Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * This contains the io-permission bitmap code - written by obz, with changes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * by Linus. 32/64 bits code unification by Miguel Botón.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <linux/capability.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/syscalls.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/bitmap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/ioport.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <asm/io_bitmap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <asm/desc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <asm/syscalls.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #ifdef CONFIG_X86_IOPL_IOPERM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) static atomic64_t io_bitmap_sequence;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) void io_bitmap_share(struct task_struct *tsk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 	/* Can be NULL when current->thread.iopl_emul == 3 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	if (current->thread.io_bitmap) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 		 * Take a refcount on current's bitmap. It can be used by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 		 * both tasks as long as none of them changes the bitmap.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 		refcount_inc(&current->thread.io_bitmap->refcnt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 		tsk->thread.io_bitmap = current->thread.io_bitmap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	set_tsk_thread_flag(tsk, TIF_IO_BITMAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) static void task_update_io_bitmap(struct task_struct *tsk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	struct thread_struct *t = &tsk->thread;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	if (t->iopl_emul == 3 || t->io_bitmap) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 		/* TSS update is handled on exit to user space */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		set_tsk_thread_flag(tsk, TIF_IO_BITMAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 		clear_tsk_thread_flag(tsk, TIF_IO_BITMAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		/* Invalidate TSS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		preempt_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		tss_update_io_bitmap();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) void io_bitmap_exit(struct task_struct *tsk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	struct io_bitmap *iobm = tsk->thread.io_bitmap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	tsk->thread.io_bitmap = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	task_update_io_bitmap(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	if (iobm && refcount_dec_and_test(&iobm->refcnt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		kfree(iobm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63)  * This changes the io permissions bitmap in the current task.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	struct thread_struct *t = &current->thread;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	unsigned int i, max_long;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	struct io_bitmap *iobm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	if (turn_on && (!capable(CAP_SYS_RAWIO) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 			security_locked_down(LOCKDOWN_IOPORT)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	 * If it's the first ioperm() call in this thread's lifetime, set the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	 * IO bitmap up. ioperm() is much less timing critical than clone(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	 * this is why we delay this operation until now:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	iobm = t->io_bitmap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	if (!iobm) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		/* No point to allocate a bitmap just to clear permissions */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		if (!turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 			return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 		iobm = kmalloc(sizeof(*iobm), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 		if (!iobm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 			return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		memset(iobm->bitmap, 0xff, sizeof(iobm->bitmap));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		refcount_set(&iobm->refcnt, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	 * If the bitmap is not shared, then nothing can take a refcount as
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	 * current can obviously not fork at the same time. If it's shared
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	 * duplicate it and drop the refcount on the original one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	if (refcount_read(&iobm->refcnt) > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		iobm = kmemdup(iobm, sizeof(*iobm), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		if (!iobm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 			return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		refcount_set(&iobm->refcnt, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		io_bitmap_exit(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	 * Store the bitmap pointer (might be the same if the task already
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	 * head one). Must be done here so freeing the bitmap when all
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	 * permissions are dropped has the pointer set up.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	t->io_bitmap = iobm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	/* Mark it active for context switching and exit to user mode */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	set_thread_flag(TIF_IO_BITMAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 * Update the tasks bitmap. The update of the TSS bitmap happens on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	 * exit to user mode. So this needs no protection.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	if (turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		bitmap_clear(iobm->bitmap, from, num);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		bitmap_set(iobm->bitmap, from, num);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	 * Search for a (possibly new) maximum. This is simple and stupid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	 * to keep it obviously correct:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	max_long = UINT_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	for (i = 0; i < IO_BITMAP_LONGS; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		if (iobm->bitmap[i] != ~0UL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 			max_long = i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	/* All permissions dropped? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	if (max_long == UINT_MAX) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		io_bitmap_exit(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	iobm->max = (max_long + 1) * sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	 * Update the sequence number to force a TSS update on return to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	 * user mode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	iobm->sequence = atomic64_add_return(1, &io_bitmap_sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	return ksys_ioperm(from, num, turn_on);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158)  * The sys_iopl functionality depends on the level argument, which if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159)  * granted for the task is used to enable access to all 65536 I/O ports.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161)  * This does not use the IOPL mechanism provided by the CPU as that would
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)  * also allow the user space task to use the CLI/STI instructions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)  * Disabling interrupts in a user space task is dangerous as it might lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)  * up the machine and the semantics vs. syscalls and exceptions is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)  * undefined.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)  * Setting IOPL to level 0-2 is disabling I/O permissions. Level 3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)  * 3 enables them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171)  * IOPL is strictly per thread and inherited on fork.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) SYSCALL_DEFINE1(iopl, unsigned int, level)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	struct thread_struct *t = &current->thread;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	unsigned int old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	if (level > 3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	old = t->iopl_emul;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	/* No point in going further if nothing changes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	if (level == old)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	/* Trying to gain more privileges? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if (level > old) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		if (!capable(CAP_SYS_RAWIO) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		    security_locked_down(LOCKDOWN_IOPORT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	t->iopl_emul = level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	task_update_io_bitmap(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) #else /* CONFIG_X86_IOPL_IOPERM */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	return -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	return -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) SYSCALL_DEFINE1(iopl, unsigned int, level)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	return -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) #endif