x86/entry/32: Add missing ASM_CLAC to general_protection entry

BugLink: https://bugs.launchpad.net/bugs/1875905

commit 3d51507f upstream.

All exception entry points must have ASM_CLAC right at the
beginning. The general_protection entry is missing one.

Fixes: e59d1b0a ("x86-32, smap: Add STAC/CLAC instructions to 32-bit kernel entry")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200225220216.219537887@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/x86/entry/entry_32.S

@@ -1071,6 +1071,7 @@ ENTRY(int3)
 END(int3)
 
 ENTRY(general_protection)
+	ASM_CLAC
 	pushl	$do_general_protection
 	jmp	error_code
 END(general_protection)