Commit 385d2ae0 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

x86/cpu: Remove "nosmep" 



There should be no need to disable SMEP anymore.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarLai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-5-bp@alien8.de
parent dbae0a93

Documentation/admin-guide/kernel-parameters.txt

+1 −1
Original line number Diff line number Diff line
@@ -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

+2 −2
Original line number Diff line number Diff line
@@ -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

+0 −7
Original line number Diff line number Diff line
@@ -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))