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Kernel: Introduce the MemoryDevice

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This is a character device that is being used by the dmidecode utility.
We only allow to map the BIOS ROM area to userspace with this device.
This commit is contained in:
Liav A 2021-01-29 14:03:25 +02:00 • committed by Andreas Kling
parent df59b80e23
commit 5ab1864497
6 changed files with 235 additions and 0 deletions
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68
Kernel/VM/MemoryManager.cpp
View file

@ -121,6 +121,45 @@ void MemoryManager::protect_kernel_image()
}
}
void MemoryManager::register_reserved_ranges()
{
ASSERT(!m_physical_memory_ranges.is_empty());
ContiguousReservedMemoryRange range;
for (auto& current_range : m_physical_memory_ranges) {
if (current_range.type != PhysicalMemoryRangeType::Reserved) {
if (range.start.is_null())
continue;
m_reserved_memory_ranges.append(ContiguousReservedMemoryRange { range.start, current_range.start.get() - range.start.get() });
range.start.set((FlatPtr) nullptr);
continue;
}
if (!range.start.is_null()) {
continue;
}
range.start = current_range.start;
}
if (m_physical_memory_ranges.last().type != PhysicalMemoryRangeType::Reserved)
return;
if (range.start.is_null())
return;
m_reserved_memory_ranges.append(ContiguousReservedMemoryRange { range.start, m_physical_memory_ranges.last().start.get() + m_physical_memory_ranges.last().length - range.start.get() });
}
bool MemoryManager::is_allowed_to_mmap_to_userspace(PhysicalAddress start_address, const Range& range) const
{
ASSERT(!m_reserved_memory_ranges.is_empty());
for (auto& current_range : m_reserved_memory_ranges) {
if (!(current_range.start <= start_address))
continue;
if (!(current_range.start.offset(current_range.length) > start_address))
continue;
if (!(current_range.length >= range.size()))
return false;
return true;
}
return false;
}
void MemoryManager::parse_memory_map()
{
RefPtr<PhysicalRegion> region;
@ -149,6 +188,31 @@ void MemoryManager::parse_memory_map()
for (auto* mmap = mmap_begin; mmap < mmap_end; mmap++) {
klog() << "MM: Multiboot mmap: address = " << String::format("0x%016llx", mmap->addr) << ", length = " << String::format("0x%016llx", mmap->len) << ", type = 0x" << String::format("%x", mmap->type);
auto start_address = PhysicalAddress(mmap->addr);
size_t length = static_cast<size_t>(mmap->len);
switch (mmap->type) {
case (MULTIBOOT_MEMORY_AVAILABLE):
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Usable, start_address, length });
break;
case (MULTIBOOT_MEMORY_RESERVED):
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Reserved, start_address, length });
break;
case (MULTIBOOT_MEMORY_ACPI_RECLAIMABLE):
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::ACPI_Reclaimable, start_address, length });
break;
case (MULTIBOOT_MEMORY_NVS):
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::ACPI_NVS, start_address, length });
break;
case (MULTIBOOT_MEMORY_BADRAM):
klog() << "MM: Warning, detected bad memory range!";
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::BadMemory, start_address, length });
break;
default:
dbgln("MM: Unknown range!");
m_physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Unknown, start_address, length });
break;
}
if (mmap->type != MULTIBOOT_MEMORY_AVAILABLE)
continue;
@ -216,6 +280,10 @@ void MemoryManager::parse_memory_map()
// We start out with no committed pages
m_user_physical_pages_uncommitted = m_user_physical_pages.load();
register_reserved_ranges();
for (auto& range : m_reserved_memory_ranges) {
dmesgln("MM: Contiguous reserved range from {}, length is {}", range.start, range.length);
}
}
PageTableEntry* MemoryManager::pte(PageDirectory& page_directory, VirtualAddress vaddr)

25
Kernel/VM/MemoryManager.h
View file

@ -85,6 +85,26 @@ struct UsedMemoryRange {
PhysicalAddress end;
};
struct ContiguousReservedMemoryRange {
PhysicalAddress start;
size_t length;
};
enum class PhysicalMemoryRangeType {
Usable = 0,
Reserved,
ACPI_Reclaimable,
ACPI_NVS,
BadMemory,
Unknown
};
struct PhysicalMemoryRange {
PhysicalMemoryRangeType type;
PhysicalAddress start;
size_t length;
};
const LogStream& operator<<(const LogStream& stream, const UsedMemoryRange& value);
#define MM Kernel::MemoryManager::the()
@ -187,11 +207,14 @@ public:
PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
const Vector<UsedMemoryRange>& used_memory_ranges() { return m_used_memory_ranges; }
bool is_allowed_to_mmap_to_userspace(PhysicalAddress, const Range&) const;
private:
MemoryManager();
~MemoryManager();
void register_reserved_ranges();
enum class AccessSpace { Kernel,
User };
enum class AccessType { Read,
@ -245,6 +268,8 @@ private:
InlineLinkedList<Region> m_user_regions;
InlineLinkedList<Region> m_kernel_regions;
Vector<UsedMemoryRange> m_used_memory_ranges;
Vector<PhysicalMemoryRange> m_physical_memory_ranges;
Vector<ContiguousReservedMemoryRange> m_reserved_memory_ranges;
InlineLinkedList<VMObject> m_vmobjects;