diff options
| -rw-r--r-- | Kernel/Syscalls/mmap.cpp | 44 | ||||
| -rw-r--r-- | Kernel/VM/Space.cpp | 11 | ||||
| -rw-r--r-- | Kernel/VM/Space.h | 1 |
3 files changed, 36 insertions, 20 deletions
diff --git a/Kernel/Syscalls/mmap.cpp b/Kernel/Syscalls/mmap.cpp index d818701629..db401a59c5 100644 --- a/Kernel/Syscalls/mmap.cpp +++ b/Kernel/Syscalls/mmap.cpp @@ -341,20 +341,24 @@ KResultOr<int> Process::sys$mprotect(Userspace<void*> addr, size_t size, int pro return EACCES; } + // Remove the old region from our regions tree, since were going to add another region + // with the exact same start address, but dont deallocate it yet + auto region = space().take_region(*old_region); + VERIFY(region); + + // Unmap the old region here, specifying that we *don't* want the VM deallocated. + region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); + // This vector is the region(s) adjacent to our range. // We need to allocate a new region for the range we wanted to change permission bits on. - auto adjacent_regions = space().split_region_around_range(*old_region, range_to_mprotect); + auto adjacent_regions = space().split_region_around_range(*region, range_to_mprotect); - size_t new_range_offset_in_vmobject = old_region->offset_in_vmobject() + (range_to_mprotect.base().get() - old_region->range().base().get()); - auto& new_region = space().allocate_split_region(*old_region, range_to_mprotect, new_range_offset_in_vmobject); + size_t new_range_offset_in_vmobject = region->offset_in_vmobject() + (range_to_mprotect.base().get() - region->range().base().get()); + auto& new_region = space().allocate_split_region(*region, range_to_mprotect, new_range_offset_in_vmobject); new_region.set_readable(prot & PROT_READ); new_region.set_writable(prot & PROT_WRITE); new_region.set_executable(prot & PROT_EXEC); - // Unmap the old region here, specifying that we *don't* want the VM deallocated. - old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); - space().deallocate_region(*old_region); - // Map the new regions using our page directory (they were just allocated and don't have one). for (auto* adjacent_region : adjacent_regions) { adjacent_region->map(space().page_directory()); @@ -475,11 +479,15 @@ KResultOr<int> Process::sys$munmap(Userspace<void*> addr, size_t size) if (!old_region->is_mmap()) return EPERM; - auto new_regions = space().split_region_around_range(*old_region, range_to_unmap); + // Remove the old region from our regions tree, since were going to add another region + // with the exact same start address, but dont deallocate it yet + auto region = space().take_region(*old_region); + VERIFY(region); // We manually unmap the old region here, specifying that we *don't* want the VM deallocated. - old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); - space().deallocate_region(*old_region); + region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); + + auto new_regions = space().split_region_around_range(*region, range_to_unmap); // Instead we give back the unwanted VM manually. space().page_directory().range_allocator().deallocate(range_to_unmap); @@ -512,13 +520,16 @@ KResultOr<int> Process::sys$munmap(Userspace<void*> addr, size_t size) continue; } - // otherwise just split the regions and collect them for future mapping - new_regions.append(space().split_region_around_range(*old_region, range_to_unmap)); + // Remove the old region from our regions tree, since were going to add another region + // with the exact same start address, but dont deallocate it yet + auto region = space().take_region(*old_region); + VERIFY(region); // We manually unmap the old region here, specifying that we *don't* want the VM deallocated. - old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); - bool res = space().deallocate_region(*old_region); - VERIFY(res); + region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); + + // otherwise just split the regions and collect them for future mapping + new_regions.append(space().split_region_around_range(*region, range_to_unmap)); } // Instead we give back the unwanted VM manually at the end. space().page_directory().range_allocator().deallocate(range_to_unmap); @@ -559,7 +570,8 @@ KResultOr<FlatPtr> Process::sys$mremap(Userspace<const Syscall::SC_mremap_params // Unmap without deallocating the VM range since we're going to reuse it. old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No); - space().deallocate_region(*old_region); + bool success = space().deallocate_region(*old_region); + VERIFY(success); auto new_vmobject = PrivateInodeVMObject::create_with_inode(inode); diff --git a/Kernel/VM/Space.cpp b/Kernel/VM/Space.cpp index 94a7628f95..bb48d700d0 100644 --- a/Kernel/VM/Space.cpp +++ b/Kernel/VM/Space.cpp @@ -118,18 +118,21 @@ KResultOr<Region*> Space::allocate_region_with_vmobject(const Range& range, Nonn bool Space::deallocate_region(Region& region) { - OwnPtr<Region> region_protector; + return take_region(region); +} + +OwnPtr<Region> Space::take_region(Region& region) +{ ScopedSpinLock lock(m_lock); if (m_region_lookup_cache.region.unsafe_ptr() == ®ion) m_region_lookup_cache.region = nullptr; for (size_t i = 0; i < m_regions.size(); ++i) { if (&m_regions[i] == ®ion) { - region_protector = m_regions.unstable_take(i); - return true; + return m_regions.unstable_take(i); } } - return false; + return {}; } Region* Space::find_region_from_range(const Range& range) diff --git a/Kernel/VM/Space.h b/Kernel/VM/Space.h index dde64230dc..fd5ae428b1 100644 --- a/Kernel/VM/Space.h +++ b/Kernel/VM/Space.h @@ -58,6 +58,7 @@ public: KResultOr<Region*> allocate_region_with_vmobject(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const String& name, int prot, bool shared); KResultOr<Region*> allocate_region(const Range&, const String& name, int prot = PROT_READ | PROT_WRITE, AllocationStrategy strategy = AllocationStrategy::Reserve); bool deallocate_region(Region& region); + OwnPtr<Region> take_region(Region& region); Region& allocate_split_region(const Region& source_region, const Range&, size_t offset_in_vmobject); Vector<Region*, 2> split_region_around_range(const Region& source_region, const Range&); |