cavium-octeon/crypto/octeon-crypto.c

0001 /*
0002  * This file is subject to the terms and conditions of the GNU General Public
0003  * License. See the file "COPYING" in the main directory of this archive
0004  * for more details.
0005  *
0006  * Copyright (C) 2004-2012 Cavium Networks
0007  */
0008
0009 #include <asm/cop2.h>
0010 #include <linux/export.h>
0011 #include <linux/interrupt.h>
0012 #include <linux/sched/task_stack.h>
0013
0014 #include "octeon-crypto.h"
0015
0016 /**
0017  * Enable access to Octeon's COP2 crypto hardware for kernel use. Wrap any
0018  * crypto operations in calls to octeon_crypto_enable/disable in order to make
0019  * sure the state of COP2 isn't corrupted if userspace is also performing
0020  * hardware crypto operations. Allocate the state parameter on the stack.
0021  * Returns with preemption disabled.
0022  *
0023  * @state: Pointer to state structure to store current COP2 state in.
0024  *
0025  * Returns: Flags to be passed to octeon_crypto_disable()
0026  */
0027 unsigned long octeon_crypto_enable(struct octeon_cop2_state *state)
0028 {
0029     int status;
0030     unsigned long flags;
0031
0032     preempt_disable();
0033     local_irq_save(flags);
0034     status = read_c0_status();
0035     write_c0_status(status | ST0_CU2);
0036     if (KSTK_STATUS(current) & ST0_CU2) {
0037         octeon_cop2_save(&(current->thread.cp2));
0038         KSTK_STATUS(current) &= ~ST0_CU2;
0039         status &= ~ST0_CU2;
0040     } else if (status & ST0_CU2) {
0041         octeon_cop2_save(state);
0042     }
0043     local_irq_restore(flags);
0044     return status & ST0_CU2;
0045 }
0046 EXPORT_SYMBOL_GPL(octeon_crypto_enable);
0047
0048 /**
0049  * Disable access to Octeon's COP2 crypto hardware in the kernel. This must be
0050  * called after an octeon_crypto_enable() before any context switch or return to
0051  * userspace.
0052  *
0053  * @state:  Pointer to COP2 state to restore
0054  * @flags:  Return value from octeon_crypto_enable()
0055  */
0056 void octeon_crypto_disable(struct octeon_cop2_state *state,
0057                unsigned long crypto_flags)
0058 {
0059     unsigned long flags;
0060
0061     local_irq_save(flags);
0062     if (crypto_flags & ST0_CU2)
0063         octeon_cop2_restore(state);
0064     else
0065         write_c0_status(read_c0_status() & ~ST0_CU2);
0066     local_irq_restore(flags);
0067     preempt_enable();
0068 }
0069 EXPORT_SYMBOL_GPL(octeon_crypto_disable);