Commit 00142bfd authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Greg Kroah-Hartman
Browse files

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: default avatarThomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221221-address-bits-v1-1-8446b13244ac@weissschuh.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e5da06b2

Documentation/ABI/testing/sysfs-kernel-address_bits

0 → 100644
+10 −0
Original line number Diff line number Diff line 
What:		/sys/kernel/address_bit

Date:		May 2023

KernelVersion:	6.3

Contact:	Thomas Weißschuh <linux@weissschuh.net>

Description:

		The address size of the running kernel in bits.



		Access: Read



Users:		util-linux

kernel/ksysfs.c

+9 −0
Original line number Diff line number Diff line
@@ -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