Export fw_vendor, runtime and config tables physical
addresses to /sys/firmware/efi/systab becaue kexec
kernel will need them.
>From EFI spec these 3 variables will be updated to
virtual address after entering virtual mode. But
kernel startup code will need the physical address.
changelog:
Greg: add standalone sysfs files instead of add lines to systab
Document them as testing ABI
Greg: use group attrs and is_visible
Boris: align comments lines
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-firmware-efi | 26 +++++++++++++++
arch/x86/platform/efi/efi.c | 4 ++
drivers/firmware/efi/efi.c | 44 +++++++++++++++++++++++++++
include/linux/efi.h | 3 +
4 files changed, 77 insertions(+)
--- efi.orig/drivers/firmware/efi/efi.c
+++ efi/drivers/firmware/efi/efi.c
@@ -32,6 +32,9 @@ struct efi __read_mostly efi = {
.hcdp = EFI_INVALID_TABLE_ADDR,
.uga = EFI_INVALID_TABLE_ADDR,
.uv_systab = EFI_INVALID_TABLE_ADDR,
+ .fw_vendor = EFI_INVALID_TABLE_ADDR,
+ .runtime = EFI_INVALID_TABLE_ADDR,
+ .config_table = EFI_INVALID_TABLE_ADDR,
};
EXPORT_SYMBOL(efi);
@@ -71,13 +74,54 @@ static ssize_t systab_show(struct kobjec
static struct kobj_attribute efi_attr_systab =
__ATTR(systab, 0400, systab_show, NULL);
+static ssize_t fw_vendor_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", efi.fw_vendor);
+}
+
+static ssize_t runtime_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", efi.runtime);
+}
+
+static ssize_t config_table_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", efi.config_table);
+}
+
+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 attribute *efi_subsys_attrs[] = {
&efi_attr_systab.attr,
+ &efi_attr_fw_vendor.attr,
+ &efi_attr_runtime.attr,
+ &efi_attr_config_table.attr,
NULL, /* maybe more in the future? */
};
+static umode_t efi_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ umode_t mode = attr->mode;
+
+ if (attr == &efi_attr_fw_vendor.attr)
+ return (efi.fw_vendor == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
+ else if (attr == &efi_attr_runtime.attr)
+ return (efi.runtime == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
+ else if (attr == &efi_attr_config_table.attr)
+ return (efi.config_table == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
+
+ return mode;
+}
+
static struct attribute_group efi_subsys_attr_group = {
.attrs = efi_subsys_attrs,
+ .is_visible = efi_attr_is_visible,
};
static struct efivars generic_efivars;
--- efi.orig/include/linux/efi.h
+++ efi/include/linux/efi.h
@@ -556,6 +556,9 @@ extern struct efi {
unsigned long hcdp; /* HCDP table */
unsigned long uga; /* UGA table */
unsigned long uv_systab; /* UV system table */
+ unsigned long fw_vendor; /* fw_vendor */
+ unsigned long runtime; /* runtime table */
+ unsigned long config_table; /* config tables */
efi_get_time_t *get_time;
efi_set_time_t *set_time;
efi_get_wakeup_time_t *get_wakeup_time;
--- efi.orig/arch/x86/platform/efi/efi.c
+++ efi/arch/x86/platform/efi/efi.c
@@ -653,6 +653,10 @@ void __init efi_init(void)
set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
+ efi.config_table = (unsigned long)efi.systab->tables;
+ efi.fw_vendor = (unsigned long)efi.systab->fw_vendor;
+ efi.runtime = (unsigned long)efi.systab->runtime;
+
/*
* Show what we know for posterity
*/
--- /dev/null
+++ efi/Documentation/ABI/testing/sysfs-firmware-efi
@@ -0,0 +1,26 @@
+What: /sys/firmware/efi/fw_vendor
+Date: Nov 2013
+Contact: Dave Young <dyoung@xxxxxxxxxx>
+Description:
+ Shows the physical address of firmware vendor in the EFI
+ system table.
+Users:
+ Kexec Mailing List <kexec@xxxxxxxxxxxxxxxxxxx>
+
+What: /sys/firmware/efi/runtime
+Date: Nov 2013
+Contact: Dave Young <dyoung@xxxxxxxxxx>
+Description:
+ Shows the physical address of runtime service table in the
+ EFI system table.
+Users:
+ Kexec Mailing List <kexec@xxxxxxxxxxxxxxxxxxx>
+
+What: /sys/firmware/efi/config_table
+Date: Nov 2013
+Contact: Dave Young <dyoung@xxxxxxxxxx>
+Description:
+ Shows the physical address of config table in the EFI
+ system table.
+Users:
+ Kexec Mailing List <kexec@xxxxxxxxxxxxxxxxxxx>
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