/*
* 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.
*/
/** @addtogroup genericddi
* @{
*/
/**
* @file
* @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 <adt/btree.h>
#include <arch.h>
#include <align.h>
#include <errno.h>
/** This lock protects the parea_btree. */
SPINLOCK_INITIALIZE(parea_lock);
/** B+tree with enabled physical memory areas. */
static btree_t parea_btree;
/** Initialize DDI. */
void ddi_init(void)
{
btree_create(&parea_btree);
}
/** Enable piece of physical memory for mapping by physmem_map().
*
* @param parea Pointer to physical area structure.
*
* @todo This function doesn't check for overlaps. It depends on the kernel to
* create disjunct physical memory areas.
*/
void ddi_parea_register(parea_t *parea)
{
ipl_t ipl;
ipl = interrupts_disable();
spinlock_lock(&parea_lock);
/*
* TODO: we should really check for overlaps here.
* However, we should be safe because the kernel is pretty sane and
* memory of different devices doesn't overlap.
*/
btree_insert(&parea_btree, (btree_key_t) parea->pbase, parea, NULL);
spinlock_unlock(&parea_lock);
interrupts_restore(ipl);
}
/** Map piece of physical memory into virtual address space of current task.
*
* @param pf Physical address of the starting frame.
* @param vp Virtual address of the starting page.
* @param pages Number of pages to map.
* @param flags Address space area flags for the mapping.
*
* @return 0 on success, EPERM if the caller lacks capabilities to use this
* syscall, ENOENT if there is no task matching the specified ID or the
* physical address space is not enabled for mapping and ENOMEM if there
* was a problem in creating address space area.
*/
static int ddi_physmem_map(uintptr_t pf, uintptr_t vp, count_t pages, int flags)
{
ipl_t ipl;
cap_t caps;
mem_backend_data_t backend_data;
backend_data.base = pf;
backend_data.frames = 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();
/*
* Check if the physical memory area is enabled for mapping.
* If the architecture supports virtually indexed caches, intercept
* attempts to create an illegal address alias.
*/
spinlock_lock(&parea_lock);
parea_t *parea;
btree_node_t *nodep;
parea = (parea_t *) btree_search(&parea_btree, (btree_key_t) pf, &nodep);
if (!parea || parea->frames < pages || ((flags & AS_AREA_CACHEABLE) &&
!parea->cacheable) || (!(flags & AS_AREA_CACHEABLE) &&
parea->cacheable)) {
/*
* This physical memory area cannot be mapped.
*/
spinlock_unlock(&parea_lock);
interrupts_restore(ipl);
return ENOENT;
}
spinlock_unlock(&parea_lock);
spinlock_lock(&TASK->lock);
if (!as_area_create(TASK->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(&TASK->lock);
interrupts_restore(ipl);
return ENOMEM;
}
/*
* Mapping is created on-demand during page fault.
*/
spinlock_unlock(&TASK->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, uintptr_t 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) || (!context_check(CONTEXT, t->context))) {
/*
* There is no task with the specified ID
* or the task belongs to a different security
* context.
*/
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ENOENT;
}
/* 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_PHYSMEM_MAP syscall.
*
* @param phys_base Physical base address to map
* @param virt_base Destination virtual address
* @param pages Number of pages
* @param flags Flags of newly mapped pages
*
* @return 0 on success, otherwise it returns error code found in errno.h
*/
unative_t sys_physmem_map(unative_t phys_base, unative_t virt_base,
unative_t pages, unative_t flags)
{
return (unative_t) ddi_physmem_map(ALIGN_DOWN((uintptr_t) phys_base,
FRAME_SIZE), ALIGN_DOWN((uintptr_t) virt_base, PAGE_SIZE),
(count_t) pages, (int) flags);
}
/** Wrapper for SYS_ENABLE_IOSPACE syscall.
*
* @param uspace_io_arg User space address of DDI argument structure.
*
* @return 0 on success, otherwise it returns error code found in errno.h
*/
unative_t 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 (unative_t) rc;
return (unative_t) ddi_iospace_enable((task_id_t) arg.task_id,
(uintptr_t) 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.
*/
unative_t sys_preempt_control(int enable)
{
if (!cap_get(TASK) & CAP_PREEMPT_CONTROL)
return EPERM;
if (enable)
preemption_enable();
else
preemption_disable();
return 0;
}
/** @}
*/