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[kernel] Pull block_allocator out into separate class

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The vm_area_guarded code to keep a list of used/free block addresses
will be useful elsewhere.
This commit is contained in:
Justin C. Miller
2022-09-11 14:12:18 -07:00
parent 1d4c66a9a0
commit 7fd39e91c1
3 changed files with 40 additions and 19 deletions
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26
src/kernel/objects/vm_area.cpp
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@@ -143,9 +143,8 @@ vm_area_open::get_page(uintptr_t offset, uintptr_t &phys)
vm_area_guarded::vm_area_guarded(uintptr_t start, size_t buf_pages, size_t size, vm_flags flags) :
m_start {start},
m_pages {buf_pages},
m_next {mem::frame_size},
m_pages {buf_pages + 1}, // Sections are N+1 pages for the leading guard page
m_stacks {start, m_pages*mem::frame_size},
vm_area_open {size, flags}
{
}
@@ -155,31 +154,26 @@ vm_area_guarded::~vm_area_guarded() {}
uintptr_t
vm_area_guarded::get_section()
{
if (m_cache.count() > 0) {
return m_cache.pop();
}
uintptr_t addr = m_next;
m_next += (m_pages + 1) * mem::frame_size;
return m_start + addr;
// Account for the leading guard page
return m_stacks.allocate() + mem::frame_size;
}
void
vm_area_guarded::return_section(uintptr_t addr)
{
m_cache.append(addr);
// Account for the leading guard page
return m_stacks.free(addr - mem::frame_size);
}
bool
vm_area_guarded::get_page(uintptr_t offset, uintptr_t &phys)
{
if (offset > m_next)
if (offset >= m_stacks.end())
return false;
// make sure this isn't in a guard page. (sections are
// m_pages big plus 1 leading guard page, so page 0 is
// invalid)
if ((offset >> 12) % (m_pages+1) == 0)
// make sure this isn't in a guard page. (sections have 1 leading
// guard page, so page 0 is invalid)
if ((offset >> 12) % m_pages == 0)
return false;
return vm_area_open::get_page(offset, phys);