Re: [PATCH] x86/mm/64: Fix an incorrect warning with CONFIG_DEBUG_VM=y, !PCID

From: Andy Lutomirski
Date: Sun Sep 10 2017 - 15:10:51 EST


On Sun, Sep 10, 2017 at 8:52 AM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> I've been staring at the word PCID too long.
>
> Fixes: f13c8e8c58ba ("x86/mm: Reinitialize TLB state on hotplug and resume")
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
> arch/x86/mm/tlb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
> index 158acdad2773..1ab3821f9e26 100644
> --- a/arch/x86/mm/tlb.c
> +++ b/arch/x86/mm/tlb.c
> @@ -261,7 +261,7 @@ void initialize_tlbstate_and_flush(void)
> * doesn't work like other CR4 bits because it can only be set from
> * long mode.)
> */
> - WARN_ON(boot_cpu_has(X86_CR4_PCIDE) &&
> + WARN_ON(boot_cpu_has(X86_FEATURE_PCID) &&
> !(cr4_read_shadow() & X86_CR4_PCIDE));
>
> /* Force ASID 0 and force a TLB flush. */
> --
> 2.13.5
>

Ugh, don't apply this. There's a somewhat deeper problem here.