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Subject[PATCH v2 2/9] arm64: efi: Add fake memory support
Date
From: Ma Wupeng <mawupeng1@huawei.com>

Fake memory map is used for faking memory's attribute values.
Commit 0f96a99dab36 ("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>
---
Documentation/admin-guide/kernel-parameters.txt | 2 +-
arch/arm64/kernel/setup.c | 2 ++
drivers/firmware/efi/Kconfig | 2 +-
3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3f1cc5e317ed..ea47c0ba7593 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1357,7 +1357,7 @@
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
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 3505789cf4bd..daade64889ff 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -344,6 +344,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)

arm64_memblock_init();

+ efi_fake_memmap();
+
paging_init();

acpi_table_upgrade();
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 2c3dac5ecb36..3c91bbd4097a 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -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.
--
2.18.0.huawei.25
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