This adds the EFI Spec version from the system table to sysfs as
/sys/firmware/efi/spec_version .
Userland tools need this information in order to work around
specification deficiencies in 2.4 and earlier firmwares.
Signed-off-by: Peter Jones <pjones@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-firmware-efi | 6 +++
arch/ia64/kernel/efi.c | 3 ++
drivers/firmware/efi/arm-init.c | 2 +
drivers/firmware/efi/efi.c | 71 ++++++++++++++++++++++++++++
4 files changed, 82 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-firmware-efi b/Documentation/ABI/testing/sysfs-firmware-efi
index e794eac..4eec7c2 100644
--- a/Documentation/ABI/testing/sysfs-firmware-efi
+++ b/Documentation/ABI/testing/sysfs-firmware-efi
@@ -28,3 +28,9 @@ Description: Displays the physical addresses of all EFI Configuration
versions are always printed first, i.e. ACPI20 comes
before ACPI.
Users: dmidecode
+
+What: /sys/firmware/efi/spec_version
+Date: August 2016
+Contact: linux-efi@xxxxxxxxxxxxxxx
+Description: Displays the UEFI Specification revision the firmware claims to
+ be based upon.
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 1212956..a48377f 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -475,6 +475,7 @@ efi_init (void)
u64 efi_desc_size;
char *cp, vendor[100] = "unknown";
int i;
+ efi_table_hdr_t *hdr;
set_bit(EFI_BOOT, &efi.flags);
set_bit(EFI_64BIT, &efi.flags);
@@ -531,6 +532,8 @@ efi_init (void)
efi.systab->hdr.revision >> 16,
efi.systab->hdr.revision & 0xffff, vendor);
+ efi.spec_version = efi.systab->hdr.version;
+
palo_phys = EFI_INVALID_TABLE_ADDR;
if (efi_config_init(arch_tables) != 0)
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index b89fc23..8e8cb8c 100644
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -133,6 +133,8 @@ static int __init uefi_init(void)
efi.spec_version = (u32)efi.systab->hdr.revision;
+ early_memunmap(tmp, sizeof(efi_table_hdr_t));
+
table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
table_size);
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 5a2631a..5947d19 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/ucs2_string.h>
+#include <linux/bcd.h>
#include <asm/early_ioremap.h>
@@ -124,6 +125,74 @@ static struct kobj_attribute efi_attr_systab =
#define EFI_FIELD(var) efi.var
+static ssize_t efi_version_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf,
+ u32 revision)
+{
+ char *str = buf;
+ u16 major;
+ u8 minor, tiny;
+
+ if (!kobj || !buf)
+ return -EINVAL;
+
+ /* The spec says:
+ * The revision of the EFI Specification to which this table
+ * conforms. The upper 16 bits of this field contain the major
+ * revision value, and the lower 16 bits contain the minor revision
+ * value. The minor revision values are binary coded decimals and are
+ * limited to the range of 00..99.
+ *
+ * When printed or displayed UEFI spec revision is referred as (Major
+ * revision).(Minor revision upper decimal).(Minor revision lower
+ * decimal) or (Major revision).(Minor revision upper decimal) in
+ * case Minor revision lower decimal is set to 0. For example:
+ *
+ * A specification with the revision value ((2<<16) | (30)) would be
+ * referred as 2.3;
+ * A specification with the revision value ((2<<16) | (31)) would be
+ * referred as 2.3.1
+ *
+ * Then later it says:
+ * Related Definitions
+ * #define EFI_SYSTEM_TABLE_SIGNATURE 0x5453595320494249
+ * #define EFI_2_40_SYSTEM_TABLE_REVISION ((2<<16) | (40))
+ * #define EFI_2_31_SYSTEM_TABLE_REVISION ((2<<16) | (31))
+ * #define EFI_2_30_SYSTEM_TABLE_REVISION ((2<<16) | (30))
+ * #define EFI_2_20_SYSTEM_TABLE_REVISION ((2<<16) | (20))
+ * #define EFI_2_10_SYSTEM_TABLE_REVISION ((2<<16) | (10))
+ * #define EFI_2_00_SYSTEM_TABLE_REVISION ((2<<16) | (00))
+ * #define EFI_1_10_SYSTEM_TABLE_REVISION ((1<<16) | (10))
+ * #define EFI_1_02_SYSTEM_TABLE_REVISION ((1<<16) | (02))
+ * #define EFI_SPECIFICATION_VERSION EFI_SYSTEM_TABLE_REVISION
+ * #define EFI_SYSTEM_TABLE_REVISION EFI_2_40_SYSTEM_TABLE_REVISION
+ *
+ * (Apparently this bit of the spec failed to get updated for 2.5
+ * and 2.6; UefiSpec.h in Tiano has been updated, though.)
+ */
+
+ major = (revision & 0xffff0000) >> 16;
+ minor = bcd2bin((revision & 0x0000ff00) >> 8);
+ tiny = bcd2bin(revision & 0x000000ff);
+
+ if (tiny == 0)
+ str += sprintf(str, "%d.%d\n", major, minor);
+ else
+ str += sprintf(str, "%d.%d.%d\n", major, minor, tiny);
+
+ return str - buf;
+}
+
+#define EFI_VERSION_ATTR_SHOW(name) \
+static ssize_t name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+{ \
+ return efi_version_show(kobj, attr, buf, EFI_FIELD(name)); \
+}
+
+EFI_VERSION_ATTR_SHOW(spec_version);
+
#define EFI_ATTR_SHOW(name) \
static ssize_t name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
@@ -146,6 +215,7 @@ 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 kobj_attribute efi_attr_spec_version = __ATTR_RO(spec_version);
static struct attribute *efi_subsys_attrs[] = {
&efi_attr_systab.attr,
@@ -153,6 +223,7 @@ static struct attribute *efi_subsys_attrs[] = {
&efi_attr_runtime.attr,
&efi_attr_config_table.attr,
&efi_attr_fw_platform_size.attr,
+ &efi_attr_spec_version.attr,
NULL,
};
--
2.7.4
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