On Tue, 2016-11-15 at 15:28 +1100, Benjamin Herrenschmidt wrote:
> Commit d3cbff1b5 "powerpc: Put exception configuration in a common place"
> broke the setting of the AIL bit (which enables taking exceptions with
> the MMU still on) on all processors, moving it incorrectly to a function
> called only on the boot CPU. This was correct for the guest case but
> not when running in hypervisor mode.
>
> This fixes it by partially reverting that commit, putting the setting
> back in cpu_ready_for_interrupts()
>
> Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Fixes: d3cbff1b5 ("powerpc: Put exception configuration in a common place")
> CC: sta...@vger.kernel.org # v4.8+
Acked-By: Michael Neuling <mi...@neuling.org>
> ---
> arch/powerpc/kernel/setup_64.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 7ac8e6e..ac75224 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -226,17 +226,25 @@ static void __init configure_exceptions(void)
> if (firmware_has_feature(FW_FEATURE_OPAL))
> opal_configure_cores();
>
> - /* Enable AIL if supported, and we are in hypervisor mode */
> - if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
> - early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
> - unsigned long lpcr = mfspr(SPRN_LPCR);
> - mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
> - }
> + /* AIL on native is done in cpu_ready_for_interrupts */
> }
> }
>
> static void cpu_ready_for_interrupts(void)
> {
> + /*
> + * Enable AIL if supported, and we are in hypervisor mode. This
> + * is called once for every processor.
> + *
> + * If we are not in hypervisor mode the job is done once for
> + * the whole partition in configure_exceptions().
> + */
> + if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
> + early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
> + unsigned long lpcr = mfspr(SPRN_LPCR);
> + mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
> + }
> +
> /* Set IR and DR in PACA MSR */
> get_paca()->kernel_msr = MSR_KERNEL;
> }
>
