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Kernel: Make VM allocation atomic for userspace regions

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This patch move AddressSpace (the per-process memory manager) to using
the new atomic "place" APIs in RegionTree as well, just like we did for
MemoryManager in the previous commit.

This required updating quite a few places where VM allocation and
actually committing a Region object to the AddressSpace were separated
by other code.

All you have to do now is call into AddressSpace once and it'll take
care of everything for you.
This commit is contained in:
Andreas Kling 2022-04-03 17:12:39 +02:00
parent e852a69a06
commit 07f3d09c55
13 changed files with 84 additions and 91 deletions
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31
Kernel/Syscalls/mmap.cpp
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@ -191,23 +191,15 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<Syscall::SC_mmap_params const*> use
Memory::Region* region = nullptr;
auto range = TRY([&]() -> ErrorOr<Memory::VirtualRange> {
if (map_randomized)
return address_space().region_tree().try_allocate_randomized(rounded_size, alignment);
// If MAP_FIXED is specified, existing mappings that intersect the requested range are removed.
if (map_fixed)
TRY(address_space().unmap_mmap_range(VirtualAddress(addr), size));
// If MAP_FIXED is specified, existing mappings that intersect the requested range are removed.
if (map_fixed)
TRY(address_space().unmap_mmap_range(VirtualAddress(addr), size));
auto range = address_space().try_allocate_range(VirtualAddress(addr), size, alignment);
if (range.is_error()) {
if (addr && !(map_fixed || map_fixed_noreplace)) {
// If there's an address but MAP_FIXED wasn't specified, the address is just a hint.
range = address_space().try_allocate_range({}, size, alignment);
}
}
return range;
}());
Memory::VirtualRange requested_range { VirtualAddress { addr }, size };
if (addr && !(map_fixed || map_fixed_noreplace)) {
// If there's an address but MAP_FIXED wasn't specified, the address is just a hint.
requested_range = { {}, 0 };
}
if (map_anonymous) {
auto strategy = map_noreserve ? AllocationStrategy::None : AllocationStrategy::Reserve;
@ -218,7 +210,7 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<Syscall::SC_mmap_params const*> use
vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(rounded_size, strategy));
}
region = TRY(address_space().allocate_region_with_vmobject(range, vmobject.release_nonnull(), 0, {}, prot, map_shared));
region = TRY(address_space().allocate_region_with_vmobject(requested_range.base(), requested_range.size(), alignment, vmobject.release_nonnull(), 0, {}, prot, map_shared));
} else {
if (offset < 0)
return EINVAL;
@ -237,7 +229,7 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<Syscall::SC_mmap_params const*> use
if (description->inode())
TRY(validate_inode_mmap_prot(prot, *description->inode(), map_shared));
region = TRY(description->mmap(*this, range, static_cast<u64>(offset), prot, map_shared));
region = TRY(description->mmap(*this, requested_range, static_cast<u64>(offset), prot, map_shared));
}
if (!region)
@ -515,8 +507,7 @@ ErrorOr<FlatPtr> Process::sys$allocate_tls(Userspace<char const*> initial_data,
if (multiple_threads)
return EINVAL;
auto range = TRY(address_space().try_allocate_range({}, size));
auto* region = TRY(address_space().allocate_region(range, "Master TLS"sv, PROT_READ | PROT_WRITE));
auto* region = TRY(address_space().allocate_region({}, size, PAGE_SIZE, "Master TLS"sv, PROT_READ | PROT_WRITE));
m_master_tls_region = TRY(region->try_make_weak_ptr());
m_master_tls_size = size;