cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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octeon-crypto.c (1990B)

      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 */
     27unsigned 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}
     46EXPORT_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 */
     56void 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}
     69EXPORT_SYMBOL_GPL(octeon_crypto_disable);