FreeBSD/Linux Kernel Cross Reference
sys/i386/iopb.c

     /* 
      * Mach Operating System
      * Copyright (c) 1993,1992,1991,1990 Carnegie Mellon University
      * All Rights Reserved.
      * 
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
      * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     * 
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     * 
     * any improvements or extensions that they make and grant Carnegie Mellon
     * the rights to redistribute these changes.
     */
    
    /*
     * HISTORY
     * $Log:        iopb.c,v $
     * Revision 2.7  93/11/17  16:36:21  dbg
     *      Never allow access to IO ports 0x00 .. 0xff.  These are system
     *      control ports on PCs.  Clobbering configuration info in CMOS may
     *      make the machine unusable!
     *      [93/10/20            dbg]
     * 
     *      Removed lint.
     *      [93/06/17            dbg]
     * 
     * Revision 2.6  93/09/01  11:32:40  mrt
     *      io_bitmap_init() now takes an argument stating whether to allow
     *      or inhibit access to ALL io ports.  Now opening iopl gives total
     *      access.
     *      [93/08/19            rvb]
     * 
     * Revision 2.5  92/07/09  22:53:28  rvb
     *      Remove io_port from list before freeing it.
     *      [92/06/29            jvh]
     * 
     * Revision 2.4  92/01/03  20:07:32  dbg
     *      Fix locking.  Move all interface routines here.
     *      [91/11/07            dbg]
     * 
     * Revision 2.3  91/05/14  16:09:50  mrt
     *      Correcting copyright
     * 
     * Revision 2.2  91/05/08  12:38:27  dbg
     *      Created.
     *      [91/03/21            dbg]
     * 
     */
    
    /*
     * Code to manipulate IO permission bitmaps.
     */
    
    #include <mach/boolean.h>
    #include <mach/kern_return.h>
    
    #include <ipc/ipc_port.h>
    
    #include <kern/kalloc.h>
    #include <kern/lock.h>
    #include <kern/memory.h>
    #include <kern/queue.h>
    #include <kern/thread.h>
    
    #include <device/dev_hdr.h>
    
    #include <i386/io_port.h>
    #include <i386/iopb.h>
    #include <i386/seg.h>
    
    /*
     * A set of ports for an IO device.
     */
    struct io_port {
            device_t        device;         /* Mach device */
            queue_chain_t   dev_list;       /* link in device list */
            queue_chain_t   io_use_list;    /* List of threads that use it */
            io_reg_t        *io_port_list;  /* list of IO ports that use it */
                                            /* list ends with IO_REG_NULL */
    };
    typedef struct io_port  *io_port_t;
    
    /*
     * Lookup table for device -> io_port mapping
     * (a linked list - I don't expect too many)
     */
    queue_head_t    device_to_io_port_list;
   
   /*
    * Cross-reference:
    *      all threads that have IO ports mapped
    *      all IO ports that have threads mapped
    */
   struct io_use {
           queue_chain_t   psq;    /* Links from port set */
           queue_chain_t   tsq;    /* links from tss */
           io_port_t       ps;     /* Port set */
           iopb_tss_t      ts;     /* Task segment */
   };
   typedef struct io_use   *io_use_t;
   
   /*
    * Big lock for the whole mess.
    */
   decl_simple_lock_data(, iopb_lock)
   
   /*
    * Initialize the package.
    */
   void
   iopb_init(void)
   {
           queue_init(&device_to_io_port_list);
           simple_lock_init(&iopb_lock);
   }
   
   /*
    * Initialize bitmap (set all bits to OFF == 1)
    */
   void
   io_bitmap_init(
           isa_iopb        bp,
           boolean_t       on_off)
   {
           register unsigned char  *b = bp;
           register int            s;
           unsigned char           c;
   
           /*
            *      Disallow access to ports 0x00 .. 0xff
            */
           for (s = 0; s < (0xff+1)/8; s++) {
               *b++ = ~0;  /* no access */
           }
   
           if (on_off)
                   c = 0;
           else
                   c = ~0;
   
           for (; s < sizeof(isa_iopb); s++) {
               *b++ = c;
           }
   }
   
   /*
    * Set selected bits in bitmap to ON == 0
    */
   void
   io_bitmap_set(
           isa_iopb        bp,
           io_reg_t        *bit_list)
   {
           io_reg_t        io_bit;
   
           while ((io_bit = *bit_list++) != IO_REG_NULL) {
               bp[io_bit>>3] &= ~(1 << (io_bit & 0x7));
           }
   }
   
   /*
    * Set selected bits in bitmap to OFF == 1
    */
   void
   io_bitmap_clear(
           isa_iopb        bp,
           io_reg_t        *bit_list)
   {
           io_reg_t        io_bit;
   
           while ((io_bit = *bit_list++) != IO_REG_NULL) {
               bp[io_bit>>3] |= (1 << (io_bit & 0x7));
           }
   }
   
   /*
    * Lookup an io-port set by device
    */
   io_port_t
   device_to_io_port_lookup(
           device_t        device)
   {
           register io_port_t io_port;
   
           queue_iterate(&device_to_io_port_list, io_port, io_port_t, dev_list) {
               if (io_port->device == device) {
                   return io_port;
               }
           }
           return 0;
   }
   
   /*
    * [exported]
    * Create an io_port set
    */
   void
   io_port_create(
           device_t        device,
           io_reg_t        *io_port_list)
   {
           register io_port_t io_port;
   
           io_port = (io_port_t) kalloc(sizeof(struct io_port));
   
           simple_lock(&iopb_lock);
           if (device_to_io_port_lookup(device) != 0) {
               simple_unlock(&iopb_lock);
               kfree((vm_offset_t) io_port, sizeof(struct io_port));
               return;
           }
   
           io_port->device = device;
           queue_init(&io_port->io_use_list);
           io_port->io_port_list = io_port_list;
   
           /*
            * Enter in lookup list.
            */
           queue_enter(&device_to_io_port_list, io_port, io_port_t, dev_list);
   
           simple_unlock(&iopb_lock);
   }
   
   /*
    * [exported]
    * Destroy an io port set, removing any IO mappings.
    */
   void
   io_port_destroy(
           device_t        device)
   {
           io_port_t       io_port;
           io_use_t        iu;
   
           simple_lock(&iopb_lock);
           io_port = device_to_io_port_lookup(device);
           if (io_port == 0) {
               simple_unlock(&iopb_lock);
               return;
           }
   
           queue_iterate(&io_port->io_use_list, iu, io_use_t, psq) {
               iopb_tss_t  io_tss;
               io_tss = iu->ts;
               io_bitmap_clear(io_tss->bitmap, io_port->io_port_list);
               queue_remove(&io_tss->io_port_list, iu, io_use_t, tsq);
           }
           queue_remove(&device_to_io_port_list, io_port, io_port_t, dev_list);
           simple_unlock(&iopb_lock);
   
           while (!queue_empty(&io_port->io_use_list)) {
               iu = (io_use_t) queue_first(&io_port->io_use_list);
               queue_remove(&io_port->io_use_list, iu, io_use_t, psq);
               kfree((vm_offset_t)iu, sizeof(struct io_use));
           }
   
           kfree((vm_offset_t)io_port, sizeof(struct io_port));
   }
   
   /*
    * Initialize an IO TSS.
    */
   void
   io_tss_init(
           iopb_tss_t      io_tss,
           boolean_t       access_all)     /* allow access or not */
   {
           vm_offset_t     addr = (vm_offset_t) io_tss;
           vm_size_t       size = (char *)&io_tss->barrier - (char *)io_tss;
   
           bzero(&io_tss->tss, sizeof(struct i386_tss));
           io_tss->tss.io_bit_map_offset
                           = (char *)&io_tss->bitmap - (char *)io_tss;
           io_tss->tss.ss0 = KERNEL_DS;
           io_bitmap_init(io_tss->bitmap, access_all);
           io_tss->barrier = ~0;
           queue_init(&io_tss->io_port_list);
           io_tss->iopb_desc[0] = ((size-1) & 0xffff)
                   | ((addr & 0xffff) << 16);
           io_tss->iopb_desc[1] = ((addr & 0x00ff0000) >> 16)
                   | ((ACC_TSS|ACC_PL_K|ACC_P) << 8)
                   | ((size-1) & 0x000f0000)
                   | (addr & 0xff000000);
   }
   
   /*
    * [exported]
    * Create an IOPB_TSS
    */
   iopb_tss_t
   iopb_create(void)
   {
           register iopb_tss_t ts;
   
           ts = (iopb_tss_t) kalloc(sizeof (struct iopb_tss));
           io_tss_init(ts, TRUE);          /* XXX */
           return ts;
   }
   
   /*
    * [exported]
    * Destroy an IOPB_TSS
    */
   void
   iopb_destroy(
           iopb_tss_t io_tss)
   {
           io_use_t        iu;
           io_port_t       io_port;
   
           simple_lock(&iopb_lock);
   
           queue_iterate(&io_tss->io_port_list, iu, io_use_t, tsq) {
               io_port = iu->ps;
               /* skip bitmap clear - entire bitmap will vanish */
               queue_remove(&io_port->io_use_list, iu, io_use_t, psq);
           }
   
           simple_unlock(&iopb_lock);
   
           while (!queue_empty(&io_tss->io_port_list)) {
               iu = (io_use_t) queue_first(&io_tss->io_port_list);
               queue_remove(&io_tss->io_port_list, iu, io_use_t, tsq);
               kfree((vm_offset_t)iu, sizeof(struct io_use));
           }
   
           kfree((vm_offset_t)io_tss, sizeof(struct iopb_tss));
   }
   
   /*
    * Add an IO mapping to a thread.
    */
   kern_return_t
   i386_io_port_add(
           thread_t        thread,
           device_t        device)
   {
           pcb_t           pcb;
           iopb_tss_t      io_tss, new_io_tss;
           io_port_t       io_port;
           io_use_t        iu, old_iu;
   
           if (thread == THREAD_NULL
            || device == DEVICE_NULL)
               return KERN_INVALID_ARGUMENT;
   
           pcb = thread->pcb;
   
           new_io_tss = 0;
           iu = (io_use_t) kalloc(sizeof(struct io_use));
   
       Retry:
           simple_lock(&iopb_lock);
   
           /* find the io_port_t for the device */
           io_port = device_to_io_port_lookup(device);
           if (io_port == 0) {
               /*
                * Device does not have IO ports available.
                */
               simple_unlock(&iopb_lock);
               if (new_io_tss)
                   kfree((vm_offset_t)new_io_tss, sizeof(struct iopb_tss));
               kfree((vm_offset_t) iu, sizeof(struct io_use));
               return KERN_INVALID_ARGUMENT;
           }
   
           /* Have the IO port. */
   
           /* Make sure the thread has a TSS. */
   
           simple_lock(&pcb->lock);
           io_tss = pcb->ims.io_tss;
           if (io_tss == 0) {
               if (new_io_tss == 0) {
                   /*
                    * Allocate an IO-tss.
                    */
                   simple_unlock(&pcb->lock);
                   simple_unlock(&iopb_lock);
   
                   new_io_tss = (iopb_tss_t) kalloc(sizeof(struct iopb_tss));
                   io_tss_init(new_io_tss, TRUE);  /* XXX */
   
                   goto Retry;
               }
               io_tss = new_io_tss;
               pcb->ims.io_tss = io_tss;
               new_io_tss = 0;
           }
   
           /*
            * Have io_port and io_tss.
            * See whether device is already mapped.
            */
           queue_iterate(&io_tss->io_port_list, old_iu, io_use_t, tsq) {
               if (old_iu->ps == io_port) {
                   /*
                    * Already mapped.
                    */
                   simple_unlock(&pcb->lock);
                   simple_unlock(&iopb_lock);
   
                   kfree((vm_offset_t)iu, sizeof(struct io_use));
                   if (new_io_tss)
                       kfree((vm_offset_t)new_io_tss, sizeof(struct iopb_tss));
                   return KERN_SUCCESS;
               }
           }
   
           /*
            * Add mapping.
            */
           iu->ps = io_port;
           iu->ts = io_tss;
           queue_enter(&io_port->io_use_list, iu, io_use_t, psq);
           queue_enter(&io_tss->io_port_list, iu, io_use_t, tsq);
           io_bitmap_set(io_tss->bitmap, io_port->io_port_list);
   
           simple_unlock(&pcb->lock);
           simple_unlock(&iopb_lock);
   
           if (new_io_tss)
               kfree((vm_offset_t)new_io_tss, sizeof(struct iopb_tss));
           return KERN_SUCCESS;
   
   }
   
   /*
    * Remove an IO mapping from a thread.
    */
   kern_return_t
   i386_io_port_remove(
           thread_t        thread,
           device_t        device)
   {
           pcb_t           pcb;
           iopb_tss_t      io_tss;
           io_port_t       io_port;
           io_use_t        iu;
   
           if (thread == THREAD_NULL
            || device == DEVICE_NULL)
               return KERN_INVALID_ARGUMENT;
   
           pcb = thread->pcb;
   
           simple_lock(&iopb_lock);
   
           /* find the io_port_t for the device */
   
           io_port = device_to_io_port_lookup(device);
           if (io_port == 0) {
               /*
                * Device does not have IO ports available.
                */
               simple_unlock(&iopb_lock);
               return KERN_INVALID_ARGUMENT;
           }
   
           simple_lock(&pcb->lock);
           io_tss = pcb->ims.io_tss;
           if (io_tss == 0) {
               simple_unlock(&pcb->lock);
               simple_unlock(&iopb_lock);
               return KERN_INVALID_ARGUMENT;       /* not mapped */
           }
   
           /*
            * Find the mapping.
            */
           queue_iterate(&io_tss->io_port_list, iu, io_use_t, tsq) {
               if (iu->ps == io_port) {
                   /*
                    * Found mapping.  Remove it.
                    */
                   io_bitmap_clear(io_tss->bitmap, io_port->io_port_list);
   
                   queue_remove(&io_port->io_use_list, iu, io_use_t, psq);
                   queue_remove(&io_tss->io_port_list, iu, io_use_t, tsq);
   
                   simple_unlock(&pcb->lock);
                   simple_unlock(&iopb_lock);
   
                   kfree((vm_offset_t)iu, sizeof(struct io_use));
   
                   return KERN_SUCCESS;
               }
           }
   
           /*
            * No mapping.
            */
           return KERN_INVALID_ARGUMENT;
   }
   
   /*
    * Return the IO ports mapped into a thread.
    */
   extern ipc_port_t       convert_device_to_port(/* device_t */);
   
   kern_return_t
   i386_io_port_list(
           thread_t        thread,
           device_t        **list,
           natural_t       *list_count)
   {
           register pcb_t  pcb;
           register iopb_tss_t io_tss;
           unsigned int    count, alloc_count;
           device_t        *devices;
           vm_size_t       size_needed;
           vm_offset_t     size = 0;
           vm_offset_t     addr;
           int             i;
   
           if (thread == THREAD_NULL)
               return KERN_INVALID_ARGUMENT;
   
           pcb = thread->pcb;
   
           alloc_count = 16;               /* a guess */
   
           do {
               size_needed = alloc_count * sizeof(ipc_port_t);
               if (size_needed <= size)
                   break;
   
               if (size != 0)
                   kfree(addr,size);
   
               assert(size_needed > 0);
               size = size_needed;
   
               addr = kalloc(size);
               if (addr == 0)
                   return KERN_RESOURCE_SHORTAGE;
   
               devices = (device_t *)addr;
               count = 0;
   
               simple_lock(&iopb_lock);
               simple_lock(&pcb->lock);
               io_tss = pcb->ims.io_tss;
               if (io_tss != 0) {
                   register io_use_t iu;
   
                   queue_iterate(&io_tss->io_port_list, iu, io_use_t, tsq) {
                       if (++count < alloc_count) {
                           *devices = iu->ps->device;
                           device_reference(*devices);
                           devices++;
                       }
                   }
               }
               simple_unlock(&pcb->lock);
               simple_unlock(&iopb_lock);
           } while (count > alloc_count);
   
           if (count == 0) {
               /*
                * No IO ports
                */
               *list = 0;
               *list_count = 0;
   
               if (size != 0)
                   kfree(addr, size);
           }
           else {
               /*
                * If we allocated too much, must copy.
                */
               size_needed = count * sizeof(ipc_port_t);
               if (size_needed < size) {
                   vm_offset_t     new_addr;
   
                   new_addr = kalloc(size_needed);
                   if (new_addr == 0) {
                       for (i = 0; i < count; i++)
                           device_deallocate(devices[i]);
                       kfree(addr, size);
                       return KERN_RESOURCE_SHORTAGE;
                   }
   
                   bcopy((void *)addr, (void *)new_addr, size_needed);
                   kfree(addr, size);
                   devices = (device_t *)new_addr;
               }
   
               for (i = 0; i < count; i++)
                   ((ipc_port_t *)devices)[i] =
                           convert_device_to_port(devices[i]);
           }
           *list = devices;
           *list_count = count;
   
           return KERN_SUCCESS;
   }
   
   /*
    * Check whether an IO device is mapped to a particular thread.
    * Used to support the 'iopl' device automatic mapping.
    */
   boolean_t
   iopb_check_mapping(
           thread_t        thread,
           device_t        device)
   {
           pcb_t           pcb;
           io_port_t       io_port;
           io_use_t        iu;
   
           pcb = thread->pcb;
   
           simple_lock(&iopb_lock);
   
           /* Find the io port for the device */
   
           io_port = device_to_io_port_lookup(device);
           if (io_port == 0) {
               simple_unlock(&iopb_lock);
               return FALSE;
           }
   
           /* Look up the mapping in the device`s mapping list. */
   
           queue_iterate(&io_port->io_use_list, iu, io_use_t, psq) {
               if (iu->ts == pcb->ims.io_tss) {
                   /*
                    * Device is mapped.
                    */
                   simple_unlock(&iopb_lock);
                   return TRUE;
               }
           }
           simple_unlock(&iopb_lock);
           return FALSE;
   }

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