x86/fpu: Fix 'no387' regression
authorAndy Lutomirski <[email protected]>
Thu, 21 Jan 2016 23:24:31 +0000 (15:24 -0800)
committerIngo Molnar <[email protected]>
Wed, 9 Mar 2016 12:54:40 +0000 (13:54 +0100)
commitf363938c70a04e6bc99023a5e0c44ef7879b903f
treefb17f54412ba7f992ac84f6308d7f711c0045cb1
parente2857b8f11a289ed2b61d18d0665e05c1053c446
x86/fpu: Fix 'no387' regression

After fixing FPU option parsing, we now parse the 'no387' boot option
too early: no387 clears X86_FEATURE_FPU before it's even probed, so
the boot CPU promptly re-enables it.

I suspect it gets even more confused on SMP.

Fix the probing code to leave X86_FEATURE_FPU off if it's been
disabled by setup_clear_cpu_cap().

Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Quentin Casasnovas <[email protected]>
Cc: Sai Praneeth Prakhya <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: yu-cheng yu <[email protected]>
Fixes: 4f81cbafcce2 ("x86/fpu: Fix early FPU command-line parsing")
Signed-off-by: Ingo Molnar <[email protected]>
arch/x86/kernel/fpu/init.c