From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966083AbeEYJua (ORCPT ); Fri, 25 May 2018 05:50:30 -0400 Received: from foss.arm.com ([217.140.101.70]:57522 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966029AbeEYJuZ (ORCPT ); Fri, 25 May 2018 05:50:25 -0400 From: Julien Thierry To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, daniel.thompson@linaro.org, joel@joelfernandes.org, marc.zyngier@arm.com, mark.rutland@arm.com, christoffer.dall@arm.com, james.morse@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, Julien Thierry Subject: [PATCH v4 12/26] arm64: Unmask PMR before going idle Date: Fri, 25 May 2018 10:49:18 +0100 Message-Id: <1527241772-48007-13-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1527241772-48007-1-git-send-email-julien.thierry@arm.com> References: <1527241772-48007-1-git-send-email-julien.thierry@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CPU does not received signals for interrupts with a priority masked by ICC_PMR_EL1. This means the CPU might not come back from a WFI instruction. Make sure ICC_PMR_EL1 does not mask interrupts when doing a WFI. Signed-off-by: Julien Thierry Suggested-by: Daniel Thompson Cc: Catalin Marinas Cc: Will Deacon --- arch/arm64/mm/proc.S | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 5f9a73a..e7cafbf 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -20,6 +20,7 @@ #include #include +#include #include #include #include @@ -53,10 +54,27 @@ * cpu_do_idle() * * Idle the processor (wait for interrupt). + * + * If the CPU supports priority masking we must do additional work to + * ensure that interrupts are not masked at the PMR (because the core will + * not wake up if we block the wake up signal in the interrupt controller). */ ENTRY(cpu_do_idle) +alternative_if_not ARM64_HAS_IRQ_PRIO_MASKING + dsb sy // WFI may enter a low-power mode + wfi + ret +alternative_else + mrs x0, daif // save I bit + msr daifset, #2 // set I bit + mrs_s x1, SYS_ICC_PMR_EL1 // save PMR +alternative_endif + mov x2, #ICC_PMR_EL1_UNMASKED + msr_s SYS_ICC_PMR_EL1, x2 // unmask at PMR dsb sy // WFI may enter a low-power mode wfi + msr_s SYS_ICC_PMR_EL1, x1 // restore PMR + msr daif, x0 // restore I bit ret ENDPROC(cpu_do_idle) -- 1.9.1