1 // SPDX-License-Identifier: GPL-2.0
3  * This contains the io-permission bitmap code - written by obz, with changes
24 	/* Can be NULL when current->thread.iopl_emul == 3 */  in io_bitmap_share()
25 	if (current->thread.io_bitmap) {  in io_bitmap_share()
30 		refcount_inc(&current->thread.io_bitmap->refcnt);  in io_bitmap_share()
31 		tsk->thread.io_bitmap = current->thread.io_bitmap;  in io_bitmap_share()
38 	struct thread_struct *t = &tsk->thread;  in task_update_io_bitmap()
40 	if (t->iopl_emul == 3 || t->io_bitmap) {  in task_update_io_bitmap()
41 		/* TSS update is handled on exit to user space */  in task_update_io_bitmap()
54 	struct io_bitmap *iobm = tsk->thread.io_bitmap;  in io_bitmap_exit()
56 	tsk->thread.io_bitmap = NULL;  in io_bitmap_exit()
58 	if (iobm && refcount_dec_and_test(&iobm->refcnt))  in io_bitmap_exit()
67 	struct thread_struct *t = &current->thread;  in ksys_ioperm()
72 		return -EINVAL;  in ksys_ioperm()
75 		return -EPERM;  in ksys_ioperm()
82 	iobm = t->io_bitmap;  in ksys_ioperm()
89 			return -ENOMEM;  in ksys_ioperm()
91 		memset(iobm->bitmap, 0xff, sizeof(iobm->bitmap));  in ksys_ioperm()
92 		refcount_set(&iobm->refcnt, 1);  in ksys_ioperm()
100 	if (refcount_read(&iobm->refcnt) > 1) {  in ksys_ioperm()
103 			return -ENOMEM;  in ksys_ioperm()
104 		refcount_set(&iobm->refcnt, 1);  in ksys_ioperm()
113 	t->io_bitmap = iobm;  in ksys_ioperm()
114 	/* Mark it active for context switching and exit to user mode */  in ksys_ioperm()
119 	 * exit to user mode. So this needs no protection.  in ksys_ioperm()
122 		bitmap_clear(iobm->bitmap, from, num);  in ksys_ioperm()
124 		bitmap_set(iobm->bitmap, from, num);  in ksys_ioperm()
132 		if (iobm->bitmap[i] != ~0UL)  in ksys_ioperm()
141 	iobm->max = (max_long + 1) * sizeof(unsigned long);  in ksys_ioperm()
145 	 * user mode.  in ksys_ioperm()
147 	iobm->sequence = atomic64_add_return(1, &io_bitmap_sequence);  in ksys_ioperm()
158  * The sys_iopl functionality depends on the level argument, which if
162  * also allow the user space task to use the CLI/STI instructions.
164  * Disabling interrupts in a user space task is dangerous as it might lock
168  * Setting IOPL to level 0-2 is disabling I/O permissions. Level 3
173 SYSCALL_DEFINE1(iopl, unsigned int, level)  in SYSCALL_DEFINE1()  argument
175 	struct thread_struct *t = &current->thread;  in SYSCALL_DEFINE1()
178 	if (level > 3)  in SYSCALL_DEFINE1()
179 		return -EINVAL;  in SYSCALL_DEFINE1()
181 	old = t->iopl_emul;  in SYSCALL_DEFINE1()
184 	if (level == old)  in SYSCALL_DEFINE1()
188 	if (level > old) {  in SYSCALL_DEFINE1()
191 			return -EPERM;  in SYSCALL_DEFINE1()
194 	t->iopl_emul = level;  in SYSCALL_DEFINE1()
204 	return -ENOSYS;  in ksys_ioperm()
208 	return -ENOSYS;  in SYSCALL_DEFINE3()
211 SYSCALL_DEFINE1(iopl, unsigned int, level)  in SYSCALL_DEFINE1()  argument
213 	return -ENOSYS;  in SYSCALL_DEFINE1()