[PATCH 93/98] x86,efi: Implement efi_no_storage_paranoia parameter

From: Luis Henriques
Date: Thu Jul 11 2013 - 10:29:13 EST


3.5.7.17 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Richard Weinberger <richard@xxxxxx>

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@xxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 6 ++++++
arch/x86/platform/efi/efi.c | 14 +++++++++++++-
2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 912785c..b5576c6 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -791,6 +791,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
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 0eb3066..da366ae 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -102,6 +102,15 @@ static int __init setup_add_efi_memmap(char *arg)
}
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)
{
@@ -988,7 +997,10 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
" 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;

--
1.8.1.2

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