Nicholas Piggin <npig...@gmail.com> writes:
> The SLBIA IH=1 hint will remove all non-zero SLBEs, but only
> invalidate ERAT entries associated with a class value of 1, for
> processors that support the hint (e.g., POWER6 and newer), which
> Linux assigns to user addresses.
>
> This prevents kernel ERAT entries from being invalidated when
> context switchig (if the thread faulted in more than 8 user SLBEs).
how about renaming stuff to indicate kernel ERAT entries are kept?
something like slb_flush_and_rebolt_user()?
>
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> arch/powerpc/mm/slb.c | 38 +++++++++++++++++++++++---------------
> 1 file changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
> index a5e58f11d676..03fa1c663ccf 100644
> --- a/arch/powerpc/mm/slb.c
> +++ b/arch/powerpc/mm/slb.c
> @@ -128,13 +128,21 @@ void slb_flush_all_realmode(void)
> asm volatile("slbmte %0,%0; slbia" : : "r" (0));
> }
>
> -static void __slb_flush_and_rebolt(void)
> +void slb_flush_and_rebolt(void)
> {
> /* If you change this make sure you change SLB_NUM_BOLTED
> * and PR KVM appropriately too. */
> unsigned long linear_llp, lflags;
> unsigned long ksp_esid_data, ksp_vsid_data;
>
> + WARN_ON(!irqs_disabled());
> +
> + /*
> + * We can't take a PMU exception in the following code, so hard
> + * disable interrupts.
> + */
> + hard_irq_disable();
> +
> linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
> lflags = SLB_VSID_KERNEL | linear_llp;
>
> @@ -160,20 +168,7 @@ static void __slb_flush_and_rebolt(void)
> :: "r"(ksp_vsid_data),
> "r"(ksp_esid_data)
> : "memory");
> -}
>
> -void slb_flush_and_rebolt(void)
> -{
> -
> - WARN_ON(!irqs_disabled());
> -
> - /*
> - * We can't take a PMU exception in the following code, so hard
> - * disable interrupts.
> - */
> - hard_irq_disable();
> -
> - __slb_flush_and_rebolt();
> get_paca()->slb_cache_ptr = 0;
> }
>
> @@ -248,7 +243,20 @@ void switch_slb(struct task_struct *tsk, struct
> mm_struct *mm)
>
> asm volatile("isync" : : : "memory");
> } else {
> - __slb_flush_and_rebolt();
> + struct slb_shadow *p = get_slb_shadow();
> + unsigned long ksp_esid_data =
> + be64_to_cpu(p->save_area[KSTACK_INDEX].esid);
> + unsigned long ksp_vsid_data =
> + be64_to_cpu(p->save_area[KSTACK_INDEX].vsid);
> +
> + asm volatile("isync\n"
> + PPC_SLBIA(1) "\n"
> + "slbmte %0,%1\n"
> + "isync"
> + :: "r"(ksp_vsid_data),
> + "r"(ksp_esid_data));
> +
> + asm volatile("isync" : : : "memory");
> }
>
> get_paca()->slb_cache_ptr = 0;
> --
> 2.18.0
