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[kernel] Move the page table cache into page_table

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Further chipping away at page_manager: the cache of pages to be used as
page tables gets moved to a static in page_table.
This commit is contained in:
Justin C. Miller
2020-09-17 21:30:05 -07:00
parent 09575370ce
commit ac67111b83
7 changed files with 86 additions and 71 deletions
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53
src/kernel/page_manager.cpp
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@@ -37,16 +37,10 @@ pt_from_phys(uintptr_t p)
}
struct free_page_header
{
free_page_header *next;
size_t count;
};
page_manager::page_manager(frame_allocator &frames, page_table *pml4) :
m_kernel_pml4(pml4),
m_page_cache(nullptr),
m_frames(frames)
{
}
@@ -54,7 +48,7 @@ page_manager::page_manager(frame_allocator &frames, page_table *pml4) :
page_table *
page_manager::create_process_map()
{
page_table *table = get_table_page();
page_table *table = page_table::get_table_page();
kutil::memset(table, 0, frame_size/2);
for (unsigned i = pml4e_kernel; i < table_entries; ++i)
@@ -107,47 +101,6 @@ page_manager::dump_pml4(page_table *pml4, bool recurse)
pml4->dump(page_table::level::pml4, recurse);
}
page_table *
page_manager::get_table_page()
{
if (!m_page_cache) {
uintptr_t phys = 0;
size_t n = m_frames.allocate(32, &phys); // TODO: indicate frames must be offset-mappable
uintptr_t virt = phys + page_offset;
m_page_cache = reinterpret_cast<free_page_header *>(virt);
// The last one needs to be null, so do n-1
uintptr_t end = virt + (n-1) * frame_size;
while (virt < end) {
reinterpret_cast<free_page_header *>(virt)->next =
reinterpret_cast<free_page_header *>(virt + frame_size);
virt += frame_size;
}
reinterpret_cast<free_page_header *>(virt)->next = nullptr;
log::info(logs::paging, "Mappd %d new page table pages at %lx", n, phys);
}
free_page_header *page = m_page_cache;
m_page_cache = page->next;
return reinterpret_cast<page_table *>(page);
}
void
page_manager::free_table_pages(void *pages, size_t count)
{
uintptr_t start = reinterpret_cast<uintptr_t>(pages);
for (size_t i = 0; i < count; ++i) {
uintptr_t addr = start + (i * frame_size);
free_page_header *header = reinterpret_cast<free_page_header *>(addr);
header->count = 1;
header->next = m_page_cache;
m_page_cache = header;
}
}
void *
page_manager::map_pages(uintptr_t address, size_t count, bool user, page_table *pml4)
{
@@ -233,7 +186,7 @@ page_manager::unmap_table(page_table *table, page_table::level lvl, bool free, p
m_frames.free(free_start, (free_count * size) / frame_size);
}
free_table_pages(table, 1);
page_table::free_table_page(table);
log::debug(logs::paging, "Unmapped%s lv %d table at %016lx",
free ? " (and freed)" : "", lvl, table);
@@ -255,7 +208,7 @@ page_manager::check_needs_page(page_table *table, unsigned index, bool user)
{
if ((table->entries[index] & 0x1) == 1) return;
page_table *new_table = get_table_page();
page_table *new_table = page_table::get_table_page();
for (int i=0; i<table_entries; ++i) new_table->entries[i] = 0;
table->entries[index] = pt_to_phys(new_table) | (user ? user_table_flags : sys_table_flags);
}