cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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thread_self.c (1899B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/cache.h>
      3#include <linux/sched.h>
      4#include <linux/slab.h>
      5#include <linux/pid_namespace.h>
      6#include "internal.h"
      7
      8/*
      9 * /proc/thread_self:
     10 */
     11static const char *proc_thread_self_get_link(struct dentry *dentry,
     12					     struct inode *inode,
     13					     struct delayed_call *done)
     14{
     15	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
     16	pid_t tgid = task_tgid_nr_ns(current, ns);
     17	pid_t pid = task_pid_nr_ns(current, ns);
     18	char *name;
     19
     20	if (!pid)
     21		return ERR_PTR(-ENOENT);
     22	name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
     23	if (unlikely(!name))
     24		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
     25	sprintf(name, "%u/task/%u", tgid, pid);
     26	set_delayed_call(done, kfree_link, name);
     27	return name;
     28}
     29
     30static const struct inode_operations proc_thread_self_inode_operations = {
     31	.get_link	= proc_thread_self_get_link,
     32};
     33
     34static unsigned thread_self_inum __ro_after_init;
     35
     36int proc_setup_thread_self(struct super_block *s)
     37{
     38	struct inode *root_inode = d_inode(s->s_root);
     39	struct proc_fs_info *fs_info = proc_sb_info(s);
     40	struct dentry *thread_self;
     41	int ret = -ENOMEM;
     42
     43	inode_lock(root_inode);
     44	thread_self = d_alloc_name(s->s_root, "thread-self");
     45	if (thread_self) {
     46		struct inode *inode = new_inode(s);
     47		if (inode) {
     48			inode->i_ino = thread_self_inum;
     49			inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
     50			inode->i_mode = S_IFLNK | S_IRWXUGO;
     51			inode->i_uid = GLOBAL_ROOT_UID;
     52			inode->i_gid = GLOBAL_ROOT_GID;
     53			inode->i_op = &proc_thread_self_inode_operations;
     54			d_add(thread_self, inode);
     55			ret = 0;
     56		} else {
     57			dput(thread_self);
     58		}
     59	}
     60	inode_unlock(root_inode);
     61
     62	if (ret)
     63		pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
     64	else
     65		fs_info->proc_thread_self = thread_self;
     66
     67	return ret;
     68}
     69
     70void __init proc_thread_self_init(void)
     71{
     72	proc_alloc_inum(&thread_self_inum);
     73}