Commit 0ceac9e0 authored Sep 08, 2014 by Mark Salter Committed by Matt Fleming Sep 09, 2014

efi/arm64: Fix fdt-related memory reservation



Commit 86c8b27a:
 "arm64: ignore DT memreserve entries when booting in UEFI mode

prevents early_init_fdt_scan_reserved_mem() from being called for
arm64 kernels booting via UEFI. This was done because the kernel
will use the UEFI memory map to determine reserved memory regions.
That approach has problems in that early_init_fdt_scan_reserved_mem()
also reserves the FDT itself and any node-specific reserved memory.
By chance of some kernel configs, the FDT may be overwritten before
it can be unflattened and the kernel will fail to boot. More subtle
problems will result if the FDT has node specific reserved memory
which is not really reserved.

This patch has the UEFI stub remove the memory reserve map entries
from the FDT as it does with the memory nodes. This allows
early_init_fdt_scan_reserved_mem() to be called unconditionally
so that the other needed reservations are made.

Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

parent 9cb0e394

arch/arm64/mm/init.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -149,7 +149,6 @@ void __init arm64_memblock_init(void)
		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
		#endif

		if (!efi_enabled(EFI_MEMMAP))
		early_init_fdt_scan_reserved_mem();

		/* 4GB maximum for 32-bit only capable devices */

drivers/firmware/efi/libstub/fdt.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -22,7 +22,7 @@ efi_status_t update_fdt(efi_system_table_t sys_table, void orig_fdt,
		unsigned long map_size, unsigned long desc_size,
		u32 desc_ver)
		{
		int node, prev;
		int node, prev, num_rsv;
		int status;
		u32 fdt_val32;
		u64 fdt_val64;
		@@ -73,6 +73,14 @@ efi_status_t update_fdt(efi_system_table_t sys_table, void orig_fdt,
		prev = node;
		}

		/*
		* Delete all memory reserve map entries. When booting via UEFI,
		* kernel will use the UEFI memory map to find reserved regions.
		*/
		num_rsv = fdt_num_mem_rsv(fdt);
		while (num_rsv-- > 0)
		fdt_del_mem_rsv(fdt, num_rsv);

		node = fdt_subnode_offset(fdt, 0, "chosen");
		if (node < 0) {
		node = fdt_add_subnode(fdt, 0, "chosen");

Admin message