ACPI: Always use the loader-reported root pointer.

We always did under EFI but not under BIOS. Now, the BIOS loader
reports the root pointer as well, so we don't need to find it again.

Change-Id: Ie83adb53f098d44f2688a1a327c084f94afa2673
Reviewed-on: https://review.haiku-os.org/c/haiku/+/8941
Reviewed-by: Fredrik Holmqvist <[email protected]>
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

headers/private/kernel/arch/x86/arch_kernel_args.h

@@ -38,8 +38,8 @@ typedef struct {
 	// hpet stuff
 	uint32	hpet_phys;
 	FixedWidthPointer<void> hpet;
-	// needed for UEFI, otherwise kernel acpi support can't find ACPI root
 	FixedWidthPointer<void> acpi_root;
 } _PACKED arch_kernel_args;
 
+
 #endif	/* KERNEL_ARCH_x86_KERNEL_ARGS_H */

src/add-ons/kernel/bus_managers/acpi/ACPICAHaiku.cpp

@@ -240,9 +240,6 @@ AcpiOsGetRootPointer()
 		phys_addr_t* acpiRootPointer = (phys_addr_t*)get_boot_item("ACPI_ROOT_POINTER", NULL);
 		if (acpiRootPointer != NULL)
 			sACPIRoot = *acpiRootPointer;
-
-		if (sACPIRoot == 0)
-			sACPIRoot = arch_init_find_root_pointer();
 	}
 	return sACPIRoot;
 #else

src/add-ons/kernel/bus_managers/acpi/arch/arm64/arch_init.cpp

@@ -13,12 +13,6 @@ extern "C" {
 
 #include "arch_init.h"
 
-ACPI_PHYSICAL_ADDRESS
-arch_init_find_root_pointer()
-{
-	return 0;
-}
-
 
 void
 arch_init_interrupt_controller()

src/add-ons/kernel/bus_managers/acpi/arch/x86/arch_init.cpp

@@ -22,18 +22,6 @@ extern "C" {
 #define APIC_MODE 1
 
 
-ACPI_PHYSICAL_ADDRESS
-arch_init_find_root_pointer()
-{
-	ACPI_PHYSICAL_ADDRESS address;
-	ACPI_STATUS status = AcpiFindRootPointer(&address);
-	if (status == AE_OK)
-		return address;
-
-	return 0;
-}
-
-
 void
 arch_init_interrupt_controller()
 {

src/add-ons/kernel/bus_managers/acpi/arch_init.h

@@ -8,13 +8,6 @@
 #define ARCH_INIT_H
 
 
-/** Find the ACPI root pointer using arch or platform-specific code.
- *
- * For example on x86, search for it in the BIOS.
- */
-ACPI_PHYSICAL_ADDRESS arch_init_find_root_pointer();
-
-
 /** Initialize platform specific interrupt controller configuration.
  *
  * For example on x86, enable PIC or APIC depending on boot options.

src/system/boot/platform/bios_ia32/acpi.cpp

@@ -10,13 +10,15 @@
 */
 
 
-#include "acpi.h"
-#include "mmu.h"
-
 #include <string.h>
 
 #include <KernelExport.h>
 
+#include <boot/stage2.h>
+
+#include "acpi.h"
+#include "mmu.h"
+
 
 //#define TRACE_ACPI
 #ifdef TRACE_ACPI
@@ -241,7 +243,9 @@ acpi_init()
 			}
 		}
 
-		if (rsdp != NULL && acpi_check_rsdt(rsdp) == B_OK)
+		if (rsdp != NULL && acpi_check_rsdt(rsdp) == B_OK) {
+			gKernelArgs.arch_args.acpi_root = rsdp;
 			break;
+		}
 	}
 }