dataspace_svr

// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
 *               Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Torsten Frenzel <frenzel@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * License: see LICENSE.spdx (in this directory or the directories above)
 */
#pragma once
 
#include <string.h>
#include <stdio.h>
#include <stddef.h>
#include <l4/bid_config.h>
#include <l4/sys/types.h>
#include <l4/cxx/minmax>
#include <l4/re/dataspace>
#include <l4/sys/cxx/ipc_legacy>
 
namespace L4Re { namespace Util {

class Dataspace_svr
{
public:
  L4_RPC_LEGACY_DISPATCH(L4Re::Dataspace);
 
  typedef L4::Ipc::Snd_fpage::Map_type Map_type;
  typedef L4::Ipc::Snd_fpage::Cacheopt Cache_type;
 
  Dataspace_svr() noexcept
  : _ds_start(0), _ds_size(0), _map_flags(L4::Ipc::Snd_fpage::Map),
    _cache_flags(L4::Ipc::Snd_fpage::Cached)
  {}
 
  virtual ~Dataspace_svr() noexcept {}

  l4_ret_t map(Dataspace::Offset offset,
               Dataspace::Map_addr local_addr,
               Dataspace::Flags flags,
               Dataspace::Map_addr min_addr,
               Dataspace::Map_addr max_addr,
               L4::Ipc::Snd_fpage &memory)
  {
    memory = L4::Ipc::Snd_fpage();
 
    offset     = l4_trunc_page(offset);
    local_addr = l4_trunc_page(local_addr);
 
    if (!check_limit(offset))
      {
#if 0
        printf("limit failed: off=%lx sz=%lx\n", offset, size());
#endif
        return -L4_ERANGE;
      }
 
    min_addr = l4_trunc_page(min_addr);
    max_addr = l4_round_page(max_addr);
 
    l4_addr_t addr = _ds_start + offset;
    unsigned char order = L4_PAGESHIFT;
 
    while (order < 30 /* limit to 1GB flexpage */)
      {
        l4_addr_t map_base = l4_trunc_size(addr, order + 1);
        if (map_base < _ds_start)
          break;
 
        if (map_base + (1UL << (order + 1)) -1 > (_ds_start + round_size() - 1))
          break;
 
        map_base = l4_trunc_size(local_addr, order + 1);
        if (map_base < min_addr)
          break;
 
        if (map_base + (1UL << (order + 1)) -1 > max_addr -1)
          break;
 
        l4_addr_t mask = ~(~0UL << (order + 1));
        if (local_addr == ~0UL || ((addr ^ local_addr) & mask))
          break;
 
        ++order;
      }
 
    l4_addr_t map_base = l4_trunc_size(addr, order);
 
    Dataspace::Map_addr b = map_base;
    unsigned send_order = order;
    l4_ret_t err = map_hook(offset /*map_base - _ds_start*/, order, flags,
                            &b, &send_order);
    if (err < 0)
      return err;
 
    l4_fpage_t fpage = l4_fpage(b, send_order, flags.fpage_rights());
 
    memory = L4::Ipc::Snd_fpage(fpage, local_addr, _map_flags, _cache_flags);
 
    return L4_EOK;
  }

  virtual l4_ret_t map_hook([[maybe_unused]] Dataspace::Offset offs,
                            [[maybe_unused]] unsigned order,
                            [[maybe_unused]] Dataspace::Flags flags,
                            [[maybe_unused]] Dataspace::Map_addr *base,
                            [[maybe_unused]] unsigned *send_order)
  {
    return 0;
  }

  virtual void take() noexcept
  {}

  virtual unsigned long release() noexcept
  { return 0; }

  virtual l4_ret_t copy([[maybe_unused]] l4_addr_t dst_offs,
                        [[maybe_unused]] l4_umword_t src_id,
                        [[maybe_unused]] l4_addr_t src_offs,
                        [[maybe_unused]] unsigned long size) noexcept
  {
    return -L4_ENODEV;
  }

  virtual l4_ret_t clear(unsigned long offs, unsigned long size) const noexcept
  {
    if (!check_limit(offs))
      return -L4_ERANGE;
 
    size = cxx::min(size, round_size() - offs);
    memset(reinterpret_cast<void *>(_ds_start + offs), 0, size);
    return 0;
  }

  virtual l4_ret_t allocate([[maybe_unused]] l4_addr_t offset,
                            [[maybe_unused]] l4_size_t size,
                            [[maybe_unused]] unsigned access) noexcept
  {
    return -L4_ENODEV;
  }

  virtual unsigned long page_shift() const noexcept
  { return L4_LOG2_PAGESIZE; }

  virtual bool is_static() const noexcept
  { return true; }

  virtual l4_ret_t map_info([[maybe_unused]] l4_addr_t &start_addr,
                            [[maybe_unused]] l4_addr_t &end_addr) noexcept
  { return -L4_EPERM; }
 
 
  l4_ret_t op_map(L4Re::Dataspace::Rights rights,
                  L4Re::Dataspace::Offset offset,
                  L4Re::Dataspace::Map_addr spot,
                  L4Re::Dataspace::Flags flags,
                  L4::Ipc::Snd_fpage &fp)
  {
    auto rf = map_flags(rights);
    if (!rf.w() && flags.w())
      return -L4_EPERM;
 
    return map(offset, spot, flags & rf, 0, ~0, fp);
  }
 
  l4_ret_t op_allocate(L4Re::Dataspace::Rights rights,
                       L4Re::Dataspace::Offset offset,
                       L4Re::Dataspace::Size size)
  { return allocate(offset, size, rights & 3); }
 
  l4_ret_t op_copy_in(L4Re::Dataspace::Rights rights,
                      L4Re::Dataspace::Offset dst_offs,
                      L4::Ipc::Snd_fpage const &src_cap,
                      L4Re::Dataspace::Offset src_offs,
                      L4Re::Dataspace::Size sz)
  {
    if (!src_cap.id_received())
      return -L4_EINVAL;
 
    if (!(rights & L4_CAP_FPAGE_W))
      return -L4_EACCESS;
 
    if (sz == 0)
      return L4_EOK;
 
    return copy(dst_offs, src_cap.data(), src_offs, sz);
  }
 
  l4_ret_t op_info(L4Re::Dataspace::Rights rights, L4Re::Dataspace::Stats &s)
  {
    s.size = size();
    // only return writable if really writable
    s.flags = Dataspace::Flags(0);
    if (map_flags(rights).w())
      s.flags |= Dataspace::F::W;
    return L4_EOK;
  }
 
  l4_ret_t op_clear(L4Re::Dataspace::Rights rights,
                    L4Re::Dataspace::Offset offset,
                    L4Re::Dataspace::Size size)
  {
    if (!map_flags(rights).w())
      return -L4_EACCESS;
 
    return clear(offset, size);
  }
 
  l4_ret_t op_map_info(L4Re::Dataspace::Rights,
                       [[maybe_unused]] l4_addr_t &start_addr,
                       [[maybe_unused]] l4_addr_t &end_addr)
  {
#ifdef CONFIG_MMU
    return 0;
#else
    return map_info(start_addr, end_addr);
#endif
  }
 
protected:
  unsigned long size() const noexcept
  { return _ds_size; }
  unsigned long map_flags() const noexcept
  { return _map_flags; }
  unsigned long page_size() const noexcept
  { return 1UL << page_shift(); }
  unsigned long round_size() const noexcept
  { return l4_round_size(size(), page_shift()); }
  bool check_limit(l4_addr_t offset) const noexcept
  { return offset < round_size(); }
 
  L4Re::Dataspace::Flags
  map_flags(L4Re::Dataspace::Rights rights = L4_CAP_FPAGE_W) const noexcept
  {
    auto f = (_rw_flags & L4Re::Dataspace::Flags(0x0f)) | L4Re::Dataspace::F::Caching_mask;
    if (!(rights & L4_CAP_FPAGE_W))
      f -= L4Re::Dataspace::F::W;
 
    return f;
  }
 
protected:
  void size(unsigned long size) noexcept { _ds_size = size; }
 
  l4_addr_t _ds_start;
  l4_size_t _ds_size;
  Map_type _map_flags;
  Cache_type _cache_flags;
  L4Re::Dataspace::Flags _rw_flags;
};
 
}}