x86/fpu: Fix the 'nofxsr' boot parameter to also clear X86_FEATURE_FXSR_OPT

commit d364a7656c1855c940dfa4baf4ebcc3c6a9e6fd2 upstream.

I tried to simulate an ancient CPU via this option, and
found that it still has fxsr_opt enabled, confusing the
FPU code.

Make the 'nofxsr' option also clear FXSR_OPT flag.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 6cfcffe6665259229e7b997da5bae6134e2b9c16..b1546961eac847be79f39d116f01103b3ddebf39 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -199,6 +199,15 @@ static int __init x86_noinvpcid_setup(char *s)
 }
 early_param("noinvpcid", x86_noinvpcid_setup);
 
+static int __init x86_fxsr_setup(char *s)
+{
+       setup_clear_cpu_cap(X86_FEATURE_FXSR);
+       setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
+       setup_clear_cpu_cap(X86_FEATURE_XMM);
+       return 1;
+}
+__setup("nofxsr", x86_fxsr_setup);
+
 #ifdef CONFIG_X86_32
 static int cachesize_override = -1;
 static int disable_x86_serial_nr = 1;
@@ -210,14 +219,6 @@ static int __init cachesize_setup(char *str)
 }
 __setup("cachesize=", cachesize_setup);
 
-static int __init x86_fxsr_setup(char *s)
-{
-       setup_clear_cpu_cap(X86_FEATURE_FXSR);
-       setup_clear_cpu_cap(X86_FEATURE_XMM);
-       return 1;
-}
-__setup("nofxsr", x86_fxsr_setup);
-
 static int __init x86_sep_setup(char *s)
 {
        setup_clear_cpu_cap(X86_FEATURE_SEP);