linux_dsm_epyc7002/fs/proc/task_mmu.c
Vitaly Mayatskikh 0816178638 pagemap: require aligned-length, non-null reads of /proc/pid/pagemap
The intention of commit aae8679b0e
("pagemap: fix bug in add_to_pagemap, require aligned-length reads of
/proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a
multiple of 8 bytes, but now it allows to read 0 bytes, which actually
puts some data to user's buffer.  According to POSIX, if count is zero,
read() should return zero and has no other results.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Cc: Thomas Tuttle <ttuttle@google.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-02 15:36:09 -07:00

778 lines
19 KiB
C

#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/pagemap.h>
#include <linux/mempolicy.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>
#include "internal.h"
void task_mem(struct seq_file *m, struct mm_struct *mm)
{
unsigned long data, text, lib;
unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
/*
* 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 = get_mm_rss(mm);
if (hiwater_rss < mm->hiwater_rss)
hiwater_rss = mm->hiwater_rss;
data = mm->total_vm - mm->shared_vm - mm->stack_vm;
text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
seq_printf(m,
"VmPeak:\t%8lu kB\n"
"VmSize:\t%8lu kB\n"
"VmLck:\t%8lu kB\n"
"VmHWM:\t%8lu kB\n"
"VmRSS:\t%8lu kB\n"
"VmData:\t%8lu kB\n"
"VmStk:\t%8lu kB\n"
"VmExe:\t%8lu kB\n"
"VmLib:\t%8lu kB\n"
"VmPTE:\t%8lu kB\n",
hiwater_vm << (PAGE_SHIFT-10),
(total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
mm->locked_vm << (PAGE_SHIFT-10),
hiwater_rss << (PAGE_SHIFT-10),
total_rss << (PAGE_SHIFT-10),
data << (PAGE_SHIFT-10),
mm->stack_vm << (PAGE_SHIFT-10), text, lib,
(PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10);
}
unsigned long task_vsize(struct mm_struct *mm)
{
return PAGE_SIZE * mm->total_vm;
}
int task_statm(struct mm_struct *mm, int *shared, int *text,
int *data, int *resident)
{
*shared = get_mm_counter(mm, file_rss);
*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
>> PAGE_SHIFT;
*data = mm->total_vm - mm->shared_vm;
*resident = *shared + get_mm_counter(mm, anon_rss);
return mm->total_vm;
}
static void pad_len_spaces(struct seq_file *m, int len)
{
len = 25 + sizeof(void*) * 6 - len;
if (len < 1)
len = 1;
seq_printf(m, "%*c", len, ' ');
}
static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
{
if (vma && vma != priv->tail_vma) {
struct mm_struct *mm = vma->vm_mm;
up_read(&mm->mmap_sem);
mmput(mm);
}
}
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
unsigned long last_addr = m->version;
struct mm_struct *mm;
struct vm_area_struct *vma, *tail_vma = NULL;
loff_t l = *pos;
/* Clear the per syscall fields in priv */
priv->task = NULL;
priv->tail_vma = NULL;
/*
* We remember last_addr rather than next_addr to hit with
* mmap_cache most of the time. We have zero last_addr at
* the beginning and also after lseek. We will have -1 last_addr
* after the end of the vmas.
*/
if (last_addr == -1UL)
return NULL;
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
return NULL;
mm = mm_for_maps(priv->task);
if (!mm)
return NULL;
tail_vma = get_gate_vma(priv->task);
priv->tail_vma = tail_vma;
/* Start with last addr hint */
vma = find_vma(mm, last_addr);
if (last_addr && vma) {
vma = vma->vm_next;
goto out;
}
/*
* Check the vma index is within the range and do
* sequential scan until m_index.
*/
vma = NULL;
if ((unsigned long)l < mm->map_count) {
vma = mm->mmap;
while (l-- && vma)
vma = vma->vm_next;
goto out;
}
if (l != mm->map_count)
tail_vma = NULL; /* After gate vma */
out:
if (vma)
return vma;
/* End of vmas has been reached */
m->version = (tail_vma != NULL)? 0: -1UL;
up_read(&mm->mmap_sem);
mmput(mm);
return tail_vma;
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
struct vm_area_struct *vma = v;
struct vm_area_struct *tail_vma = priv->tail_vma;
(*pos)++;
if (vma && (vma != tail_vma) && vma->vm_next)
return vma->vm_next;
vma_stop(priv, vma);
return (vma != tail_vma)? tail_vma: NULL;
}
static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct vm_area_struct *vma = v;
vma_stop(priv, vma);
if (priv->task)
put_task_struct(priv->task);
}
static int do_maps_open(struct inode *inode, struct file *file,
const struct seq_operations *ops)
{
struct proc_maps_private *priv;
int ret = -ENOMEM;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (priv) {
priv->pid = proc_pid(inode);
ret = seq_open(file, ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = priv;
} else {
kfree(priv);
}
}
return ret;
}
static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
{
struct mm_struct *mm = vma->vm_mm;
struct file *file = vma->vm_file;
int flags = vma->vm_flags;
unsigned long ino = 0;
unsigned long long pgoff = 0;
dev_t dev = 0;
int len;
if (file) {
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
}
seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
vma->vm_start,
vma->vm_end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? 's' : 'p',
pgoff,
MAJOR(dev), MINOR(dev), ino, &len);
/*
* Print the dentry name for named mappings, and a
* special [heap] marker for the heap:
*/
if (file) {
pad_len_spaces(m, len);
seq_path(m, &file->f_path, "\n");
} else {
const char *name = arch_vma_name(vma);
if (!name) {
if (mm) {
if (vma->vm_start <= mm->start_brk &&
vma->vm_end >= mm->brk) {
name = "[heap]";
} else if (vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack) {
name = "[stack]";
}
} else {
name = "[vdso]";
}
}
if (name) {
pad_len_spaces(m, len);
seq_puts(m, name);
}
}
seq_putc(m, '\n');
}
static int show_map(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
show_map_vma(m, vma);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task))? vma->vm_start: 0;
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 maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_maps_op);
}
const struct file_operations proc_maps_operations = {
.open = maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
/*
* 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 {
struct vm_area_struct *vma;
unsigned long resident;
unsigned long shared_clean;
unsigned long shared_dirty;
unsigned long private_clean;
unsigned long private_dirty;
unsigned long referenced;
unsigned long swap;
u64 pss;
};
static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = mss->vma;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
int mapcount;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = *pte;
if (is_swap_pte(ptent)) {
mss->swap += PAGE_SIZE;
continue;
}
if (!pte_present(ptent))
continue;
mss->resident += PAGE_SIZE;
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
/* Accumulate the size in pages that have been accessed. */
if (pte_young(ptent) || PageReferenced(page))
mss->referenced += PAGE_SIZE;
mapcount = page_mapcount(page);
if (mapcount >= 2) {
if (pte_dirty(ptent))
mss->shared_dirty += PAGE_SIZE;
else
mss->shared_clean += PAGE_SIZE;
mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
} else {
if (pte_dirty(ptent))
mss->private_dirty += PAGE_SIZE;
else
mss->private_clean += PAGE_SIZE;
mss->pss += (PAGE_SIZE << PSS_SHIFT);
}
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static int show_smap(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
struct vm_area_struct *vma = v;
struct mem_size_stats mss;
struct mm_walk smaps_walk = {
.pmd_entry = smaps_pte_range,
.mm = vma->vm_mm,
.private = &mss,
};
memset(&mss, 0, sizeof mss);
mss.vma = vma;
if (vma->vm_mm && !is_vm_hugetlb_page(vma))
walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
show_map_vma(m, vma);
seq_printf(m,
"Size: %8lu kB\n"
"Rss: %8lu kB\n"
"Pss: %8lu kB\n"
"Shared_Clean: %8lu kB\n"
"Shared_Dirty: %8lu kB\n"
"Private_Clean: %8lu kB\n"
"Private_Dirty: %8lu kB\n"
"Referenced: %8lu kB\n"
"Swap: %8lu kB\n"
"KernelPageSize: %8lu kB\n"
"MMUPageSize: %8lu kB\n",
(vma->vm_end - vma->vm_start) >> 10,
mss.resident >> 10,
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
mss.shared_clean >> 10,
mss.shared_dirty >> 10,
mss.private_clean >> 10,
mss.private_dirty >> 10,
mss.referenced >> 10,
mss.swap >> 10,
vma_kernel_pagesize(vma) >> 10,
vma_mmu_pagesize(vma) >> 10);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
return 0;
}
static const struct seq_operations proc_pid_smaps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_smap
};
static int smaps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_smaps_op);
}
const struct file_operations proc_smaps_operations = {
.open = smaps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, struct mm_walk *walk)
{
struct vm_area_struct *vma = walk->private;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = *pte;
if (!pte_present(ptent))
continue;
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
/* Clear accessed and referenced bits. */
ptep_test_and_clear_young(vma, addr, pte);
ClearPageReferenced(page);
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
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], *end;
struct mm_struct *mm;
struct vm_area_struct *vma;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
if (!simple_strtol(buffer, &end, 0))
return -EINVAL;
if (*end == '\n')
end++;
task = get_proc_task(file->f_path.dentry->d_inode);
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
struct mm_walk clear_refs_walk = {
.pmd_entry = clear_refs_pte_range,
.mm = mm,
};
down_read(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
clear_refs_walk.private = vma;
if (!is_vm_hugetlb_page(vma))
walk_page_range(vma->vm_start, vma->vm_end,
&clear_refs_walk);
}
flush_tlb_mm(mm);
up_read(&mm->mmap_sem);
mmput(mm);
}
put_task_struct(task);
if (end - buffer == 0)
return -EIO;
return end - buffer;
}
const struct file_operations proc_clear_refs_operations = {
.write = clear_refs_write,
};
struct pagemapread {
u64 __user *out, *end;
};
#define PM_ENTRY_BYTES sizeof(u64)
#define PM_STATUS_BITS 3
#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS)
#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
#define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
#define PM_PSHIFT_BITS 6
#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
#define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1)
#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
#define PM_PRESENT PM_STATUS(4LL)
#define PM_SWAP PM_STATUS(2LL)
#define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT)
#define PM_END_OF_BUFFER 1
static int add_to_pagemap(unsigned long addr, u64 pfn,
struct pagemapread *pm)
{
if (put_user(pfn, pm->out))
return -EFAULT;
pm->out++;
if (pm->out >= pm->end)
return PM_END_OF_BUFFER;
return 0;
}
static int pagemap_pte_hole(unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct pagemapread *pm = walk->private;
unsigned long addr;
int err = 0;
for (addr = start; addr < end; addr += PAGE_SIZE) {
err = add_to_pagemap(addr, PM_NOT_PRESENT, pm);
if (err)
break;
}
return err;
}
static u64 swap_pte_to_pagemap_entry(pte_t pte)
{
swp_entry_t e = pte_to_swp_entry(pte);
return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
}
static u64 pte_to_pagemap_entry(pte_t pte)
{
u64 pme = 0;
if (is_swap_pte(pte))
pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))
| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;
else if (pte_present(pte))
pme = PM_PFRAME(pte_pfn(pte))
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
return pme;
}
static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct vm_area_struct *vma;
struct pagemapread *pm = walk->private;
pte_t *pte;
int err = 0;
/* find the first VMA at or above 'addr' */
vma = find_vma(walk->mm, addr);
for (; addr != end; addr += PAGE_SIZE) {
u64 pfn = PM_NOT_PRESENT;
/* check to see if we've left 'vma' behind
* and need a new, higher one */
if (vma && (addr >= vma->vm_end))
vma = find_vma(walk->mm, addr);
/* check that 'vma' actually covers this address,
* and that it isn't a huge page vma */
if (vma && (vma->vm_start <= addr) &&
!is_vm_hugetlb_page(vma)) {
pte = pte_offset_map(pmd, addr);
pfn = pte_to_pagemap_entry(*pte);
/* unmap before userspace copy */
pte_unmap(pte);
}
err = add_to_pagemap(addr, pfn, pm);
if (err)
return err;
}
cond_resched();
return err;
}
/*
* /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 0-55 page frame number (PFN) if present
* Bits 0-4 swap type if swapped
* Bits 5-55 swap offset if swapped
* Bits 55-60 page shift (page size = 1<<page shift)
* Bit 61 reserved for future use
* 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 task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
struct page **pages, *page;
unsigned long uaddr, uend;
struct mm_struct *mm;
struct pagemapread pm;
int pagecount;
int ret = -ESRCH;
struct mm_walk pagemap_walk = {};
unsigned long src;
unsigned long svpfn;
unsigned long start_vaddr;
unsigned long end_vaddr;
if (!task)
goto out;
ret = -EACCES;
if (!ptrace_may_access(task, PTRACE_MODE_READ))
goto out_task;
ret = -EINVAL;
/* file position must be aligned */
if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
goto out_task;
ret = 0;
if (!count)
goto out_task;
mm = get_task_mm(task);
if (!mm)
goto out_task;
uaddr = (unsigned long)buf & PAGE_MASK;
uend = (unsigned long)(buf + count);
pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE;
ret = 0;
if (pagecount == 0)
goto out_mm;
pages = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
ret = -ENOMEM;
if (!pages)
goto out_mm;
down_read(&current->mm->mmap_sem);
ret = get_user_pages(current, current->mm, uaddr, pagecount,
1, 0, pages, NULL);
up_read(&current->mm->mmap_sem);
if (ret < 0)
goto out_free;
if (ret != pagecount) {
pagecount = ret;
ret = -EFAULT;
goto out_pages;
}
pm.out = (u64 __user *)buf;
pm.end = (u64 __user *)(buf + count);
pagemap_walk.pmd_entry = pagemap_pte_range;
pagemap_walk.pte_hole = pagemap_pte_hole;
pagemap_walk.mm = mm;
pagemap_walk.private = &pm;
src = *ppos;
svpfn = src / PM_ENTRY_BYTES;
start_vaddr = svpfn << PAGE_SHIFT;
end_vaddr = TASK_SIZE_OF(task);
/* watch out for wraparound */
if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT)
start_vaddr = end_vaddr;
/*
* The odds are that this will stop walking way
* before end_vaddr, because the length of the
* user buffer is tracked in "pm", and the walk
* will stop when we hit the end of the buffer.
*/
ret = walk_page_range(start_vaddr, end_vaddr, &pagemap_walk);
if (ret == PM_END_OF_BUFFER)
ret = 0;
/* don't need mmap_sem for these, but this looks cleaner */
*ppos += (char __user *)pm.out - buf;
if (!ret)
ret = (char __user *)pm.out - buf;
out_pages:
for (; pagecount; pagecount--) {
page = pages[pagecount-1];
if (!PageReserved(page))
SetPageDirty(page);
page_cache_release(page);
}
out_free:
kfree(pages);
out_mm:
mmput(mm);
out_task:
put_task_struct(task);
out:
return ret;
}
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
};
#endif /* CONFIG_PROC_PAGE_MONITOR */
#ifdef CONFIG_NUMA
extern int show_numa_map(struct seq_file *m, void *v);
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 numa_maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_numa_maps_op);
}
const struct file_operations proc_numa_maps_operations = {
.open = numa_maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
#endif