x86,efi: Implement efi_no_storage_paranoia parameter
commit 8c58bf3eec3b8fc8162fe557e9361891c20758f2 upstream.
Using this parameter one can disable the storage_size/2 check if
he is really sure that the UEFI does sane gc and fulfills the spec.
This parameter is useful if a devices uses more than 50% of the
storage by default.
The Intel DQSW67 desktop board is such a sucker for exmaple.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0797ba8..f1d2484 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -782,6 +782,12 @@
edd= [EDD]
Format: {"off" | "on" | "skip[mbr]"}
+ efi_no_storage_paranoia [EFI; X86]
+ Using this parameter you can use more than 50% of
+ your efi variable storage. Use this parameter only if
+ you are really sure that your UEFI does sane gc and
+ fulfills the spec otherwise your board may brick.
+
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 15d0328..8a13238 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -102,6 +102,15 @@
}
early_param("add_efi_memmap", setup_add_efi_memmap);
+static bool efi_no_storage_paranoia;
+
+static int __init setup_storage_paranoia(char *arg)
+{
+ efi_no_storage_paranoia = true;
+ return 0;
+}
+early_param("efi_no_storage_paranoia", setup_storage_paranoia);
+
static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
@@ -984,7 +993,10 @@
" is returning MaxVariableSize=0\n");
if (!storage_size || size > remaining_size ||
- (max_size && size > max_size) ||
+ (max_size && size > max_size))
+ return EFI_OUT_OF_RESOURCES;
+
+ if (!efi_no_storage_paranoia &&
(remaining_size - size) < (storage_size / 2))
return EFI_OUT_OF_RESOURCES;