* [PATCH v2 1/2] efi: Constify sysfs attributes
2026-10-08 8:13 [PATCH v2 0/2] EFI sysfs constification Ard Biesheuvel
@ 2026-10-08 8:13 ` Ard Biesheuvel
2026-10-08 8:13 ` [PATCH v2 2/2] efi: Use sysfs_emit() not sprintf() to generate sysfs file contents Ard Biesheuvel
2026-10-08 13:04 ` [PATCH v2 0/2] EFI sysfs constification Thomas Weißschuh
2 siblings, 0 replies; 4+ messages in thread
From: Ard Biesheuvel @ 2026-10-08 8:13 UTC (permalink / raw)
To: linux-efi; +Cc: linux-kernel, Ard Biesheuvel, Thomas Weißschuh
From: Ard Biesheuvel <ardb@kernel.org>
Implement Thomas's suggestions to constify sysfs kobject attributes.
Cc: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/platform/efi/efi.c | 11 +++---
drivers/firmware/efi/efi.c | 36 +++++++++++---------
include/linux/efi.h | 3 +-
3 files changed, 28 insertions(+), 22 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 0c39adb96b91..d8fe93770c2a 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -891,7 +891,7 @@ bool efi_is_table_address(unsigned long phys_addr)
#define EFI_ATTR_SHOW(name) \
static ssize_t name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
+ const struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
}
@@ -900,11 +900,12 @@ EFI_ATTR_SHOW(fw_vendor);
EFI_ATTR_SHOW(runtime);
EFI_ATTR_SHOW(config_table);
-struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);
-struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);
-struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);
+const struct kobj_attribute efi_attr_fw_vendor = __KOBJ_ATTR_RO(fw_vendor);
+const struct kobj_attribute efi_attr_runtime = __KOBJ_ATTR_RO(runtime);
+const struct kobj_attribute efi_attr_config_table = __KOBJ_ATTR_RO(config_table);
-umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+umode_t efi_attr_is_visible(struct kobject *kobj, const struct attribute *attr,
+ int n)
{
if (attr == &efi_attr_fw_vendor.attr) {
if (efi_enabled(EFI_PARAVIRT) ||
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index e08ce813a3d4..8026264d4990 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -131,7 +131,7 @@ struct kobject *efi_kobj;
* one value per file rule!
*/
static ssize_t systab_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
+ const struct kobj_attribute *attr, char *buf)
{
char *str = buf;
@@ -155,21 +155,21 @@ static ssize_t systab_show(struct kobject *kobj,
return str - buf;
}
-static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400);
+static const struct kobj_attribute efi_attr_systab = __KOBJ_ATTR_RO_MODE(systab, 0400);
static ssize_t fw_platform_size_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
+ const struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
}
-extern __weak struct kobj_attribute efi_attr_fw_vendor;
-extern __weak struct kobj_attribute efi_attr_runtime;
-extern __weak struct kobj_attribute efi_attr_config_table;
-static struct kobj_attribute efi_attr_fw_platform_size =
- __ATTR_RO(fw_platform_size);
+extern __weak const struct kobj_attribute efi_attr_fw_vendor;
+extern __weak const struct kobj_attribute efi_attr_runtime;
+extern __weak const struct kobj_attribute efi_attr_config_table;
+static const struct kobj_attribute efi_attr_fw_platform_size =
+ __KOBJ_ATTR_RO(fw_platform_size);
-static struct attribute *efi_subsys_attrs[] = {
+static const struct attribute *const efi_subsys_attrs[] = {
&efi_attr_systab.attr,
&efi_attr_fw_platform_size.attr,
&efi_attr_fw_vendor.attr,
@@ -178,15 +178,16 @@ static struct attribute *efi_subsys_attrs[] = {
NULL,
};
-umode_t __weak efi_attr_is_visible(struct kobject *kobj, struct attribute *attr,
+umode_t __weak efi_attr_is_visible(struct kobject *kobj,
+ const struct attribute *attr,
int n)
{
return attr->mode;
}
static const struct attribute_group efi_subsys_attr_group = {
- .attrs = efi_subsys_attrs,
- .is_visible = efi_attr_is_visible,
+ .attrs_const = efi_subsys_attrs,
+ .is_visible_const = efi_attr_is_visible,
};
struct blocking_notifier_head efivar_ops_nh;
@@ -401,12 +402,15 @@ static void __init efi_debugfs_init(void)
static inline void efi_debugfs_init(void) {}
#endif
-static ssize_t efi_runtime_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+static ssize_t efi_runtime_show(struct kobject *kobj,
+ const struct kobj_attribute *attr,
+ char *buf)
{
return sprintf(buf, "%d\n", efi_enabled(EFI_RUNTIME_SERVICES));
}
-static ssize_t efi_runtime_store(struct kobject *kobj, struct kobj_attribute *attr,
+static ssize_t efi_runtime_store(struct kobject *kobj,
+ const struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret;
@@ -424,8 +428,8 @@ static ssize_t efi_runtime_store(struct kobject *kobj, struct kobj_attribute *at
return count;
}
-static struct kobj_attribute efi_runtime_attr =
- __ATTR(runtime_enable, 0644, efi_runtime_show, efi_runtime_store);
+static const struct kobj_attribute efi_runtime_attr =
+ __KOBJ_ATTR(runtime_enable, 0644, efi_runtime_show, efi_runtime_store);
static int __init efipostcore_init(void)
{
diff --git a/include/linux/efi.h b/include/linux/efi.h
index ecb34be37a87..fda81d7c4850 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1353,7 +1353,8 @@ bool efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table)
return xen_efi_config_table_is_usable(guid, table);
}
-umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n);
+umode_t efi_attr_is_visible(struct kobject *kobj, const struct attribute *attr,
+ int n);
int ovmf_log_probe(unsigned long ovmf_debug_log_table);
--
2.56.0.360.g66cac248cb-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 2/2] efi: Use sysfs_emit() not sprintf() to generate sysfs file contents
2026-10-08 8:13 [PATCH v2 0/2] EFI sysfs constification Ard Biesheuvel
2026-10-08 8:13 ` [PATCH v2 1/2] efi: Constify sysfs attributes Ard Biesheuvel
@ 2026-10-08 8:13 ` Ard Biesheuvel
2026-10-08 13:04 ` [PATCH v2 0/2] EFI sysfs constification Thomas Weißschuh
2 siblings, 0 replies; 4+ messages in thread
From: Ard Biesheuvel @ 2026-10-08 8:13 UTC (permalink / raw)
To: linux-efi; +Cc: linux-kernel, Ard Biesheuvel, Thomas Weißschuh
From: Ard Biesheuvel <ardb@kernel.org>
Use sysfs_emit() where appropriate to generate the contents of EFI
related sysfs nodes. This is a more robust wrapper around sprintf()
designed for this purpose.
Reported-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/platform/efi/efi.c | 2 +-
drivers/firmware/efi/efi.c | 16 ++++++++--------
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index d8fe93770c2a..5eb96c17883e 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -893,7 +893,7 @@ bool efi_is_table_address(unsigned long phys_addr)
static ssize_t name##_show(struct kobject *kobj, \
const struct kobj_attribute *attr, char *buf) \
{ \
- return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
+ return sysfs_emit(buf, "0x%lx\n", EFI_FIELD(name)); \
}
EFI_ATTR_SHOW(fw_vendor);
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8026264d4990..b4504542cb2c 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -133,26 +133,26 @@ struct kobject *efi_kobj;
static ssize_t systab_show(struct kobject *kobj,
const struct kobj_attribute *attr, char *buf)
{
- char *str = buf;
+ int offset = 0;
if (!kobj || !buf)
return -EINVAL;
if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
+ offset = sysfs_emit(buf, "ACPI20=0x%lx\n", efi.acpi20);
if (efi.acpi != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
+ offset += sysfs_emit_at(buf, offset, "ACPI=0x%lx\n", efi.acpi);
/*
* If both SMBIOS and SMBIOS3 entry points are implemented, the
* SMBIOS3 entry point shall be preferred, so we list it first to
* let applications stop parsing after the first match.
*/
if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
+ offset += sysfs_emit_at(buf, offset, "SMBIOS3=0x%lx\n", efi.smbios3);
if (efi.smbios != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
+ offset += sysfs_emit_at(buf, offset, "SMBIOS=0x%lx\n", efi.smbios);
- return str - buf;
+ return offset;
}
static const struct kobj_attribute efi_attr_systab = __KOBJ_ATTR_RO_MODE(systab, 0400);
@@ -160,7 +160,7 @@ static const struct kobj_attribute efi_attr_systab = __KOBJ_ATTR_RO_MODE(systab,
static ssize_t fw_platform_size_show(struct kobject *kobj,
const struct kobj_attribute *attr, char *buf)
{
- return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
+ return sysfs_emit(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
}
extern __weak const struct kobj_attribute efi_attr_fw_vendor;
@@ -406,7 +406,7 @@ static ssize_t efi_runtime_show(struct kobject *kobj,
const struct kobj_attribute *attr,
char *buf)
{
- return sprintf(buf, "%d\n", efi_enabled(EFI_RUNTIME_SERVICES));
+ return sysfs_emit(buf, "%d\n", efi_enabled(EFI_RUNTIME_SERVICES));
}
static ssize_t efi_runtime_store(struct kobject *kobj,
--
2.56.0.360.g66cac248cb-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread