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https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
Kernel: Move sys$munmap functionality into a helper method
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b9d693665b
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95c2166ca9
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@ -507,100 +507,9 @@ KResultOr<int> Process::sys$munmap(Userspace<void*> addr, size_t size)
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{
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REQUIRE_PROMISE(stdio);
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if (!size)
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return EINVAL;
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auto range_or_error = expand_range_to_page_boundaries(addr, size);
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if (range_or_error.is_error())
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return range_or_error.error();
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auto range_to_unmap = range_or_error.value();
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if (!is_user_range(range_to_unmap))
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return EFAULT;
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if (auto* whole_region = space().find_region_from_range(range_to_unmap)) {
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if (!whole_region->is_mmap())
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return EPERM;
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PerformanceManager::add_unmap_perf_event(*this, whole_region->range());
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bool success = space().deallocate_region(*whole_region);
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VERIFY(success);
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return 0;
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}
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if (auto* old_region = space().find_region_containing(range_to_unmap)) {
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if (!old_region->is_mmap())
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return EPERM;
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// Remove the old region from our regions tree, since were going to add another region
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// with the exact same start address, but dont deallocate it yet
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auto region = space().take_region(*old_region);
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VERIFY(region);
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// We manually unmap the old region here, specifying that we *don't* want the VM deallocated.
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region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
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auto new_regions = space().split_region_around_range(*region, range_to_unmap);
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// Instead we give back the unwanted VM manually.
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space().page_directory().range_allocator().deallocate(range_to_unmap);
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// And finally we map the new region(s) using our page directory (they were just allocated and don't have one).
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for (auto* new_region : new_regions) {
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new_region->map(space().page_directory());
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}
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if (auto* event_buffer = current_perf_events_buffer()) {
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[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_MUNMAP, range_to_unmap.base().get(), range_to_unmap.size(), nullptr);
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}
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return 0;
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}
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// Try again while checkin multiple regions at a time
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// slow: without caching
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const auto& regions = space().find_regions_intersecting(range_to_unmap);
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// Check if any of the regions is not mmapped, to not accidentally
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// error-out with just half a region map left
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for (auto* region : regions) {
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if (!region->is_mmap())
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return EPERM;
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}
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Vector<Region*, 2> new_regions;
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for (auto* old_region : regions) {
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// if it's a full match we can delete the complete old region
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if (old_region->range().intersect(range_to_unmap).size() == old_region->size()) {
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bool res = space().deallocate_region(*old_region);
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VERIFY(res);
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continue;
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}
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// Remove the old region from our regions tree, since were going to add another region
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// with the exact same start address, but dont deallocate it yet
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auto region = space().take_region(*old_region);
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VERIFY(region);
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// We manually unmap the old region here, specifying that we *don't* want the VM deallocated.
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region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
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// Otherwise just split the regions and collect them for future mapping
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if (new_regions.try_append(space().split_region_around_range(*region, range_to_unmap)))
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return ENOMEM;
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}
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// Instead we give back the unwanted VM manually at the end.
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space().page_directory().range_allocator().deallocate(range_to_unmap);
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// And finally we map the new region(s) using our page directory (they were just allocated and don't have one).
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for (auto* new_region : new_regions) {
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new_region->map(space().page_directory());
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}
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PerformanceManager::add_unmap_perf_event(*this, range_to_unmap);
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auto result = space().unmap_mmap_range(VirtualAddress { addr }, size);
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if (result.is_error())
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return result;
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return 0;
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}
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@ -7,6 +7,7 @@
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#include <AK/Vector.h>
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#include <Kernel/Arch/x86/CPU.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/Range.h>
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namespace Kernel {
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@ -35,4 +36,21 @@ Range Range::intersect(const Range& other) const
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return Range(new_base, (new_end - new_base).get());
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}
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KResultOr<Range> Range::expand_to_page_boundaries(FlatPtr address, size_t size)
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{
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if (page_round_up_would_wrap(size))
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return EINVAL;
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if ((address + size) < address)
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return EINVAL;
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if (page_round_up_would_wrap(address + size))
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return EINVAL;
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auto base = VirtualAddress { address }.page_base();
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auto end = page_round_up(address + size);
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return Range { base, end - base.get() };
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}
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}
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@ -50,6 +50,8 @@ public:
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Vector<Range, 2> carve(const Range&) const;
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Range intersect(const Range&) const;
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static KResultOr<Range> expand_to_page_boundaries(FlatPtr address, size_t size);
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private:
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VirtualAddress m_base;
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size_t m_size { 0 };
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@ -6,6 +6,7 @@
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*/
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#include <AK/QuickSort.h>
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#include <Kernel/PerformanceManager.h>
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#include <Kernel/Process.h>
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#include <Kernel/SpinLock.h>
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#include <Kernel/VM/AnonymousVMObject.h>
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@ -37,6 +38,103 @@ Space::~Space()
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{
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}
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KResult Space::unmap_mmap_range(VirtualAddress addr, size_t size)
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{
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if (!size)
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return EINVAL;
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auto range_or_error = Range::expand_to_page_boundaries(addr.get(), size);
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if (range_or_error.is_error())
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return range_or_error.error();
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auto range_to_unmap = range_or_error.value();
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if (!is_user_range(range_to_unmap))
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return EFAULT;
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if (auto* whole_region = find_region_from_range(range_to_unmap)) {
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if (!whole_region->is_mmap())
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return EPERM;
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PerformanceManager::add_unmap_perf_event(*Process::current(), whole_region->range());
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bool success = deallocate_region(*whole_region);
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VERIFY(success);
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return KSuccess;
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}
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if (auto* old_region = find_region_containing(range_to_unmap)) {
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if (!old_region->is_mmap())
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return EPERM;
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// Remove the old region from our regions tree, since were going to add another region
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// with the exact same start address, but dont deallocate it yet
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auto region = take_region(*old_region);
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VERIFY(region);
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// We manually unmap the old region here, specifying that we *don't* want the VM deallocated.
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region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
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auto new_regions = split_region_around_range(*region, range_to_unmap);
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// Instead we give back the unwanted VM manually.
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page_directory().range_allocator().deallocate(range_to_unmap);
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// And finally we map the new region(s) using our page directory (they were just allocated and don't have one).
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for (auto* new_region : new_regions) {
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new_region->map(page_directory());
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}
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PerformanceManager::add_unmap_perf_event(*Process::current(), range_to_unmap);
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return KSuccess;
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}
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// Try again while checkin multiple regions at a time
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// slow: without caching
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const auto& regions = find_regions_intersecting(range_to_unmap);
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// Check if any of the regions is not mmapped, to not accidentally
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// error-out with just half a region map left
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for (auto* region : regions) {
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if (!region->is_mmap())
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return EPERM;
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}
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Vector<Region*, 2> new_regions;
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for (auto* old_region : regions) {
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// if it's a full match we can delete the complete old region
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if (old_region->range().intersect(range_to_unmap).size() == old_region->size()) {
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bool res = deallocate_region(*old_region);
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VERIFY(res);
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continue;
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}
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// Remove the old region from our regions tree, since were going to add another region
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// with the exact same start address, but dont deallocate it yet
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auto region = take_region(*old_region);
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VERIFY(region);
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// We manually unmap the old region here, specifying that we *don't* want the VM deallocated.
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region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
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// Otherwise just split the regions and collect them for future mapping
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if (new_regions.try_append(split_region_around_range(*region, range_to_unmap)))
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return ENOMEM;
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}
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// Instead we give back the unwanted VM manually at the end.
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page_directory().range_allocator().deallocate(range_to_unmap);
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// And finally we map the new region(s) using our page directory (they were just allocated and don't have one).
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for (auto* new_region : new_regions) {
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new_region->map(page_directory());
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}
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PerformanceManager::add_unmap_perf_event(*Process::current(), range_to_unmap);
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return KSuccess;
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}
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Optional<Range> Space::allocate_range(VirtualAddress vaddr, size_t size, size_t alignment)
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{
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vaddr.mask(PAGE_MASK);
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@ -33,6 +33,8 @@ public:
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void dump_regions();
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KResult unmap_mmap_range(VirtualAddress, size_t);
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Optional<Range> allocate_range(VirtualAddress, size_t, size_t alignment = PAGE_SIZE);
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KResultOr<Region*> allocate_region_with_vmobject(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, StringView name, int prot, bool shared);
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