Bug#775191: [PATCH] efi: Expose underlying UEFI firmware platform size to userland
Package: src:linux
Severity: wishlist
Tags: patch
Hi folks,
This patch has been accepted by the efi maintainer for the efi/next
tree. It would be lovely if you'd accept it for the Jessie kernel
too, for the Bay Trail etc. support.
--
Steve McIntyre, Cambridge, UK. steve@einval.com
"You can't barbecue lettuce!" -- Ellie Crane
>From 2859dff97e54db4795b8b7d9606cb8efcec722ff Mon Sep 17 00:00:00 2001
From: Steve McIntyre <steve@einval.com>
Date: Fri, 9 Jan 2015 15:29:53 +0000
Subject: [PATCH] efi: Expose underlying UEFI firmware platform size to
userland
In some cases (e.g. Intel Bay Trail machines), the kernel will happily
run in 64-bit even if the underlying UEFI firmware platform is
32-bit. That's great, but it's difficult for userland utilities like
grub-install to do the right thing in such a situation.
The kernel already knows about the size of the firmware via
efi_enabled(EFI_64BIT). Add an extra sysfs interface
/sys/firmware/efi/fw_platform_size to expose that information to
userland for low-level utilities to use.
Signed-off-by: Steve McIntyre <steve@einval.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
---
drivers/firmware/efi/efi.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index ff0bbe3..9bdbc05 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -112,15 +112,24 @@ EFI_ATTR_SHOW(fw_vendor);
EFI_ATTR_SHOW(runtime);
EFI_ATTR_SHOW(config_table);
+static ssize_t fw_platform_size_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
+}
+
static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);
static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);
static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);
+static struct kobj_attribute efi_attr_fw_platform_size =
+ __ATTR_RO(fw_platform_size);
static struct attribute *efi_subsys_attrs[] = {
&efi_attr_systab.attr,
&efi_attr_fw_vendor.attr,
&efi_attr_runtime.attr,
&efi_attr_config_table.attr,
+ &efi_attr_fw_platform_size.attr,
NULL,
};
--
1.7.10.4
Reply to: