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Kernel: Remove user/kernel flags from Region

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Now that we no longer need to support the signal trampolines being
user-accessible inside the kernel memory range, we can get rid of the
"kernel" and "user-accessible" flags on Region and simply use the
address of the region to determine whether it's kernel or user.

This also tightens the page table mapping code, since it can now set
user-accessibility based solely on the virtual address of a page.
This commit is contained in:
Andreas Kling 2021-02-14 01:25:22 +01:00
parent 1593219a41
commit 8415866c03
13 changed files with 54 additions and 70 deletions
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26
Kernel/VM/Region.cpp
View file

@ -38,16 +38,15 @@
namespace Kernel {
Region::Region(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, u8 access, bool cacheable, bool kernel, bool shared)
Region::Region(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, String name, u8 access, Cacheable cacheable, bool shared)
: PurgeablePageRanges(vmobject)
, m_range(range)
, m_offset_in_vmobject(offset_in_vmobject)
, m_vmobject(move(vmobject))
, m_name(name)
, m_name(move(name))
, m_access(access | ((access & 0x7) << 4))
, m_shared(shared)
, m_cacheable(cacheable)
, m_kernel(kernel)
, m_cacheable(cacheable == Cacheable::Yes)
{
ASSERT(m_range.base().is_page_aligned());
ASSERT(m_range.size());
@ -104,7 +103,7 @@ OwnPtr<Region> Region::clone(Process& new_owner)
// Create a new region backed by the same VMObject.
auto region = Region::create_user_accessible(
&new_owner, m_range, m_vmobject, m_offset_in_vmobject, m_name, m_access, m_cacheable, m_shared);
&new_owner, m_range, m_vmobject, m_offset_in_vmobject, m_name, m_access, m_cacheable ? Cacheable::Yes : Cacheable::No, m_shared);
if (m_vmobject->is_anonymous())
region->copy_purgeable_page_ranges(*this);
region->set_mmap(m_mmap);
@ -123,7 +122,7 @@ OwnPtr<Region> Region::clone(Process& new_owner)
// Set up a COW region. The parent (this) region becomes COW as well!
remap();
auto clone_region = Region::create_user_accessible(
&new_owner, m_range, vmobject_clone.release_nonnull(), m_offset_in_vmobject, m_name, m_access, m_cacheable, m_shared);
&new_owner, m_range, vmobject_clone.release_nonnull(), m_offset_in_vmobject, m_name, m_access, m_cacheable ? Cacheable::Yes : Cacheable::No, m_shared);
if (m_vmobject->is_anonymous())
clone_region->copy_purgeable_page_ranges(*this);
if (m_stack) {
@ -228,20 +227,17 @@ size_t Region::amount_shared() const
return bytes;
}
NonnullOwnPtr<Region> Region::create_user_accessible(Process* owner, const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable, bool shared)
NonnullOwnPtr<Region> Region::create_user_accessible(Process* owner, const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, String name, u8 access, Cacheable cacheable, bool shared)
{
auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access, cacheable, false, shared);
auto region = make<Region>(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, shared);
if (owner)
region->m_owner = owner->make_weak_ptr();
region->m_user_accessible = true;
return region;
}
NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable)
NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, String name, u8 access, Cacheable cacheable)
{
auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access, cacheable, true, false);
region->m_user_accessible = false;
return region;
return make<Region>(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, false);
}
bool Region::should_cow(size_t page_index) const
@ -278,7 +274,7 @@ bool Region::map_individual_page_impl(size_t page_index)
pte->set_writable(is_writable());
if (Processor::current().has_feature(CPUFeature::NX))
pte->set_execute_disabled(!is_executable());
pte->set_user_allowed(is_user_accessible());
pte->set_user_allowed(page_vaddr.get() >= 0x00800000 && is_user_address(page_vaddr));
}
return true;
}
@ -388,7 +384,7 @@ bool Region::map(PageDirectory& page_directory)
ScopedSpinLock page_lock(page_directory.get_lock());
// FIXME: Find a better place for this sanity check(?)
if (is_user_accessible() && !is_shared()) {
if (is_user() && !is_shared()) {
ASSERT(!vmobject().is_shared_inode());
}