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pmm: Reclaim bootservices entries last and disallow allocations after

This commit is contained in:
mintsuki 2022-07-26 19:55:18 +02:00
parent 4c6fba824c
commit fb5d903ccf
1 changed files with 39 additions and 36 deletions
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75
common/mm/pmm.s2.c
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@ -474,42 +474,6 @@ fail:
static void pmm_reclaim_uefi_mem(struct e820_entry_t *m, size_t *_count) {
size_t count = *_count;
// First, ensure the boot services are still boot services, or free, in
// the EFI memmap
for (size_t i = 0; i < count; i++) {
if (m[i].type != MEMMAP_EFI_BOOTSERVICES)
continue;
// Go through EFI memmap and ensure this entry fits within a boot services
// or conventional entry
size_t entry_count = efi_mmap_size / efi_desc_size;
for (size_t j = 0; j < entry_count; j++) {
EFI_MEMORY_DESCRIPTOR *entry = (void *)efi_mmap + j * efi_desc_size;
switch (entry->Type) {
case EfiBootServicesCode:
case EfiBootServicesData:
case EfiConventionalMemory:
break;
default:
continue;
}
uintptr_t base = m[i].base;
uintptr_t top = base + m[i].length;
uintptr_t efi_base = entry->PhysicalStart;
uintptr_t efi_size = entry->NumberOfPages * 4096;
uintptr_t efi_top = efi_base + efi_size;
if (!(base >= efi_base && base < efi_top
&& top > efi_base && top <= efi_top))
continue;
m[i].type = MEMMAP_USABLE;
}
}
size_t recl_i = 0;
for (size_t i = 0; i < count; i++) {
@ -600,6 +564,45 @@ another_recl:;
goto another_recl;
}
// Ensure the boot services are still boot services, or free, in
// the EFI memmap, and disallow allocations since our stack and page tables
// are placed in this newly freed memory.
for (size_t i = 0; i < count; i++) {
if (m[i].type != MEMMAP_EFI_BOOTSERVICES)
continue;
// Go through EFI memmap and ensure this entry fits within a boot services
// or conventional entry
size_t entry_count = efi_mmap_size / efi_desc_size;
for (size_t j = 0; j < entry_count; j++) {
EFI_MEMORY_DESCRIPTOR *entry = (void *)efi_mmap + j * efi_desc_size;
switch (entry->Type) {
case EfiBootServicesCode:
case EfiBootServicesData:
case EfiConventionalMemory:
break;
default:
continue;
}
uintptr_t base = m[i].base;
uintptr_t top = base + m[i].length;
uintptr_t efi_base = entry->PhysicalStart;
uintptr_t efi_size = entry->NumberOfPages * 4096;
uintptr_t efi_top = efi_base + efi_size;
if (!(base >= efi_base && base < efi_top
&& top > efi_base && top <= efi_top))
continue;
m[i].type = MEMMAP_USABLE;
}
}
allocations_disallowed = true;
sanitise_entries(m, &count, false);
*_count = count;