Commit 4159882e authored Feb 23, 2022 by Ma Wupeng Committed by Zheng Zengkai Feb 23, 2022

arm64: efi: Add fake memory support

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4PM01


CVE: NA

--------------------------------

Fake memory map is used for faking memory's attribute values.
Commit 0f96a99d ("efi: Add "efi_fake_mem" boot option") introduce the
efi_fake_mem function. Now it can support arm64 with this patch.
For example you can mark 0-6G memory as EFI_MEMORY_MORE_RELIABLE by adding
efi_fake_mem=6G@0:0x10000 in the bootarg. You find more info about
fake memmap in kernel-parameters.txt.

Variable memstart_addr is only confirmed after arm64_memblock_init(). So
efi_fake_memmap() is needed to add after arm64_memblock_init().

Otherwise:

efi_memmap_alloc
   memblock_phys_alloc
     kmemleak_alloc_phys
        kmemleak_alloc(__va(phys), size, min_count, gfp);

this __va() will convert phys to a fault va and lead to a kmemleak error.

Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>

parent 2e5602aa

Documentation/admin-guide/kernel-parameters.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -1290,7 +1290,7 @@
		you are really sure that your UEFI does sane gc and
		fulfills the spec otherwise your board may brick.

		efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI; X86]
		efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI; X86; ARM64]
		Add arbitrary attribute to specific memory range by
		updating original EFI memory map.
		Region of memory which aa attribute is added to is

arch/arm64/kernel/setup.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -387,6 +387,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)

		arm64_memblock_init();

		efi_fake_memmap();

		paging_init();

		acpi_table_upgrade();

drivers/firmware/efi/Kconfig

+1 −1

Original line number	Diff line number	Diff line
		@@ -50,7 +50,7 @@ config EFI_RUNTIME_MAP

		config EFI_FAKE_MEMMAP
		bool "Enable EFI fake memory map"
		depends on EFI && X86
		depends on EFI && (X86 \|\| ARM64)
		default n
		help
		Saying Y here will enable "efi_fake_mem" boot option.