap_pss += pss_delta;
} else {
mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
}
} else if (is_pfn_swap_entry(swpent)) {
if (is_device_private_entry(swpent))
present = true;
page = pfn_swap_entry_to_page(swpent);
}
} else {
smaps_pte_hole_lookup(addr, walk);
return;
}
if (!page)
return;
smaps_account(mss, page, false, young, dirty, locked, present);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
struct mm_walk *walk)
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
bool locked = !!(vma->vm_flags & VM_LOCKED);
struct page *page = NULL;
bool present = false;
struct folio *folio;
if (pmd_present(*pmd)) {
page = vm_normal_page_pmd(vma, addr, *pmd);
present = true;
} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
swp_entry_t entry = pmd_to_swp_entry(*pmd);
if (is_pfn_swap_entry(entry))
page = pfn_swap_entry_to_page(entry);
}
if (IS_ERR_OR_NULL(page))
return;
folio = page_folio(page);
if (folio_test_anon(folio))
mss->anonymous_thp += HPAGE_PMD_SIZE;
else if (folio_test_swapbacked(folio))
mss->shmem_thp += HPAGE_PMD_SIZE;
else if (folio_is_zone_device(folio))
/* pass */;
else
mss->file_thp += HPAGE_PMD_SIZE;
smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd),
locked, present);
}
#else
static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
struct mm_walk *walk)
{
}
#endif
static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct vm_area_struct *vma = walk->vma;
pte_t *pte;
spinlock_t *ptl;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
smaps_pmd_entry(pmd, addr, walk);
spin_unlock(ptl);
goto out;
}
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return 0;
}
for (; addr != end; pte++, addr += PAGE_SIZE)
smaps_pte_entry(pte, addr, walk);
pte_unmap_unlock(pte - 1, ptl);
out:
cond_resched();
return 0;
}
static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
{
/*
* Don't forget to update Documentation/ on changes.
*/
static const char mnemonics[BITS_PER_LONG][2] = {
/*
* In case if we meet a flag we don't know about.
*/
[0 ... (BITS_PER_LONG-1)] = "??",
[ilog2(VM_READ)] = "rd",
[ilog2(VM_WRITE)] = "wr",
[ilog2(VM_EXEC)] = "ex",
[ilog2(VM_SHARED)] = "sh",
[ilog2(VM_MAYREAD)] = "mr",
[ilog2(VM_MAYWRITE)] = "mw",
[ilog2(VM_MAYEXEC)] = "me",
[ilog2(VM_MAYSHARE)] = "ms",
[ilog2(VM_GROWSDOWN)] = "gd",
[ilog2(VM_PFNMAP)] = "pf",
[ilog2(VM_LOCKED)] = "lo",
[ilog2(VM_IO)] = "io",
[ilog2(VM_SEQ_READ)] = "sr",
[ilog2(VM_RAND_READ)] = "rr",
[ilog2(VM_DONTCOPY)] = "dc",
[ilog2(VM_DONTEXPAND)] = "de",
[ilog2(VM_LOCKONFAULT)] = "lf",
[ilog2(VM_ACCOUNT)] = "ac",
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
[ilog2(VM_SYNC)] = "sf",
[ilog2(VM_ARCH_1)] = "ar",
[ilog2(VM_WIPEONFORK)] = "wf",
[ilog2(VM_DONTDUMP)] = "dd",
#ifdef CONFIG_ARM64_BTI
[ilog2(VM_ARM64_BTI)] = "bt",
#endif
#ifdef CONFIG_MEM_SOFT_DIRTY
[ilog2(VM_SOFTDIRTY)] = "sd",
#endif
[ilog2(VM_MIXEDMAP)] = "mm",
[ilog2(VM_HUGEPAGE)] = "hg",
[ilog2(VM_NOHUGEPAGE)] = "nh",
[ilog2(VM_MERGEABLE)] = "mg",
[ilog2(VM_UFFD_MISSING)]= "um",
[ilog2(VM_UFFD_WP)] = "uw",
#ifdef CONFIG_ARM64_MTE
[ilog2(VM_MTE)] = "mt",
[ilog2(VM_MTE_ALLOWED)] = "",
#endif
#ifdef CONFIG_ARCH_HAS_PKEYS
/* These come out via ProtectionKey: */
[ilog2(VM_PKEY_BIT0)] = "",
[ilog2(VM_PKEY_BIT1)] = "",
[ilog2(VM_PKEY_BIT2)] = "",
[ilog2(VM_PKEY_BIT3)] = "",
#if VM_PKEY_BIT4
[ilog2(VM_PKEY_BIT4)] = "",
#endif
#endif /* CONFIG_ARCH_HAS_PKEYS */
#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
[ilog2(VM_UFFD_MINOR)] = "ui",
#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
#ifdef CONFIG_X86_USER_SHADOW_STACK
[ilog2(VM_SHADOW_STACK)] = "ss",
#endif
#ifdef CONFIG_64BIT
[ilog2(VM_DROPPABLE)] = "dp",
[ilog2(VM_SEALED)] = "sl",
#endif
};
size_t i;
seq_puts(m, "VmFlags: ");
for (i = 0; i < BITS_PER_LONG; i++) {
if (!mnemonics[i][0])
continue;
if (vma->vm_flags & (1UL << i)) {
seq_putc(m, mnemonics[i][0]);
seq_putc(m, mnemonics[i][1]);
seq_putc(m, ' ');
}
}
seq_putc(m, '\n');
}
#ifdef CONFIG_HUGETLB_PAGE
static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
pte_t ptent = huge_ptep_get(walk->mm, addr, pte);
struct folio *folio = NULL;
bool present = false;
if (pte_present(ptent)) {
folio = page_folio(pte_page(ptent));
present = true;
} else if (is_swap_pte(ptent)) {
swp_entry_t swpent = pte_to_swp_entry(ptent);
if (is_pfn_swap_entry(swpent))
folio = pfn_swap_entry_folio(swpent);
}
if (folio) {
/* We treat non-present entries as "maybe shared". */
if (!present || folio_likely_mapped_shared(folio) ||
hugetlb_pmd_shared(pte))
mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
else
mss->private_hugetlb += huge_page_size(hstate_vma(vma));
}
return 0;
}
#else
#define smaps_hugetlb_range NULL
#endif /* HUGETLB_PAGE */
static const struct mm_walk_ops smaps_walk_ops = {
.pmd_entry = smaps_pte_range,
.hugetlb_entry = smaps_hugetlb_range,
.walk_lock = PGWALK_RDLOCK,
};
static const struct mm_walk_ops smaps_shmem_walk_ops = {
.pmd_entry = smaps_pte_range,
.hugetlb_entry = smaps_hugetlb_range,
.pte_hole = smaps_pte_hole,
.walk_lock = PGWALK_RDLOCK,
};
/*
* Gather mem stats from @vma with the indicated beginning
* address @start, and keep them in @mss.
*
* Use vm_start of @vma as the beginning address if @start is 0.
*/
static void smap_gather_stats(struct vm_area_struct *vma,
struct mem_size_stats *mss, unsigned long start)
{
const struct mm_walk_ops *ops = &smaps_walk_ops;
/* Invalid start */
if (start >= vma->vm_end)
return;
if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
/*
* For shared or readonly shmem mappings we know that all
* swapped out pages belong to the shmem object, and we can
* obtain the swap value much more efficiently. For private
* writable mappings, we might have COW pages that are
* not affected by the parent swapped out pages of the shmem
* object, so we have to distinguish them during the page walk.
* Unless we know that the shmem object (or the part mapped by
* our VMA) has no swapped out pages at all.
*/
unsigned long shmem_swapped = shmem_swap_usage(vma);
if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
!(vma->vm_flags & VM_WRITE))) {
mss->swap += shmem_swapped;
} else {
ops = &smaps_shmem_walk_ops;
}
}
/* mmap_lock is held in m_start */
if (!start)
walk_page_vma(vma, ops, mss);
else
walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
}
#define SEQ_PUT_DEC(str, val) \
seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
/* Show the contents common for smaps and smaps_rollup */
static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
bool rollup_mode)
{
SEQ_PUT_DEC("Rss: ", mss->resident);
SEQ_PUT_DEC(" kB\nPss: ", mss->pss >> PSS_SHIFT);
SEQ_PUT_DEC(" kB\nPss_Dirty: ", mss->pss_dirty >> PSS_SHIFT);
if (rollup_mode) {
/*
* These are meaningful only for smaps_rollup, otherwise two of
* them are zero, and the other one is the same as Pss.
*/
SEQ_PUT_DEC(" kB\nPss_Anon: ",
mss->pss_anon >> PSS_SHIFT);
SEQ_PUT_DEC(" kB\nPss_File: ",
mss->pss_file >> PSS_SHIFT);
SEQ_PUT_DEC(" kB\nPss_Shmem: ",
mss->pss_shmem >> PSS_SHIFT);
}
SEQ_PUT_DEC(" kB\nShared_Clean: ", mss->shared_clean);
SEQ_PUT_DEC(" kB\nShared_Dirty: ", mss->shared_dirty);
SEQ_PUT_DEC(" kB\nPrivate_Clean: ", mss->private_clean);
SEQ_PUT_DEC(" kB\nPrivate_Dirty: ", mss->private_dirty);
SEQ_PUT_DEC(" kB\nReferenced: ", mss->referenced);
SEQ_PUT_DEC(" kB\nAnonymous: ", mss->anonymous);
SEQ_PUT_DEC(" kB\nKSM: ", mss->ksm);
SEQ_PUT_DEC(" kB\nLazyFree: ", mss->lazyfree);
SEQ_PUT_DEC(" kB\nAnonHugePages: ", mss->anonymous_thp);
SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
SEQ_PUT_DEC(" kB\nFilePmdMapped: ", mss->file_thp);
SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
mss->private_hugetlb >> 10, 7);
SEQ_PUT_DEC(" kB\nSwap: ", mss->swap);
SEQ_PUT_DEC(" kB\nSwapPss: ",
mss->swap_pss >> PSS_SHIFT);
SEQ_PUT_DEC(" kB\nLocked: ",
mss->pss_locked >> PSS_SHIFT);
seq_puts(m, " kB\n");
}
static int show_smap(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
struct mem_size_stats mss = {};
smap_gather_stats(vma, &mss, 0);
show_map_vma(m, vma);
SEQ_PUT_DEC("Size: ", vma->vm_end - vma->vm_start);
SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
SEQ_PUT_DEC(" kB\nMMUPageSize: ", vma_mmu_pagesize(vma));
seq_puts(m, " kB\n");
__show_smap(m, &mss, false);
seq_printf(m, "THPeligible: %8u\n",
!!thp_vma_allowable_orders(vma, vma->vm_flags,
TVA_SMAPS | TVA_ENFORCE_SYSFS, THP_ORDERS_ALL));
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
show_smap_vma_flags(m, vma);
return 0;
}
static int show_smaps_rollup(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct mem_size_stats mss = {};
struct mm_struct *mm = priv->mm;
struct vm_area_struct *vma;
unsigned long vma_start = 0, last_vma_end = 0;
int ret = 0;
VMA_ITERATOR(vmi, mm, 0);
priv->task = get_proc_task(priv->inode);
if (!priv->task)
return -ESRCH;
if (!mm || !mmget_not_zero(mm)) {
ret = -ESRCH;
goto out_put_task;
}
ret = mmap_read_lock_killable(mm);
if (ret)
goto out_put_mm;
hold_task_mempolicy(priv);
vma = vma_next(&vmi);
if (unlikely(!vma))
goto empty_set;
vma_start = vma->vm_start;
do {
smap_gather_stats(vma, &mss, 0);
last_vma_end = vma->vm_end;
/*
* Release mmap_lock temporarily if someone wants to
* access it for write request.
*/
if (mmap_lock_is_contended(mm)) {
vma_iter_invalidate(&vmi);
mmap_read_unlock(mm);
ret = mmap_read_lock_killable(mm);
if (ret) {
release_task_mempolicy(priv);
goto out_put_mm;
}
/*
* After dropping the lock, there are four cases to
* consider. See the following example for explanation.
*
* +------+------+-----------+
* | VMA1 | VMA2 | VMA3 |
* +------+------+-----------+
* | | | |
* 4k 8k 16k 400k
*
* Suppose we drop the lock after reading VMA2 due to
* contention, then we get:
*
* last_vma_end = 16k
*
* 1) VMA2 is freed, but VMA3 exists:
*
* vma_next(vmi) will return VMA3.
* In this case, just continue from VMA3.
*
* 2) VMA2 still exists:
*
* vma_next(vmi) will return VMA3.
* In this case, just continue from VMA3.
*
* 3) No more VMAs can be found:
*
* vma_next(vmi) will return NULL.
* No more things to do, just break.
*
* 4) (last_vma_end - 1) is the middle of a vma (VMA'):
*
* vma_next(vmi) will return VMA' whose range
* contains last_vma_end.
* Iterate VMA' from last_vma_end.
*/
vma = vma_next(&vmi);
/* Case 3 above */
if (!vma)
break;
/* Case 1 and 2 above */
if (vma->vm_start >= last_vma_end) {
smap_gather_stats(vma, &mss, 0);
last_vma_end = vma->vm_end;
continue;
}
/* Case 4 above */
if (vma->vm_end > last_vma_end) {
smap_gather_stats(vma, &mss, last_vma_end);
last_vma_end = vma->vm_end;
}
}
} for_each_vma(vmi, vma);
empty_set:
show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
seq_pad(m, ' ');
seq_puts(m, "[rollup]\n");
__show_smap(m, &mss, true);
release_task_mempolicy(priv);
mmap_read_unlock(mm);
out_put_mm:
mmput(mm);
out_put_task:
put_task_struct(priv->task);
priv->task = NULL;
return ret;
}
#undef SEQ_PUT_DEC
static const struct seq_operations proc_pid_smaps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_smap
};
static int pid_smaps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_smaps_op);
}
static int smaps_rollup_open(struct inode *inode, struct file *file)
{
int ret;
struct proc_maps_private *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL_ACCOUNT);
if (!priv)
return -ENOMEM;
ret = single_open(file, show_smaps_rollup, priv);
if (ret)
goto out_free;
priv->inode = inode;
priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
if (IS_ERR(priv->mm)) {
ret = PTR_ERR(priv->mm);
single_release(inode, file);
goto out_free;
}
return 0;
out_free:
kfree(priv);
return ret;
}
static int smaps_rollup_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
struct proc_maps_private *priv = seq->private;
if (priv->mm)
mmdrop(priv->mm);
kfree(priv);
return single_release(inode, file);
}
const struct file_operations proc_pid_smaps_operations = {
.open = pid_smaps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = proc_map_release,
};
const struct file_operations proc_pid_smaps_rollup_operations = {
.open = smaps_rollup_open,
.read = seq_read,
.llseek = seq_lseek,
.release = smaps_rollup_release,
};
enum clear_refs_types {
CLEAR_REFS_ALL = 1,
CLEAR_REFS_ANON,
CLEAR_REFS_MAPPED,
CLEAR_REFS_SOFT_DIRTY,
CLEAR_REFS_MM_HIWATER_RSS,
CLEAR_REFS_LAST,
};
struct clear_refs_private {
enum clear_refs_types type;
};
#ifdef CONFIG_MEM_SOFT_DIRTY
static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
struct folio *folio;
if (!pte_write(pte))
return false;
if (!is_cow_mapping(vma->vm_flags))
return false;
if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
return false;
folio = vm_normal_folio(vma, addr, pte);
if (!folio)
return false;
return folio_maybe_dma_pinned(folio);
}
static inline void clear_soft_dirty(struct vm_area_struct *vma,
unsigned long addr, pte_t *pte)
{
/*
* The soft-dirty tracker uses #PF-s to catch writes
* to pages, so write-protect the pte as well. See the
* Documentation/admin-guide/mm/soft-dirty.rst for full description
* of how soft-dirty works.
*/
pte_t ptent = ptep_get(pte);
if (pte_present(ptent)) {
pte_t old_pte;
if (pte_is_pinned(vma, addr, ptent))
return;
old_pte = ptep_modify_prot_start(vma, addr, pte);
ptent = pte_wrprotect(old_pte);
ptent = pte_clear_soft_dirty(ptent);
ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
} else if (is_swap_pte(ptent)) {
ptent = pte_swp_clear_soft_dirty(ptent);
set_pte_at(vma->vm_mm, addr, pte, ptent);
}
}
#else
static inline void clear_soft_dirty(struct vm_area_struct *vma,
unsigned long addr, pte_t *pte)
{
}
#endif
#if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old, pmd = *pmdp;
if (pmd_present(pmd)) {
/* See comment in change_huge_pmd() */
old = pmdp_invalidate(vma, addr, pmdp);
if (pmd_dirty(old))
pmd = pmd_mkdirty(pmd);
if (pmd_young(old))
pmd = pmd_mkyoung(pmd);
pmd = pmd_wrprotect(pmd);
pmd = pmd_clear_soft_dirty(pmd);
set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
} else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
pmd = pmd_swp_clear_soft_dirty(pmd);
set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
}
}
#else
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
}
#endif
static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, struct mm_walk *walk)
{
struct clear_refs_private *cp = walk->private;
struct vm_area_struct *vma = walk->vma;
pte_t *pte, ptent;
spinlock_t *ptl;
struct folio *folio;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
clear_soft_dirty_pmd(vma, addr, pmd);
goto out;
}
if (!pmd_present(*pmd))
goto out;
folio = pmd_folio(*pmd);
/* Clear accessed and referenced bits. */
pmdp_test_and_clear_young(vma, addr, pmd);
folio_test_clear_young(folio);
folio_clear_referenced(folio);
out:
spin_unlock(ptl);
return 0;
}
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return 0;
}
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = ptep_get(pte);
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
clear_soft_dirty(vma, addr, pte);
continue;
}
if (!pte_present(ptent))
continue;
folio = vm_normal_folio(vma, addr, ptent);
if (!folio)
continue;
/* Clear accessed and referenced bits. */
ptep_test_and_clear_young(vma, addr, pte);
folio_test_clear_young(folio);
folio_clear_referenced(folio);
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static int clear_refs_test_walk(unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct clear_refs_private *cp = walk->private;
struct vm_area_struct *vma = walk->vma;
if (vma->vm_flags & VM_PFNMAP)
return 1;
/*
* Writing 1 to /proc/pid/clear_refs affects all pages.
* Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
* Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
* Writing 4 to /proc/pid/clear_refs affects all pages.
*/
if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
return 1;
if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
return 1;
return 0;
}
static const struct mm_walk_ops clear_refs_walk_ops = {
.pmd_entry = clear_refs_pte_range,
.test_walk = clear_refs_test_walk,
.walk_lock = PGWALK_WRLOCK,
};
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF] = {};
struct mm_struct *mm;
struct vm_area_struct *vma;
enum clear_refs_types type;
int itype;
int rv;
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
rv = kstrtoint(strstrip(buffer), 10, &itype);
if (rv < 0)
return rv;
type = (enum clear_refs_types)itype;
if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
return -EINVAL;
task = get_proc_task(file_inode(file));
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
VMA_ITERATOR(vmi, mm, 0);
struct mmu_notifier_range range;
struct clear_refs_private cp = {
.type = type,
};
if (mmap_write_lock_killable(mm)) {
count = -EINTR;
goto out_mm;
}
if (type == CLEAR_REFS_MM_HIWATER_RSS) {
/*
* Writing 5 to /proc/pid/clear_refs resets the peak
* resident set size to this mm's current rss value.
*/
reset_mm_hiwater_rss(mm);
goto out_unlock;
}
if (type == CLEAR_REFS_SOFT_DIRTY) {
for_each_vma(vmi, vma) {
if (!(vma->vm_flags & VM_SOFTDIRTY))
continue;
vm_flags_clear(vma, VM_SOFTDIRTY);
vma_set_page_prot(vma);
}
inc_tlb_flush_pending(mm);
mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
0, mm, 0, -1UL);
mmu_notifier_invalidate_range_start(&range);
}
walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp);
if (type == CLEAR_REFS_SOFT_DIRTY) {
mmu_notifier_invalidate_range_end(&range);
flush_tlb_mm(mm);
dec_tlb_flush_pending(mm);
}
out_unlock:
mmap_write_unlock(mm);
out_mm:
mmput(mm);
}
put_task_struct(task);
return count;
}
const struct file_operations proc_clear_refs_operations = {
.write = clear_refs_write,
.llseek = noop_llseek,
};
typedef struct {
u64 pme;
} pagemap_entry_t;
struct pagemapread {
int pos, len; /* units: PM_ENTRY_BYTES, not bytes */
pagemap_entry_t *buffer;
bool show_pfn;
};
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
#define PAGEMAP_WALK_MASK (PMD_MASK)
#define PM_ENTRY_BYTES sizeof(pagemap_entry_t)
#define PM_PFRAME_BITS 55
#define PM_PFRAME_MASK GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
#define PM_SOFT_DIRTY BIT_ULL(55)
#define PM_MMAP_EXCLUSIVE BIT_ULL(56)
#define PM_UFFD_WP BIT_ULL(57)
#define PM_FILE BIT_ULL(61)
#define PM_SWAP BIT_ULL(62)
#define PM_PRESENT BIT_ULL(63)
#define PM_END_OF_BUFFER 1
static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
{
return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
}
static int add_to_pagemap(pagemap_entry_t *pme, struct pagemapread *pm)
{
pm->buffer[pm->pos++] = *pme;
if (pm->pos >= pm->len)
return PM_END_OF_BUFFER;
return 0;
}
static int pagemap_pte_hole(unsigned long start, unsigned long end,
__always_unused int depth, struct mm_walk *walk)
{
struct pagemapread *pm = walk->private;
unsigned long addr = start;
int err = 0;
while (addr < end) {
struct vm_area_struct *vma = find_vma(walk->mm, addr);
pagemap_entry_t pme = make_pme(0, 0);
/* End of address space hole, which we mark as non-present. */
unsigned long hole_end;
if (vma)
hole_end = min(end, vma->vm_start);
else
hole_end = end;
for (; addr < hole_end; addr += PAGE_SIZE) {
err = add_to_pagemap(&pme, pm);
if (err)
goto out;
}
if (!vma)
break;
/* Addresses in the VMA. */
if (vma->vm_flags & VM_SOFTDIRTY)
pme = make_pme(0, PM_SOFT_DIRTY);
for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
err = add_to_pagemap(&pme, pm);
if (err)
goto out;
}
}
out:
return err;
}
static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
u64 frame = 0, flags = 0;
struct page *page = NULL;
struct folio *folio;
if (pte_present(pte)) {
if (pm->show_pfn)
frame = pte_pfn(pte);
flags |= PM_PRESENT;
page = vm_normal_page(vma, addr, pte);
if (pte_soft_dirty(pte))
flags |= PM_SOFT_DIRTY;
if (pte_uffd_wp(pte))
flags |= PM_UFFD_WP;
} else if (is_swap_pte(pte)) {
swp_entry_t entry;
if (pte_swp_soft_dirty(pte))
flags |= PM_SOFT_DIRTY;
if (pte_swp_uffd_wp(pte))
flags |= PM_UFFD_WP;
entry = pte_to_swp_entry(pte);
if (pm->show_pfn) {
pgoff_t offset;
/*
* For PFN swap offsets, keeping the offset field
* to be PFN only to be compatible with old smaps.
*/
if (is_pfn_swap_entry(entry))
offset = swp_offset_pfn(entry);
else
offset = swp_offset(entry);
frame = swp_type(entry) |
(offset << MAX_SWAPFILES_SHIFT);
}
flags |= PM_SWAP;
if (is_pfn_swap_entry(entry))
page = pfn_swap_entry_to_page(entry);
if (pte_marker_entry_uffd_wp(entry))
flags |= PM_UFFD_WP;
}
if (page) {
folio = page_folio(page);
if (!folio_test_anon(folio))
flags |= PM_FILE;
if ((flags & PM_PRESENT) &&
folio_precise_page_mapcount(folio, page) == 1)
flags |= PM_MMAP_EXCLUSIVE;
}
if (vma->vm_flags & VM_SOFTDIRTY)
flags |= PM_SOFT_DIRTY;
return make_pme(frame, flags);
}
static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct vm_area_struct *vma = walk->vma;
struct pagemapread *pm = walk->private;
spinlock_t *ptl;
pte_t *pte, *orig_pte;
int err = 0;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
ptl = pmd_trans_huge_lock(pmdp, vma);
if (ptl) {
unsigned int idx = (addr & ~PMD_MASK) >> PAGE_SHIFT;
u64 flags = 0, frame = 0;
pmd_t pmd = *pmdp;
struct page *page = NULL;
struct folio *folio = NULL;
if (vma->vm_flags & VM_SOFTDIRTY)
flags |= PM_SOFT_DIRTY;
if (pmd_present(pmd)) {
page = pmd_page(pmd);
flags |= PM_PRESENT;
if (pmd_soft_dirty(pmd))
flags |= PM_SOFT_DIRTY;
if (pmd_uffd_wp(pmd))
flags |= PM_UFFD_WP;
if (pm->show_pfn)
frame = pmd_pfn(pmd) + idx;
}
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
else if (is_swap_pmd(pmd)) {
swp_entry_t entry = pmd_to_swp_entry(pmd);
unsigned long offset;
if (pm->show_pfn) {
if (is_pfn_swap_entry(entry))
offset = swp_offset_pfn(entry) + idx;
else
offset = swp_offset(entry) + idx;
frame = swp_type(entry) |
(offset << MAX_SWAPFILES_SHIFT);
}
flags |= PM_SWAP;
if (pmd_swp_soft_dirty(pmd))
flags |= PM_SOFT_DIRTY;
if (pmd_swp_uffd_wp(pmd))
flags |= PM_UFFD_WP;
VM_BUG_ON(!is_pmd_migration_entry(pmd));
page = pfn_swap_entry_to_page(entry);
}
#endif
if (page) {
folio = page_folio(page);
if (!folio_test_anon(folio))
flags |= PM_FILE;
}
for (; addr != end; addr += PAGE_SIZE, idx++) {
unsigned long cur_flags = flags;
pagemap_entry_t pme;
if (folio && (flags & PM_PRESENT) &&
folio_precise_page_mapcount(folio, page + idx) == 1)
cur_flags |= PM_MMAP_EXCLUSIVE;
pme = make_pme(frame, cur_flags);
err = add_to_pagemap(&pme, pm);
if (err)
break;
if (pm->show_pfn) {
if (flags & PM_PRESENT)
frame++;
else if (flags & PM_SWAP)
frame += (1 << MAX_SWAPFILES_SHIFT);
}
}
spin_unlock(ptl);
return err;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/*
* We can assume that @vma always points to a valid one and @end never
* goes beyond vma->vm_end.
*/
orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return err;
}
for (; addr < end; pte++, addr += PAGE_SIZE) {
pagemap_entry_t pme;
pme = pte_to_pagemap_entry(pm, vma, addr, ptep_get(pte));
err = add_to_pagemap(&pme, pm);
if (err)
break;
}
pte_unmap_unlock(orig_pte, ptl);
cond_resched();
return err;
}
#ifdef CONFIG_HUGETLB_PAGE
/* This function walks within one hugetlb entry in the single call */
static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct pagemapread *pm = walk->private;
struct vm_area_struct *vma = walk->vma;
u64 flags = 0, frame = 0;
int err = 0;
pte_t pte;
if (vma->vm_flags & VM_SOFTDIRTY)
flags |= PM_SOFT_DIRTY;
pte = huge_ptep_get(walk->mm, addr, ptep);
if (pte_present(pte)) {
struct folio *folio = page_folio(pte_page(pte));
if (!folio_test_anon(folio))
flags |= PM_FILE;
if (!folio_likely_mapped_shared(folio) &&
!hugetlb_pmd_shared(ptep))
flags |= PM_MMAP_EXCLUSIVE;
if (huge_pte_uffd_wp(pte))
flags |= PM_UFFD_WP;
flags |= PM_PRESENT;
if (pm->show_pfn)
frame = pte_pfn(pte) +
((addr & ~hmask) >> PAGE_SHIFT);
} else if (pte_swp_uffd_wp_any(pte)) {
flags |= PM_UFFD_WP;
}
for (; addr != end; addr += PAGE_SIZE) {
pagemap_entry_t pme = make_pme(frame, flags);
err = add_to_pagemap(&pme, pm);
if (err)
return err;
if (pm->show_pfn && (flags & PM_PRESENT))
frame++;
}
cond_resched();
return err;
}
#else
#define pagemap_hugetlb_range NULL
#endif /* HUGETLB_PAGE */
static const struct mm_walk_ops pagemap_ops = {
.pmd_entry = pagemap_pmd_range,
.pte_hole = pagemap_pte_hole,
.hugetlb_entry = pagemap_hugetlb_range,
.walk_lock = PGWALK_RDLOCK,
};
/*
* /proc/pid/pagemap - an array mapping virtual pages to pfns
*
* For each page in the address space, this file contains one 64-bit entry
* consisting of the following:
*
* Bits 0-54 page frame number (PFN) if present
* Bits 0-4 swap type if swapped
* Bits 5-54 swap offset if swapped
* Bit 55 pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
* Bit 56 page exclusively mapped
* Bit 57 pte is uffd-wp write-protected
* Bits 58-60 zero
* Bit 61 page is file-page or shared-anon
* Bit 62 page swapped
* Bit 63 page present
*
* If the page is not present but in swap, then the PFN contains an
* encoding of the swap file number and the page's offset into the
* swap. Unmapped pages return a null PFN. This allows determining
* precisely which pages are mapped (or in swap) and comparing mapped
* pages between processes.
*
* Efficient users of this interface will use /proc/pid/maps to
* determine which areas of memory are actually mapped and llseek to
* skip over unmapped regions.
*/
static ssize_t pagemap_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct mm_struct *mm = file->private_data;
struct pagemapread pm;
unsigned long src;
unsigned long svpfn;
unsigned long start_vaddr;
unsigned long end_vaddr;
int ret = 0, copied = 0;
if (!mm || !mmget_not_zero(mm))
goto out;
ret = -EINVAL;
/* file position must be aligned */
if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
goto out_mm;
ret = 0;
if (!count)
goto out_mm;
/* do not disclose physical addresses: attack vector */
pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
pm.buffer = kmalloc_array(pm.len, PM_ENTRY_BYTES, GFP_KERNEL);
ret = -ENOMEM;
if (!pm.buffer)
goto out_mm;
src = *ppos;
svpfn = src / PM_ENTRY_BYTES;
end_vaddr = mm->task_size;
/* watch out for wraparound */
start_vaddr = end_vaddr;
if (svpfn <= (ULONG_MAX >> PAGE_SHIFT)) {
unsigned long end;
ret = mmap_read_lock_killable(mm);
if (ret)
goto out_free;
start_vaddr = untagged_addr_remote(mm, svpfn << PAGE_SHIFT);
mmap_read_unlock(mm);
end = start_vaddr + ((count / PM_ENTRY_BYTES) << PAGE_SHIFT);
if (end >= start_vaddr && end < mm->task_size)
end_vaddr = end;
}
/* Ensure the address is inside the task */
if (start_vaddr > mm->task_size)
start_vaddr = end_vaddr;
ret = 0;
while (count && (start_vaddr < end_vaddr)) {
int len;
unsigned long end;
pm.pos = 0;
end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
/* overflow ? */
if (end < start_vaddr || end > end_vaddr)
end = end_vaddr;
ret = mmap_read_lock_killable(mm);
if (ret)
goto out_free;
ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
mmap_read_unlock(mm);
start_vaddr = end;
len = min(count, PM_ENTRY_BYTES * pm.pos);
if (copy_to_user(buf, pm.buffer, len)) {
ret = -EFAULT;
goto out_free;
}
copied += len;
buf += len;
count -= len;
}
*ppos += copied;
if (!ret || ret == PM_END_OF_BUFFER)
ret = copied;
out_free:
kfree(pm.buffer);
out_mm:
mmput(mm);
out:
return ret;
}
static int pagemap_open(struct inode *inode, struct file *file)
{
struct mm_struct *mm;
mm = proc_mem_open(inode, PTRACE_MODE_READ);
if (IS_ERR(mm))
return PTR_ERR(mm);
file->private_data = mm;
return 0;
}
static int pagemap_release(struct inode *inode, struct file *file)
{
struct mm_struct *mm = file->private_data;
if (mm)
mmdrop(mm);
return 0;
}
#define PM_SCAN_CATEGORIES (PAGE_IS_WPALLOWED | PAGE_IS_WRITTEN | \
PAGE_IS_FILE | PAGE_IS_PRESENT | \
PAGE_IS_SWAPPED | PAGE_IS_PFNZERO | \
PAGE_IS_HUGE | PAGE_IS_SOFT_DIRTY)
#define PM_SCAN_FLAGS (PM_SCAN_WP_MATCHING | PM_SCAN_CHECK_WPASYNC)
struct pagemap_scan_private {
struct pm_scan_arg arg;
unsigned long masks_of_interest, cur_vma_category;
struct page_region *vec_buf;
unsigned long vec_buf_len, vec_buf_index, found_pages;
struct page_region __user *vec_out;
};
static unsigned long pagemap_page_category(struct pagemap_scan_private *p,
struct vm_area_struct *vma,
unsigned long addr, pte_t pte)
{
unsigned long categories = 0;
if (pte_present(pte)) {
struct page *page;
categories |= PAGE_IS_PRESENT;
if (!pte_uffd_wp(pte))
categories |= PAGE_IS_WRITTEN;
if (p->masks_of_interest & PAGE_IS_FILE) {
page = vm_normal_page(vma, addr, pte);
if (page && !PageAnon(page))
categories |= PAGE_IS_FILE;
}
if (is_zero_pfn(pte_pfn(pte)))
categories |= PAGE_IS_PFNZERO;
if (pte_soft_dirty(pte))
categories |= PAGE_IS_SOFT_DIRTY;
} else if (is_swap_pte(pte)) {
swp_entry_t swp;
categories |= PAGE_IS_SWAPPED;
if (!pte_swp_uffd_wp_any(pte))
categories |= PAGE_IS_WRITTEN;
if (p->masks_of_interest & PAGE_IS_FILE) {
swp = pte_to_swp_entry(pte);
if (is_pfn_swap_entry(swp) &&
!folio_test_anon(pfn_swap_entry_folio(swp)))
categories |= PAGE_IS_FILE;
}
if (pte_swp_soft_dirty(pte))
categories |= PAGE_IS_SOFT_DIRTY;
}
return categories;
}
static void make_uffd_wp_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t *pte, pte_t ptent)
{
if (pte_present(ptent)) {
pte_t old_pte;
old_pte = ptep_modify_prot_start(vma, addr, pte);
ptent = pte_mkuffd_wp(old_pte);
ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
} else if (is_swap_pte(ptent)) {
ptent = pte_swp_mkuffd_wp(ptent);
set_pte_at(vma->vm_mm, addr, pte, ptent);
} else {
set_pte_at(vma->vm_mm, addr, pte,
make_pte_marker(PTE_MARKER_UFFD_WP));
}
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd)
{
unsigned long categories = PAGE_IS_HUGE;
if (pmd_present(pmd)) {
struct page *page;
categories |= PAGE_IS_PRESENT;
if (!pmd_uffd_wp(pmd))
categories |= PAGE_IS_WRITTEN;
if (p->masks_of_interest & PAGE_IS_FILE) {
page = vm_normal_page_pmd(vma, addr, pmd);
if (page && !PageAnon(page))
categories |= PAGE_IS_FILE;
}
if (is_zero_pfn(pmd_pfn(pmd)))
categories |= PAGE_IS_PFNZERO;
if (pmd_soft_dirty(pmd))
categories |= PAGE_IS_SOFT_DIRTY;
} else if (is_swap_pmd(pmd)) {
swp_entry_t swp;
categories |= PAGE_IS_SWAPPED;
if (!pmd_swp_uffd_wp(pmd))
categories |= PAGE_IS_WRITTEN;
if (pmd_swp_soft_dirty(pmd))
categories |= PAGE_IS_SOFT_DIRTY;
if (p->masks_of_interest & PAGE_IS_FILE) {
swp = pmd_to_swp_entry(pmd);
if (is_pfn_swap_entry(swp) &&
!folio_test_anon(pfn_swap_entry_folio(swp)))
categories |= PAGE_IS_FILE;
}
}
return categories;
}
static void make_uffd_wp_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old, pmd = *pmdp;
if (pmd_present(pmd)) {
old = pmdp_invalidate_ad(vma, addr, pmdp);
pmd = pmd_mkuffd_wp(old);
set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
} else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
pmd = pmd_swp_mkuffd_wp(pmd);
set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
}
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#ifdef CONFIG_HUGETLB_PAGE
static unsigned long pagemap_hugetlb_category(pte_t pte)
{
unsigned long categories = PAGE_IS_HUGE;
/*
* According to pagemap_hugetlb_range(), file-backed HugeTLB
* page cannot be swapped. So PAGE_IS_FILE is not checked for
* swapped pages.
*/
if (pte_present(pte)) {
categories |= PAGE_IS_PRESENT;
if (!huge_pte_uffd_wp(pte))
categories |= PAGE_IS_WRITTEN;
if (!PageAnon(pte_page(pte)))
categories |= PAGE_IS_FILE;
if (is_zero_pfn(pte_pfn(pte)))
categories |= PAGE_IS_PFNZERO;
if (pte_soft_dirty(pte))
categories |= PAGE_IS_SOFT_DIRTY;
} else if (is_swap_pte(pte)) {
categories |= PAGE_IS_SWAPPED;
if (!pte_swp_uffd_wp_any(pte))
categories |= PAGE_IS_WRITTEN;
if (pte_swp_soft_dirty(pte))
categories |= PAGE_IS_SOFT_DIRTY;
}
return categories;
}
static void make_uffd_wp_huge_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t ptent)
{
unsigned long psize;
if (is_hugetlb_entry_hwpoisoned(ptent) || is_pte_marker(ptent))
return;
psize = huge_page_size(hstate_vma(vma));
if (is_hugetlb_entry_migration(ptent))
set_huge_pte_at(vma->vm_mm, addr, ptep,
pte_swp_mkuffd_wp(ptent), psize);
else if (!huge_pte_none(ptent))
huge_ptep_modify_prot_commit(vma, addr, ptep, ptent,
huge_pte_mkuffd_wp(ptent));
else
set_huge_pte_at(vma->vm_mm, addr, ptep,
make_pte_marker(PTE_MARKER_UFFD_WP), psize);
}
#endif /* CONFIG_HUGETLB_PAGE */
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
unsigned long addr, unsigned long end)
{
struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
if (cur_buf->start != addr)
cur_buf->end = addr;
else
cur_buf->start = cur_buf->end = 0;
p->found_pages -= (end - addr) / PAGE_SIZE;
}
#endif
static bool pagemap_scan_is_interesting_page(unsigned long categories,
const struct pagemap_scan_private *p)
{
categories ^= p->arg.category_inverted;
if ((categories & p->arg.category_mask) != p->arg.category_mask)
return false;
if (p->arg.category_anyof_mask && !(categories & p->arg.category_anyof_mask))
return false;
return true;
}
static bool pagemap_scan_is_interesting_vma(unsigned long categories,
const struct pagemap_scan_private *p)
{
unsigned long required = p->arg.category_mask & PAGE_IS_WPALLOWED;
categories ^= p->arg.category_inverted;
if ((categories & required) != required)
return false;
return true;
}
static int pagemap_scan_test_walk(unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned long vma_category = 0;
bool wp_allowed = userfaultfd_wp_async(vma) &&
userfaultfd_wp_use_markers(vma);
if (!wp_allowed) {
/* User requested explicit failure over wp-async capability */
if (p->arg.flags & PM_SCAN_CHECK_WPASYNC)
return -EPERM;
/*
* User requires wr-protect, and allows silently skipping
* unsupported vmas.
*/
if (p->arg.flags & PM_SCAN_WP_MATCHING)
return 1;
/*
* Then the request doesn't involve wr-protects at all,
* fall through to the rest checks, and allow vma walk.
*/
}
if (vma->vm_flags & VM_PFNMAP)
return 1;
if (wp_allowed)
vma_category |= PAGE_IS_WPALLOWED;
if (vma->vm_flags & VM_SOFTDIRTY)
vma_category |= PAGE_IS_SOFT_DIRTY;
if (!pagemap_scan_is_interesting_vma(vma_category, p))
return 1;
p->cur_vma_category = vma_category;
return 0;
}
static bool pagemap_scan_push_range(unsigned long categories,
struct pagemap_scan_private *p,
unsigned long addr, unsigned long end)
{
struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
/*
* When there is no output buffer provided at all, the sentinel values
* won't match here. There is no other way for `cur_buf->end` to be
* non-zero other than it being non-empty.
*/
if (addr == cur_buf->end && categories == cur_buf->categories) {
cur_buf->end = end;
return true;
}
if (cur_buf->end) {
if (p->vec_buf_index >= p->vec_buf_len - 1)
return false;
cur_buf = &p->vec_buf[++p->vec_buf_index];
}
cur_buf->start = addr;
cur_buf->end = end;
cur_buf->categories = categories;
return true;
}
static int pagemap_scan_output(unsigned long categories,
struct pagemap_scan_private *p,
unsigned long addr, unsigned long *end)
{
unsigned long n_pages, total_pages;
int ret = 0;
if (!p->vec_buf)
return 0;
categories &= p->arg.return_mask;
n_pages = (*end - addr) / PAGE_SIZE;
if (check_add_overflow(p->found_pages, n_pages, &total_pages) ||
total_pages > p->arg.max_pages) {
size_t n_too_much = total_pages - p->arg.max_pages;
*end -= n_too_much * PAGE_SIZE;
n_pages -= n_too_much;
ret = -ENOSPC;
}
if (!pagemap_scan_push_range(categories, p, addr, *end)) {
*end = addr;
n_pages = 0;
ret = -ENOSPC;
}
p->found_pages += n_pages;
if (ret)
p->arg.walk_end = *end;
return ret;
}
static int pagemap_scan_thp_entry(pmd_t *pmd, unsigned long start,
unsigned long end, struct mm_walk *walk)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned long categories;
spinlock_t *ptl;
int ret = 0;
ptl = pmd_trans_huge_lock(pmd, vma);
if (!ptl)
return -ENOENT;
categories = p->cur_vma_category |
pagemap_thp_category(p, vma, start, *pmd);
if (!pagemap_scan_is_interesting_page(categories, p))
goto out_unlock;
ret = pagemap_scan_output(categories, p, start, &end);
if (start == end)
goto out_unlock;
if (~p->arg.flags & PM_SCAN_WP_MATCHING)
goto out_unlock;
if (~categories & PAGE_IS_WRITTEN)
goto out_unlock;
/*
* Break huge page into small pages if the WP operation
* needs to be performed on a portion of the huge page.
*/
if (end != start + HPAGE_SIZE) {
spin_unlock(ptl);
split_huge_pmd(vma, pmd, start);
pagemap_scan_backout_range(p, start, end);
/* Report as if there was no THP */
return -ENOENT;
}
make_uffd_wp_pmd(vma, start, pmd);
flush_tlb_range(vma, start, end);
out_unlock:
spin_unlock(ptl);
return ret;
#else /* !CONFIG_TRANSPARENT_HUGEPAGE */
return -ENOENT;
#endif
}
static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
unsigned long end, struct mm_walk *walk)
{
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned long addr, flush_end = 0;
pte_t *pte, *start_pte;
spinlock_t *ptl;
int ret;
arch_enter_lazy_mmu_mode();
ret = pagemap_scan_thp_entry(pmd, start, end, walk);
if (ret != -ENOENT) {
arch_leave_lazy_mmu_mode();
return ret;
}
ret = 0;
start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
if (!pte) {
arch_leave_lazy_mmu_mode();
walk->action = ACTION_AGAIN;
return 0;
}
if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) {
/* Fast path for performing exclusive WP */
for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
pte_t ptent = ptep_get(pte);
if ((pte_present(ptent) && pte_uffd_wp(ptent)) ||
pte_swp_uffd_wp_any(ptent))
continue;
make_uffd_wp_pte(vma, addr, pte, ptent);
if (!flush_end)
start = addr;
flush_end = addr + PAGE_SIZE;
}
goto flush_and_return;
}
if (!p->arg.category_anyof_mask && !p->arg.category_inverted &&
p->arg.category_mask == PAGE_IS_WRITTEN &&
p->arg.return_mask == PAGE_IS_WRITTEN) {
for (addr = start; addr < end; pte++, addr += PAGE_SIZE) {
unsigned long next = addr + PAGE_SIZE;
pte_t ptent = ptep_get(pte);
if ((pte_present(ptent) && pte_uffd_wp(ptent)) ||
pte_swp_uffd_wp_any(ptent))
continue;
ret = pagemap_scan_output(p->cur_vma_category | PAGE_IS_WRITTEN,
p, addr, &next);
if (next == addr)
break;
if (~p->arg.flags & PM_SCAN_WP_MATCHING)
continue;
make_uffd_wp_pte(vma, addr, pte, ptent);
if (!flush_end)
start = addr;
flush_end = next;
}
goto flush_and_return;
}
for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
pte_t ptent = ptep_get(pte);
unsigned long categories = p->cur_vma_category |
pagemap_page_category(p, vma, addr, ptent);
unsigned long next = addr + PAGE_SIZE;
if (!pagemap_scan_is_interesting_page(categories, p))
continue;
ret = pagemap_scan_output(categories, p, addr, &next);
if (next == addr)
break;
if (~p->arg.flags & PM_SCAN_WP_MATCHING)
continue;
if (~categories & PAGE_IS_WRITTEN)
continue;
make_uffd_wp_pte(vma, addr, pte, ptent);
if (!flush_end)
start = addr;
flush_end = next;
}
flush_and_return:
if (flush_end)
flush_tlb_range(vma, start, addr);
pte_unmap_unlock(start_pte, ptl);
arch_leave_lazy_mmu_mode();
cond_resched();
return ret;
}
#ifdef CONFIG_HUGETLB_PAGE
static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned long categories;
spinlock_t *ptl;
int ret = 0;
pte_t pte;
if (~p->arg.flags & PM_SCAN_WP_MATCHING) {
/* Go the short route when not write-protecting pages. */
pte = huge_ptep_get(walk->mm, start, ptep);
categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
if (!pagemap_scan_is_interesting_page(categories, p))
return 0;
return pagemap_scan_output(categories, p, start, &end);
}
i_mmap_lock_write(vma->vm_file->f_mapping);
ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep);
pte = huge_ptep_get(walk->mm, start, ptep);
categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
if (!pagemap_scan_is_interesting_page(categories, p))
goto out_unlock;
ret = pagemap_scan_output(categories, p, start, &end);
if (start == end)
goto out_unlock;
if (~categories & PAGE_IS_WRITTEN)
goto out_unlock;
if (end != start + HPAGE_SIZE) {
/* Partial HugeTLB page WP isn't possible. */
pagemap_scan_backout_range(p, start, end);
p->arg.walk_end = start;
ret = 0;
goto out_unlock;
}
make_uffd_wp_huge_pte(vma, start, ptep, pte);
flush_hugetlb_tlb_range(vma, start, end);
out_unlock:
spin_unlock(ptl);
i_mmap_unlock_write(vma->vm_file->f_mapping);
return ret;
}
#else
#define pagemap_scan_hugetlb_entry NULL
#endif
static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
int depth, struct mm_walk *walk)
{
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
int ret, err;
if (!vma || !pagemap_scan_is_interesting_page(p->cur_vma_category, p))
return 0;
ret = pagemap_scan_output(p->cur_vma_category, p, addr, &end);
if (addr == end)
return ret;
if (~p->arg.flags & PM_SCAN_WP_MATCHING)
return ret;
err = uffd_wp_range(vma, addr, end - addr, true);
if (err < 0)
ret = err;
return ret;
}
static const struct mm_walk_ops pagemap_scan_ops = {
.test_walk = pagemap_scan_test_walk,
.pmd_entry = pagemap_scan_pmd_entry,
.pte_hole = pagemap_scan_pte_hole,
.hugetlb_entry = pagemap_scan_hugetlb_entry,
};
static int pagemap_scan_get_args(struct pm_scan_arg *arg,
unsigned long uarg)
{
if (copy_from_user(arg, (void __user *)uarg, sizeof(*arg)))
return -EFAULT;
if (arg->size != sizeof(struct pm_scan_arg))
return -EINVAL;
/* Validate requested features */
if (arg->flags & ~PM_SCAN_FLAGS)
return -EINVAL;
if ((arg->category_inverted | arg->category_mask |
arg->category_anyof_mask | arg->return_mask) & ~PM_SCAN_CATEGORIES)
return -EINVAL;
arg->start = untagged_addr((unsigned long)arg->start);
arg->end = untagged_addr((unsigned long)arg->end);
arg->vec = untagged_addr((unsigned long)arg->vec);
/* Validate memory pointers */
if (!IS_ALIGNED(arg->start, PAGE_SIZE))
return -EINVAL;
if (!access_ok((void __user *)(long)arg->start, arg->end - arg->start))
return -EFAULT;
if (!arg->vec && arg->vec_len)
return -EINVAL;
if (arg->vec && !access_ok((void __user *)(long)arg->vec,
arg->vec_len * sizeof(struct page_region)))
return -EFAULT;
/* Fixup default values */
arg->end = ALIGN(arg->end, PAGE_SIZE);
arg->walk_end = 0;
if (!arg->max_pages)
arg->max_pages = ULONG_MAX;
return 0;
}
static int pagemap_scan_writeback_args(struct pm_scan_arg *arg,
unsigned long uargl)
{
struct pm_scan_arg __user *uarg = (void __user *)uargl;
if (copy_to_user(&uarg->walk_end, &arg->walk_end, sizeof(arg->walk_end)))
return -EFAULT;
return 0;
}
static int pagemap_scan_init_bounce_buffer(struct pagemap_scan_private *p)
{
if (!p->arg.vec_len)
return 0;
p->vec_buf_len = min_t(size_t, PAGEMAP_WALK_SIZE >> PAGE_SHIFT,
p->arg.vec_len);
p->vec_buf = kmalloc_array(p->vec_buf_len, sizeof(*p->vec_buf),
GFP_KERNEL);
if (!p->vec_buf)
return -ENOMEM;
p->vec_buf->start = p->vec_buf->end = 0;
p->vec_out = (struct page_region __user *)(long)p->arg.vec;
return 0;
}
static long pagemap_scan_flush_buffer(struct pagemap_scan_private *p)
{
const struct page_region *buf = p->vec_buf;
long n = p->vec_buf_index;
if (!p->vec_buf)
return 0;
if (buf[n].end != buf[n].start)
n++;
if (!n)
return 0;
if (copy_to_user(p->vec_out, buf, n * sizeof(*buf)))
return -EFAULT;
p->arg.vec_len -= n;
p->vec_out += n;
p->vec_buf_index = 0;
p->vec_buf_len = min_t(size_t, p->vec_buf_len, p->arg.vec_len);
p->vec_buf->start = p->vec_buf->end = 0;
return n;
}
static long do_pagemap_scan(struct mm_struct *mm, unsigned long uarg)
{
struct pagemap_scan_private p = {0};
unsigned long walk_start;
size_t n_ranges_out = 0;
int ret;
ret = pagemap_scan_get_args(&p.arg, uarg);
if (ret)
return ret;
p.masks_of_interest = p.arg.category_mask | p.arg.category_anyof_mask |
p.arg.return_mask;
ret = pagemap_scan_init_bounce_buffer(&p);
if (ret)
return ret;
for (walk_start = p.arg.start; walk_start < p.arg.end;
walk_start = p.arg.walk_end) {
struct mmu_notifier_range range;
long n_out;
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
}
ret = mmap_read_lock_killable(mm);
if (ret)
break;
/* Protection change for the range is going to happen. */
if (p.arg.flags & PM_SCAN_WP_MATCHING) {
mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0,
mm, walk_start, p.arg.end);
mmu_notifier_invalidate_range_start(&range);
}
ret = walk_page_range(mm, walk_start, p.arg.end,
&pagemap_scan_ops, &p);
if (p.arg.flags & PM_SCAN_WP_MATCHING)
mmu_notifier_invalidate_range_end(&range);
mmap_read_unlock(mm);
n_out = pagemap_scan_flush_buffer(&p);
if (n_out < 0)
ret = n_out;
else
n_ranges_out += n_out;
if (ret != -ENOSPC)
break;
if (p.arg.vec_len == 0 || p.found_pages == p.arg.max_pages)
break;
}
/* ENOSPC signifies early stop (buffer full) from the walk. */
if (!ret || ret == -ENOSPC)
ret = n_ranges_out;
/* The walk_end isn't set when ret is zero */
if (!p.arg.walk_end)
p.arg.walk_end = p.arg.end;
if (pagemap_scan_writeback_args(&p.arg, uarg))
ret = -EFAULT;
kfree(p.vec_buf);
return ret;
}
static long do_pagemap_cmd(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct mm_struct *mm = file->private_data;
switch (cmd) {
case PAGEMAP_SCAN:
return do_pagemap_scan(mm, arg);
default:
return -EINVAL;
}
}
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
.open = pagemap_open,
.release = pagemap_release,
.unlocked_ioctl = do_pagemap_cmd,
.compat_ioctl = do_pagemap_cmd,
};
#endif /* CONFIG_PROC_PAGE_MONITOR */
#ifdef CONFIG_NUMA
struct numa_maps {
unsigned long pages;
unsigned long anon;
unsigned long active;
unsigned long writeback;
unsigned long mapcount_max;
unsigned long dirty;
unsigned long swapcache;
unsigned long node[MAX_NUMNODES];
};
struct numa_maps_private {
struct proc_maps_private proc_maps;
struct numa_maps md;
};
static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
unsigned long nr_pages)
{
struct folio *folio = page_folio(page);
int count = folio_precise_page_mapcount(folio, page);
md->pages += nr_pages;
if (pte_dirty || folio_test_dirty(folio))
md->dirty += nr_pages;
if (folio_test_swapcache(folio))
md->swapcache += nr_pages;
if (folio_test_active(folio) || folio_test_unevictable(folio))
md->active += nr_pages;
if (folio_test_writeback(folio))
md->writeback += nr_pages;
if (folio_test_anon(folio))
md->anon += nr_pages;
if (count > md->mapcount_max)
md->mapcount_max = count;
md->node[folio_nid(folio)] += nr_pages;
}
static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
unsigned long addr)
{
struct page *page;
int nid;
if (!pte_present(pte))
return NULL;
page = vm_normal_page(vma, addr, pte);
if (!page || is_zone_device_page(page))
return NULL;
if (PageReserved(page))
return NULL;
nid = page_to_nid(page);
if (!node_isset(nid, node_states[N_MEMORY]))
return NULL;
return page;
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
struct vm_area_struct *vma,
unsigned long addr)
{
struct page *page;
int nid;
if (!pmd_present(pmd))
return NULL;
page = vm_normal_page_pmd(vma, addr, pmd);
if (!page)
return NULL;
if (PageReserved(page))
return NULL;
nid = page_to_nid(page);
if (!node_isset(nid, node_states[N_MEMORY]))
return NULL;
return page;
}
#endif
static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
unsigned long end, struct mm_walk *walk)
{
struct numa_maps *md = walk->private;
struct vm_area_struct *vma = walk->vma;
spinlock_t *ptl;
pte_t *orig_pte;
pte_t *pte;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
struct page *page;
page = can_gather_numa_stats_pmd(*pmd, vma, addr);
if (page)
gather_stats(page, md, pmd_dirty(*pmd),
HPAGE_PMD_SIZE/PAGE_SIZE);
spin_unlock(ptl);
return 0;
}
#endif
orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return 0;
}
do {
pte_t ptent = ptep_get(pte);
struct page *page = can_gather_numa_stats(ptent, vma, addr);
if (!page)
continue;
gather_stats(page, md, pte_dirty(ptent), 1);
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap_unlock(orig_pte, ptl);
cond_resched();
return 0;
}
#ifdef CONFIG_HUGETLB_PAGE
static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long end, struct mm_walk *walk)
{
pte_t huge_pte = huge_ptep_get(walk->mm, addr, pte);
struct numa_maps *md;
struct page *page;
if (!pte_present(huge_pte))
return 0;
page = pte_page(huge_pte);
md = walk->private;
gather_stats(page, md, pte_dirty(huge_pte), 1);
return 0;
}
#else
static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long end, struct mm_walk *walk)
{
return 0;
}
#endif
static const struct mm_walk_ops show_numa_ops = {
.hugetlb_entry = gather_hugetlb_stats,
.pmd_entry = gather_pte_stats,
.walk_lock = PGWALK_RDLOCK,
};
/*
* Display pages allocated per node and memory policy via /proc.
*/
static int show_numa_map(struct seq_file *m, void *v)
{
struct numa_maps_private *numa_priv = m->private;
struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
struct vm_area_struct *vma = v;
struct numa_maps *md = &numa_priv->md;
struct file *file = vma->vm_file;
struct mm_struct *mm = vma->vm_mm;
char buffer[64];
struct mempolicy *pol;
pgoff_t ilx;
int nid;
if (!mm)
return 0;
/* Ensure we start with an empty set of numa_maps statistics. */
memset(md, 0, sizeof(*md));
pol = __get_vma_policy(vma, vma->vm_start, &ilx);
if (pol) {
mpol_to_str(buffer, sizeof(buffer), pol);
mpol_cond_put(pol);
} else {
mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
}
seq_printf(m, "%08lx %s", vma->vm_start, buffer);
if (file) {
seq_puts(m, " file=");
seq_path(m, file_user_path(file), "\n\t= ");
} else if (vma_is_initial_heap(vma)) {
seq_puts(m, " heap");
} else if (vma_is_initial_stack(vma)) {
seq_puts(m, " stack");
}
if (is_vm_hugetlb_page(vma))
seq_puts(m, " huge");
/* mmap_lock is held by m_start */
walk_page_vma(vma, &show_numa_ops, md);
if (!md->pages)
goto out;
if (md->anon)
seq_printf(m, " anon=%lu", md->anon);
if (md->dirty)
seq_printf(m, " dirty=%lu", md->dirty);
if (md->pages != md->anon && md->pages != md->dirty)
seq_printf(m, " mapped=%lu", md->pages);
if (md->mapcount_max > 1)
seq_printf(m, " mapmax=%lu", md->mapcount_max);
if (md->swapcache)
seq_printf(m, " swapcache=%lu", md->swapcache);
if (md->active < md->pages && !is_vm_hugetlb_page(vma))
seq_printf(m, " active=%lu", md->active);
if (md->writeback)
seq_printf(m, " writeback=%lu", md->writeback);
for_each_node_state(nid, N_MEMORY)
if (md->node[nid])
seq_printf(m, " N%d=%lu", nid, md->node[nid]);
seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
out:
seq_putc(m, '\n');
return 0;
}
static const struct seq_operations proc_pid_numa_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_numa_map,
};
static int pid_numa_maps_open(struct inode *inode, struct file *file)
{
return proc_maps_open(inode, file, &proc_pid_numa_maps_op,
sizeof(struct numa_maps_private));
}
const struct file_operations proc_pid_numa_maps_operations = {
.open = pid_numa_maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = proc_map_release,
};
#endif /* CONFIG_NUMA */
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