// vi:set ft=cpp: -*- Mode: C++ -*-
/**
 * \internal
 * \file
 * \brief Region mapper server template.
 */
/*
 * (c) 2014 Alexander Warg <alexander.warg@kernkonzept.com>
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
#pragma once

#include <l4/sys/types.h>
#include <l4/re/rm>
#include <l4/re/util/region_mapping>

namespace L4Re { namespace Util {

template<typename DERIVED, typename Dbg>
struct Rm_server
{
private:
  DERIVED *rm() { return static_cast<DERIVED*>(this); }
  DERIVED const *rm() const { return static_cast<DERIVED const *>(this); }

public:

  /**
   * Implementation of L4Re::Rm::_attach
   */
  long op_attach(L4Re::Rm::Rights, l4_addr_t &_start,
                 unsigned long size, Rm::Flags flags,
                 L4::Ipc::Snd_fpage ds_cap, L4Re::Rm::Offset offs,
                 unsigned char align, l4_cap_idx_t client_cap_idx)
  {
    typename DERIVED::Dataspace ds;

    if (!(flags & Rm::F::Reserved))
      {
        if (long r = rm()->validate_ds(static_cast<DERIVED*>(this)->server_iface(), ds_cap, flags.region_flags(), &ds))
          return r;
      }

    size  = l4_round_page(size);
    l4_addr_t start = l4_trunc_page(_start);

    if (size < L4_PAGESIZE)
      return -L4_EINVAL;

    Rm::Region_flags r_flags = flags.region_flags();
    Rm::Attach_flags a_flags = flags.attach_flags();

    start = l4_addr_t(rm()->attach((void*)start, size,
                                   typename DERIVED::Region_handler(ds, client_cap_idx, offs, r_flags),
                                   a_flags, align));

    if (start == L4_INVALID_ADDR)
      return -L4_EADDRNOTAVAIL;

    _start = start;
    return L4_EOK;
  }

  /**
   * Implementation of L4Re::Rm::free_area
   */
  long op_free_area(L4Re::Rm::Rights, l4_addr_t start)
  {
    if (!rm()->detach_area(start))
      return -L4_ENOENT;

    return L4_EOK;
  }

  /**
   * Implementation of L4Re::Rm::_find
   */
  long op_find(L4Re::Rm::Rights, l4_addr_t &addr, unsigned long &size,
               L4Re::Rm::Flags &flags, L4Re::Rm::Offset &offset,
               L4::Cap<L4Re::Dataspace> &m)
  {
    if (!DERIVED::Have_find)
      return -L4_EPERM;

    Rm::Flags flag_area { 0 };

    typename DERIVED::Node r = rm()->find(Region(addr, addr + size -1));
    if (!r)
      {
        r = rm()->area_find(Region(addr, addr + size - 1));
        if (!r)
          return -L4_ENOENT;
        flag_area = Rm::F::In_area;
      }

    addr = r->first.start();
    size = r->first.end() + 1 - addr;

    flags = r->second.flags() | flag_area;
    offset = r->second.offset();
    m = L4::Cap<L4Re::Dataspace>(DERIVED::find_res(r->second.memory()));
    return L4_EOK;
  }

  /**
   * Implementation of L4Re::Rm::_detach
   */
  long op_detach(L4Re::Rm::Rights, l4_addr_t addr,
                 unsigned long size, unsigned flags,
                 l4_addr_t &start, l4_addr_t &rsize,
                 l4_cap_idx_t &mem_cap)
  {
    Region r;
    typename DERIVED::Region_handler h;
    int err = rm()->detach((void*)addr, size, flags, &r, &h);
    if (err < 0)
      return err;

    if (r.invalid())
      return -L4_ENOENT;

    start = r.start();
    rsize = r.size();
    mem_cap = h.client_cap_idx();
    return err;
  }

  /**
   * Implementation of L4Re::Rm::_reserve_area
   */
  long op_reserve_area(L4Re::Rm::Rights, l4_addr_t &start, unsigned long size,
                       L4Re::Rm::Flags flags, unsigned char align)
  {
    start = rm()->attach_area(start, size, flags, align);
    if (start == L4_INVALID_ADDR)
      return -L4_EADDRNOTAVAIL;
    return L4_EOK;
  }

  /**
   * Implementation of L4Re::Rm::get_regions
   */
  long op_get_regions(L4Re::Rm::Rights, l4_addr_t addr,
                      L4::Ipc::Ret_array<L4Re::Rm::Region> regions)
  {
    typename DERIVED::Node r;
    unsigned num = 0;
    while ((r = rm()->lower_bound(Region(addr))))
      {
        Rm::Region &x = regions.value[num];
        x.start  = r->first.start();
        x.end    = r->first.end();

        if (++num >= regions.max)
          break;

        if (x.end >= rm()->max_addr())
          break;
        addr = x.end + 1;
      }
    return num;
  }

  /**
   * Implementation of L4Re::Rm::get_areas
   */
  long op_get_areas(L4Re::Rm::Rights, l4_addr_t addr,
                    L4::Ipc::Ret_array<L4Re::Rm::Area> areas)
  {
    typename DERIVED::Node r;
    unsigned num = 0;
    while ((r = rm()->lower_bound_area(Region(addr))))
      {
        Rm::Area &x = areas.value[num];
        x.start  = r->first.start();
        x.end    = r->first.end();

        if (++num >= areas.max)
          break;

        if (x.end >= rm()->max_addr())
          break;

        addr = x.end + 1;
      }
    return num;
  }

private:
  static void pager_set_result(L4::Ipc::Opt<L4::Ipc::Snd_fpage> *fp,
                               L4::Ipc::Snd_fpage const &f)
  { *fp = f;  }

  static void pager_set_result(L4::Ipc::Opt<L4::Ipc::Snd_fpage> *, ...)
  {}
public:

  /**
   * Pager API
   */
  long op_io_page_fault(L4::Io_pager::Rights, l4_fpage_t, l4_umword_t,
                        L4::Ipc::Opt<L4::Ipc::Snd_fpage> &)
  {
    // generate exception
    return -L4_ENOMEM;
  }

  long op_page_fault(L4::Pager::Rights, l4_umword_t addr, l4_umword_t pc,
                     L4::Ipc::Opt<L4::Ipc::Snd_fpage> &fp)
  {
    Dbg(Dbg::Server).printf("page fault: %lx pc=%lx\n", addr, pc);

    bool need_w = addr & 2;
    bool need_x = addr & 4;

    typename DERIVED::Node n = rm()->find(addr);

    if (!n || !n->second.memory())
      {
        Dbg(Dbg::Warn, "rm").printf("unhandled %s page fault at 0x%lx pc=0x%lx\n",
                                    need_w ? "write" : "read", addr, pc);
        // generate exception
        return -L4_ENOMEM;
      }

    if (!(n->second.flags() & L4Re::Rm::F::W) && need_w)
      {
        Dbg(Dbg::Warn, "rm").printf("write page fault in readonly region at 0x%lx pc=0x%lx\n",
                                    addr, pc);
        // generate exception
        return -L4_EACCESS;
      }

    if (!(n->second.flags() & L4Re::Rm::F::X) && need_x)
      {
        Dbg(Dbg::Warn, "rm").printf("instruction page fault in non-exec region at 0x%lx pc=0x%lx\n",
                                    addr, pc);
        // generate exception
        return -L4_EACCESS;
      }

    typename DERIVED::Region_handler::Ops::Map_result map_res;
    if (int err = n->second.map(addr, n->first, need_w, &map_res))
      {
        Dbg(Dbg::Warn, "rm").printf("mapping for page fault failed with error %d at 0x%lx pc=0x%lx\n",
                                    err, addr, pc);
        // generate exception
        return -L4_ENOMEM;
      }

    pager_set_result(&fp, map_res);
    return L4_EOK;
  }
};

}}