author Bas Schouten <>
Fri, 06 Mar 2015 02:37:12 +0100
changeset 250308 a0dcce4081087e2e1f9d6ec7ebf3b9e37b7dc619
parent 248970 3928ee1b0381453833c00fbe1e1b72a26143f13a
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1138934 - Make sure the white texture of a component alpha pair is fully uploaded when new. r=nical, a=lmandel This is slightly wasteful since this will also always upload the full black texture. The wastage here is so rare and generally so few though that I don't think it's worth adding plumming for the texture host to know if this is the texture on white of on black.

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at */

#ifdef ANDROID

#include "mozilla/TaggedAnonymousMemory.h"

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <unistd.h>

#include "mozilla/Assertions.h"

// These constants are copied from <sys/prctl.h>, because the headers
// used for building may not have them even though the running kernel
// supports them.
#ifndef PR_SET_VMA
#define PR_SET_VMA		0x53564d41

namespace mozilla {

// Returns 0 for success and -1 (with errno) for error.
static int
TagAnonymousMemoryAligned(const void* aPtr, size_t aLength, const char* aTag)
  return prctl(PR_SET_VMA,
               reinterpret_cast<unsigned long>(aPtr),
               reinterpret_cast<unsigned long>(aTag));

// On some architectures, it's possible for the page size to be larger
// than the PAGE_SIZE we were compiled with.  This computes the
// equivalent of PAGE_MASK.
static uintptr_t
  static uintptr_t mask = 0;

  if (mask == 0) {
    uintptr_t pageSize = sysconf(_SC_PAGESIZE);
    mask = ~(pageSize - 1);
    MOZ_ASSERT((pageSize & (pageSize - 1)) == 0,
               "Page size must be a power of 2!");
  return mask;

} // namespace mozilla

  static int supported = -1;

  if (supported == -1) {
    // Tagging an empty range always "succeeds" if the feature is supported,
    // regardless of the start pointer.
    supported = mozilla::TagAnonymousMemoryAligned(nullptr, 0, nullptr) == 0;
  return supported;

MozTagAnonymousMemory(const void* aPtr, size_t aLength, const char* aTag)
  if (MozTaggedMemoryIsSupported()) {
    // The kernel will round up the end of the range to the next page
    // boundary if it's not aligned (comments indicate this behavior
    // is based on that of madvise), but it will reject the request if
    // the start is not aligned.  We therefore round down the start
    // address and adjust the length accordingly.
    uintptr_t addr = reinterpret_cast<uintptr_t>(aPtr);
    uintptr_t end = addr + aLength;
    uintptr_t addrRounded = addr & mozilla::GetPageMask();
    const void* ptrRounded = reinterpret_cast<const void*>(addrRounded);

    mozilla::TagAnonymousMemoryAligned(ptrRounded, end - addrRounded, aTag);

MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt, int aFlags,
                       int aFd, off_t aOffset, const char* aTag)
  void* mapped = mmap(aAddr, aLength, aProt, aFlags, aFd, aOffset);
  if (MozTaggedMemoryIsSupported() &&
      (aFlags & MAP_ANONYMOUS) == MAP_ANONYMOUS &&
      mapped != MAP_FAILED) {
    mozilla::TagAnonymousMemoryAligned(mapped, aLength, aTag);
  return mapped;

#endif // ANDROID