Kernel: Create a basic SMBIOS Decoder

We use DMI decoding now just to determine if PCI is available.
The DMIDecoder is initialized during early boot, thus making it possible
to probe useful data about the machine.

Other purposes are not supported yet.

Kernel/ACPI/DMIDecoder.cpp

@@ -0,0 +1,260 @@
+#include <Kernel/ACPI/DMIDecoder.h>
+#include <Kernel/StdLib.h>
+#include <Kernel/VM/MemoryManager.h>
+
+static DMIDecoder* s_dmi_decoder;
+
+//#define SMBIOS_DEBUG
+
+#define SMBIOS_BASE_SEARCH_ADDR 0xf0000
+#define SMBIOS_END_SEARCH_ADDR 0xfffff
+#define SMBIOS_SEARCH_AREA_SIZE (SMBIOS_END_SEARCH_ADDR - SMBIOS_BASE_SEARCH_ADDR)
+
+DMIDecoder& DMIDecoder::the()
+{
+    if (s_dmi_decoder == nullptr) {
+        s_dmi_decoder = new DMIDecoder(true);
+    }
+    return *s_dmi_decoder;
+}
+
+void DMIDecoder::initialize()
+{
+    if (s_dmi_decoder == nullptr) {
+        s_dmi_decoder = new DMIDecoder(true);
+    }
+}
+
+void DMIDecoder::initialize_untrusted()
+{
+    if (s_dmi_decoder == nullptr) {
+        s_dmi_decoder = new DMIDecoder(false);
+    }
+}
+
+void DMIDecoder::initialize_parser()
+{
+    if (m_entry32bit_point != nullptr || m_entry64bit_point != nullptr) {
+        m_operable = true;
+        kprintf("DMI Decoder is enabled\n");
+        if (m_entry64bit_point != nullptr) {
+            kprintf("DMIDecoder: SMBIOS 64bit Entry point @ P 0x%x\n", m_entry64bit_point);
+            m_use_64bit_entry = true;
+            m_structure_table = (SMBIOS::TableHeader*)m_entry64bit_point->table_ptr;
+            m_structures_count = m_entry64bit_point->table_maximum_size;
+            m_table_length = m_entry64bit_point->table_maximum_size;
+        } else if (m_entry32bit_point != nullptr) {
+            kprintf("DMIDecoder: SMBIOS 32bit Entry point @ P 0x%x\n", m_entry32bit_point);
+            m_use_64bit_entry = false;
+            m_structure_table = (SMBIOS::TableHeader*)m_entry32bit_point->legacy_structure.smbios_table_ptr;
+            m_structures_count = m_entry32bit_point->legacy_structure.smbios_tables_count;
+            m_table_length = m_entry32bit_point->legacy_structure.smboios_table_length;
+        }
+        kprintf("DMIDecoder: Data table @ P 0x%x\n", m_structure_table);
+        enumerate_smbios_tables();
+    } else {
+        m_operable = false;
+        kprintf("DMI Decoder is disabled. Cannot find SMBIOS tables.\n");
+    }
+}
+
+void DMIDecoder::enumerate_smbios_tables()
+{
+    u32 table_length = m_table_length;
+    SMBIOS::TableHeader* physical_table = m_structure_table;
+
+    auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(table_length), "DMI Decoder Entry Point Finding", Region::Access::Read);
+    PhysicalAddress paddr = PhysicalAddress((u32)physical_table & PAGE_MASK);
+    mmap_region(*region, paddr);
+
+    auto* v_smbios_table = (SMBIOS::TableHeader*)(region->vaddr().get() + ((u32)physical_table & (~PAGE_MASK)));
+
+    u32 structures_count = 0;
+    while (table_length > 0) {
+#ifdef SMBIOS_DEBUG
+        dbgprintf("DMIDecoder: Examining table @ P 0x%x\n", physical_table);
+#endif
+        structures_count++;
+        if (v_smbios_table->type == (u32)SMBIOS::TableType::EndOfTable) {
+            kprintf("DMIDecoder: Detected table with type 127, End of SMBIOS data.\n");
+            break;
+        }
+        m_smbios_tables.append(physical_table);
+        table_length -= v_smbios_table->length;
+        kprintf("DMIDecoder: Detected table with type %u\n", v_smbios_table->type);
+        SMBIOS::TableHeader* physical_next_table = get_next_physical_table(*physical_table);
+#ifdef SMBIOS_DEBUG
+        dbgprintf("DMIDecoder: Next table @ P 0x%x\n", physical_next_table);
+#endif
+        if (physical_next_table == nullptr)
+            break;
+
+        v_smbios_table = (SMBIOS::TableHeader*)(region->vaddr().get() + (u32)physical_next_table - paddr.get());
+        physical_table = physical_next_table;
+    }
+    m_structures_count = structures_count;
+}
+
+size_t DMIDecoder::get_table_size(SMBIOS::TableHeader& table)
+{
+    // FIXME: Make sure we have some mapping here so we don't rely on existing identity mapping...
+#ifdef SMBIOS_DEBUG
+    dbgprintf("DMIDecoder: table legnth - 0x%x\n", table.length);
+#endif
+    const char* strtab = (char*)&table + table.length;
+    size_t index = 1;
+    while (strtab[index - 1] != '\0' || strtab[index] != '\0') {
+        if (index > m_table_length) {
+            ASSERT_NOT_REACHED(); // FIXME: Instead of halting, find a better solution (Hint: use m_operable to disallow further use of DMIDecoder)
+        }
+        index++;
+    }
+#ifdef SMBIOS_DEBUG
+    dbgprintf("DMIDecoder: table size - 0x%x\n", table.length + i + 1);
+#endif
+    return table.length + index + 1;
+}
+
+SMBIOS::TableHeader* DMIDecoder::get_next_physical_table(SMBIOS::TableHeader& p_table)
+{
+    return (SMBIOS::TableHeader*)((u32)&p_table + get_table_size(p_table));
+}
+
+SMBIOS::TableHeader* DMIDecoder::get_smbios_physical_table_by_handle(u16 handle)
+{
+    auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(PAGE_SIZE * 2), "DMI Decoder Finding Table", Region::Access::Read);
+
+    for (auto* table : m_smbios_tables) {
+        if (!table)
+            continue;
+        PhysicalAddress paddr = PhysicalAddress((u32)table & PAGE_MASK);
+        mmap_region(*region, paddr);
+        SMBIOS::TableHeader* table_v_ptr = (SMBIOS::TableHeader*)(region->vaddr().get() + ((u32)table & (~PAGE_MASK)));
+        if (table_v_ptr->handle == handle) {
+            return table;
+        }
+    }
+    return nullptr;
+}
+SMBIOS::TableHeader* DMIDecoder::get_smbios_physical_table_by_type(u8 table_type)
+{
+    auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(PAGE_SIZE * 2), "DMI Decoder Finding Table", Region::Access::Read);
+
+    for (auto* table : m_smbios_tables) {
+        if (!table)
+            continue;
+        PhysicalAddress paddr = PhysicalAddress((u32)table & PAGE_MASK);
+        mmap_region(*region, paddr);
+        SMBIOS::TableHeader* table_v_ptr = (SMBIOS::TableHeader*)(region->vaddr().get() + ((u32)table & (~PAGE_MASK)));
+        if (table_v_ptr->type == table_type) {
+            return table;
+        }
+    }
+    return nullptr;
+}
+
+DMIDecoder::DMIDecoder(bool trusted)
+    : m_entry32bit_point(find_entry32bit_point())
+    , m_entry64bit_point(find_entry64bit_point())
+    , m_structure_table(nullptr)
+    , m_untrusted(!trusted)
+{
+    if (!trusted) {
+        kprintf("DMI Decoder initialized as untrusted due to user request.\n");
+    }
+    initialize_parser();
+}
+
+SMBIOS::EntryPoint64bit* DMIDecoder::find_entry64bit_point()
+{
+    auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(SMBIOS_SEARCH_AREA_SIZE), "DMI Decoder Entry Point Finding", Region::Access::Read);
+    PhysicalAddress paddr = PhysicalAddress(SMBIOS_BASE_SEARCH_ADDR);
+    mmap_region(*region, paddr);
+
+    char* tested_physical_ptr = (char*)paddr.get();
+    for (char* entry_str = (char*)(region->vaddr().get()); entry_str < (char*)(region->vaddr().get() + (SMBIOS_SEARCH_AREA_SIZE)); entry_str += 16) {
+#ifdef SMBIOS_DEBUG
+        dbgprintf("DMI Decoder: Looking for 64 bit Entry point @ P 0x%x\n", entry_str, tested_physical_ptr);
+#endif
+        if (!strncmp("_SM3_", entry_str, strlen("_SM3_")))
+            return (SMBIOS::EntryPoint64bit*)tested_physical_ptr;
+
+        tested_physical_ptr += 16;
+    }
+    return nullptr;
+}
+
+SMBIOS::EntryPoint32bit* DMIDecoder::find_entry32bit_point()
+{
+    auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(SMBIOS_SEARCH_AREA_SIZE), "DMI Decoder Entry Point Finding", Region::Access::Read);
+    PhysicalAddress paddr = PhysicalAddress(SMBIOS_BASE_SEARCH_ADDR);
+    mmap_region(*region, paddr);
+
+    char* tested_physical_ptr = (char*)paddr.get();
+    for (char* entry_str = (char*)(region->vaddr().get()); entry_str < (char*)(region->vaddr().get() + (SMBIOS_SEARCH_AREA_SIZE)); entry_str += 16) {
+#ifdef SMBIOS_DEBUG
+        dbgprintf("DMI Decoder: Looking for 32 bit Entry point @ P 0x%x\n", tested_physical_ptr);
+#endif
+        if (!strncmp("_SM_", entry_str, strlen("_SM_")))
+            return (SMBIOS::EntryPoint32bit*)tested_physical_ptr;
+
+        tested_physical_ptr += 16;
+    }
+    return nullptr;
+}
+
+void DMIDecoder::mmap(VirtualAddress vaddr, PhysicalAddress paddr, u32 length)
+{
+    unsigned i = 0;
+    while (length >= PAGE_SIZE) {
+        MM.map_for_kernel(VirtualAddress(vaddr.offset(i * PAGE_SIZE).get()), PhysicalAddress(paddr.offset(i * PAGE_SIZE).get()));
+#ifdef SMBIOS_DEBUG
+        dbgprintf("DMI Decoder: map - V 0x%x -> P 0x%x\n", vaddr.offset(i * PAGE_SIZE).get(), paddr.offset(i * PAGE_SIZE).get());
+#endif
+        length -= PAGE_SIZE;
+        i++;
+    }
+    if (length > 0) {
+        MM.map_for_kernel(vaddr.offset(i * PAGE_SIZE), paddr.offset(i * PAGE_SIZE), true);
+    }
+#ifdef SMBIOS_DEBUG
+    dbgprintf("DMI Decoder: Finished mapping\n");
+#endif
+}
+
+void DMIDecoder::mmap_region(Region& region, PhysicalAddress paddr)
+{
+#ifdef SMBIOS_DEBUG
+    dbgprintf("DMI Decoder: Mapping region, size - %u\n", region.size());
+#endif
+    mmap(region.vaddr(), paddr, region.size());
+}
+
+Vector<SMBIOS::PhysicalMemoryArray*>& DMIDecoder::get_physical_memory_areas()
+{
+    // FIXME: Implement it...
+    kprintf("DMIDecoder::get_physical_memory_areas() is not implemented.\n");
+    ASSERT_NOT_REACHED();
+}
+bool DMIDecoder::is_reliable()
+{
+    return !m_untrusted;
+}
+u64 DMIDecoder::get_bios_characteristics()
+{
+    // FIXME: Make sure we have some mapping here so we don't rely on existing identity mapping...
+    ASSERT(m_operable == true);
+    SMBIOS::BIOSInfo* bios_info = (SMBIOS::BIOSInfo*)get_smbios_physical_table_by_type(0);
+    ASSERT(bios_info != nullptr);
+    kprintf("DMIDecoder: BIOS info @ P 0x%x\n", bios_info);
+    return bios_info->bios_characteristics;
+}
+
+char* DMIDecoder::get_smbios_string(SMBIOS::TableHeader&, u8)
+{
+    // FIXME: Implement it...
+    // FIXME: Make sure we have some mapping here so we don't rely on existing identity mapping...
+    kprintf("DMIDecoder::get_smbios_string() is not implemented.\n");
+    ASSERT_NOT_REACHED();
+    return nullptr;
+}