diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-10-31 15:18:47 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-11-01 07:47:54 +0100 |
| commit | bef8b6da95229f780a0a7f63e23124058bfad6d3 (patch) | |
| tree | c754093dab4dfe4262457d82c98eacd271c2c899 /arch/x86 | |
| parent | cd95ea81f25608c403052d0508ee5c9b32e2bc7d (diff) | |
x86/fpu: Handle #NM without FPU emulation as an error
Don't use CR0.TS. Make it an error rather than making nonsensical
changes to the FPU state.
(The cond_local_irq_enable() appears to have been pointless, too.)
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm list <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/f1ee6bf73ed1025fccaab321ba43d0594245f927.1477951965.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/traps.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index bd4e3d4d3625..bf0c6d049080 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -853,6 +853,8 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) dotraplinkage void do_device_not_available(struct pt_regs *regs, long error_code) { + unsigned long cr0; + RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); #ifdef CONFIG_MATH_EMULATION @@ -866,10 +868,20 @@ do_device_not_available(struct pt_regs *regs, long error_code) return; } #endif - fpu__restore(¤t->thread.fpu); /* interrupts still off */ -#ifdef CONFIG_X86_32 - cond_local_irq_enable(regs); -#endif + + /* This should not happen. */ + cr0 = read_cr0(); + if (WARN(cr0 & X86_CR0_TS, "CR0.TS was set")) { + /* Try to fix it up and carry on. */ + write_cr0(cr0 & ~X86_CR0_TS); + } else { + /* + * Something terrible happened, and we're better off trying + * to kill the task than getting stuck in a never-ending + * loop of #NM faults. + */ + die("unexpected #NM exception", regs, error_code); + } } NOKPROBE_SYMBOL(do_device_not_available); |