From: Thomas Weißschuh Date: Wed, 21 Dec 2022 16:17:52 +0000 (+0000) Subject: kernels/ksysfs.c: export kernel address bits X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=00142bfd5a916a0b3899cc709bf8f5042cf3d084;p=linux.git kernels/ksysfs.c: export kernel address bits This can be used by userspace to determine the address size of the running kernel. It frees userspace from having to interpret this information from the UTS machine field. Userspace implementation: https://github.com/util-linux/util-linux/pull/1966 Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20221221-address-bits-v1-1-8446b13244ac@weissschuh.net Signed-off-by: Greg Kroah-Hartman --- diff --git a/Documentation/ABI/testing/sysfs-kernel-address_bits b/Documentation/ABI/testing/sysfs-kernel-address_bits new file mode 100644 index 0000000000000..5d09ff84d4d6e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-address_bits @@ -0,0 +1,10 @@ +What: /sys/kernel/address_bit +Date: May 2023 +KernelVersion: 6.3 +Contact: Thomas Weißschuh +Description: + The address size of the running kernel in bits. + + Access: Read + +Users: util-linux diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 2df00b789b907..0408aab80941b 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -51,6 +51,14 @@ static ssize_t cpu_byteorder_show(struct kobject *kobj, } KERNEL_ATTR_RO(cpu_byteorder); +/* address bits */ +static ssize_t address_bits_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */); +} +KERNEL_ATTR_RO(address_bits); + #ifdef CONFIG_UEVENT_HELPER /* uevent helper program, used during early boot */ static ssize_t uevent_helper_show(struct kobject *kobj, @@ -233,6 +241,7 @@ static struct attribute * kernel_attrs[] = { &fscaps_attr.attr, &uevent_seqnum_attr.attr, &cpu_byteorder_attr.attr, + &address_bits_attr.attr, #ifdef CONFIG_UEVENT_HELPER &uevent_helper_attr.attr, #endif