efi: Add "efi_fake_mem" boot option
This patch introduces new boot option named "efi_fake_mem".
By specifying this parameter, you can add arbitrary attribute
to specific memory range.
This is useful for debugging of Address Range Mirroring feature.
For example, if "efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000"
is specified, the original (firmware provided) EFI memmap will be
updated so that the specified memory regions have
EFI_MEMORY_MORE_RELIABLE attribute (0x10000):
<original>
efi: mem36: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)
<updated>
efi: mem36: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000) (2048MB)
efi: mem37: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000) (61952MB)
efi: mem38: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000) (2048MB)
efi: mem39: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000) (63488MB)
And you will find that the following message is output:
efi: Memory: 4096M/131455M mirrored memory
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..cd5312f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1092,6 +1092,21 @@
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]
+ Add arbitrary attribute to specific memory range by
+ updating original EFI memory map.
+ Region of memory which aa attribute is added to is
+ from ss to ss+nn.
+ If efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000
+ is specified, EFI_MEMORY_MORE_RELIABLE(0x10000)
+ attribute is added to range 0x100000000-0x180000000 and
+ 0x10a0000000-0x1120000000.
+
+ Using this parameter you can do debugging of EFI memmap
+ related feature. For example, you can do debugging of
+ Address Range Mirroring feature even if your box
+ doesn't support it.
+
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.