text: /*
   *  mmap support for qemu
   *
   *  Copyright (c) 2003 Fabrice Bellard
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, see <http://www.gnu.org/licenses/>.
   */
  #include "qemu/osdep.h"
  #include <sys/mman.h>
  #include <linux/mman.h>
  #include <linux/unistd.h>
  
  #include "qemu.h"
  #include "qemu-common.h"
  #include "translate-all.h"
  
  //#define DEBUG_MMAP
  
  static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
  static __thread int mmap_lock_count;
  
  void mmap_lock(void)
  {
      if (mmap_lock_count++ == 0) {
          pthread_mutex_lock(&mmap_mutex);
      }
  }
  
  void mmap_unlock(void)
  {
      if (--mmap_lock_count == 0) {
          pthread_mutex_unlock(&mmap_mutex);
      }
  }
  
  /* Grab lock to make sure things are in a consistent state after fork().  */
  void mmap_fork_start(void)
  {
      if (mmap_lock_count)
          abort();
      pthread_mutex_lock(&mmap_mutex);
  }
  
  void mmap_fork_end(int child)
  {
      if (child)
          pthread_mutex_init(&mmap_mutex, NULL);
      else
          pthread_mutex_unlock(&mmap_mutex);
  }
  
  /* NOTE: all the constants are the HOST ones, but addresses are target. */
  int target_mprotect(abi_ulong start, abi_ulong len, int prot)
  {
      abi_ulong end, host_start, host_end, addr;
      int prot1, ret;
  
  #ifdef DEBUG_MMAP
      printf("mprotect: start=0x" TARGET_ABI_FMT_lx
             "len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c\n", start, len,
             prot & PROT_READ ? 'r' : '-',
             prot & PROT_WRITE ? 'w' : '-',
             prot & PROT_EXEC ? 'x' : '-');
  #endif
  
      if ((start & ~TARGET_PAGE_MASK) != 0)
          return -EINVAL;
      len = TARGET_PAGE_ALIGN(len);
      end = start + len;
      if (end < start)
          return -EINVAL;
      prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
      if (len == 0)
          return 0;
  
      mmap_lock();
      host_start = start & qemu_host_page_mask;
      host_end = HOST_PAGE_ALIGN(end);
      if (start > host_start) {
          /* handle host page containing start */
          prot1 = prot;
          for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
              prot1 |= page_get_flags(addr);
          }
          if (host_end == host_start + qemu_host_page_size) {
              for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
                  prot1 |= page_get_flags(addr);
              }
              end = host_end;
          }
          ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
          if (ret != 0)
              goto error;
          host_start += qemu_host_page_size;
      }
      if (end < host_end) {
          prot1 = prot;
          for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
              prot1 |= page_get_flags(addr);
          }
          ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
                         prot1 & PAGE_BITS);
          if (ret != 0)
              goto error;
          host_end -= qemu_host_page_size;
      }
  
      /* handle the pages in the middle */
      if (host_start < host_end) {
          ret = mprotect(g2h(host_start), host_end - host_start, prot);
          if (ret != 0)
              goto error;
      }
      page_set_flags(start, start + len, prot | PAGE_VALID);
      mmap_unlock();
      return 0;
  error:
      mmap_unlock();
      return ret;
  }
  
  /* map an incomplete host page */
  static int mmap_frag(abi_ulong real_start,
                       abi_ulong start, abi_ulong end,
                       int prot, int flags, int fd, abi_ulong offset)
  {
      abi_ulong real_end, addr;
      void *host_start;
      int prot1, prot_new;
  
      real_end = real_start + qemu_host_page_size;
      host_start = g2h(real_start);
  
      /* get the protection of the target pages outside the mapping */
      prot1 = 0;
      for(addr = real_start; addr < real_end; addr++) {
          if (addr < start || addr >= end)
              prot1 |= page_get_flags(addr);
      }
  
      if (prot1 == 0) {
          /* no page was there, so we allocate one */
          void *p = mmap(host_start, qemu_host_page_size, prot,
                         flags | MAP_ANONYMOUS, -1, 0);
          if (p == MAP_FAILED)
              return -1;
          prot1 = prot;
      }
      prot1 &= PAGE_BITS;
  
      prot_new = prot | prot1;
      if (!(flags & MAP_ANONYMOUS)) {
          /* msync() won't work here, so we return an error if write is
             possible while it is a shared mapping */
          if ((flags & MAP_TYPE) == MAP_SHARED &&
              (prot & PROT_WRITE))
              return -1;
  
          /* adjust protection to be able to read */
          if (!(prot1 & PROT_WRITE))
              mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
  
          /* read the corresponding file data */
          if (pread(fd, g2h(start), end - start, offset) == -1)
              return -1;
  
          /* put final protection */
          if (prot_new != (prot1 | PROT_WRITE))
              mprotect(host_start, qemu_host_page_size, prot_new);
      } else {
          if (prot_new != prot1) {
              mprotect(host_start, qemu_host_page_size, prot_new);
          }
          if (prot_new & PROT_WRITE) {
              memset(g2h(start), 0, end - start);
          }
      }
      return 0;
  }
  
  #if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
  # define TASK_UNMAPPED_BASE  (1ul << 38)
  #elif defined(__CYGWIN__)
  /* Cygwin doesn't have a whole lot of address space.  */
  # define TASK_UNMAPPED_BASE  0x18000000
  #else
  # define TASK_UNMAPPED_BASE  0x40000000
  #endif
  abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
  
  unsigned long last_brk;
  
  /* Subroutine of mmap_find_vma, used when we have pre-allocated a chunk
     of guest address space.  */
  static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size)
  {
      abi_ulong addr;
      abi_ulong end_addr;
      int prot;
      int looped = 0;
  
      if (size > reserved_va) {
          return (abi_ulong)-1;
      }
  
      size = HOST_PAGE_ALIGN(size);
      end_addr = start + size;
      if (end_addr > reserved_va) {
          end_addr = reserved_va;
      }
      addr = end_addr - qemu_host_page_size;
  
      while (1) {
          if (addr > end_addr) {
              if (looped) {
                  return (abi_ulong)-1;
              }
              end_addr = reserved_va;
              addr = end_addr - qemu_host_page_size;
              looped = 1;
              continue;
          }
          prot = page_get_flags(addr);
          if (prot) {
              end_addr = addr;
          }
          if (addr + size == end_addr) {
              break;
          }
          addr -= qemu_host_page_size;
      }
  
      if (start == mmap_next_start) {
          mmap_next_start = addr;
      }
  
      return addr;
  }
  
  /*
   * Find and reserve a free memory area of size 'size'. The search
   * starts at 'start'.
   * It must be called with mmap_lock() held.
   * Return -1 if error.
   */
  abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
  {
      void *ptr, *prev;
      abi_ulong addr;
      int wrapped, repeat;
  
      /* If 'start' == 0, then a default start address is used. */
      if (start == 0) {
          start = mmap_next_start;
      } else {
          start &= qemu_host_page_mask;
      }
  
      size = HOST_PAGE_ALIGN(size);
  
      if (reserved_va) {
          return mmap_find_vma_reserved(start, size);
      }
  
      addr = start;
      wrapped = repeat = 0;
      prev = 0;
  
      for (;; prev = ptr) {
          /*
           * Reserve needed memory area to avoid a race.
           * It should be discarded using:
           *  - mmap() with MAP_FIXED flag
           *  - mremap() with MREMAP_FIXED flag
           *  - shmat() with SHM_REMAP flag
           */
          ptr = mmap(g2h(addr), size, PROT_NONE,
                     MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
  
          /* ENOMEM, if host address space has no memory */
          if (ptr == MAP_FAILED) {
              return (abi_ulong)-1;
          }
  
          /* Count the number of sequential returns of the same address.
             This is used to modify the search algorithm below.  */
          repeat = (ptr == prev ? repeat + 1 : 0);
  
          if (h2g_valid(ptr + size - 1)) {
              addr = h2g(ptr);
  
              if ((addr & ~TARGET_PAGE_MASK) == 0) {
                  /* Success.  */
                  if (start == mmap_next_start && addr >= TASK_UNMAPPED_BASE) {
                      mmap_next_start = addr + size;
                  }
                  return addr;
              }
  
              /* The address is not properly aligned for the target.  */
              switch (repeat) {
              case 0:
                  /* Assume the result that the kernel gave us is the
                     first with enough free space, so start again at the
                     next higher target page.  */
                  addr = TARGET_PAGE_ALIGN(addr);
                  break;
              case 1:
                  /* Sometimes the kernel decides to perform the allocation
                     at the top end of memory instead.  */
                  addr &= TARGET_PAGE_MASK;
                  break;
              case 2:
                  /* Start over at low memory.  */
                  addr = 0;
                  break;
              default:
                  /* Fail.  This unaligned block must the last.  */
                  addr = -1;
                  break;
              }
          } else {
              /* Since the result the kernel gave didn't fit, start
                 again at low memory.  If any repetition, fail.  */
              addr = (repeat ? -1 : 0);
          }
  
          /* Unmap and try again.  */
          munmap(ptr, size);
  
          /* ENOMEM if we checked the whole of the target address space.  */
          if (addr == (abi_ulong)-1) {
              return (abi_ulong)-1;
          } else if (addr == 0) {
              if (wrapped) {
                  return (abi_ulong)-1;
              }
              wrapped = 1;
              /* Don't actually use 0 when wrapping, instead indicate
                 that we'd truly like an allocation in low memory.  */
              addr = (mmap_min_addr > TARGET_PAGE_SIZE
                       ? TARGET_PAGE_ALIGN(mmap_min_addr)
                       : TARGET_PAGE_SIZE);
          } else if (wrapped && addr >= start) {
              return (abi_ulong)-1;
          }
      }
  }
  
  /* NOTE: all the constants are the HOST ones */
  abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                       int flags, int fd, abi_ulong offset)
  {
      abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
  
      mmap_lock();
  #ifdef DEBUG_MMAP
      {
          printf("mmap: start=0x" TARGET_ABI_FMT_lx
                 " len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c flags=",
                 start, len,
                 prot & PROT_READ ? 'r' : '-',
                 prot & PROT_WRITE ? 'w' : '-',
                 prot & PROT_EXEC ? 'x' : '-');
          if (flags & MAP_FIXED)
              printf("MAP_FIXED ");
          if (flags & MAP_ANONYMOUS)
              printf("MAP_ANON ");
          switch(flags & MAP_TYPE) {
          case MAP_PRIVATE:
              printf("MAP_PRIVATE ");
              break;
          case MAP_SHARED:
              printf("MAP_SHARED ");
              break;
          default:
              printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
              break;
          }
          printf("fd=%d offset=" TARGET_ABI_FMT_lx "\n", fd, offset);
      }
  #endif
  
      if (offset & ~TARGET_PAGE_MASK) {
          errno = EINVAL;
          goto fail;
      }
  
      len = TARGET_PAGE_ALIGN(len);
      if (len == 0)
          goto the_end;
      real_start = start & qemu_host_page_mask;
      host_offset = offset & qemu_host_page_mask;
  
      /* If the user is asking for the kernel to find a location, do that
         before we truncate the length for mapping files below.  */
      if (!(flags & MAP_FIXED)) {
          host_len = len + offset - host_offset;
          host_len = HOST_PAGE_ALIGN(host_len);
          start = mmap_find_vma(real_start, host_len);
          if (start == (abi_ulong)-1) {
              errno = ENOMEM;
              goto fail;
          }
      }
  
      /* When mapping files into a memory area larger than the file, accesses
         to pages beyond the file size will cause a SIGBUS. 
  
         For example, if mmaping a file of 100 bytes on a host with 4K pages
         emulating a target with 8K pages, the target expects to be able to
         access the first 8K. But the host will trap us on any access beyond
         4K.  
  
         When emulating a target with a larger page-size than the hosts, we
         may need to truncate file maps at EOF and add extra anonymous pages
         up to the targets page boundary.  */
  
      if ((qemu_real_host_page_size < TARGET_PAGE_SIZE)
          && !(flags & MAP_ANONYMOUS)) {
         struct stat sb;
  
         if (fstat (fd, &sb) == -1)
             goto fail;
  
         /* Are we trying to create a map beyond EOF?.  */
         if (offset + len > sb.st_size) {
             /* If so, truncate the file map at eof aligned with 
                the hosts real pagesize. Additional anonymous maps
                will be created beyond EOF.  */
             len = REAL_HOST_PAGE_ALIGN(sb.st_size - offset);
         }
      }
  
      if (!(flags & MAP_FIXED)) {
          unsigned long host_start;
          void *p;
  
          host_len = len + offset - host_offset;
          host_len = HOST_PAGE_ALIGN(host_len);
  
          /* Note: we prefer to control the mapping address. It is
             especially important if qemu_host_page_size >
             qemu_real_host_page_size */
          p = mmap(g2h(start), host_len, prot,
                   flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
          if (p == MAP_FAILED)
              goto fail;
          /* update start so that it points to the file position at 'offset' */
          host_start = (unsigned long)p;
          if (!(flags & MAP_ANONYMOUS)) {
              p = mmap(g2h(start), len, prot,
                       flags | MAP_FIXED, fd, host_offset);
              if (p == MAP_FAILED) {
                  munmap(g2h(start), host_len);
                  goto fail;
              }
              host_start += offset - host_offset;
          }
          start = h2g(host_start);
      } else {
          if (start & ~TARGET_PAGE_MASK) {
              errno = EINVAL;
              goto fail;
          }
          end = start + len;
          real_end = HOST_PAGE_ALIGN(end);
  
  	/*
  	 * Test if requested memory area fits target address space
  	 * It can fail only on 64-bit host with 32-bit target.
  	 * On any other target/host host mmap() handles this error correctly.
  	 */
          if ((unsigned long)start + len - 1 > (abi_ulong) -1) {
              errno = EINVAL;
              goto fail;
          }
  
          /* worst case: we cannot map the file because the offset is not
             aligned, so we read it */
          if (!(flags & MAP_ANONYMOUS) &&
              (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
              /* msync() won't work here, so we return an error if write is
                 possible while it is a shared mapping */
              if ((flags & MAP_TYPE) == MAP_SHARED &&
                  (prot & PROT_WRITE)) {
                  errno = EINVAL;
                  goto fail;
              }
              retaddr = target_mmap(start, len, prot | PROT_WRITE,
                                    MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
                                    -1, 0);
              if (retaddr == -1)
                  goto fail;
              if (pread(fd, g2h(start), len, offset) == -1)
                  goto fail;
              if (!(prot & PROT_WRITE)) {
                  ret = target_mprotect(start, len, prot);
                  assert(ret == 0);
              }
              goto the_end;
          }
          
          /* handle the start of the mapping */
          if (start > real_start) {
              if (real_end == real_start + qemu_host_page_size) {
                  /* one single host page */
                  ret = mmap_frag(real_start, start, end,
                                  prot, flags, fd, offset);
                  if (ret == -1)
                      goto fail;
                  goto the_end1;
              }
              ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
                              prot, flags, fd, offset);
              if (ret == -1)
                  goto fail;
              real_start += qemu_host_page_size;
          }
          /* handle the end of the mapping */
          if (end < real_end) {
              ret = mmap_frag(real_end - qemu_host_page_size,
                              real_end - qemu_host_page_size, end,
                              prot, flags, fd,
                              offset + real_end - qemu_host_page_size - start);
              if (ret == -1)
                  goto fail;
              real_end -= qemu_host_page_size;
          }
  
          /* map the middle (easier) */
          if (real_start < real_end) {
              void *p;
              unsigned long offset1;
              if (flags & MAP_ANONYMOUS)
                  offset1 = 0;
              else
                  offset1 = offset + real_start - start;
              p = mmap(g2h(real_start), real_end - real_start,
                       prot, flags, fd, offset1);
              if (p == MAP_FAILED)
                  goto fail;
          }
      }
   the_end1:
      page_set_flags(start, start + len, prot | PAGE_VALID);
   the_end:
  #ifdef DEBUG_MMAP
      printf("ret=0x" TARGET_ABI_FMT_lx "\n", start);
      page_dump(stdout);
      printf("\n");
  #endif
      tb_invalidate_phys_range(start, start + len);
      mmap_unlock();
      return start;
  fail:
      mmap_unlock();
      return -1;
  }
  
  static void mmap_reserve(abi_ulong start, abi_ulong size)
  {
      abi_ulong real_start;
      abi_ulong real_end;
      abi_ulong addr;
      abi_ulong end;
      int prot;
  
      real_start = start & qemu_host_page_mask;
      real_end = HOST_PAGE_ALIGN(start + size);
      end = start + size;
      if (start > real_start) {
          /* handle host page containing start */
          prot = 0;
          for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
              prot |= page_get_flags(addr);
          }
          if (real_end == real_start + qemu_host_page_size) {
              for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
                  prot |= page_get_flags(addr);
              }
              end = real_end;
          }
          if (prot != 0)
              real_start += qemu_host_page_size;
      }
      if (end < real_end) {
          prot = 0;
          for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
              prot |= page_get_flags(addr);
          }
          if (prot != 0)
              real_end -= qemu_host_page_size;
      }
      if (real_start != real_end) {
          mmap(g2h(real_start), real_end - real_start, PROT_NONE,
                   MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE,
                   -1, 0);
      }
  }
  
  int target_munmap(abi_ulong start, abi_ulong len)
  {
      abi_ulong end, real_start, real_end, addr;
      int prot, ret;
  
  #ifdef DEBUG_MMAP
      printf("munmap: start=0x" TARGET_ABI_FMT_lx " len=0x"
             TARGET_ABI_FMT_lx "\n",
             start, len);
  #endif
      if (start & ~TARGET_PAGE_MASK)
          return -EINVAL;
      len = TARGET_PAGE_ALIGN(len);
      if (len == 0)
          return -EINVAL;
      mmap_lock();
      end = start + len;
      real_start = start & qemu_host_page_mask;
      real_end = HOST_PAGE_ALIGN(end);
  
      if (start > real_start) {
          /* handle host page containing start */
          prot = 0;
          for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
              prot |= page_get_flags(addr);
          }
          if (real_end == real_start + qemu_host_page_size) {
              for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
                  prot |= page_get_flags(addr);
              }
              end = real_end;
          }
          if (prot != 0)
              real_start += qemu_host_page_size;
      }
      if (end < real_end) {
          prot = 0;
          for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
              prot |= page_get_flags(addr);
          }
          if (prot != 0)
              real_end -= qemu_host_page_size;
      }
  
      ret = 0;
      /* unmap what we can */
      if (real_start < real_end) {
          if (reserved_va) {
              mmap_reserve(real_start, real_end - real_start);
          } else {
              ret = munmap(g2h(real_start), real_end - real_start);
          }
      }
  
      if (ret == 0) {
          page_set_flags(start, start + len, 0);
          tb_invalidate_phys_range(start, start + len);
      }
      mmap_unlock();
      return ret;
  }
  
  abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                         abi_ulong new_size, unsigned long flags,
                         abi_ulong new_addr)
  {
      int prot;
      void *host_addr;
  
      mmap_lock();
  
      if (flags & MREMAP_FIXED) {
          host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
                                       old_size, new_size,
                                       flags,
                                       g2h(new_addr));
  
          if (reserved_va && host_addr != MAP_FAILED) {
              /* If new and old addresses overlap then the above mremap will
                 already have failed with EINVAL.  */
              mmap_reserve(old_addr, old_size);
          }
      } else if (flags & MREMAP_MAYMOVE) {
          abi_ulong mmap_start;
  
          mmap_start = mmap_find_vma(0, new_size);
  
          if (mmap_start == -1) {
              errno = ENOMEM;
              host_addr = MAP_FAILED;
          } else {
              host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
                                           old_size, new_size,
                                           flags | MREMAP_FIXED,
                                           g2h(mmap_start));
              if (reserved_va) {
                  mmap_reserve(old_addr, old_size);
              }
          }
      } else {
          int prot = 0;
          if (reserved_va && old_size < new_size) {
              abi_ulong addr;
              for (addr = old_addr + old_size;
                   addr < old_addr + new_size;
                   addr++) {
                  prot |= page_get_flags(addr);
              }
          }
          if (prot == 0) {
              host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
              if (host_addr != MAP_FAILED && reserved_va && old_size > new_size) {
                  mmap_reserve(old_addr + old_size, new_size - old_size);
              }
          } else {
              errno = ENOMEM;
              host_addr = MAP_FAILED;
          }
          /* Check if address fits target address space */
          if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
              /* Revert mremap() changes */
              host_addr = mremap(g2h(old_addr), new_size, old_size, flags);
              errno = ENOMEM;
              host_addr = MAP_FAILED;
          }
      }
  
      if (host_addr == MAP_FAILED) {
          new_addr = -1;
      } else {
          new_addr = h2g(host_addr);
          prot = page_get_flags(old_addr);
          page_set_flags(old_addr, old_addr + old_size, 0);
          page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
      }
      tb_invalidate_phys_range(new_addr, new_addr + new_size);
      mmap_unlock();
      return new_addr;
  }
  
  int target_msync(abi_ulong start, abi_ulong len, int flags)
  {
      abi_ulong end;
  
      if (start & ~TARGET_PAGE_MASK)
          return -EINVAL;
      len = TARGET_PAGE_ALIGN(len);
      end = start + len;
      if (end < start)
          return -EINVAL;
      if (end == start)
          return 0;
  
      start &= qemu_host_page_mask;
      return msync(g2h(start), end - start, flags);
  }
  