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>
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1 changed files with 16 additions and 4 deletions
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@ -853,6 +853,8 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
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dotraplinkage void
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dotraplinkage void
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do_device_not_available(struct pt_regs *regs, long error_code)
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do_device_not_available(struct pt_regs *regs, long error_code)
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{
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{
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unsigned long cr0;
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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#ifdef CONFIG_MATH_EMULATION
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#ifdef CONFIG_MATH_EMULATION
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@ -866,10 +868,20 @@ do_device_not_available(struct pt_regs *regs, long error_code)
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return;
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return;
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}
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}
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#endif
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#endif
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fpu__restore(¤t->thread.fpu); /* interrupts still off */
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#ifdef CONFIG_X86_32
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/* This should not happen. */
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cond_local_irq_enable(regs);
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cr0 = read_cr0();
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#endif
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if (WARN(cr0 & X86_CR0_TS, "CR0.TS was set")) {
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/* Try to fix it up and carry on. */
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write_cr0(cr0 & ~X86_CR0_TS);
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} else {
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/*
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* Something terrible happened, and we're better off trying
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* to kill the task than getting stuck in a never-ending
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* loop of #NM faults.
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*/
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die("unexpected #NM exception", regs, error_code);
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}
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}
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}
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NOKPROBE_SYMBOL(do_device_not_available);
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NOKPROBE_SYMBOL(do_device_not_available);
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