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Clean up process memory on exit.

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Additionally, there were several bug fixes needed to allow this:
- frame_allocator was allocating its frame_blocks from the heap, causing
  a circular dependency. Now it gives itself a page on its own when
  needed.
- frame_allocator::free was putting any trailing pages in a block back
  into the list after the current block, so they would be the next block
  iterated to.
- frame_allocator::free was updating the address it was looking for
  after freeing some pages, but not the count it was looking for, so it
  would eventually free all pages after the initial address.
This commit is contained in:
Justin C. Miller
2019-04-06 11:19:38 -07:00
parent c605793a9d
commit 863555ec6b
8 changed files with 110 additions and 31 deletions
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32
src/kernel/page_manager.cpp
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@@ -96,6 +96,8 @@ page_manager::copy_page(uintptr_t orig)
paged_copy = true;
}
// TODO: multiple page copies at a time, so that we don't have to keep
// paying this mapping penalty
if (paged_orig || paged_copy) {
set_pml4(get_pml4());
__sync_synchronize();
@@ -265,17 +267,15 @@ page_manager::map_pages(uintptr_t address, size_t count, bool user, page_table *
}
void
page_manager::unmap_table(page_table *table, page_table::level lvl, bool free)
page_manager::unmap_table(page_table *table, page_table::level lvl, bool free, page_table_indices index)
{
log::debug(logs::paging, "Unmapping%s lv %d table at %016lx",
free ? " (and freeing)" : "", lvl, table);
const int max =
lvl == page_table::level::pml4 ?
510 :
512;
uintptr_t free_start = 0;
uintptr_t free_start_virt = 0;
uintptr_t free_count = 0;
size_t size =
@@ -287,6 +287,8 @@ page_manager::unmap_table(page_table *table, page_table::level lvl, bool free)
for (int i = 0; i < max; ++i) {
if (!table->is_present(i)) continue;
index[lvl] = i;
bool is_page =
lvl == page_table::level::pt ||
table->is_large_page(lvl, i);
@@ -295,24 +297,40 @@ page_manager::unmap_table(page_table *table, page_table::level lvl, bool free)
uintptr_t frame = table->entries[i] & ~0xfffull;
if (!free_count || frame != free_start + free_count * size) {
if (free_count && free) {
log::debug(logs::paging,
" freeing v:%016lx-%016lx p:%016lx-%016lx",
free_start_virt, free_start_virt + free_count * frame_size,
free_start, free_start + free_count * frame_size);
m_frames.free(free_start, (free_count * size) / frame_size);
free_count = 0;
}
if (!free_count)
if (!free_count) {
free_start = frame;
free_start_virt = index.addr();
}
}
free_count += 1;
} else {
page_table *next = table->get(i);
unmap_table(next, page_table::deeper(lvl), free);
unmap_table(next, page_table::deeper(lvl), free, index);
}
}
if (free_count && free)
if (free_count && free) {
log::debug(logs::paging,
" freeing v:%016lx-%016lx p:%016lx-%016lx",
free_start_virt, free_start_virt + free_count * frame_size,
free_start, free_start + free_count * frame_size);
m_frames.free(free_start, (free_count * size) / frame_size);
}
free_table_pages(table, 1);
log::debug(logs::paging, "Unmapped%s lv %d table at %016lx",
free ? " (and freed)" : "", lvl, table);
}
void