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[kutil] Flag static allocated vectors

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ktuil::vector can take a static area of memory as its initial memory,
but the case was never handled where it outgrew that memory and had to
reallocate. Steal the high bit from the capacity value to indicate the
current memory should not be kfree()'d. Also added checks in the heap
allocator to make sure pointers look valid.
This commit is contained in:
Justin C. Miller
2021-01-30 20:07:30 -08:00
parent 3595c3a440
commit c364e30240
4 changed files with 37 additions and 23 deletions
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24
src/libraries/kutil/heap_allocator.cpp
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@@ -62,10 +62,13 @@ private:
};
heap_allocator::heap_allocator() : m_next(0), m_size(0) {}
heap_allocator::heap_allocator() : m_start {0}, m_end {0} {}
heap_allocator::heap_allocator(uintptr_t start, size_t size) :
m_next(start), m_size(size), m_allocated_size(0)
m_start {start},
m_end {start+size},
m_blocks {0},
m_allocated_size {0}
{
kutil::memset(m_free, 0, sizeof(m_free));
}
@@ -97,6 +100,11 @@ heap_allocator::free(void *p)
{
if (!p) return;
static constexpr uintptr_t bad_mask = (1 << min_order) - 1;
uintptr_t addr = reinterpret_cast<uintptr_t>(p);
kassert(addr >= m_start && addr < m_end && !(addr & bad_mask),
"Attempt to free non-heap pointer");
mem_header *header = reinterpret_cast<mem_header *>(p);
header -= 1; // p points after the header
header->set_used(false);
@@ -133,12 +141,12 @@ heap_allocator::ensure_block(unsigned order)
if (order == max_order) {
size_t bytes = (1 << max_order);
if (bytes <= m_size) {
mem_header *next = reinterpret_cast<mem_header *>(m_next);
new (next) mem_header(nullptr, nullptr, order);
get_free(order) = next;
m_next += bytes;
m_size -= bytes;
uintptr_t next = m_start + m_blocks * bytes;
if (next + bytes <= m_end) {
mem_header *nextp = reinterpret_cast<mem_header *>(next);
new (nextp) mem_header(nullptr, nullptr, order);
get_free(order) = nextp;
++m_blocks;
}
} else {
mem_header *orig = pop_free(order + 1);