[PATCH] D33874: Implement AllocateRWX and ReleaseRWX for NetBSD

[Kamil Rytarowski via Phabricator via llvm-commits]

krytarowski added a comment.

On demand I tested the following patch:

  $NetBSD$
  
  --- lib/Support/Unix/Memory.inc.orig	2016-12-16 22:52:53.000000000 +0000
  +++ lib/Support/Unix/Memory.inc
  @@ -195,9 +195,10 @@ Memory::AllocateRWX(size_t NumBytes, con
   #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
     void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_EXEC,
                       flags, fd, 0);
  -#else
  -  void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
  -                    flags, fd, 0);
  +#elif defined(__NetBSD__) && defined(PROT_MPROTECT)
  +  void *pa =
  +      ::mmap(start, PageSize * NumPages,
  +             PROT_READ | PROT_WRITE | PROT_MPROTECT(PROT_EXEC), flags, fd, 0);
   #endif
     if (pa == MAP_FAILED) {
       if (NearBlock) //Try again without a near hint
  @@ -223,10 +224,35 @@ Memory::AllocateRWX(size_t NumBytes, con
       MakeErrMsg(ErrMsg, "vm_protect RW failed");
       return MemoryBlock();
     }
  +#elif defined(__NetBSD__) && defined(PROT_MPROTECT) && 0
  +  void *codeseg =
  +      ::mremap(pa, PageSize * NumPages, NULL, PageSize * NumPages,
  +               MAP_REMAPDUP);
  +  if (codeseg == MAP_FAILED) {
  +    ::munmap(pa, PageSize * NumPages);
  +
  +    if (NearBlock) // Try again without a near hint
  +      return AllocateRWX(NumBytes, nullptr);
  +
  +    MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
  +    return MemoryBlock();
  +  }
  +  if (::mprotect(codeseg, PageSize * NumPages, PROT_READ | PROT_EXEC) == -1) {
  +    ::munmap(pa, PageSize * NumPages);
  +    ::munmap(codeseg, PageSize * NumPages);
  +    if (NearBlock) // Try again without a near hint
  +      return AllocateRWX(NumBytes, nullptr);
  +
  +    MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
  +    return MemoryBlock();
  +  }
   #endif
   
     MemoryBlock result;
     result.Address = pa;
  +#if defined(__NetBSD__) && defined(PROT_MPROTECT) && 0
  +  result.SecondaryAddress = codeseg;
  +#endif
     result.Size = NumPages*PageSize;
   
     return result;
  @@ -236,6 +262,9 @@ bool Memory::ReleaseRWX(MemoryBlock &M, 
     if (M.Address == nullptr || M.Size == 0) return false;
     if (0 != ::munmap(M.Address, M.Size))
       return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
  +  if (M.SecondaryAddress)
  +    if (0 != ::munmap(M.SecondaryAddress, M.Size))
  +      return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
     return false;
   }
   

There are no regressions compared to the pending patch. I don't understand why it works..


Repository:
  rL LLVM

https://reviews.llvm.org/D33874