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[kernel] Remove 'allowed' page table flag

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The allowed flag was janky and easy to get lost when doing page table
manipulation. All allocation goes throug vm_area now, so 'allowed' can
be dropped.
This commit is contained in:
Justin C. Miller
2020-09-27 16:06:25 -07:00
parent f7f8bb3f45
commit 2d44e8112b
5 changed files with 8 additions and 83 deletions
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24
src/kernel/page_table.cpp
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@@ -100,27 +100,6 @@ page_table::iterator::next(level l)
}
}
bool
page_table::iterator::allowed() const
{
level d = depth();
while (true) {
if (entry(d) & flag::allowed) return true;
else if (d == level::pml4) return false;
--d;
}
}
void
page_table::iterator::allow(level at, bool allowed)
{
for (level l = level::pdp; l <= at; ++l)
ensure_table(l);
if (allowed) entry(at) |= flag::allowed;
else entry(at) &= ~flag::allowed;
}
bool
page_table::iterator::operator!=(const iterator &o) const
{
@@ -159,7 +138,7 @@ page_table::iterator::ensure_table(level l)
uintptr_t phys = reinterpret_cast<uintptr_t>(table) & ~page_offset;
uint64_t &parent = entry(l - 1);
flag flags = table_flags | (parent & flag::allowed);
flag flags = table_flags;
if (m_index[0] < memory::pml4e_kernel)
flags |= flag::user;
@@ -185,7 +164,6 @@ page_table::get(int i, uint16_t *flags) const
void
page_table::set(int i, page_table *p, uint16_t flags)
{
if (entries[i] & flag::allowed) flags |= flag::allowed;
entries[i] =
(reinterpret_cast<uint64_t>(p) - page_offset) |
(flags & 0xfff);