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[boot] Fix a bug with address-index translation

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When `page_entry_iterator` became a template and changed its static shifts
translating virtual address to table indices into a for loop, that loop
was getting the indices backwards (ie, PML4E index was really the PTE
index, and so on).

Tags: paging
This commit is contained in:
Justin C. Miller
2020-05-22 00:32:04 -07:00
parent b491a09686
commit e1d148a34d
2 changed files with 13 additions and 4 deletions
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11
src/boot/paging.cpp
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@@ -71,11 +71,20 @@ public:
{
m_table[0] = pml4;
for (unsigned i = 0; i < D; ++i) {
m_index[i] = static_cast<uint16_t>((virt >> (12 + 9*i)) & 0x1ff);
m_index[i] = static_cast<uint16_t>((virt >> (12 + 9*(3-i))) & 0x1ff);
ensure_table(i);
}
}
uintptr_t vaddress() const {
uintptr_t address = 0;
for (unsigned i = 0; i < D; ++i)
address |= static_cast<uintptr_t>(m_index[i]) << (12 + 9*(3-i));
if (address & (1ull<<47)) // canonicalize the address
address |= (0xffffull<<48);
return address;
}
void increment()
{
for (unsigned i = D - 1; i >= 0; --i) {