docs: Update nosmt support for arm64

commit eed4583bcf9a6 ("arm64: Kconfig: Enable HOTPLUG_SMT") enable
HOTPLUG_SMT for SMT control for arm64, but the documentation was
not updated accordingly to reflect that ARM64 now supports control SMT
via boot parameter and sysfs knobs:

1. Boot parameters:

nosmt:          Disable SMT, can be enabled via sysfs knobs.
nosmt=force:    Disable SMT, cannot be enabled via sysfs knobs.

2. Runtime sysfs controls:

Write "on", "off", "forceoff" or the number of SMT threads (1, 2, ...)
to /sys/devices/system/cpu/smt/control.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260417032540.3720627-1-ruanjinjie@huawei.com>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b1e2e50d5c8d1bd4c88d3773afda91c9c93a2f40..8c22943e51c0e26a297cabbc73c477d09b469243 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4638,7 +4638,7 @@ Kernel parameters
        nosmt           [KNL,MIPS,PPC,EARLY] Disable symmetric multithreading (SMT).
                        Equivalent to smt=1.
 
-                       [KNL,LOONGARCH,X86,PPC,S390] Disable symmetric multithreading (SMT).
+                       [KNL,LOONGARCH,X86,ARM64,PPC,S390] Disable symmetric multithreading (SMT).
                        nosmt=force: Force disable SMT, cannot be undone
                                     via the sysfs control file.