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LibWeb: Make VM allocation atomic for kernel regions

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Instead of first allocating the VM range, and then inserting a region
with that range into the MM region tree, we now do both things in a
single atomic operation:

    - RegionTree::place_anywhere(Region&, size, alignment)
    - RegionTree::place_specifically(Region&, address, size)

To reduce the number of things we do while locking the region tree,
we also require callers to provide a constructed Region object.
This commit is contained in:
Andreas Kling 2022-04-03 15:27:47 +02:00
parent cbf52d474c
commit e852a69a06
7 changed files with 85 additions and 57 deletions
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21
Kernel/Interrupts/APIC.cpp
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@ -319,19 +319,14 @@ UNMAP_AFTER_INIT bool APIC::init_bsp()
return true;
}
UNMAP_AFTER_INIT static NonnullOwnPtr<Memory::Region> create_identity_mapped_region(PhysicalAddress paddr, size_t size)
UNMAP_AFTER_INIT static ErrorOr<NonnullOwnPtr<Memory::Region>> create_identity_mapped_region(PhysicalAddress paddr, size_t size)
{
auto maybe_vmobject = Memory::AnonymousVMObject::try_create_for_physical_range(paddr, size);
// FIXME: Would be nice to be able to return a ErrorOr from here.
VERIFY(!maybe_vmobject.is_error());
auto region_or_error = MM.allocate_kernel_region_with_vmobject(
Memory::VirtualRange { VirtualAddress { static_cast<FlatPtr>(paddr.get()) }, size },
maybe_vmobject.release_value(),
{},
Memory::Region::Access::ReadWriteExecute);
VERIFY(!region_or_error.is_error());
return region_or_error.release_value();
auto vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(paddr, size));
auto region = TRY(Memory::Region::create_unplaced(move(vmobject), 0, {}, Memory::Region::Access::ReadWriteExecute));
Memory::VirtualRange range { VirtualAddress { paddr.get() }, size };
TRY(MM.region_tree().place_specifically(*region, range));
TRY(region->map(MM.kernel_page_directory()));
return region;
}
UNMAP_AFTER_INIT void APIC::setup_ap_boot_environment()
@ -347,7 +342,7 @@ UNMAP_AFTER_INIT void APIC::setup_ap_boot_environment()
constexpr u64 apic_startup_region_base = 0x8000;
auto apic_startup_region_size = Memory::page_round_up(apic_ap_start_size + (2 * aps_to_enable * sizeof(FlatPtr))).release_value_but_fixme_should_propagate_errors();
VERIFY(apic_startup_region_size < USER_RANGE_BASE);
auto apic_startup_region = create_identity_mapped_region(PhysicalAddress(apic_startup_region_base), apic_startup_region_size);
auto apic_startup_region = MUST(create_identity_mapped_region(PhysicalAddress(apic_startup_region_base), apic_startup_region_size));
u8* apic_startup_region_ptr = apic_startup_region->vaddr().as_ptr();
memcpy(apic_startup_region_ptr, reinterpret_cast<void const*>(apic_ap_start), apic_ap_start_size);