1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License. See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 2004-2012 Cavium Networks
7  */
8 
9 #include <asm/cop2.h>
10 #include <linux/export.h>
11 #include <linux/interrupt.h>
12 #include <linux/sched/task_stack.h>
13 
14 #include "octeon-crypto.h"
15 
16 /**
17  * Enable access to Octeon's COP2 crypto hardware for kernel use. Wrap any
18  * crypto operations in calls to octeon_crypto_enable/disable in order to make
19  * sure the state of COP2 isn't corrupted if userspace is also performing
20  * hardware crypto operations. Allocate the state parameter on the stack.
21  * Returns with preemption disabled.
22  *
23  * @state: Pointer to state structure to store current COP2 state in.
24  *
25  * Returns: Flags to be passed to octeon_crypto_disable()
26  */
octeon_crypto_enable(struct octeon_cop2_state * state)27 unsigned long octeon_crypto_enable(struct octeon_cop2_state *state)
28 {
29 	int status;
30 	unsigned long flags;
31 
32 	preempt_disable();
33 	local_irq_save(flags);
34 	status = read_c0_status();
35 	write_c0_status(status | ST0_CU2);
36 	if (KSTK_STATUS(current) & ST0_CU2) {
37 		octeon_cop2_save(&(current->thread.cp2));
38 		KSTK_STATUS(current) &= ~ST0_CU2;
39 		status &= ~ST0_CU2;
40 	} else if (status & ST0_CU2) {
41 		octeon_cop2_save(state);
42 	}
43 	local_irq_restore(flags);
44 	return status & ST0_CU2;
45 }
46 EXPORT_SYMBOL_GPL(octeon_crypto_enable);
47 
48 /**
49  * Disable access to Octeon's COP2 crypto hardware in the kernel. This must be
50  * called after an octeon_crypto_enable() before any context switch or return to
51  * userspace.
52  *
53  * @state:	Pointer to COP2 state to restore
54  * @flags:	Return value from octeon_crypto_enable()
55  */
octeon_crypto_disable(struct octeon_cop2_state * state,unsigned long crypto_flags)56 void octeon_crypto_disable(struct octeon_cop2_state *state,
57 			   unsigned long crypto_flags)
58 {
59 	unsigned long flags;
60 
61 	local_irq_save(flags);
62 	if (crypto_flags & ST0_CU2)
63 		octeon_cop2_restore(state);
64 	else
65 		write_c0_status(read_c0_status() & ~ST0_CU2);
66 	local_irq_restore(flags);
67 	preempt_enable();
68 }
69 EXPORT_SYMBOL_GPL(octeon_crypto_disable);
70