Linux-libre 4.3.2-gnu

6 files changed, 295 insertions, 253 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index ce065cf31..eed2050db 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -308,7 +308,8 @@ static void render_cap_t(struct seq_file *m, const char *header,
 static inline void task_cap(struct seq_file *m, struct task_struct *p)
 {
 	const struct cred *cred;
-	kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;
+	kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
+			cap_bset, cap_ambient;
 
 	rcu_read_lock();
 	cred = __task_cred(p);
@@ -316,12 +317,14 @@ static inline void task_cap(struct seq_file *m, struct task_struct *p)
 	cap_permitted	= cred->cap_permitted;
 	cap_effective	= cred->cap_effective;
 	cap_bset	= cred->cap_bset;
+	cap_ambient	= cred->cap_ambient;
 	rcu_read_unlock();
 
 	render_cap_t(m, "CapInh:\t", &cap_inheritable);
 	render_cap_t(m, "CapPrm:\t", &cap_permitted);
 	render_cap_t(m, "CapEff:\t", &cap_effective);
 	render_cap_t(m, "CapBnd:\t", &cap_bset);
+	render_cap_t(m, "CapAmb:\t", &cap_ambient);
 }
 
 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
@@ -372,7 +375,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task, int whole)
 {
-	unsigned long vsize, eip, esp, wchan = ~0UL;
+	unsigned long vsize, eip, esp, wchan = 0;
 	int priority, nice;
 	int tty_pgrp = -1, tty_nr = 0;
 	sigset_t sigign, sigcatch;
@@ -504,7 +507,19 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
 	seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
 	seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
-	seq_put_decimal_ull(m, ' ', wchan);
+
+	/*
+	 * We used to output the absolute kernel address, but that's an
+	 * information leak - so instead we show a 0/1 flag here, to signal
+	 * to user-space whether there's a wchan field in /proc/PID/wchan.
+	 *
+	 * This works with older implementations of procps as well.
+	 */
+	if (wchan)
+		seq_puts(m, " 1");
+	else
+		seq_puts(m, " 0");
+
 	seq_put_decimal_ull(m, ' ', 0);
 	seq_put_decimal_ull(m, ' ', 0);
 	seq_put_decimal_ll(m, ' ', task->exit_signal);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index f2193218a..ac5498d9b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -430,13 +430,10 @@ static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 
 	wchan = get_wchan(task);
 
-	if (lookup_symbol_name(wchan, symname) < 0) {
-		if (!ptrace_may_access(task, PTRACE_MODE_READ))
-			return 0;
-		seq_printf(m, "%lu", wchan);
-	} else {
+	if (wchan && ptrace_may_access(task, PTRACE_MODE_READ) && !lookup_symbol_name(wchan, symname))
 		seq_printf(m, "%s", symname);
-	}
+	else
+		seq_putc(m, '0');
 
 	return 0;
 }
@@ -507,7 +504,7 @@ static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 		seq_printf(m, "0 0 0\n");
 	else
 		seq_printf(m, "%llu %llu %lu\n",
-		   (unsigned long long)task->se.sum_exec_runtime,
+		   (unsigned long long)tsk_seruntime(task),
 		   (unsigned long long)task->sched_info.run_delay,
 		   task->sched_info.pcount);
 
@@ -1230,10 +1227,9 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 				   size_t count, loff_t *ppos)
 {
 	struct inode * inode = file_inode(file);
-	char *page, *tmp;
-	ssize_t length;
 	uid_t loginuid;
 	kuid_t kloginuid;
+	int rv;
 
 	rcu_read_lock();
 	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
@@ -1242,46 +1238,28 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 	}
 	rcu_read_unlock();
 
-	if (count >= PAGE_SIZE)
-		count = PAGE_SIZE - 1;
-
 	if (*ppos != 0) {
 		/* No partial writes. */
 		return -EINVAL;
 	}
-	page = (char*)__get_free_page(GFP_TEMPORARY);
-	if (!page)
-		return -ENOMEM;
-	length = -EFAULT;
-	if (copy_from_user(page, buf, count))
-		goto out_free_page;
 
-	page[count] = '\0';
-	loginuid = simple_strtoul(page, &tmp, 10);
-	if (tmp == page) {
-		length = -EINVAL;
-		goto out_free_page;
-
-	}
+	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
+	if (rv < 0)
+		return rv;
 
 	/* is userspace tring to explicitly UNSET the loginuid? */
 	if (loginuid == AUDIT_UID_UNSET) {
 		kloginuid = INVALID_UID;
 	} else {
 		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
-		if (!uid_valid(kloginuid)) {
-			length = -EINVAL;
-			goto out_free_page;
-		}
+		if (!uid_valid(kloginuid))
+			return -EINVAL;
 	}
 
-	length = audit_set_loginuid(kloginuid);
-	if (likely(length == 0))
-		length = count;
-
-out_free_page:
-	free_page((unsigned long) page);
-	return length;
+	rv = audit_set_loginuid(kloginuid);
+	if (rv < 0)
+		return rv;
+	return count;
 }
 
 static const struct file_operations proc_loginuid_operations = {
@@ -1335,8 +1313,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
 			const char __user * buf, size_t count, loff_t *ppos)
 {
 	struct task_struct *task;
-	char buffer[PROC_NUMBUF], *end;
+	char buffer[PROC_NUMBUF];
 	int make_it_fail;
+	int rv;
 
 	if (!capable(CAP_SYS_RESOURCE))
 		return -EPERM;
@@ -1345,9 +1324,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
 		count = sizeof(buffer) - 1;
 	if (copy_from_user(buffer, buf, count))
 		return -EFAULT;
-	make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
-	if (*end)
-		return -EINVAL;
+	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
+	if (rv < 0)
+		return rv;
 	if (make_it_fail < 0 || make_it_fail > 1)
 		return -EINVAL;
 
@@ -1836,8 +1815,6 @@ end_instantiate:
 	return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
 }
 
-#ifdef CONFIG_CHECKPOINT_RESTORE
-
 /*
  * dname_to_vma_addr - maps a dentry name into two unsigned longs
  * which represent vma start and end addresses.
@@ -1864,11 +1841,6 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
 
-	if (!capable(CAP_SYS_ADMIN)) {
-		status = -EPERM;
-		goto out_notask;
-	}
-
 	inode = d_inode(dentry);
 	task = get_proc_task(inode);
 	if (!task)
@@ -1957,6 +1929,29 @@ struct map_files_info {
 	unsigned char	name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
 };
 
+/*
+ * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
+ * symlinks may be used to bypass permissions on ancestor directories in the
+ * path to the file in question.
+ */
+static const char *
+proc_map_files_follow_link(struct dentry *dentry, void **cookie)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return ERR_PTR(-EPERM);
+
+	return proc_pid_follow_link(dentry, NULL);
+}
+
+/*
+ * Identical to proc_pid_link_inode_operations except for follow_link()
+ */
+static const struct inode_operations proc_map_files_link_inode_operations = {
+	.readlink	= proc_pid_readlink,
+	.follow_link	= proc_map_files_follow_link,
+	.setattr	= proc_setattr,
+};
+
 static int
 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
 			   struct task_struct *task, const void *ptr)
@@ -1972,7 +1967,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
 	ei = PROC_I(inode);
 	ei->op.proc_get_link = proc_map_files_get_link;
 
-	inode->i_op = &proc_pid_link_inode_operations;
+	inode->i_op = &proc_map_files_link_inode_operations;
 	inode->i_size = 64;
 	inode->i_mode = S_IFLNK;
 
@@ -1996,10 +1991,6 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
 	int result;
 	struct mm_struct *mm;
 
-	result = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
-		goto out;
-
 	result = -ENOENT;
 	task = get_proc_task(dir);
 	if (!task)
@@ -2053,10 +2044,6 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
 	struct map_files_info *p;
 	int ret;
 
-	ret = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
-		goto out;
-
 	ret = -ENOENT;
 	task = get_proc_task(file_inode(file));
 	if (!task)
@@ -2245,7 +2232,6 @@ static const struct file_operations proc_timers_operations = {
 	.llseek		= seq_lseek,
 	.release	= seq_release_private,
 };
-#endif /* CONFIG_CHECKPOINT_RESTORE */
 
 static int proc_pident_instantiate(struct inode *dir,
 	struct dentry *dentry, struct task_struct *task, const void *ptr)
@@ -2481,32 +2467,20 @@ static ssize_t proc_coredump_filter_write(struct file *file,
 {
 	struct task_struct *task;
 	struct mm_struct *mm;
-	char buffer[PROC_NUMBUF], *end;
 	unsigned int val;
 	int ret;
 	int i;
 	unsigned long mask;
 
-	ret = -EFAULT;
-	memset(buffer, 0, sizeof(buffer));
-	if (count > sizeof(buffer) - 1)
-		count = sizeof(buffer) - 1;
-	if (copy_from_user(buffer, buf, count))
-		goto out_no_task;
-
-	ret = -EINVAL;
-	val = (unsigned int)simple_strtoul(buffer, &end, 0);
-	if (*end == '\n')
-		end++;
-	if (end - buffer == 0)
-		goto out_no_task;
+	ret = kstrtouint_from_user(buf, count, 0, &val);
+	if (ret < 0)
+		return ret;
 
 	ret = -ESRCH;
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		goto out_no_task;
 
-	ret = end - buffer;
 	mm = get_task_mm(task);
 	if (!mm)
 		goto out_no_mm;
@@ -2522,7 +2496,9 @@ static ssize_t proc_coredump_filter_write(struct file *file,
  out_no_mm:
 	put_task_struct(task);
  out_no_task:
-	return ret;
+	if (ret < 0)
+		return ret;
+	return count;
 }
 
 static const struct file_operations proc_coredump_filter_operations = {
@@ -2744,9 +2720,7 @@ static const struct inode_operations proc_task_inode_operations;
 static const struct pid_entry tgid_base_stuff[] = {
 	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
 	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
-#ifdef CONFIG_CHECKPOINT_RESTORE
 	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
-#endif
 	DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
 	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
 #ifdef CONFIG_NET
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index e5dee5c31..ff3ffc76a 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -26,7 +26,7 @@
 
 #include "internal.h"
 
-static DEFINE_SPINLOCK(proc_subdir_lock);
+static DEFINE_RWLOCK(proc_subdir_lock);
 
 static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
 {
@@ -172,9 +172,9 @@ static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
 {
 	int rv;
 
-	spin_lock(&proc_subdir_lock);
+	read_lock(&proc_subdir_lock);
 	rv = __xlate_proc_name(name, ret, residual);
-	spin_unlock(&proc_subdir_lock);
+	read_unlock(&proc_subdir_lock);
 	return rv;
 }
 
@@ -231,11 +231,11 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 {
 	struct inode *inode;
 
-	spin_lock(&proc_subdir_lock);
+	read_lock(&proc_subdir_lock);
 	de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
 	if (de) {
 		pde_get(de);
-		spin_unlock(&proc_subdir_lock);
+		read_unlock(&proc_subdir_lock);
 		inode = proc_get_inode(dir->i_sb, de);
 		if (!inode)
 			return ERR_PTR(-ENOMEM);
@@ -243,7 +243,7 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 		d_add(dentry, inode);
 		return NULL;
 	}
-	spin_unlock(&proc_subdir_lock);
+	read_unlock(&proc_subdir_lock);
 	return ERR_PTR(-ENOENT);
 }
 
@@ -270,12 +270,12 @@ int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
 	if (!dir_emit_dots(file, ctx))
 		return 0;
 
-	spin_lock(&proc_subdir_lock);
+	read_lock(&proc_subdir_lock);
 	de = pde_subdir_first(de);
 	i = ctx->pos - 2;
 	for (;;) {
 		if (!de) {
-			spin_unlock(&proc_subdir_lock);
+			read_unlock(&proc_subdir_lock);
 			return 0;
 		}
 		if (!i)
@@ -287,19 +287,19 @@ int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
 	do {
 		struct proc_dir_entry *next;
 		pde_get(de);
-		spin_unlock(&proc_subdir_lock);
+		read_unlock(&proc_subdir_lock);
 		if (!dir_emit(ctx, de->name, de->namelen,
 			    de->low_ino, de->mode >> 12)) {
 			pde_put(de);
 			return 0;
 		}
-		spin_lock(&proc_subdir_lock);
+		read_lock(&proc_subdir_lock);
 		ctx->pos++;
 		next = pde_subdir_next(de);
 		pde_put(de);
 		de = next;
 	} while (de);
-	spin_unlock(&proc_subdir_lock);
+	read_unlock(&proc_subdir_lock);
 	return 1;
 }
 
@@ -338,16 +338,16 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
 	if (ret)
 		return ret;
 
-	spin_lock(&proc_subdir_lock);
+	write_lock(&proc_subdir_lock);
 	dp->parent = dir;
 	if (pde_subdir_insert(dir, dp) == false) {
 		WARN(1, "proc_dir_entry '%s/%s' already registered\n",
 		     dir->name, dp->name);
-		spin_unlock(&proc_subdir_lock);
+		write_unlock(&proc_subdir_lock);
 		proc_free_inum(dp->low_ino);
 		return -EEXIST;
 	}
-	spin_unlock(&proc_subdir_lock);
+	write_unlock(&proc_subdir_lock);
 
 	return 0;
 }
@@ -549,9 +549,9 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
 	const char *fn = name;
 	unsigned int len;
 
-	spin_lock(&proc_subdir_lock);
+	write_lock(&proc_subdir_lock);
 	if (__xlate_proc_name(name, &parent, &fn) != 0) {
-		spin_unlock(&proc_subdir_lock);
+		write_unlock(&proc_subdir_lock);
 		return;
 	}
 	len = strlen(fn);
@@ -559,7 +559,7 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
 	de = pde_subdir_find(parent, fn, len);
 	if (de)
 		rb_erase(&de->subdir_node, &parent->subdir);
-	spin_unlock(&proc_subdir_lock);
+	write_unlock(&proc_subdir_lock);
 	if (!de) {
 		WARN(1, "name '%s'\n", name);
 		return;
@@ -583,16 +583,16 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
 	const char *fn = name;
 	unsigned int len;
 
-	spin_lock(&proc_subdir_lock);
+	write_lock(&proc_subdir_lock);
 	if (__xlate_proc_name(name, &parent, &fn) != 0) {
-		spin_unlock(&proc_subdir_lock);
+		write_unlock(&proc_subdir_lock);
 		return -ENOENT;
 	}
 	len = strlen(fn);
 
 	root = pde_subdir_find(parent, fn, len);
 	if (!root) {
-		spin_unlock(&proc_subdir_lock);
+		write_unlock(&proc_subdir_lock);
 		return -ENOENT;
 	}
 	rb_erase(&root->subdir_node, &parent->subdir);
@@ -605,7 +605,7 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
 			de = next;
 			continue;
 		}
-		spin_unlock(&proc_subdir_lock);
+		write_unlock(&proc_subdir_lock);
 
 		proc_entry_rundown(de);
 		next = de->parent;
@@ -616,7 +616,7 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
 			break;
 		pde_put(de);
 
-		spin_lock(&proc_subdir_lock);
+		write_lock(&proc_subdir_lock);
 		de = next;
 	}
 	pde_put(root);
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 7eee2d8b9..93484034a 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -9,12 +9,16 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/hugetlb.h>
+#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
 #include <linux/kernel-page-flags.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
 #define KPMSIZE sizeof(u64)
 #define KPMMASK (KPMSIZE - 1)
+#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
 
 /* /proc/kpagecount - an array exposing page counts
  *
@@ -54,6 +58,8 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf,
 		pfn++;
 		out++;
 		count -= KPMSIZE;
+
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -146,6 +152,9 @@ u64 stable_page_flags(struct page *page)
 	if (PageBalloon(page))
 		u |= 1 << KPF_BALLOON;
 
+	if (page_is_idle(page))
+		u |= 1 << KPF_IDLE;
+
 	u |= kpf_copy_bit(k, KPF_LOCKED,	PG_locked);
 
 	u |= kpf_copy_bit(k, KPF_SLAB,		PG_slab);
@@ -212,6 +221,8 @@ static ssize_t kpageflags_read(struct file *file, char __user *buf,
 		pfn++;
 		out++;
 		count -= KPMSIZE;
+
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -225,10 +236,64 @@ static const struct file_operations proc_kpageflags_operations = {
 	.read = kpageflags_read,
 };
 
+#ifdef CONFIG_MEMCG
+static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	u64 __user *out = (u64 __user *)buf;
+	struct page *ppage;
+	unsigned long src = *ppos;
+	unsigned long pfn;
+	ssize_t ret = 0;
+	u64 ino;
+
+	pfn = src / KPMSIZE;
+	count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
+	if (src & KPMMASK || count & KPMMASK)
+		return -EINVAL;
+
+	while (count > 0) {
+		if (pfn_valid(pfn))
+			ppage = pfn_to_page(pfn);
+		else
+			ppage = NULL;
+
+		if (ppage)
+			ino = page_cgroup_ino(ppage);
+		else
+			ino = 0;
+
+		if (put_user(ino, out)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		pfn++;
+		out++;
+		count -= KPMSIZE;
+
+		cond_resched();
+	}
+
+	*ppos += (char __user *)out - buf;
+	if (!ret)
+		ret = (char __user *)out - buf;
+	return ret;
+}
+
+static const struct file_operations proc_kpagecgroup_operations = {
+	.llseek = mem_lseek,
+	.read = kpagecgroup_read,
+};
+#endif /* CONFIG_MEMCG */
+
 static int __init proc_page_init(void)
 {
 	proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
 	proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
+#ifdef CONFIG_MEMCG
+	proc_create("kpagecgroup", S_IRUSR, NULL, &proc_kpagecgroup_operations);
+#endif
 	return 0;
 }
 fs_initcall(proc_page_init);
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 68feb0f70..361ab4ee4 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -134,6 +134,8 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 		}
 
 		sb->s_flags |= MS_ACTIVE;
+		/* User space would break if executables appear on proc */
+		sb->s_iflags |= SB_I_NOEXEC;
 	}
 
 	return dget(sb->s_root);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8940e47e3..5e7e631af 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -13,6 +13,7 @@
 #include <linux/swap.h>
 #include <linux/swapops.h>
 #include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
 
 #include <asm/elf.h>
 #include <asm/uaccess.h>
@@ -449,6 +450,7 @@ struct mem_size_stats {
 	unsigned long anonymous_thp;
 	unsigned long swap;
 	u64 pss;
+	u64 swap_pss;
 };
 
 static void smaps_account(struct mem_size_stats *mss, struct page *page,
@@ -461,7 +463,7 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
 
 	mss->resident += size;
 	/* Accumulate the size in pages that have been accessed. */
-	if (young || PageReferenced(page))
+	if (young || page_is_young(page) || PageReferenced(page))
 		mss->referenced += size;
 	mapcount = page_mapcount(page);
 	if (mapcount >= 2) {
@@ -495,9 +497,20 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 	} else if (is_swap_pte(*pte)) {
 		swp_entry_t swpent = pte_to_swp_entry(*pte);
 
-		if (!non_swap_entry(swpent))
+		if (!non_swap_entry(swpent)) {
+			int mapcount;
+
 			mss->swap += PAGE_SIZE;
-		else if (is_migration_entry(swpent))
+			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_migration_entry(swpent))
 			page = migration_entry_to_page(swpent);
 	}
 
@@ -600,6 +613,8 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 		[ilog2(VM_HUGEPAGE)]	= "hg",
 		[ilog2(VM_NOHUGEPAGE)]	= "nh",
 		[ilog2(VM_MERGEABLE)]	= "mg",
+		[ilog2(VM_UFFD_MISSING)]= "um",
+		[ilog2(VM_UFFD_WP)]	= "uw",
 	};
 	size_t i;
 
@@ -641,6 +656,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 		   "Anonymous:      %8lu kB\n"
 		   "AnonHugePages:  %8lu kB\n"
 		   "Swap:           %8lu kB\n"
+		   "SwapPss:        %8lu kB\n"
 		   "KernelPageSize: %8lu kB\n"
 		   "MMUPageSize:    %8lu kB\n"
 		   "Locked:         %8lu kB\n",
@@ -655,6 +671,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 		   mss.anonymous >> 10,
 		   mss.anonymous_thp >> 10,
 		   mss.swap >> 10,
+		   (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)),
 		   vma_kernel_pagesize(vma) >> 10,
 		   vma_mmu_pagesize(vma) >> 10,
 		   (vma->vm_flags & VM_LOCKED) ?
@@ -713,23 +730,6 @@ const struct file_operations proc_tid_smaps_operations = {
 	.release	= proc_map_release,
 };
 
-/*
- * We do not want to have constant page-shift bits sitting in
- * pagemap entries and are about to reuse them some time soon.
- *
- * Here's the "migration strategy":
- * 1. when the system boots these bits remain what they are,
- *    but a warning about future change is printed in log;
- * 2. once anyone clears soft-dirty bits via clear_refs file,
- *    these flag is set to denote, that user is aware of the
- *    new API and those page-shift bits change their meaning.
- *    The respective warning is printed in dmesg;
- * 3. In a couple of releases we will remove all the mentions
- *    of page-shift in pagemap entries.
- */
-
-static bool soft_dirty_cleared __read_mostly;
-
 enum clear_refs_types {
 	CLEAR_REFS_ALL = 1,
 	CLEAR_REFS_ANON,
@@ -811,6 +811,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 
 		/* Clear accessed and referenced bits. */
 		pmdp_test_and_clear_young(vma, addr, pmd);
+		test_and_clear_page_young(page);
 		ClearPageReferenced(page);
 out:
 		spin_unlock(ptl);
@@ -838,6 +839,7 @@ out:
 
 		/* Clear accessed and referenced bits. */
 		ptep_test_and_clear_young(vma, addr, pte);
+		test_and_clear_page_young(page);
 		ClearPageReferenced(page);
 	}
 	pte_unmap_unlock(pte - 1, ptl);
@@ -890,13 +892,6 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
 		return -EINVAL;
 
-	if (type == CLEAR_REFS_SOFT_DIRTY) {
-		soft_dirty_cleared = true;
-		pr_warn_once("The pagemap bits 55-60 has changed their meaning!"
-			     " See the linux/Documentation/vm/pagemap.txt for "
-			     "details.\n");
-	}
-
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		return -ESRCH;
@@ -964,36 +959,26 @@ typedef struct {
 struct pagemapread {
 	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
 	pagemap_entry_t *buffer;
-	bool v2;
+	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_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)
-/* in "new" pagemap pshift bits are occupied with more status bits */
-#define PM_STATUS2(v2, x)   (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
-
-#define __PM_SOFT_DIRTY      (1LL)
-#define PM_PRESENT          PM_STATUS(4LL)
-#define PM_SWAP             PM_STATUS(2LL)
-#define PM_FILE             PM_STATUS(1LL)
-#define PM_NOT_PRESENT(v2)  PM_STATUS2(v2, 0)
+#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_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 val)
+static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
 {
-	return (pagemap_entry_t) { .pme = val };
+	return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
 }
 
 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
@@ -1014,7 +999,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
 
 	while (addr < end) {
 		struct vm_area_struct *vma = find_vma(walk->mm, addr);
-		pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
+		pagemap_entry_t pme = make_pme(0, 0);
 		/* End of address space hole, which we mark as non-present. */
 		unsigned long hole_end;
 
@@ -1034,7 +1019,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
 
 		/* Addresses in the VMA. */
 		if (vma->vm_flags & VM_SOFTDIRTY)
-			pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY);
+			pme = make_pme(0, PM_SOFT_DIRTY);
 		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
 			err = add_to_pagemap(addr, &pme, pm);
 			if (err)
@@ -1045,67 +1030,42 @@ out:
 	return err;
 }
 
-static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 {
-	u64 frame, flags;
+	u64 frame = 0, flags = 0;
 	struct page *page = NULL;
-	int flags2 = 0;
 
 	if (pte_present(pte)) {
-		frame = pte_pfn(pte);
-		flags = PM_PRESENT;
+		if (pm->show_pfn)
+			frame = pte_pfn(pte);
+		flags |= PM_PRESENT;
 		page = vm_normal_page(vma, addr, pte);
 		if (pte_soft_dirty(pte))
-			flags2 |= __PM_SOFT_DIRTY;
+			flags |= PM_SOFT_DIRTY;
 	} else if (is_swap_pte(pte)) {
 		swp_entry_t entry;
 		if (pte_swp_soft_dirty(pte))
-			flags2 |= __PM_SOFT_DIRTY;
+			flags |= PM_SOFT_DIRTY;
 		entry = pte_to_swp_entry(pte);
 		frame = swp_type(entry) |
 			(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
-		flags = PM_SWAP;
+		flags |= PM_SWAP;
 		if (is_migration_entry(entry))
 			page = migration_entry_to_page(entry);
-	} else {
-		if (vma->vm_flags & VM_SOFTDIRTY)
-			flags2 |= __PM_SOFT_DIRTY;
-		*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, flags2));
-		return;
 	}
 
 	if (page && !PageAnon(page))
 		flags |= PM_FILE;
-	if ((vma->vm_flags & VM_SOFTDIRTY))
-		flags2 |= __PM_SOFT_DIRTY;
-
-	*pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
-}
+	if (page && page_mapcount(page) == 1)
+		flags |= PM_MMAP_EXCLUSIVE;
+	if (vma->vm_flags & VM_SOFTDIRTY)
+		flags |= PM_SOFT_DIRTY;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
-		pmd_t pmd, int offset, int pmd_flags2)
-{
-	/*
-	 * Currently pmd for thp is always present because thp can not be
-	 * swapped-out, migrated, or HWPOISONed (split in such cases instead.)
-	 * This if-check is just to prepare for future implementation.
-	 */
-	if (pmd_present(pmd))
-		*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
-				| PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
-	else
-		*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, pmd_flags2));
+	return make_pme(frame, flags);
 }
-#else
-static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
-		pmd_t pmd, int offset, int pmd_flags2)
-{
-}
-#endif
 
-static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+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;
@@ -1114,41 +1074,58 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	pte_t *pte, *orig_pte;
 	int err = 0;
 
-	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-		int pmd_flags2;
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (pmd_trans_huge_lock(pmdp, vma, &ptl) == 1) {
+		u64 flags = 0, frame = 0;
+		pmd_t pmd = *pmdp;
 
-		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
-			pmd_flags2 = __PM_SOFT_DIRTY;
-		else
-			pmd_flags2 = 0;
+		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))
+			flags |= PM_SOFT_DIRTY;
+
+		/*
+		 * Currently pmd for thp is always present because thp
+		 * can not be swapped-out, migrated, or HWPOISONed
+		 * (split in such cases instead.)
+		 * This if-check is just to prepare for future implementation.
+		 */
+		if (pmd_present(pmd)) {
+			struct page *page = pmd_page(pmd);
+
+			if (page_mapcount(page) == 1)
+				flags |= PM_MMAP_EXCLUSIVE;
+
+			flags |= PM_PRESENT;
+			if (pm->show_pfn)
+				frame = pmd_pfn(pmd) +
+					((addr & ~PMD_MASK) >> PAGE_SHIFT);
+		}
 
 		for (; addr != end; addr += PAGE_SIZE) {
-			unsigned long offset;
-			pagemap_entry_t pme;
+			pagemap_entry_t pme = make_pme(frame, flags);
 
-			offset = (addr & ~PAGEMAP_WALK_MASK) >>
-					PAGE_SHIFT;
-			thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2);
 			err = add_to_pagemap(addr, &pme, pm);
 			if (err)
 				break;
+			if (pm->show_pfn && (flags & PM_PRESENT))
+				frame++;
 		}
 		spin_unlock(ptl);
 		return err;
 	}
 
-	if (pmd_trans_unstable(pmd))
+	if (pmd_trans_unstable(pmdp))
 		return 0;
+#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, pmd, addr, &ptl);
+	orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
 	for (; addr < end; pte++, addr += PAGE_SIZE) {
 		pagemap_entry_t pme;
 
-		pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
+		pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
 		err = add_to_pagemap(addr, &pme, pm);
 		if (err)
 			break;
@@ -1161,40 +1138,44 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
-static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
-					pte_t pte, int offset, int flags2)
-{
-	if (pte_present(pte))
-		*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)	|
-				PM_STATUS2(pm->v2, flags2)		|
-				PM_PRESENT);
-	else
-		*pme = make_pme(PM_NOT_PRESENT(pm->v2)			|
-				PM_STATUS2(pm->v2, flags2));
-}
-
 /* This function walks within one hugetlb entry in the single call */
-static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
+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;
-	int flags2;
-	pagemap_entry_t pme;
+	pte_t pte;
 
 	if (vma->vm_flags & VM_SOFTDIRTY)
-		flags2 = __PM_SOFT_DIRTY;
-	else
-		flags2 = 0;
+		flags |= PM_SOFT_DIRTY;
+
+	pte = huge_ptep_get(ptep);
+	if (pte_present(pte)) {
+		struct page *page = pte_page(pte);
+
+		if (!PageAnon(page))
+			flags |= PM_FILE;
+
+		if (page_mapcount(page) == 1)
+			flags |= PM_MMAP_EXCLUSIVE;
+
+		flags |= PM_PRESENT;
+		if (pm->show_pfn)
+			frame = pte_pfn(pte) +
+				((addr & ~hmask) >> PAGE_SHIFT);
+	}
 
 	for (; addr != end; addr += PAGE_SIZE) {
-		int offset = (addr & ~hmask) >> PAGE_SHIFT;
-		huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2);
+		pagemap_entry_t pme = make_pme(frame, flags);
+
 		err = add_to_pagemap(addr, &pme, pm);
 		if (err)
 			return err;
+		if (pm->show_pfn && (flags & PM_PRESENT))
+			frame++;
 	}
 
 	cond_resched();
@@ -1212,7 +1193,9 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
  * Bits 0-54  page frame number (PFN) if present
  * Bits 0-4   swap type if swapped
  * Bits 5-54  swap offset if swapped
- * Bits 55-60 page shift (page size = 1<<page shift)
+ * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
+ * Bit  56    page exclusively mapped
+ * Bits 57-60 zero
  * Bit  61    page is file-page or shared-anon
  * Bit  62    page swapped
  * Bit  63    page present
@@ -1230,42 +1213,37 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
 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_inode(file));
-	struct mm_struct *mm;
+	struct mm_struct *mm = file->private_data;
 	struct pagemapread pm;
-	int ret = -ESRCH;
 	struct mm_walk pagemap_walk = {};
 	unsigned long src;
 	unsigned long svpfn;
 	unsigned long start_vaddr;
 	unsigned long end_vaddr;
-	int copied = 0;
+	int ret = 0, copied = 0;
 
-	if (!task)
+	if (!mm || !atomic_inc_not_zero(&mm->mm_users))
 		goto out;
 
 	ret = -EINVAL;
 	/* file position must be aligned */
 	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
-		goto out_task;
+		goto out_mm;
 
 	ret = 0;
 	if (!count)
-		goto out_task;
+		goto out_mm;
+
+	/* do not disclose physical addresses: attack vector */
+	pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
 
-	pm.v2 = soft_dirty_cleared;
 	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
 	pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
 	ret = -ENOMEM;
 	if (!pm.buffer)
-		goto out_task;
-
-	mm = mm_access(task, PTRACE_MODE_READ);
-	ret = PTR_ERR(mm);
-	if (!mm || IS_ERR(mm))
-		goto out_free;
+		goto out_mm;
 
-	pagemap_walk.pmd_entry = pagemap_pte_range;
+	pagemap_walk.pmd_entry = pagemap_pmd_range;
 	pagemap_walk.pte_hole = pagemap_pte_hole;
 #ifdef CONFIG_HUGETLB_PAGE
 	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
@@ -1276,10 +1254,10 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 	src = *ppos;
 	svpfn = src / PM_ENTRY_BYTES;
 	start_vaddr = svpfn << PAGE_SHIFT;
-	end_vaddr = TASK_SIZE_OF(task);
+	end_vaddr = mm->task_size;
 
 	/* watch out for wraparound */
-	if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT)
+	if (svpfn > mm->task_size >> PAGE_SHIFT)
 		start_vaddr = end_vaddr;
 
 	/*
@@ -1306,7 +1284,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 		len = min(count, PM_ENTRY_BYTES * pm.pos);
 		if (copy_to_user(buf, pm.buffer, len)) {
 			ret = -EFAULT;
-			goto out_mm;
+			goto out_free;
 		}
 		copied += len;
 		buf += len;
@@ -1316,24 +1294,31 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 	if (!ret || ret == PM_END_OF_BUFFER)
 		ret = copied;
 
-out_mm:
-	mmput(mm);
 out_free:
 	kfree(pm.buffer);
-out_task:
-	put_task_struct(task);
+out_mm:
+	mmput(mm);
 out:
 	return ret;
 }
 
 static int pagemap_open(struct inode *inode, struct file *file)
 {
-	/* do not disclose physical addresses: attack vector */
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-	pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
-			"to stop being page-shift some time soon. See the "
-			"linux/Documentation/vm/pagemap.txt for details.\n");
+	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;
 }
 
@@ -1341,6 +1326,7 @@ const struct file_operations proc_pagemap_operations = {
 	.llseek		= mem_lseek, /* borrow this */
 	.read		= pagemap_read,
 	.open		= pagemap_open,
+	.release	= pagemap_release,
 };
 #endif /* CONFIG_PROC_PAGE_MONITOR */