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[kernel] Move page mapping into vm_space

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vm_space no longer relies on page_manager to map pages during a page
fault. Other changes that come with this commit:

- C++ standard has been changed to C++17
- enum bitfield operators became constexpr
- enum bifrield operators can take a mix of ints and enum arguments
- added page table flags enum instead of relying on ints
- remove page_table::unmap_table and page_table::unmap_pages
This commit is contained in:
Justin C. Miller
2020-09-20 10:52:57 -07:00
parent deb2fa0a09
commit 1b392a0551
7 changed files with 107 additions and 143 deletions
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28
src/kernel/page_table.cpp
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@@ -14,17 +14,10 @@ free_page_header * page_table::s_page_cache = nullptr;
size_t page_table::s_cache_count = 0;
constexpr size_t page_table::entry_sizes[4];
// Flags: 0 0 0 0 0 0 0 0 0 0 1 1 = 0x0003
// IGNORED | | | | | | | +- Present
// | | | | | | +--- Writeable
// | | | | | +----- Usermode access (Supervisor only)
// | | | | +------- PWT (determining memory type for pdpt)
// | | | +---------- PCD (determining memory type for pdpt)
// | | +------------ Accessed flag (not accessed yet)
// | +-------------- Ignored
// +---------------- Reserved 0 (Table pointer, not page)
/// Page table entry flags for entries pointing at another table
constexpr uint16_t table_flags = 0x003;
constexpr page_table::flag table_flags =
page_table::flag::present |
page_table::flag::write;
page_table::iterator::iterator(uintptr_t virt, page_table *pml4) :
@@ -114,7 +107,7 @@ page_table::iterator::allowed() const
{
level d = depth();
while (true) {
if (entry(d) & flag_allowed) return true;
if (entry(d) & flag::allowed) return true;
else if (d == level::pml4) return false;
--d;
}
@@ -126,8 +119,8 @@ 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;
if (allowed) entry(at) |= flag::allowed;
else entry(at) &= ~flag::allowed;
}
bool
@@ -169,8 +162,9 @@ page_table::iterator::ensure_table(level l)
kassert(n, "Failed to allocate a page table");
uint64_t &parent = entry(l - 1);
uint64_t flags = table_flags |
(parent & flag_allowed) ? flag_allowed : 0;
flag flags = table_flags | (parent & flag::allowed);
if (m_index[0] < memory::pml4e_kernel)
flags |= flag::user;
m_table[unsigned(l)] = reinterpret_cast<page_table*>(phys | page_offset);
parent = (reinterpret_cast<uintptr_t>(phys) & ~0xfffull) | flags;
@@ -193,7 +187,7 @@ 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;
if (entries[i] & flag::allowed) flags |= flag::allowed;
entries[i] =
(reinterpret_cast<uint64_t>(p) - page_offset) |
(flags & 0xfff);