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/*
* xen/arch/arm/io.c
*
* ARM I/O handlers
*
* Copyright (c) 2011 Citrix Systems.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <xen/ioreq.h>
#include <xen/lib.h>
#include <xen/spinlock.h>
#include <xen/sched.h>
#include <xen/sort.h>
#include <asm/cpuerrata.h>
#include <asm/current.h>
#include <asm/ioreq.h>
#include <asm/mmio.h>
#include <asm/traps.h>
#include "decode.h"
static enum io_state handle_read(const struct mmio_handler *handler,
struct vcpu *v,
mmio_info_t *info)
{
const struct hsr_dabt dabt = info->dabt;
struct cpu_user_regs *regs = guest_cpu_user_regs();
/*
* Initialize to zero to avoid leaking data if there is an
* implementation error in the emulation (such as not correctly
* setting r).
*/
register_t r = 0;
if ( !handler->ops->read(v, info, &r, handler->priv) )
return IO_ABORT;
r = sign_extend(dabt, r);
set_user_reg(regs, dabt.reg, r);
return IO_HANDLED;
}
static enum io_state handle_write(const struct mmio_handler *handler,
struct vcpu *v,
mmio_info_t *info)
{
const struct hsr_dabt dabt = info->dabt;
struct cpu_user_regs *regs = guest_cpu_user_regs();
int ret;
ret = handler->ops->write(v, info, get_user_reg(regs, dabt.reg),
handler->priv);
return ret ? IO_HANDLED : IO_ABORT;
}
/* This function assumes that mmio regions are not overlapped */
static int cmp_mmio_handler(const void *key, const void *elem)
{
const struct mmio_handler *handler0 = key;
const struct mmio_handler *handler1 = elem;
if ( handler0->addr < handler1->addr )
return -1;
if ( handler0->addr >= (handler1->addr + handler1->size) )
return 1;
return 0;
}
static const struct mmio_handler *find_mmio_handler(struct domain *d,
paddr_t gpa)
{
struct vmmio *vmmio = &d->arch.vmmio;
struct mmio_handler key = {.addr = gpa};
const struct mmio_handler *handler;
read_lock(&vmmio->lock);
handler = bsearch(&key, vmmio->handlers, vmmio->num_entries,
sizeof(*handler), cmp_mmio_handler);
read_unlock(&vmmio->lock);
return handler;
}
enum io_state try_handle_mmio(struct cpu_user_regs *regs,
const union hsr hsr,
paddr_t gpa)
{
struct vcpu *v = current;
const struct mmio_handler *handler = NULL;
const struct hsr_dabt dabt = hsr.dabt;
mmio_info_t info = {
.gpa = gpa,
.dabt = dabt
};
ASSERT(hsr.ec == HSR_EC_DATA_ABORT_LOWER_EL);
handler = find_mmio_handler(v->domain, info.gpa);
if ( !handler )
{
int rc;
rc = try_fwd_ioserv(regs, v, &info);
if ( rc == IO_HANDLED )
return handle_ioserv(regs, v);
return rc;
}
/* All the instructions used on emulated MMIO region should be valid */
if ( !dabt.valid )
return IO_ABORT;
/*
* Erratum 766422: Thumb store translation fault to Hypervisor may
* not have correct HSR Rt value.
*/
if ( check_workaround_766422() && (regs->cpsr & PSR_THUMB) &&
dabt.write )
{
int rc;
rc = decode_instruction(regs, &info.dabt);
if ( rc )
{
gprintk(XENLOG_DEBUG, "Unable to decode instruction\n");
return IO_ABORT;
}
}
if ( info.dabt.write )
return handle_write(handler, v, &info);
else
return handle_read(handler, v, &info);
}
void register_mmio_handler(struct domain *d,
const struct mmio_handler_ops *ops,
paddr_t addr, paddr_t size, void *priv)
{
struct vmmio *vmmio = &d->arch.vmmio;
struct mmio_handler *handler;
BUG_ON(vmmio->num_entries >= vmmio->max_num_entries);
write_lock(&vmmio->lock);
handler = &vmmio->handlers[vmmio->num_entries];
handler->ops = ops;
handler->addr = addr;
handler->size = size;
handler->priv = priv;
vmmio->num_entries++;
/* Sort mmio handlers in ascending order based on base address */
sort(vmmio->handlers, vmmio->num_entries, sizeof(struct mmio_handler),
cmp_mmio_handler, NULL);
write_unlock(&vmmio->lock);
}
int domain_io_init(struct domain *d, int max_count)
{
rwlock_init(&d->arch.vmmio.lock);
d->arch.vmmio.num_entries = 0;
d->arch.vmmio.max_num_entries = max_count;
d->arch.vmmio.handlers = xzalloc_array(struct mmio_handler, max_count);
if ( !d->arch.vmmio.handlers )
return -ENOMEM;
return 0;
}
void domain_io_free(struct domain *d)
{
xfree(d->arch.vmmio.handlers);
}
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* indent-tabs-mode: nil
* End:
*/
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