int clone_area(const char name[], void **clone_addr, int searchFlags,
PageProtection protection, int sourceArea)
{
Area *area = static_cast<Area*>(GetResource(sourceArea, OBJ_AREA));
if (area == 0) {
printf("clone_area: source area id %08x is invalid\n", sourceArea);
return E_BAD_HANDLE;
}
unsigned int addr = INVALID_PAGE;
if (searchFlags & EXACT_ADDRESS)
addr = reinterpret_cast<unsigned int>(*clone_addr);
// It is important that CreateArea not incur a fault!
char nameCopy[OS_NAME_LENGTH];
if (!CopyUser(nameCopy, name, OS_NAME_LENGTH))
return E_BAD_ADDRESS;
Area *newArea = AddressSpace::GetCurrentAddressSpace()->CreateArea(nameCopy, area->GetSize(), AREA_NOT_WIRED,
protection | USER_READ | SYSTEM_READ | ((protection & USER_WRITE)
? SYSTEM_WRITE : 0), area->GetPageCache(), 0, addr, searchFlags);
area->ReleaseRef();
if (newArea == 0)
return E_ERROR;
*clone_addr = reinterpret_cast<void*>(newArea->GetBaseAddress());
return OpenHandle(newArea);
}
int create_area(const char name[], void **requestAddr, int flags, unsigned int size,
AreaWiring lock, PageProtection protection)
{
unsigned int va = INVALID_PAGE;
if (flags & EXACT_ADDRESS)
va = reinterpret_cast<unsigned int>(*requestAddr);
PageCache *cache = new PageCache;
if (cache == 0)
return E_NO_MEMORY;
// It is important that CreateArea not incur a fault!
char nameCopy[OS_NAME_LENGTH];
if (!CopyUser(nameCopy, name, OS_NAME_LENGTH))
return E_BAD_ADDRESS;
Area *newArea = AddressSpace::GetCurrentAddressSpace()->CreateArea(nameCopy, size, lock,
protection | USER_READ | SYSTEM_READ | ((protection & USER_WRITE)
? SYSTEM_WRITE : 0), cache, 0, va, flags);
if (newArea == 0) {
delete cache;
return E_NO_MEMORY;
}
*requestAddr = reinterpret_cast<void*>(newArea->GetBaseAddress());
return OpenHandle(newArea);
}
status_t AddressSpace::HandleFault(unsigned int va, bool write, bool user)
{
va &= ~(PAGE_SIZE - 1); // Round down to a page boundry.
fAreaLock.LockRead();
int lastChangeCount = fChangeCount;
Area *area = static_cast<Area*>(fAreas.Find(va));
if (area == 0) {
fAreaLock.UnlockRead();
return E_BAD_ADDRESS;
}
PageProtection protection = area->GetProtection();
if ((user && write && !(protection & USER_WRITE))
|| (user && !write && !(protection & USER_READ))
|| (!user && write && !(protection & SYSTEM_WRITE))
|| (!user && !write && !(protection & SYSTEM_READ))) {
fAreaLock.UnlockRead();
return E_NOT_ALLOWED;
}
PageCache *cache = area->GetPageCache();
if (cache == 0) {
fAreaLock.UnlockRead();
return E_NOT_ALLOWED;
}
bool copy = cache->IsCopy();
cache->AcquireRef();
fAreaLock.UnlockRead();
off_t offset = va - area->GetBaseAddress() + area->GetCacheOffset();
Page *page = cache->GetPage(offset, write && cache->IsCopy());
cache->ReleaseRef();
if (page == 0)
return E_IO;
fAreaLock.LockRead();
if (lastChangeCount != fChangeCount) {
// Changes have occured to this address. Make sure that
// the area hasn't changed underneath the fault handler.
Area *newArea = static_cast<Area*>(fAreas.Find(va));
if (newArea != area || newArea->GetPageCache() != cache ||
newArea->GetCacheOffset() != offset)
fAreaLock.UnlockRead();
return E_BAD_ADDRESS;
}
// If this is a read from copy-on-write page, it is shared with the
// original cache. Mark it read only.
if (copy && !write)
protection &= ~(USER_WRITE | SYSTEM_WRITE);
fPhysicalMap->Map(va, page->GetPhysicalAddress(), protection);
fAreaLock.UnlockRead();
AtomicAdd(&fFaultCount, 1);
return E_NO_ERROR;
}