kernel/arm64: introduce virtual_ranges_to_keep

Change-Id: I6de950cb18892ebf2dd2aefa34b65b90a17e3f2c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5682
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>
Reviewed-by: David Karoly <[email protected]>

headers/private/kernel/arch/arm64/arch_kernel_args.h

@@ -17,12 +17,17 @@
 
 #define _PACKED __attribute__((packed))
 
+#define MAX_VIRTUAL_RANGES_TO_KEEP	32
 
 typedef struct {
 	uint64	phys_pgdir;
 	uint64	vir_pgdir;
 	uint64	next_pagetable;
 
+	// The virtual ranges we want to keep in the kernel.
+	uint32		num_virtual_ranges_to_keep;
+	addr_range	virtual_ranges_to_keep[MAX_VIRTUAL_RANGES_TO_KEEP];
+
 	// needed for UEFI, otherwise kernel acpi support can't find ACPI root
 	FixedWidthPointer<void>	acpi_root;
 	FixedWidthPointer<void>	fdt;

src/system/boot/platform/efi/arch/arm64/arch_mmu.cpp

@@ -402,6 +402,13 @@ arch_mmu_post_efi_setup(size_t memory_map_size,
 			start, start + size, size));
 	}
 
+	TRACE(("virt memory ranges to keep:\n"));
+	for (uint32_t i = 0; i < gKernelArgs.arch_args.num_virtual_ranges_to_keep; i++) {
+		uint64 start = gKernelArgs.arch_args.virtual_ranges_to_keep[i].start;
+		uint64 size = gKernelArgs.arch_args.virtual_ranges_to_keep[i].size;
+		TRACE(("    0x%08" B_PRIx32 "-0x%08" B_PRIx64 ", length 0x%08" B_PRIx64 "\n",
+			start, start + size, size));
+	}
 }
 
 

src/system/kernel/arch/arm64/arch_vm.cpp

@@ -9,6 +9,7 @@
 
 #include <arch/vm.h>
 #include <vm/vm.h>
+#include <vm/VMAddressSpace.h>
 #include <vm/vm_types.h>
 
 
@@ -47,7 +48,39 @@ arch_vm_init_post_area(kernel_args* args)
 status_t
 arch_vm_init_end(kernel_args* args)
 {
-	TRACE("arch_vm_init_end\n");
+	TRACE("arch_vm_init_end(): %" B_PRIu32 " virtual ranges to keep:\n",
+		args->arch_args.num_virtual_ranges_to_keep);
+
+	for (int i = 0; i < (int)args->arch_args.num_virtual_ranges_to_keep; i++) {
+		addr_range &range = args->arch_args.virtual_ranges_to_keep[i];
+
+		TRACE("  start: %p, size: %#" B_PRIxSIZE "\n", (void*)range.start, range.size);
+
+		// skip ranges outside the kernel address space
+		if (!IS_KERNEL_ADDRESS(range.start)) {
+			TRACE("    no kernel address, skipping...\n");
+			continue;
+		}
+
+		phys_addr_t physicalAddress;
+		void *address = (void*)range.start;
+		if (vm_get_page_mapping(VMAddressSpace::KernelID(), range.start,
+			&physicalAddress) != B_OK)
+			panic("arch_vm_init_end(): No page mapping for %p\n", address);
+
+		area_id area = vm_map_physical_memory(VMAddressSpace::KernelID(),
+			"boot loader reserved area", &address,
+			B_EXACT_ADDRESS, range.size,
+			B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA,
+			physicalAddress, true);
+
+		if (area < 0) {
+			panic("arch_vm_init_end(): Failed to create area for boot loader "
+				"reserved area: %p - %p\n", (void*)range.start,
+				(void*)(range.start + range.size));
+		}
+	}
+
 	return B_OK;
 }