Kernel/ACPI: Use the EFI-provided RSDP address, if present

The EFIPrekernel will set `acpi_rsdp_paddr` to the RSDP address found in the configuration table.
SerenityOS · Jan 26, 2025 · 395ab9a · 395ab9a
1 parent 2e5e8c1
commit 395ab9a
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/Kernel/Firmware/ACPI/Initialize.cpp b/Kernel/Firmware/ACPI/Initialize.cpp
@@ -5,6 +5,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/Boot/BootInfo.h>
 #include <Kernel/Boot/CommandLine.h>
 #include <Kernel/Firmware/ACPI/Parser.h>
 #include <Kernel/Firmware/ACPI/StaticParsing.h>
@@ -19,7 +20,12 @@ UNMAP_AFTER_INIT void initialize()
     if (feature_level == AcpiFeatureLevel::Disabled)
         return;
 
-    auto rsdp = MUST(StaticParsing::find_rsdp_in_platform_specific_memory_locations());
+    Optional<PhysicalAddress> rsdp;
+    if (!g_boot_info.acpi_rsdp_paddr.is_null())
+        rsdp = g_boot_info.acpi_rsdp_paddr;
+    else
+        MUST(StaticParsing::find_rsdp_in_platform_specific_memory_locations());
+
     if (!rsdp.has_value())
         return;
 

diff --git a/Kernel/Prekernel/Prekernel.h b/Kernel/Prekernel/Prekernel.h
@@ -89,6 +89,8 @@ struct BootInfo {
     PhysicalAddress flattened_devicetree_paddr { 0 };
     size_t flattened_devicetree_size { 0 };
 
+    PhysicalAddress acpi_rsdp_paddr { 0 };
+
     size_t physical_to_virtual_offset { 0 };
     FlatPtr kernel_mapping_base { 0 };
     FlatPtr kernel_load_base { 0 };