nuttx/sched/irq/irq_dispatch.c
Jussi Kivilinna dffb8a67e3 Add entropy pool and strong random number generator
Entropy pool gathers environmental noise from device drivers, user-space, etc., and returns good random numbers, suitable for cryptographic use. Based on entropy pool design from *BSDs and uses BLAKE2Xs algorithm for CSPRNG output.

Patch also adds /dev/urandom support for using entropy pool RNG and new 'getrandom' system call for getting randomness without file-descriptor usage (thus avoiding file-descriptor exhaustion attacks). The 'getrandom' interface is similar as 'getentropy' and 'getrandom' available on OpenBSD and Linux respectively.
2017-03-30 07:38:37 -06:00

111 lines
3.5 KiB
C

/****************************************************************************
* sched/irq/irq_dispatch.c
*
* Copyright (C) 2007, 2008, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/random.h>
#include "irq/irq.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: irq_dispatch
*
* Description:
* This function must be called from the architecture-specific logic in
* order to dispatch an interrupt to the appropriate, registered handling
* logic.
*
****************************************************************************/
void irq_dispatch(int irq, FAR void *context)
{
xcpt_t vector;
FAR void *arg;
/* Perform some sanity checks */
#if NR_IRQS > 0
if ((unsigned)irq >= NR_IRQS)
{
vector = irq_unexpected_isr;
arg = NULL;
}
else
{
#ifdef CONFIG_ARCH_MINIMAL_VECTORTABLE
irq_mapped_t ndx = g_irqmap[irq];
if (ndx >= CONFIG_ARCH_NUSER_INTERRUPTS)
{
vector = irq_unexpected_isr;
arg = NULL;
}
else
{
vector = g_irqvector[ndx].handler;
arg = g_irqvector[ndx].arg;
}
#else
vector = g_irqvector[irq].handler;
arg = g_irqvector[irq].arg;
#endif
}
#else
vector = irq_unexpected_isr;
arg = NULL;
#endif
#ifdef CONFIG_CRYPTO_RANDOM_POOL_COLLECT_IRQ_RANDOMNESS
/* Add interrupt timing randomness to entropy pool */
add_irq_randomness(irq);
#endif
/* Then dispatch to the interrupt handler */
vector(irq, context, arg);
}