Messages in this thread | | | Date | Thu, 25 Sep 2014 06:57:55 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: Quark: Flush TLB via CR3 not CR4.PGE in setup_arch() |
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* Bryan O'Donoghue <pure.logic@nexus-software.ie> wrote:
> Quark X1000 requires CR3 to be rewritten to flush TLB entries > irrespective of the PGE bits in CR4 or PTE.PGE > > This patch flushes the TLB in the required way for Quark in setup_arch() > See Quark Core_DevMan_001.pdf section 6.4.11 > > Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> > --- > arch/x86/kernel/setup.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index 41ead8d..1d2396a 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -879,7 +879,10 @@ void __init setup_arch(char **cmdline_p) > KERNEL_PGD_PTRS); > > load_cr3(swapper_pg_dir); > - __flush_tlb_all(); > + if (boot_cpu_data.x86 == 5 && boot_cpu_data.x86_model == 9) > + __flush_tlb(); > + else > + __flush_tlb_all();
So why not make __flush_tlb_all() Quark-quirk-aware and be done with it, instead of having to validate every single __flush_tlb_all() user?
Quark breaks the x86 'flush all TLBs' semantics - the way to fix it is to restore those semantics, not to sprinkle the breakage all around the code ...
Thanks,
Ingo
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