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-rw-r--r--Documentation/kernel-parameters.txt3
-rw-r--r--Documentation/x86/x86_64/uefi.txt4
-rw-r--r--arch/x86/kernel/efi.c16
3 files changed, 21 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index da13d6d1b2b0..795c487af8e4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2150,6 +2150,9 @@ and is between 256 and 4096 characters. It is defined in the file
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
+ add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
+ kernel's map of available physical RAM.
+
vdso= [X86-32,SH,x86-64]
vdso=2: enable compat VDSO (default with COMPAT_VDSO)
vdso=1: enable VDSO (default)
diff --git a/Documentation/x86/x86_64/uefi.txt b/Documentation/x86/x86_64/uefi.txt
index 7d77120a5184..a5e2b4fdb170 100644
--- a/Documentation/x86/x86_64/uefi.txt
+++ b/Documentation/x86/x86_64/uefi.txt
@@ -36,3 +36,7 @@ Mechanics:
services.
noefi turn off all EFI runtime services
reboot_type=k turn off EFI reboot runtime service
+- If the EFI memory map has additional entries not in the E820 map,
+ you can include those entries in the kernels memory map of available
+ physical RAM by using the following kernel command line parameter.
+ add_efi_memmap include EFI memory map of available physical RAM
diff --git a/arch/x86/kernel/efi.c b/arch/x86/kernel/efi.c
index a03ca36a302c..94382faeadb6 100644
--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -64,6 +64,17 @@ static int __init setup_noefi(char *arg)
}
early_param("noefi", setup_noefi);
+int add_efi_memmap;
+EXPORT_SYMBOL(add_efi_memmap);
+
+static int __init setup_add_efi_memmap(char *arg)
+{
+ add_efi_memmap = 1;
+ return 0;
+}
+early_param("add_efi_memmap", setup_add_efi_memmap);
+
+
static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
return efi_call_virt2(get_time, tm, tc);
@@ -219,7 +230,7 @@ unsigned long efi_get_time(void)
* (zeropage) memory map.
*/
-static void __init add_efi_memmap(void)
+static void __init do_add_efi_memmap(void)
{
void *p;
@@ -406,7 +417,8 @@ void __init efi_init(void)
if (memmap.desc_size != sizeof(efi_memory_desc_t))
printk(KERN_WARNING "Kernel-defined memdesc"
"doesn't match the one from EFI!\n");
- add_efi_memmap();
+ if (add_efi_memmap)
+ do_add_efi_memmap();
/* Setup for EFI runtime service */
reboot_type = BOOT_EFI;