Kernel: Make the ACPI DSDT table accessible

Expose the DSDT table in ACPI::Parser and in
/sys/firmware/acpi as a first little step toward
interpreting the AML bytecode from ACPI.

3 files changed, 22 insertions, 1 deletions

diff --git a/Kernel/Firmware/ACPI/Definitions.h b/Kernel/Firmware/ACPI/Definitions.h
index 4375651ca1..9c432ece87 100644
--- a/Kernel/Firmware/ACPI/Definitions.h
+++ b/Kernel/Firmware/ACPI/Definitions.h
@@ -320,6 +320,11 @@ struct [[gnu::packed]] MCFG {
     u64 reserved;
     PCI_MMIO_Descriptor descriptors[];
 };
+
+struct [[gnu::packed]] DSDT {
+    SDTHeader h;
+    unsigned char definition_block[];
+};
 }
 
 class Parser;
diff --git a/Kernel/Firmware/ACPI/Parser.cpp b/Kernel/Firmware/ACPI/Parser.cpp
index b9cd91f41a..34084723f0 100644
--- a/Kernel/Firmware/ACPI/Parser.cpp
+++ b/Kernel/Firmware/ACPI/Parser.cpp
@@ -130,6 +130,7 @@ UNMAP_AFTER_INIT void Parser::locate_static_data()
     locate_main_system_description_table();
     initialize_main_system_description_table();
     process_fadt_data();
+    process_dsdt();
 }
 
 UNMAP_AFTER_INIT Optional<PhysicalAddress> Parser::find_table(StringView signature)
@@ -170,7 +171,6 @@ UNMAP_AFTER_INIT void Parser::process_fadt_data()
 
     auto sdt = Memory::map_typed<Structures::FADT>(m_fadt).release_value_but_fixme_should_propagate_errors();
     dmesgln("ACPI: Fixed ACPI data, Revision {}, length: {} bytes", (size_t)sdt->h.revision, (size_t)sdt->h.length);
-    dmesgln("ACPI: DSDT {}", PhysicalAddress(sdt->dsdt_ptr));
     m_x86_specific_flags.cmos_rtc_not_present = (sdt->ia_pc_boot_arch_flags & (u8)FADTFlags::IA_PC_Flags::CMOS_RTC_Not_Present);
 
     // FIXME: QEMU doesn't report that we have an i8042 controller in these flags, even if it should (when FADT revision is 3),
@@ -205,6 +205,21 @@ UNMAP_AFTER_INIT void Parser::process_fadt_data()
     m_hardware_flags.wbinvd_flush = (sdt->flags & (u32)FADTFlags::FeatureFlags::WBINVD_FLUSH);
 }
 
+UNMAP_AFTER_INIT void Parser::process_dsdt()
+{
+    auto sdt = Memory::map_typed<Structures::FADT>(m_fadt).release_value_but_fixme_should_propagate_errors();
+
+    // Add DSDT-pointer to expose the full table in /sys/firmware/acpi/
+    m_sdt_pointers.append(PhysicalAddress(sdt->dsdt_ptr));
+
+    auto dsdt_or_error = Memory::map_typed<Structures::DSDT>(PhysicalAddress(sdt->dsdt_ptr));
+    if (dsdt_or_error.is_error()) {
+        dmesgln("ACPI: DSDT is unmappable");
+        return;
+    }
+    dmesgln("ACPI: Using DSDT @ {} with {} bytes", PhysicalAddress(sdt->dsdt_ptr), dsdt_or_error.value()->h.length);
+}
+
 bool Parser::can_reboot()
 {
     auto fadt_or_error = Memory::map_typed<Structures::FADT>(m_fadt);
diff --git a/Kernel/Firmware/ACPI/Parser.h b/Kernel/Firmware/ACPI/Parser.h
index 25239f8a93..9f90320ec9 100644
--- a/Kernel/Firmware/ACPI/Parser.h
+++ b/Kernel/Firmware/ACPI/Parser.h
@@ -89,6 +89,7 @@ private:
     size_t get_table_size(PhysicalAddress);
     u8 get_table_revision(PhysicalAddress);
     void process_fadt_data();
+    void process_dsdt();
 
     bool validate_reset_register(Memory::TypedMapping<Structures::FADT> const&);
     void access_generic_address(Structures::GenericAddressStructure const&, u32 value);