1 files changed, 477 insertions, 0 deletions
diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
new file mode 100644
index 0000000000..ada8314993
--- /dev/null
+++ b/arch/s390/hypfs/inode.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-1.0+
+/*
+ *    Hypervisor filesystem for Linux on s390.
+ *
+ *    Copyright IBM Corp. 2006, 2008
+ *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "hypfs"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/namei.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/time.h>
+#include <linux/sysfs.h>
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/seq_file.h>
+#include <linux/uio.h>
+#include <asm/ebcdic.h>
+#include "hypfs.h"
+
+#define HYPFS_MAGIC 0x687970	/* ASCII 'hyp' */
+#define TMP_SIZE 64		/* size of temporary buffers */
+
+static struct dentry *hypfs_create_update_file(struct dentry *dir);
+
+struct hypfs_sb_info {
+	kuid_t uid;			/* uid used for files and dirs */
+	kgid_t gid;			/* gid used for files and dirs */
+	struct dentry *update_file;	/* file to trigger update */
+	time64_t last_update;		/* last update, CLOCK_MONOTONIC time */
+	struct mutex lock;		/* lock to protect update process */
+};
+
+static const struct file_operations hypfs_file_ops;
+static struct file_system_type hypfs_type;
+static const struct super_operations hypfs_s_ops;
+
+/* start of list of all dentries, which have to be deleted on update */
+static struct dentry *hypfs_last_dentry;
+
+static void hypfs_update_update(struct super_block *sb)
+{
+	struct hypfs_sb_info *sb_info = sb->s_fs_info;
+	struct inode *inode = d_inode(sb_info->update_file);
+
+	sb_info->last_update = ktime_get_seconds();
+	inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
+}
+
+/* directory tree removal functions */
+
+static void hypfs_add_dentry(struct dentry *dentry)
+{
+	dentry->d_fsdata = hypfs_last_dentry;
+	hypfs_last_dentry = dentry;
+}
+
+static void hypfs_remove(struct dentry *dentry)
+{
+	struct dentry *parent;
+
+	parent = dentry->d_parent;
+	inode_lock(d_inode(parent));
+	if (simple_positive(dentry)) {
+		if (d_is_dir(dentry))
+			simple_rmdir(d_inode(parent), dentry);
+		else
+			simple_unlink(d_inode(parent), dentry);
+	}
+	d_drop(dentry);
+	dput(dentry);
+	inode_unlock(d_inode(parent));
+}
+
+static void hypfs_delete_tree(struct dentry *root)
+{
+	while (hypfs_last_dentry) {
+		struct dentry *next_dentry;
+		next_dentry = hypfs_last_dentry->d_fsdata;
+		hypfs_remove(hypfs_last_dentry);
+		hypfs_last_dentry = next_dentry;
+	}
+}
+
+static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
+{
+	struct inode *ret = new_inode(sb);
+
+	if (ret) {
+		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
+		ret->i_ino = get_next_ino();
+		ret->i_mode = mode;
+		ret->i_uid = hypfs_info->uid;
+		ret->i_gid = hypfs_info->gid;
+		ret->i_atime = ret->i_mtime = inode_set_ctime_current(ret);
+		if (S_ISDIR(mode))
+			set_nlink(ret, 2);
+	}
+	return ret;
+}
+
+static void hypfs_evict_inode(struct inode *inode)
+{
+	clear_inode(inode);
+	kfree(inode->i_private);
+}
+
+static int hypfs_open(struct inode *inode, struct file *filp)
+{
+	char *data = file_inode(filp)->i_private;
+	struct hypfs_sb_info *fs_info;
+
+	if (filp->f_mode & FMODE_WRITE) {
+		if (!(inode->i_mode & S_IWUGO))
+			return -EACCES;
+	}
+	if (filp->f_mode & FMODE_READ) {
+		if (!(inode->i_mode & S_IRUGO))
+			return -EACCES;
+	}
+
+	fs_info = inode->i_sb->s_fs_info;
+	if(data) {
+		mutex_lock(&fs_info->lock);
+		filp->private_data = kstrdup(data, GFP_KERNEL);
+		if (!filp->private_data) {
+			mutex_unlock(&fs_info->lock);
+			return -ENOMEM;
+		}
+		mutex_unlock(&fs_info->lock);
+	}
+	return nonseekable_open(inode, filp);
+}
+
+static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	char *data = file->private_data;
+	size_t available = strlen(data);
+	loff_t pos = iocb->ki_pos;
+	size_t count;
+
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= available || !iov_iter_count(to))
+		return 0;
+	count = copy_to_iter(data + pos, available - pos, to);
+	if (!count)
+		return -EFAULT;
+	iocb->ki_pos = pos + count;
+	file_accessed(file);
+	return count;
+}
+
+static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	int rc;
+	struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
+	struct hypfs_sb_info *fs_info = sb->s_fs_info;
+	size_t count = iov_iter_count(from);
+
+	/*
+	 * Currently we only allow one update per second for two reasons:
+	 * 1. diag 204 is VERY expensive
+	 * 2. If several processes do updates in parallel and then read the
+	 *    hypfs data, the likelihood of collisions is reduced, if we restrict
+	 *    the minimum update interval. A collision occurs, if during the
+	 *    data gathering of one process another process triggers an update
+	 *    If the first process wants to ensure consistent data, it has
+	 *    to restart data collection in this case.
+	 */
+	mutex_lock(&fs_info->lock);
+	if (fs_info->last_update == ktime_get_seconds()) {
+		rc = -EBUSY;
+		goto out;
+	}
+	hypfs_delete_tree(sb->s_root);
+	if (MACHINE_IS_VM)
+		rc = hypfs_vm_create_files(sb->s_root);
+	else
+		rc = hypfs_diag_create_files(sb->s_root);
+	if (rc) {
+		pr_err("Updating the hypfs tree failed\n");
+		hypfs_delete_tree(sb->s_root);
+		goto out;
+	}
+	hypfs_update_update(sb);
+	rc = count;
+	iov_iter_advance(from, count);
+out:
+	mutex_unlock(&fs_info->lock);
+	return rc;
+}
+
+static int hypfs_release(struct inode *inode, struct file *filp)
+{
+	kfree(filp->private_data);
+	return 0;
+}
+
+enum { Opt_uid, Opt_gid, };
+
+static const struct fs_parameter_spec hypfs_fs_parameters[] = {
+	fsparam_u32("gid", Opt_gid),
+	fsparam_u32("uid", Opt_uid),
+	{}
+};
+
+static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct hypfs_sb_info *hypfs_info = fc->s_fs_info;
+	struct fs_parse_result result;
+	kuid_t uid;
+	kgid_t gid;
+	int opt;
+
+	opt = fs_parse(fc, hypfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		uid = make_kuid(current_user_ns(), result.uint_32);
+		if (!uid_valid(uid))
+			return invalf(fc, "Unknown uid");
+		hypfs_info->uid = uid;
+		break;
+	case Opt_gid:
+		gid = make_kgid(current_user_ns(), result.uint_32);
+		if (!gid_valid(gid))
+			return invalf(fc, "Unknown gid");
+		hypfs_info->gid = gid;
+		break;
+	}
+	return 0;
+}
+
+static int hypfs_show_options(struct seq_file *s, struct dentry *root)
+{
+	struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
+
+	seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
+	seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
+	return 0;
+}
+
+static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct hypfs_sb_info *sbi = sb->s_fs_info;
+	struct inode *root_inode;
+	struct dentry *root_dentry, *update_file;
+	int rc;
+
+	sb->s_blocksize = PAGE_SIZE;
+	sb->s_blocksize_bits = PAGE_SHIFT;
+	sb->s_magic = HYPFS_MAGIC;
+	sb->s_op = &hypfs_s_ops;
+
+	root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
+	if (!root_inode)
+		return -ENOMEM;
+	root_inode->i_op = &simple_dir_inode_operations;
+	root_inode->i_fop = &simple_dir_operations;
+	sb->s_root = root_dentry = d_make_root(root_inode);
+	if (!root_dentry)
+		return -ENOMEM;
+	if (MACHINE_IS_VM)
+		rc = hypfs_vm_create_files(root_dentry);
+	else
+		rc = hypfs_diag_create_files(root_dentry);
+	if (rc)
+		return rc;
+	update_file = hypfs_create_update_file(root_dentry);
+	if (IS_ERR(update_file))
+		return PTR_ERR(update_file);
+	sbi->update_file = update_file;
+	hypfs_update_update(sb);
+	pr_info("Hypervisor filesystem mounted\n");
+	return 0;
+}
+
+static int hypfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_single(fc, hypfs_fill_super);
+}
+
+static void hypfs_free_fc(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations hypfs_context_ops = {
+	.free		= hypfs_free_fc,
+	.parse_param	= hypfs_parse_param,
+	.get_tree	= hypfs_get_tree,
+};
+
+static int hypfs_init_fs_context(struct fs_context *fc)
+{
+	struct hypfs_sb_info *sbi;
+
+	sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	mutex_init(&sbi->lock);
+	sbi->uid = current_uid();
+	sbi->gid = current_gid();
+
+	fc->s_fs_info = sbi;
+	fc->ops = &hypfs_context_ops;
+	return 0;
+}
+
+static void hypfs_kill_super(struct super_block *sb)
+{
+	struct hypfs_sb_info *sb_info = sb->s_fs_info;
+
+	if (sb->s_root)
+		hypfs_delete_tree(sb->s_root);
+	if (sb_info && sb_info->update_file)
+		hypfs_remove(sb_info->update_file);
+	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
+	kill_litter_super(sb);
+}
+
+static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
+					char *data, umode_t mode)
+{
+	struct dentry *dentry;
+	struct inode *inode;
+
+	inode_lock(d_inode(parent));
+	dentry = lookup_one_len(name, parent, strlen(name));
+	if (IS_ERR(dentry)) {
+		dentry = ERR_PTR(-ENOMEM);
+		goto fail;
+	}
+	inode = hypfs_make_inode(parent->d_sb, mode);
+	if (!inode) {
+		dput(dentry);
+		dentry = ERR_PTR(-ENOMEM);
+		goto fail;
+	}
+	if (S_ISREG(mode)) {
+		inode->i_fop = &hypfs_file_ops;
+		if (data)
+			inode->i_size = strlen(data);
+		else
+			inode->i_size = 0;
+	} else if (S_ISDIR(mode)) {
+		inode->i_op = &simple_dir_inode_operations;
+		inode->i_fop = &simple_dir_operations;
+		inc_nlink(d_inode(parent));
+	} else
+		BUG();
+	inode->i_private = data;
+	d_instantiate(dentry, inode);
+	dget(dentry);
+fail:
+	inode_unlock(d_inode(parent));
+	return dentry;
+}
+
+struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
+{
+	struct dentry *dentry;
+
+	dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
+	if (IS_ERR(dentry))
+		return dentry;
+	hypfs_add_dentry(dentry);
+	return dentry;
+}
+
+static struct dentry *hypfs_create_update_file(struct dentry *dir)
+{
+	struct dentry *dentry;
+
+	dentry = hypfs_create_file(dir, "update", NULL,
+				   S_IFREG | UPDATE_FILE_MODE);
+	/*
+	 * We do not put the update file on the 'delete' list with
+	 * hypfs_add_dentry(), since it should not be removed when the tree
+	 * is updated.
+	 */
+	return dentry;
+}
+
+struct dentry *hypfs_create_u64(struct dentry *dir,
+				const char *name, __u64 value)
+{
+	char *buffer;
+	char tmp[TMP_SIZE];
+	struct dentry *dentry;
+
+	snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
+	buffer = kstrdup(tmp, GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+	dentry =
+	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
+	if (IS_ERR(dentry)) {
+		kfree(buffer);
+		return ERR_PTR(-ENOMEM);
+	}
+	hypfs_add_dentry(dentry);
+	return dentry;
+}
+
+struct dentry *hypfs_create_str(struct dentry *dir,
+				const char *name, char *string)
+{
+	char *buffer;
+	struct dentry *dentry;
+
+	buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+	sprintf(buffer, "%s\n", string);
+	dentry =
+	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
+	if (IS_ERR(dentry)) {
+		kfree(buffer);
+		return ERR_PTR(-ENOMEM);
+	}
+	hypfs_add_dentry(dentry);
+	return dentry;
+}
+
+static const struct file_operations hypfs_file_ops = {
+	.open		= hypfs_open,
+	.release	= hypfs_release,
+	.read_iter	= hypfs_read_iter,
+	.write_iter	= hypfs_write_iter,
+	.llseek		= no_llseek,
+};
+
+static struct file_system_type hypfs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "s390_hypfs",
+	.init_fs_context = hypfs_init_fs_context,
+	.parameters	= hypfs_fs_parameters,
+	.kill_sb	= hypfs_kill_super
+};
+
+static const struct super_operations hypfs_s_ops = {
+	.statfs		= simple_statfs,
+	.evict_inode	= hypfs_evict_inode,
+	.show_options	= hypfs_show_options,
+};
+
+int __init __hypfs_fs_init(void)
+{
+	int rc;
+
+	rc = sysfs_create_mount_point(hypervisor_kobj, "s390");
+	if (rc)
+		return rc;
+	rc = register_filesystem(&hypfs_type);
+	if (rc)
+		goto fail;
+	return 0;
+fail:
+	sysfs_remove_mount_point(hypervisor_kobj, "s390");
+	return rc;
+}