xref: /openbmc/linux/fs/proc/task_nommu.c (revision 4a44a19b)
1 
2 #include <linux/mm.h>
3 #include <linux/file.h>
4 #include <linux/fdtable.h>
5 #include <linux/fs_struct.h>
6 #include <linux/mount.h>
7 #include <linux/ptrace.h>
8 #include <linux/slab.h>
9 #include <linux/seq_file.h>
10 #include "internal.h"
11 
12 /*
13  * Logic: we've got two memory sums for each process, "shared", and
14  * "non-shared". Shared memory may get counted more than once, for
15  * each process that owns it. Non-shared memory is counted
16  * accurately.
17  */
18 void task_mem(struct seq_file *m, struct mm_struct *mm)
19 {
20 	struct vm_area_struct *vma;
21 	struct vm_region *region;
22 	struct rb_node *p;
23 	unsigned long bytes = 0, sbytes = 0, slack = 0, size;
24 
25 	down_read(&mm->mmap_sem);
26 	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
27 		vma = rb_entry(p, struct vm_area_struct, vm_rb);
28 
29 		bytes += kobjsize(vma);
30 
31 		region = vma->vm_region;
32 		if (region) {
33 			size = kobjsize(region);
34 			size += region->vm_end - region->vm_start;
35 		} else {
36 			size = vma->vm_end - vma->vm_start;
37 		}
38 
39 		if (atomic_read(&mm->mm_count) > 1 ||
40 		    vma->vm_flags & VM_MAYSHARE) {
41 			sbytes += size;
42 		} else {
43 			bytes += size;
44 			if (region)
45 				slack = region->vm_end - vma->vm_end;
46 		}
47 	}
48 
49 	if (atomic_read(&mm->mm_count) > 1)
50 		sbytes += kobjsize(mm);
51 	else
52 		bytes += kobjsize(mm);
53 
54 	if (current->fs && current->fs->users > 1)
55 		sbytes += kobjsize(current->fs);
56 	else
57 		bytes += kobjsize(current->fs);
58 
59 	if (current->files && atomic_read(&current->files->count) > 1)
60 		sbytes += kobjsize(current->files);
61 	else
62 		bytes += kobjsize(current->files);
63 
64 	if (current->sighand && atomic_read(&current->sighand->count) > 1)
65 		sbytes += kobjsize(current->sighand);
66 	else
67 		bytes += kobjsize(current->sighand);
68 
69 	bytes += kobjsize(current); /* includes kernel stack */
70 
71 	seq_printf(m,
72 		"Mem:\t%8lu bytes\n"
73 		"Slack:\t%8lu bytes\n"
74 		"Shared:\t%8lu bytes\n",
75 		bytes, slack, sbytes);
76 
77 	up_read(&mm->mmap_sem);
78 }
79 
80 unsigned long task_vsize(struct mm_struct *mm)
81 {
82 	struct vm_area_struct *vma;
83 	struct rb_node *p;
84 	unsigned long vsize = 0;
85 
86 	down_read(&mm->mmap_sem);
87 	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
88 		vma = rb_entry(p, struct vm_area_struct, vm_rb);
89 		vsize += vma->vm_end - vma->vm_start;
90 	}
91 	up_read(&mm->mmap_sem);
92 	return vsize;
93 }
94 
95 unsigned long task_statm(struct mm_struct *mm,
96 			 unsigned long *shared, unsigned long *text,
97 			 unsigned long *data, unsigned long *resident)
98 {
99 	struct vm_area_struct *vma;
100 	struct vm_region *region;
101 	struct rb_node *p;
102 	unsigned long size = kobjsize(mm);
103 
104 	down_read(&mm->mmap_sem);
105 	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
106 		vma = rb_entry(p, struct vm_area_struct, vm_rb);
107 		size += kobjsize(vma);
108 		region = vma->vm_region;
109 		if (region) {
110 			size += kobjsize(region);
111 			size += region->vm_end - region->vm_start;
112 		}
113 	}
114 
115 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
116 		>> PAGE_SHIFT;
117 	*data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
118 		>> PAGE_SHIFT;
119 	up_read(&mm->mmap_sem);
120 	size >>= PAGE_SHIFT;
121 	size += *text + *data;
122 	*resident = size;
123 	return size;
124 }
125 
126 static pid_t pid_of_stack(struct proc_maps_private *priv,
127 				struct vm_area_struct *vma, bool is_pid)
128 {
129 	struct inode *inode = priv->inode;
130 	struct task_struct *task;
131 	pid_t ret = 0;
132 
133 	rcu_read_lock();
134 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
135 	if (task) {
136 		task = task_of_stack(task, vma, is_pid);
137 		if (task)
138 			ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);
139 	}
140 	rcu_read_unlock();
141 
142 	return ret;
143 }
144 
145 /*
146  * display a single VMA to a sequenced file
147  */
148 static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
149 			  int is_pid)
150 {
151 	struct mm_struct *mm = vma->vm_mm;
152 	struct proc_maps_private *priv = m->private;
153 	unsigned long ino = 0;
154 	struct file *file;
155 	dev_t dev = 0;
156 	int flags;
157 	unsigned long long pgoff = 0;
158 
159 	flags = vma->vm_flags;
160 	file = vma->vm_file;
161 
162 	if (file) {
163 		struct inode *inode = file_inode(vma->vm_file);
164 		dev = inode->i_sb->s_dev;
165 		ino = inode->i_ino;
166 		pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
167 	}
168 
169 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
170 	seq_printf(m,
171 		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
172 		   vma->vm_start,
173 		   vma->vm_end,
174 		   flags & VM_READ ? 'r' : '-',
175 		   flags & VM_WRITE ? 'w' : '-',
176 		   flags & VM_EXEC ? 'x' : '-',
177 		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
178 		   pgoff,
179 		   MAJOR(dev), MINOR(dev), ino);
180 
181 	if (file) {
182 		seq_pad(m, ' ');
183 		seq_path(m, &file->f_path, "");
184 	} else if (mm) {
185 		pid_t tid = pid_of_stack(priv, vma, is_pid);
186 
187 		if (tid != 0) {
188 			seq_pad(m, ' ');
189 			/*
190 			 * Thread stack in /proc/PID/task/TID/maps or
191 			 * the main process stack.
192 			 */
193 			if (!is_pid || (vma->vm_start <= mm->start_stack &&
194 			    vma->vm_end >= mm->start_stack))
195 				seq_printf(m, "[stack]");
196 			else
197 				seq_printf(m, "[stack:%d]", tid);
198 		}
199 	}
200 
201 	seq_putc(m, '\n');
202 	return 0;
203 }
204 
205 /*
206  * display mapping lines for a particular process's /proc/pid/maps
207  */
208 static int show_map(struct seq_file *m, void *_p, int is_pid)
209 {
210 	struct rb_node *p = _p;
211 
212 	return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb),
213 			      is_pid);
214 }
215 
216 static int show_pid_map(struct seq_file *m, void *_p)
217 {
218 	return show_map(m, _p, 1);
219 }
220 
221 static int show_tid_map(struct seq_file *m, void *_p)
222 {
223 	return show_map(m, _p, 0);
224 }
225 
226 static void *m_start(struct seq_file *m, loff_t *pos)
227 {
228 	struct proc_maps_private *priv = m->private;
229 	struct mm_struct *mm;
230 	struct rb_node *p;
231 	loff_t n = *pos;
232 
233 	/* pin the task and mm whilst we play with them */
234 	priv->task = get_proc_task(priv->inode);
235 	if (!priv->task)
236 		return ERR_PTR(-ESRCH);
237 
238 	mm = priv->mm;
239 	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
240 		return NULL;
241 
242 	down_read(&mm->mmap_sem);
243 	/* start from the Nth VMA */
244 	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
245 		if (n-- == 0)
246 			return p;
247 
248 	up_read(&mm->mmap_sem);
249 	mmput(mm);
250 	return NULL;
251 }
252 
253 static void m_stop(struct seq_file *m, void *_vml)
254 {
255 	struct proc_maps_private *priv = m->private;
256 
257 	if (!IS_ERR_OR_NULL(_vml)) {
258 		up_read(&priv->mm->mmap_sem);
259 		mmput(priv->mm);
260 	}
261 	if (priv->task) {
262 		put_task_struct(priv->task);
263 		priv->task = NULL;
264 	}
265 }
266 
267 static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
268 {
269 	struct rb_node *p = _p;
270 
271 	(*pos)++;
272 	return p ? rb_next(p) : NULL;
273 }
274 
275 static const struct seq_operations proc_pid_maps_ops = {
276 	.start	= m_start,
277 	.next	= m_next,
278 	.stop	= m_stop,
279 	.show	= show_pid_map
280 };
281 
282 static const struct seq_operations proc_tid_maps_ops = {
283 	.start	= m_start,
284 	.next	= m_next,
285 	.stop	= m_stop,
286 	.show	= show_tid_map
287 };
288 
289 static int maps_open(struct inode *inode, struct file *file,
290 		     const struct seq_operations *ops)
291 {
292 	struct proc_maps_private *priv;
293 
294 	priv = __seq_open_private(file, ops, sizeof(*priv));
295 	if (!priv)
296 		return -ENOMEM;
297 
298 	priv->inode = inode;
299 	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
300 	if (IS_ERR(priv->mm)) {
301 		int err = PTR_ERR(priv->mm);
302 
303 		seq_release_private(inode, file);
304 		return err;
305 	}
306 
307 	return 0;
308 }
309 
310 
311 static int map_release(struct inode *inode, struct file *file)
312 {
313 	struct seq_file *seq = file->private_data;
314 	struct proc_maps_private *priv = seq->private;
315 
316 	if (priv->mm)
317 		mmdrop(priv->mm);
318 
319 	return seq_release_private(inode, file);
320 }
321 
322 static int pid_maps_open(struct inode *inode, struct file *file)
323 {
324 	return maps_open(inode, file, &proc_pid_maps_ops);
325 }
326 
327 static int tid_maps_open(struct inode *inode, struct file *file)
328 {
329 	return maps_open(inode, file, &proc_tid_maps_ops);
330 }
331 
332 const struct file_operations proc_pid_maps_operations = {
333 	.open		= pid_maps_open,
334 	.read		= seq_read,
335 	.llseek		= seq_lseek,
336 	.release	= map_release,
337 };
338 
339 const struct file_operations proc_tid_maps_operations = {
340 	.open		= tid_maps_open,
341 	.read		= seq_read,
342 	.llseek		= seq_lseek,
343 	.release	= map_release,
344 };
345 
346