linux-kernel - [PATCH 4/6] x86/cpu: Remove "nosmep"

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Message-Id: <20211112103246.7555-5-bp@alien8.de>
Date:   Fri, 12 Nov 2021 11:32:44 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 4/6] x86/cpu: Remove "nosmep"

From: Borislav Petkov <bp@...e.de>

There should be no need to disable SMEP anymore.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 Documentation/admin-guide/kernel-parameters.txt | 4 ----
 Documentation/x86/cpuinfo.rst                   | 4 ++--
 arch/x86/kernel/cpu/common.c                    | 7 -------
 3 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 54ae0378add4..b3fbb0930997 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3365,10 +3365,6 @@
 			noexec=on: enable non-executable mappings (default)
 			noexec=off: disable non-executable mappings
 
-	nosmep		[X86,PPC]
-			Disable SMEP (Supervisor Mode Execution Prevention)
-			even if it is supported by processor.
-
 	noexec32	[X86-64]
 			This affects only 32-bit executables.
 			noexec32=on: enable non-executable mappings (default)
diff --git a/Documentation/x86/cpuinfo.rst b/Documentation/x86/cpuinfo.rst
index 12fbe2b1e98a..08246e8ac835 100644
--- a/Documentation/x86/cpuinfo.rst
+++ b/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.
 ----------------------------------------------
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 796aa31fd3c8..7e70c54cdff5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -291,13 +291,6 @@ 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))
-- 
2.29.2