kernel/utsname_sysctl.c: print kernel arch

Print the machine hardware name (UTS_MACHINE) in /proc/sys/kernel/arch.

This helps people who debug kernel with initramfs with minimal environment
(i.e.  without coreutils or even busybox) or allow to open sysfs file
instead of run 'uname -m' in high level languages.

Link: https://lkml.kernel.org/r/20220901194403.3819-1-pvorel@suse.cz
Signed-off-by: Petr Vorel <pvorel@suse.cz>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Sterba <dsterba@suse.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index ee6572b..bbaa851 100644 (file)
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -65,6 +65,11 @@ combining the following values:
 4 s3_beep
 = =======
 
+arch
+====
+
+The machine hardware name, the same output as ``uname -m``
+(e.g. ``x86_64`` or ``aarch64``).
 
 auto_msgmni
 ===========

diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c
index 4ca61d4..7ffdd2c 100644 (file)
--- a/kernel/utsname_sysctl.c
+++ b/kernel/utsname_sysctl.c
@@ -74,6 +74,13 @@ static DEFINE_CTL_TABLE_POLL(domainname_poll);
 
 static struct ctl_table uts_kern_table[] = {
        {
+               .procname       = "arch",
+               .data           = init_uts_ns.name.machine,
+               .maxlen         = sizeof(init_uts_ns.name.machine),
+               .mode           = 0444,
+               .proc_handler   = proc_do_uts_string,
+       },
+       {
                .procname       = "ostype",
                .data           = init_uts_ns.name.sysname,
                .maxlen         = sizeof(init_uts_ns.name.sysname),