x86/cpu: Remove "nosmep"

There should be no need to disable SMEP anymore.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-5-bp@alien8.de

Documentation/admin-guide/kernel-parameters.txt

@@ -3465,7 +3465,7 @@
 			Disable SMAP (Supervisor Mode Access Prevention)
 			even if it is supported by processor.
 
-	nosmep		[X86,PPC64s]
+	nosmep		[PPC64s]
 			Disable SMEP (Supervisor Mode Execution Prevention)
 			even if it is supported by processor.
 

Documentation/x86/cpuinfo.rst

@@ -140,8 +140,8 @@ from #define X86_FEATURE_UMIP (16*32 + 2).
 
 In addition, there exists a variety of custom command-line parameters that
 disable specific features. The list of parameters includes, but is not limited
-to, nofsgsbase, and nosmep. 5-level paging can also be disabled using
-"no5lvl". SMEP is disabled with the aforementioned parameter.
+to, nofsgsbase, nosgx, noxsave, etc. 5-level paging can also be disabled using
+"no5lvl".
 
 e: The feature was known to be non-functional.
 ----------------------------------------------

arch/x86/kernel/cpu/common.c

@@ -369,13 +369,6 @@ static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
 }
 #endif
 
-static __init int setup_disable_smep(char *arg)
-{
-	setup_clear_cpu_cap(X86_FEATURE_SMEP);
-	return 1;
-}
-__setup("nosmep", setup_disable_smep);
-
 static __always_inline void setup_smep(struct cpuinfo_x86 *c)
 {
 	if (cpu_has(c, X86_FEATURE_SMEP))