From: Borislav Petkov <bp@suse.de>
Date: Thu, 27 Jan 2022 11:56:22 +0000 (+0100)
Subject: x86/cpu: Remove "nosep"
X-Git-Tag: v6.1-rc5~799^2~11
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c949110ef4e31cb5d3387bd8273fd5de66b5227b;p=platform%2Fkernel%2Flinux-starfive.git

x86/cpu: Remove "nosep"

That chicken bit was added by

  4f88651125e2 ("[PATCH] i386: allow disabling X86_FEATURE_SEP at boot")

but measuring int80 vsyscall performance on 32-bit doesn't matter
anymore.

If still needed, one can boot with

  clearcpuid=sep

to disable that feature for testing.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-3-bp@alien8.de
---

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0ea1786..a9f3d31 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3665,8 +3665,6 @@
 
 	nosbagart	[IA-64]
 
-	nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
-
 	nosgx		[X86-64,SGX] Disables Intel SGX kernel support.
 
 	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 69c7ea8..c71d107 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -298,13 +298,6 @@ static int __init cachesize_setup(char *str)
 }
 __setup("cachesize=", cachesize_setup);
 
-static int __init x86_sep_setup(char *s)
-{
-	setup_clear_cpu_cap(X86_FEATURE_SEP);
-	return 1;
-}
-__setup("nosep", x86_sep_setup);
-
 /* Standard macro to see if a specific flag is changeable */
 static inline int flag_is_changeable_p(u32 flag)
 {