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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericddi
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Device Driver Interface functions.
  36.  *
  37.  * This file contains functions that comprise the Device Driver Interface.
  38.  * These are the functions for mapping physical memory and enabling I/O
  39.  * space to tasks.
  40.  */
  41.  
  42. #include <ddi/ddi.h>
  43. #include <ddi/ddi_arg.h>
  44. #include <proc/task.h>
  45. #include <security/cap.h>
  46. #include <mm/frame.h>
  47. #include <mm/as.h>
  48. #include <synch/spinlock.h>
  49. #include <syscall/copy.h>
  50. #include <adt/btree.h>
  51. #include <arch.h>
  52. #include <align.h>
  53. #include <errno.h>
  54.  
  55. /** This lock protects the parea_btree. */
  56. SPINLOCK_INITIALIZE(parea_lock);
  57.  
  58. /** B+tree with enabled physical memory areas. */
  59. static btree_t parea_btree;
  60.  
  61. /** Initialize DDI. */
  62. void ddi_init(void)
  63. {
  64.     btree_create(&parea_btree);
  65. }
  66.  
  67. /** Enable piece of physical memory for mapping by physmem_map().
  68.  *
  69.  * @param parea Pointer to physical area structure.
  70.  *
  71.  * @todo This function doesn't check for overlaps. It depends on the kernel to
  72.  * create disjunct physical memory areas.
  73.  */
  74. void ddi_parea_register(parea_t *parea)
  75. {
  76.     ipl_t ipl;
  77.  
  78.     ipl = interrupts_disable();
  79.     spinlock_lock(&parea_lock);
  80.    
  81.     /*
  82.      * TODO: we should really check for overlaps here.
  83.      * However, we should be safe because the kernel is pretty sane and
  84.      * memory of different devices doesn't overlap.
  85.      */
  86.     btree_insert(&parea_btree, (btree_key_t) parea->pbase, parea, NULL);
  87.  
  88.     spinlock_unlock(&parea_lock);
  89.     interrupts_restore(ipl);   
  90. }
  91.  
  92. /** Map piece of physical memory into virtual address space of current task.
  93.  *
  94.  * @param pf Physical address of the starting frame.
  95.  * @param vp Virtual address of the starting page.
  96.  * @param pages Number of pages to map.
  97.  * @param flags Address space area flags for the mapping.
  98.  *
  99.  * @return 0 on success, EPERM if the caller lacks capabilities to use this
  100.  *  syscall, ENOENT if there is no task matching the specified ID or the
  101.  *  physical address space is not enabled for mapping and ENOMEM if there
  102.  *  was a problem in creating address space area.
  103.  */
  104. static int ddi_physmem_map(uintptr_t pf, uintptr_t vp, count_t pages, int flags)
  105. {
  106.     ipl_t ipl;
  107.     cap_t caps;
  108.     mem_backend_data_t backend_data;
  109.  
  110.     backend_data.base = pf;
  111.     backend_data.frames = pages;
  112.    
  113.     /*
  114.      * Make sure the caller is authorised to make this syscall.
  115.      */
  116.     caps = cap_get(TASK);
  117.     if (!(caps & CAP_MEM_MANAGER))
  118.         return EPERM;
  119.  
  120.     ipl = interrupts_disable();
  121.  
  122.     /*
  123.      * Check if the physical memory area is enabled for mapping.
  124.      * If the architecture supports virtually indexed caches, intercept
  125.      * attempts to create an illegal address alias.
  126.      */
  127.     spinlock_lock(&parea_lock);
  128.     parea_t *parea;
  129.     btree_node_t *nodep;
  130.     parea = (parea_t *) btree_search(&parea_btree, (btree_key_t) pf, &nodep);
  131.     if (!parea || parea->frames < pages || ((flags & AS_AREA_CACHEABLE) &&
  132.         !parea->cacheable) || (!(flags & AS_AREA_CACHEABLE) &&
  133.         parea->cacheable)) {
  134.         /*
  135.          * This physical memory area cannot be mapped.
  136.          */
  137.         spinlock_unlock(&parea_lock);
  138.         interrupts_restore(ipl);
  139.         return ENOENT;
  140.     }
  141.     spinlock_unlock(&parea_lock);
  142.  
  143.     spinlock_lock(&TASK->lock);
  144.    
  145.     if (!as_area_create(TASK->as, flags, pages * PAGE_SIZE, vp, AS_AREA_ATTR_NONE,
  146.         &phys_backend, &backend_data)) {
  147.         /*
  148.          * The address space area could not have been created.
  149.          * We report it using ENOMEM.
  150.          */
  151.         spinlock_unlock(&TASK->lock);
  152.         interrupts_restore(ipl);
  153.         return ENOMEM;
  154.     }
  155.    
  156.     /*
  157.      * Mapping is created on-demand during page fault.
  158.      */
  159.    
  160.     spinlock_unlock(&TASK->lock);
  161.     interrupts_restore(ipl);
  162.     return 0;
  163. }
  164.  
  165. /** Enable range of I/O space for task.
  166.  *
  167.  * @param id Task ID of the destination task.
  168.  * @param ioaddr Starting I/O address.
  169.  * @param size Size of the enabled I/O space..
  170.  *
  171.  * @return 0 on success, EPERM if the caller lacks capabilities to use this
  172.  *  syscall, ENOENT if there is no task matching the specified ID.
  173.  */
  174. static int ddi_iospace_enable(task_id_t id, uintptr_t ioaddr, size_t size)
  175. {
  176.     ipl_t ipl;
  177.     cap_t caps;
  178.     task_t *t;
  179.     int rc;
  180.    
  181.     /*
  182.      * Make sure the caller is authorised to make this syscall.
  183.      */
  184.     caps = cap_get(TASK);
  185.     if (!(caps & CAP_IO_MANAGER))
  186.         return EPERM;
  187.    
  188.     ipl = interrupts_disable();
  189.     spinlock_lock(&tasks_lock);
  190.    
  191.     t = task_find_by_id(id);
  192.    
  193.     if ((!t) || (!context_check(CONTEXT, t->context))) {
  194.         /*
  195.          * There is no task with the specified ID
  196.          * or the task belongs to a different security
  197.          * context.
  198.          */
  199.         spinlock_unlock(&tasks_lock);
  200.         interrupts_restore(ipl);
  201.         return ENOENT;
  202.     }
  203.  
  204.     /* Lock the task and release the lock protecting tasks_btree. */
  205.     spinlock_lock(&t->lock);
  206.     spinlock_unlock(&tasks_lock);
  207.  
  208.     rc = ddi_iospace_enable_arch(t, ioaddr, size);
  209.    
  210.     spinlock_unlock(&t->lock);
  211.     interrupts_restore(ipl);
  212.     return rc;
  213. }
  214.  
  215. /** Wrapper for SYS_PHYSMEM_MAP syscall.
  216.  *
  217.  * @param phys_base Physical base address to map
  218.  * @param virt_base Destination virtual address
  219.  * @param pages Number of pages
  220.  * @param flags Flags of newly mapped pages
  221.  *
  222.  * @return 0 on success, otherwise it returns error code found in errno.h
  223.  */
  224. unative_t sys_physmem_map(unative_t phys_base, unative_t virt_base,
  225.     unative_t pages, unative_t flags)
  226. {
  227.     return (unative_t) ddi_physmem_map(ALIGN_DOWN((uintptr_t) phys_base,
  228.         FRAME_SIZE), ALIGN_DOWN((uintptr_t) virt_base, PAGE_SIZE),
  229.         (count_t) pages, (int) flags);
  230. }
  231.  
  232. /** Wrapper for SYS_ENABLE_IOSPACE syscall.
  233.  *
  234.  * @param uspace_io_arg User space address of DDI argument structure.
  235.  *
  236.  * @return 0 on success, otherwise it returns error code found in errno.h
  237.  */
  238. unative_t sys_iospace_enable(ddi_ioarg_t *uspace_io_arg)
  239. {
  240.     ddi_ioarg_t arg;
  241.     int rc;
  242.    
  243.     rc = copy_from_uspace(&arg, uspace_io_arg, sizeof(ddi_ioarg_t));
  244.     if (rc != 0)
  245.         return (unative_t) rc;
  246.        
  247.     return (unative_t) ddi_iospace_enable((task_id_t) arg.task_id,
  248.         (uintptr_t) arg.ioaddr, (size_t) arg.size);
  249. }
  250.  
  251. /** Disable or enable preemption.
  252.  *
  253.  * @param enable If non-zero, the preemption counter will be decremented,
  254.  *  leading to potential enabling of preemption. Otherwise the preemption
  255.  *  counter will be incremented, preventing preemption from occurring.
  256.  *
  257.  * @return Zero on success or EPERM if callers capabilities are not sufficient.
  258.  */
  259. unative_t sys_preempt_control(int enable)
  260. {
  261.         if (!cap_get(TASK) & CAP_PREEMPT_CONTROL)
  262.                 return EPERM;
  263.         if (enable)
  264.                 preemption_enable();
  265.         else
  266.                 preemption_disable();
  267.         return 0;
  268. }
  269.  
  270. /** @}
  271.  */
  272.