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 */
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 */
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);