arm: relocate UART when remapping virtual memory

The uart virtual address changes as soon as we apply the kernel memory
map. gUART is used only after that, from serial_init() onwards. So it
should use the virtual address, and not the physical address it was
previously created with while parsing the FDT.

Change-Id: I8c8a024fe564b49d6555f8e48f5ab31652d30708
Reviewed-on: https://review.haiku-os.org/c/haiku/+/10068
Reviewed-by: Fredrik Holmqvist <[email protected]>
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

headers/private/kernel/arch/generic/debug_uart.h

@@ -35,6 +35,7 @@ public:
 	virtual	void			FlushTx() = 0;
 	virtual	void			FlushRx() = 0;
 
+			void			SetBase(addr_t base) { fBase = base; }
 			addr_t			Base() const { return fBase; }
 			int64			Clock() const { return fClock; }
 			bool			Enabled() const { return fEnabled; }

src/system/boot/platform/efi/arch/arm/arch_mmu.cpp

@@ -8,12 +8,14 @@
 
 #include <arm_mmu.h>
 #include <kernel.h>
+#include <arch/generic/debug_uart.h>
 #include <arch_kernel.h>
 #include <boot/platform.h>
 #include <boot/stage2.h>
 #include <efi/types.h>
 #include <efi/boot-services.h>
 
+
 #include "efi_platform.h"
 #include "generic_mmu.h"
 #include "mmu.h"
@@ -30,6 +32,8 @@
 static constexpr bool kTraceMemoryMap = false;
 static constexpr bool kTracePageDirectory = false;
 
+extern DebugUART* gUART;
+
 
 // Ignore memory above 512GB
 #define PHYSICAL_MEMORY_LOW		0x00000000
@@ -281,6 +285,7 @@ arch_mmu_generate_post_efi_page_tables(size_t memoryMapSize,
 
 	map_range_to_new_area(gKernelArgs.arch_args.uart.regs,
 		ARM_MMU_L2_FLAG_B | ARM_MMU_L2_FLAG_HAIKU_KERNEL_RW | ARM_MMU_L2_FLAG_XN);
+	gUART->SetBase(gKernelArgs.arch_args.uart.regs.start);
 
 	sort_address_ranges(gKernelArgs.virtual_allocated_range,
 		gKernelArgs.num_virtual_allocated_ranges);