/*
* Copyright (C) 2006 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/**
* @file ddi.c
* @brief Device Driver Interface functions.
*
* This file contains functions that comprise the Device Driver Interface.
* These are the functions for mapping physical memory and enabling I/O
* space to tasks.
*/
#include <ddi/ddi.h>
#include <ddi/ddi_arg.h>
#include <proc/task.h>
#include <security/cap.h>
#include <mm/frame.h>
#include <mm/as.h>
#include <synch/spinlock.h>
#include <syscall/copy.h>
#include <arch.h>
#include <align.h>
#include <errno.h>
/** Map piece of physical memory into virtual address space of specified task.
*
* @param id Task ID of the destination task.
* @param pf Physical frame address of the starting frame.
* @param vp Virtual page address of the starting page.
* @param pages Number of pages to map.
* @param writable If true, the mapping will be created writable.
*
* @return 0 on success, EPERM if the caller lacks capabilities to use this syscall,
* ENOENT if there is no task matching the specified ID and ENOMEM if
* there was a problem in creating address space area.
*/
static int ddi_physmem_map(task_id_t id, __address pf, __address vp, count_t pages, bool writable)
{
ipl_t ipl;
cap_t caps;
task_t *t;
int flags;
mem_backend_data_t backend_data = { .d1 = (__native) pf, .d2 = (__native) pages };
/*
* Make sure the caller is authorised to make this syscall.
*/
caps = cap_get(TASK);
if (!(caps & CAP_MEM_MANAGER))
return EPERM;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
t = task_find_by_id(id);
if (!t) {
/*
* There is no task with the specified ID.
*/
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ENOENT;
}
/*
* TODO: We are currently lacking support for task destroying.
* Once it is added to the kernel, we must take care to
* synchronize in a way that prevents race conditions here.
*/
/* Lock the task and release the lock protecting tasks_btree. */
spinlock_lock(&t->lock);
spinlock_unlock(&tasks_lock);
flags = AS_AREA_READ;
if (writable)
flags |= AS_AREA_WRITE;
if (!as_area_create(t->as, flags, pages * PAGE_SIZE, vp, AS_AREA_ATTR_NONE,
&phys_backend, &backend_data)) {
/*
* The address space area could not have been created.
* We report it using ENOMEM.
*/
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
return ENOMEM;
}
/*
* Mapping is created on-demand during page fault.
*/
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
return 0;
}
/** Enable range of I/O space for task.
*
* @param id Task ID of the destination task.
* @param ioaddr Starting I/O address.
* @param size Size of the enabled I/O space..
*
* @return 0 on success, EPERM if the caller lacks capabilities to use this syscall,
* ENOENT if there is no task matching the specified ID.
*/
static int ddi_iospace_enable(task_id_t id, __address ioaddr, size_t size)
{
ipl_t ipl;
cap_t caps;
task_t *t;
int rc;
/*
* Make sure the caller is authorised to make this syscall.
*/
caps = cap_get(TASK);
if (!(caps & CAP_IO_MANAGER))
return EPERM;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
t = task_find_by_id(id);
if (!t) {
/*
* There is no task with the specified ID.
*/
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ENOENT;
}
/*
* TODO: We are currently lacking support for task destroying.
* Once it is added to the kernel, we must take care to
* synchronize in a way that prevents race conditions here.
*/
/* Lock the task and release the lock protecting tasks_btree. */
spinlock_lock(&t->lock);
spinlock_unlock(&tasks_lock);
rc = ddi_iospace_enable_arch(t, ioaddr, size);
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
return rc;
}
/** Wrapper for SYS_MAP_PHYSMEM syscall.
*
* @param User space address of memory DDI argument structure.
*
* @return 0 on success, otherwise it returns error code found in errno.h
*/
__native sys_physmem_map(ddi_memarg_t *uspace_mem_arg)
{
ddi_memarg_t arg;
int rc;
rc = copy_from_uspace(&arg, uspace_mem_arg, sizeof(ddi_memarg_t));
if (rc != 0)
return (__native) rc;
return (__native) ddi_physmem_map((task_id_t) arg.task_id, ALIGN_DOWN((__address) arg.phys_base, FRAME_SIZE),
ALIGN_DOWN((__address) arg.virt_base, PAGE_SIZE), (count_t) arg.pages,
(bool) arg.writable);
}
/** Wrapper for SYS_ENABLE_IOSPACE syscall.
*
* @param User space address of DDI argument structure.
*
* @return 0 on success, otherwise it returns error code found in errno.h
*/
__native sys_iospace_enable(ddi_ioarg_t *uspace_io_arg)
{
ddi_ioarg_t arg;
int rc;
rc = copy_from_uspace(&arg, uspace_io_arg, sizeof(ddi_ioarg_t));
if (rc != 0)
return (__native) rc;
return (__native) ddi_iospace_enable((task_id_t) arg.task_id, (__address) arg.ioaddr, (size_t) arg.size);
}
/** Disable or enable preemption.
*
* @param enable If non-zero, the preemption counter will be decremented, leading to potential
* enabling of preemption. Otherwise the preemption counter will be incremented,
* preventing preemption from occurring.
*
* @return Zero on success or EPERM if callers capabilities are not sufficient.
*/
__native sys_preempt_control(int enable)
{
if (! cap_get(TASK) & CAP_PREEMPT_CONTROL)
return EPERM;
if (enable)
preemption_enable();
else
preemption_disable();
return 0;
}