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linux/fs/proc/task_mmu.c
Brahmajit Das 5778ace04e fs/proc: fix build with GCC 15 due to -Werror=unterminated-string-initialization 
show show_smap_vma_flags() has been a using misspelled initializer in
mnemonics[] - it needed to initialize 2 element array of char and it used
NUL-padded 2 character string literals (i.e.  3-element initializer).

This has been spotted by gcc-15[*]; prior to that gcc quietly dropped the
3rd eleemnt of initializers.  To fix this we are increasing the size of
mnemonics[] (from mnemonics[BITS_PER_LONG][2] to
mnemonics[BITS_PER_LONG][3]) to accomodate the NUL-padded string literals.

This also helps us in simplyfying the logic for printing of the flags as
instead of printing each character from the mnemonics[], we can just print
the mnemonics[] using seq_printf.

[*]: fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
  917 |                 [0 ... (BITS_PER_LONG-1)] = "??",
      |                                                 ^~~~
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
...


Stephen pointed out:

: The C standard explicitly allows for a string initializer to be too long
: due to the NUL byte at the end ...  so this warning may be overzealous.

but let's make the warning go away anwyay.

Link: https://lkml.kernel.org/r/20241005063700.2241027-1-brahmajit.xyz@gmail.com
Link: https://lkml.kernel.org/r/20241003093040.47c08382@canb.auug.org.au
Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-17 00:28:07 -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.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.
*
* The length of the second argument of mnemonics[]
* needs to be 3 instead of previously set 2
* (i.e. from [BITS_PER_LONG][2] to [BITS_PER_LONG][3])
* to avoid spurious
* -Werror=unterminated-string-initialization warning
* with GCC 15
*/
static const char mnemonics[BITS_PER_LONG][3] = {
/*
* 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)] = "",
#if VM_PKEY_BIT3
[ilog2(VM_PKEY_BIT3)] = "",
#endif
#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
#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
[ilog2(VM_DROPPABLE)] = "dp",
#endif
#ifdef CONFIG_64BIT
[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_printf(m, "%s ", mnemonics[i]);
}
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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