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authorDan Williams <dan.j.williams@intel.com>2019-11-06 17:43:26 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-11-07 15:44:23 +0100
commit199c8471761273b7e287914cee968ddf21dfbfe0 (patch)
tree9f99308b4861d2cc74bc1ca61e4c0e3bb5e61943 /Documentation/admin-guide
parent16993c0f0a43213e23666ea40e9163887f593ac7 (diff)
downloadlinux-199c8471761273b7e287914cee968ddf21dfbfe0.tar.bz2
x86/efi: Add efi_fake_mem support for EFI_MEMORY_SP
Given that EFI_MEMORY_SP is platform BIOS policy decision for marking memory ranges as "reserved for a specific purpose" there will inevitably be scenarios where the BIOS omits the attribute in situations where it is desired. Unlike other attributes if the OS wants to reserve this memory from the kernel the reservation needs to happen early in init. So early, in fact, that it needs to happen before e820__memblock_setup() which is a pre-requisite for efi_fake_memmap() that wants to allocate memory for the updated table. Introduce an x86 specific efi_fake_memmap_early() that can search for attempts to set EFI_MEMORY_SP via efi_fake_mem and update the e820 table accordingly. The KASLR code that scans the command line looking for user-directed memory reservations also needs to be updated to consider "efi_fake_mem=nn@ss:0x40000" requests. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt10
1 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2359dc56d82c..5eee3ea05ac5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1196,15 +1196,21 @@
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.
+ If efi_fake_mem=8G@9G:0x40000 is specified, the
+ EFI_MEMORY_SP(0x40000) attribute is added to
+ range 0x240000000-0x43fffffff.
+
Using this parameter you can do debugging of EFI memmap
- related feature. For example, you can do debugging of
+ related features. For example, you can do debugging of
Address Range Mirroring feature even if your box
- doesn't support it.
+ doesn't support it, or mark specific memory as
+ "soft reserved".
efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT
that is to be dynamically loaded by Linux. If there are